Well not a shield as to speak but there's two strips of foil separated by mylar dielectric all rolled up. Obviously one of them is going to be on the outside.
Its not that they are polarized, the outside foil acts like an antenna and picks up stray induction. That is why the outside foil needs to go the the low impedance side, either ground or supply, so that the induced current will not hot the next amplifier stage (grid of the tube) and be amplified. It will make an amplifier hum slightly if put in backwards.
@@12voltvids Ah, so the shield needs to be connected to the lowest impedance connection instead of the lowest potential? The funny thing is, most (unbalanced)wires have the negative contact as a shield (like the shield of RCA connectors), instead of ground as shield. When I turn up my phono preamp gain real high and touch the input cable, I can hear the noise coupling into the wire.
@@QoraxAudio Right. Usually it is the ground as it would be in a filter or bypass cap such as kathode coupler to ground. The outside foil is connected to the plate on the leading stage because in this role it is a blocking capacitor to block the high voltage from getting into the grid in the following stage. If the outside foil was connected to the grid of the following stage any noise induced on it would be amplified. When it is connected to the plate side noise will still be picked up by the foil but the ratio of it is much lower by comparison to the signal coming off that stage.
@@12voltvids Yeah, that makes sense. But now I start to wonder how much RFI is picked up by all the metal filament parts within the tubes when they're not mounted in a metal can. For me, there's always something to ponder or worry about when it comes to noise and accuracy while doing an electronics project haha
There were shielded tubes in metal cans. Used in Rf and if circuits. 6sc7 is one I remember but there are many others. The filiment really isn't an issue because on indirectly heated tubes the metal cathode surrounds it and that is at ground potential anyway. After the metal jacket tubes they started putting a metal screen, around the outside of the plates to stop electrons that missed the plate from flying out of the tube.
If the plate is glowing red hot the tube is over biased. Either a bias resistor has failed or a capacitor has gone electrically leaky. This will burn out the tube and also the transformer.
Sorry, but I said the screen grid, not the plate. If the plate has no voltage the screen grid will act as an anode,( assuming it has voltage), and the screen grid will glow red hot because it can’t handle the current and over dissipates. I’ve seen this many times.
@@widecast If you loose your plate there should not be any flow of electrons as the screen grid should be negatively biased. If it isn't then you will get full flow of current to the plate which wil burn out the output transformer. If your grid is glowing hot, it is because the negative bias is lost on the screen, likely due to a open resistor or electrically leaky cap. This will over saturate the tube, likely burn out the winding of the output transformer. Then you lose your B+. If the screen is positive at this point it will get hot, but the screen should never have a positive voltage on it. It is biased slightly negative, and is modulated by the signal. Now saying that, I would never apply power to one of these dinosaurs with the original paper caps. In all likelyhood the screen would have glowed red hot had I tried to power it up with the open transformer because the grid would have been pulled positive by the leaky paper caps, but since I replaced them all BEFORE attempting to power up, the negative bias would have been restored therefore there was no grid glow. The plate would have glowed red hot while the transformer was burning up. Since these radios are getting scarce and the parts hard to find I would never risk doing damage to one of these. I have 5 in my personal collection all restored. I don't run them much, just turn them on once in awhile and let them play for an hour or so, more to show them off to people.
Trivia: (same company listed on Cap? Hamilton, Ont.) December 1938: The Aerovox Corp., maker of condensers, announces it is moving its plant and offices to Belleville Avenue in New Bedford. 1938 to mid-1970s: Aerovox emerges as major manufacturer of capacitors and other electrical components.
A good substitute for those multi-part electrolytics is 47 uF @ 300 VDC. 2 sections were for the B+, and one for the cathode bias on the output tube (usually). Once you find the schematic/parts-list, you can sub in values closer to the design specs. They usually range from a low of 8 uF, all the way up to about 100 uF or so, in those AA5 sets.
Great video. I recently restored a 1937 Murphy A34. To say it had Been interfered with would be an understatement! Got it working though and after some RF alignment works really well. Very satisfying.
If you have the patience of a saint, you can carefully cut into the transformer paper to try and find the open winding and possibly get lucky where it's very near the connection points, then reconnect it. I had to do this for an unobtanium transformer some years ago and it's been working fine ever since.
If you are a real glutton for punishment, you can rewind the transformer too. Takes a lot more effort, but it is doable. Trouble is, how much will the customer pay? They 'aint going to pay for several hours of my time to rewind that thing, even supposing I could. If, as you said, the break is near the solder tabs, you may get lucky.
Andrew Hull try Radio days or the anteak radio forum hear are the Web sites I bealeve www.radiodays.com and www.anteakradioforum.com love your videos Don Hiscock From Newwestminster British Columbia dghiscock@gmail.com
Andrew Hull I rewound a hair clipper for a barber once took about 8 hours he had a 400 dollar bill for labour a new one would of been 1500 dollars so he saved some coin and made me 425 dollars richer win win for both us
i found this on that series E 662 radio. pacifictv.ca/schematics/phonola6525ldata.pdfl back in the late 80s a friend brought an old 1969 Marshal amp over for me to look at. It had prior owner hacks i suspected were done wrong. It was or had been burning tubes out in less than a minute, but sounded really good. And i remembered 2 yrs prior i set the bias when we replaced the tubes and that didnt work he said. So i suggested recapping everything and replace all of the resistors. he agreed and had the cash. SO we get our list of everything we needed and head to our local Radio Shack, this is way before interweb, and $50 later we're set. Now this amp hadnt been plugged in for over a yr, but i pulled a tube next to the transformer and my hand touched it...and i got one hell of a zap!! lol I was shocked(literally) that the caps or anything was storing that much voltage for that length of time not being plugged in. but i was young and didnt know alot back then. lol It was horrible inside! Someone jumped a bunch of stuff i think they just started touching things and when it sounded good and distorted they soldered it down not having a clue wth they were doing. Good thing Marshal put the wire diagram inside the head cabinet, so i just put it back to factory and replaced everything. It worked out great and sounded better than ever. One thing it stopped blowing tubes. The caps turning to resistors was my guess too as to what was over driving the tubes, and several resistors and caps were blown/popped open, so i knew somewhere they had gotten some OV. Thanks for sharing this video! i love this old stuff, they just dont makem like that anymore.
Electronics was really in it's infancy when this radio was made in the thirties but they understood electronics very well back then and achieved amazing things with the technology of the time.
When I was taught to solder, I was told that you had to make a good mechanical connection and then solder it. Relying on merely solder to hold wires together, I was taught, is a no-no!
Swarf Rat I did make a good connection. A few were tacked down to hold one side in so the other side could be soldered in and then I went back to the other side. And twisted , resoldered the first. This radio is by no means finished. The electrolytics need replacing, but I need to find that transformer first. This was an investigative look to see what exactly needed replacing.
Never heard of or seen jacketed wire containing asbestos and I work on old electronics all the time. Last thing I worked on which had asbestos in it was a ceramic glowbar heater from the 1940s which was used for defrosting freezers. BTW the stuff is still mined and used in certain industrial applications.
I'm not saying that the jacket has asbestos, however it might. We don't know. I haven't had it tested. I am referring to the insulation tubing that is often places on leads to power resistors that can get hot on old electronics. Since asbestor was so common it is entirely possible that a component may contain it. For that matter the water main that supplies my house is asbestos concrete. It broke last year, and when they hauled out the piece that they cut out they put it in a hazmat bag. They also kept the area wet as the worker was cutting it and he was in full PPE to make the cut.. It used to be used in many things, and unless you know for sure that insulation does not have it, then you have to assume that it does, and take the appropriate measures to avoid cutting, drilling, or disturbing it.
Piotr Misiuna I have seen worse. At least no mice have chewed all the wires and with a proper audio transformer this thing will be making noises again. There is something about these vintage pieces. Love the old tube stuff, so simple but they work and last forever. Tubes rarely fail unless over driven or mechanical shock. These ones all look to be original.
Another awesome radio with those vintage tubes! I know it would be nice to be able to replace the caps with originals, however that's not that important as you can't see those parts normally anyway in normal everyday use. As long as the unit performs well. An original engine in a classic car is more desirable, but with the hood down, it doesn't matter.
Nice job, I prefer to work on Vintage kit. Much greater sense of achievement when you get a piece working, especially when you watch a customer as they hear music from a previously silent Vintage radio or record player etc.
It looks like someone took the Viking to a Philco dealer/service representative at one point earlier in it's life, I see at least two Philco branded paper caps under there. Watch out for those dogbone BED coded resistors, they are almost as unreliable as the paper caps, they love to drift upward in value. I would not worry too much about asbestos, the spaghetti tube was usually made out of a phenolic or fiberglass product. As for the wiring asbestos cost money and radio manufacturers used to cut corners anywhere they could, some even used bare rubber covered wire because it was cheaper then the cloth covered stuff. Even if the wire had a some asbestos insulation it's easy to tell, for one thing it's much thicker then normal wire, a there would be a layer of fluffy white material under the cloth jacket. The Viking is a 1937-38 model I believe, Electrohome used to use a code in their model numbers, the first number being the year it was designed which would have been in late 1936, the second, the number of tubes, also a six, and the third the number of bands the set had, which was two. The "E" just stood for Eatons, but if it had been an "S" it would have stood for Simpsons, and if it had a "P" it would have been marketed under the Phonola brand. On battery radios they would place a letter "B" between the first and second numbers, so if it were a battery set it would be branded as a 6B62-E, AC sets had no letter between the first and second numbers, and AC/DC series string sets had a "U" placed between those numbers. It should be listed in the RCC manuals under "Phonola" but you might also have a look at the Pacific TV site for a schematic. Nice cabinet, it looks very similar to a 1936-37 Canadian Westinghouse model, but with a much cheaper and plainer looking tin dial rather then glass. At least nobody has ruined the finish on top with a potted plant, which seems to be the fate of many console radios.
Very good video. Lots of valve output transformers on ebay. Some cheap generic reproduction ones out there ive used in a few valve radio repairs before and had good luck with. Just need to find out what the output impedance of that 42 tube is and the speaker impedance and should be able to find something. For how much and how it mounts in the radio is a different question though. Good luck with it.
You should definitely change those electrolytics, and that box cap, they are probably already gone or are about to go, the only reason you didn't hear the loud buzz is because the speaker wasn't working right, but I could start to see ripple in that scope waveform. Those cardboard electrolytic caps are awful too, they fail often, and that would mean it would be returning for more service. I thought I saw a tiny bulge on the end of that red cap which means it's starting to spew it's guts. P.S. you can figure out what that box cap is just by tracing it's connections on the schematic, these old machines don't care what you use as a substitute as long as it's close. If you need the space just rip it's guts out and glue the new one in the empty can.
Don't worry about the electrolytic, they will be changed. I am still trying to locate a suitable output transformer. The paper caps had to be changed before attempting to power it up. Now that I know that the tubes work, I can spend some more time and money on it once I locate a transformer that is.
I use the same multi-meter, was 35 bucks on Amazon. Works pretty good compared to my fluke that was over 200 that I didn't like to travel with. Mines a different name tho, they are re-labled meters.
Not the cloth covered wire I am concerned about. The heat tubing that is ised to insulate quite often is asbestos or mica, and mica very often has asbestos in it.
I really enjoy watching your channel. It is very therapeutic to me. I have a 1957 Motorola Tube Radio that works really well, and I want it to continue to work well. Should I take it to someone to see if the capacitors can be replaced?
You might be able to repair the transformer...sometimes the connections from the windings to the hook-up leads fail...you might want to peel the paper back to examine the leads.
Isolation transformer plugged into mains. Variac plugged into isolation transformer. Current limiter (100W incandescent) light bulb in series with line cord. This isolates the chassis from mains, allows me to vary the voltage, and limits the current to 800 miliamps (100 watts) which will protect things like the power transformer, tubes ect. My current limiter might not be as sexy as paul carlson's but it works exactly the same way.
When I posted that the Type 42 was equivalent to a 6V6, I was in error. it is equivalent to a 6F6! All those power pentodes are similar anyway. Sorry for the confusion! Have a good one! Dave
Right, well the tubes all look to be OK. Once I find a sutable transformer I will be replacing the electrolytic caps. Don't know what I will do with that box cap yet. Don't know the values but with the print it may be easier to identify what it is it. Looks like a few have already been replaced, as a few wires are already cut off it..
A type 42 is a power pentode, a 6V6 is a beam power tube, the difference is that one of the grids is replaced with deflection plates in a beam power tube.
Luc Peeters Pc boards had not been invented yet. They didn't actually come along until the early 60's and initially were for cheap portables transistor radios. This one is over 80 years old. It is the oldest piece of equipment I have ever worked on.
Interesting. Still feels strange opening a device and finding a mess in it. I used to work for a big company electronics company in the 90's and sometimes did work on old stuff, but this is something else. Very nice to see someone still trying to make things work again, as I like progress I always dislike seeing stuff being thrown away.
I loved this video. I miss fault finding in my job as an electrical fitter in a power station. It didn't involve much in the way of electronics as it was mostly relays, limit switches etc in control circuitry so I'm learning loads in your videos. Anything below 50 volts and we usually got an instrument tech involved although that's changing more these days, I think! Can't wait to see this up and running. What's your day job btw?
I work for the phone company now, but it isn't just phones. Actually very little palin old telephone service (POTS) it is now more DSL / Bonded DSL, PON and IPTV work that I do. I ran the service dept in a repair shop for 20 years, and still work on stuff, but not as much as before. I like the old vintage stuff. I am searching out the output transformer for this radio now. I have a few leads, and am going to probably go with the universal replacement option.
I had to retire early after an accident at work but still miss (some of) the work and the banter! I started doing a bit of electronics to keep my hand in on the electrical side and am thoroughly enjoying it. I particularly enjoy radio but I'm afraid it's all new to me so any hints and tips on your channel are well received! Your job sounds interesting although I know from experience that when you do it every day it can become a bit tedious at times! Keep up the excellent work Davy
gartmorn My day job is actually not boring because every day is different. I drive around from one customer to the next. Some installs some troubles and upgrades. Yesterday I had to configure a security system for remote monitoring and that required forwarding ports and setting static ip. Today I am upgrading service to HS 100 over copper and after lunch I have trouble on fiber for low light levels. Every day is different so the day goes by quickly.
My job was varied and involved troubleshooting and maintenance on power plant from 11 kv down to 50 v. Then I did a spell on day work doing routine maintenance which was quite repetitive! I moved onto operations after that (mistake) which was even more monotonous! Having said that I did cover in the control room which could be interesting as I was operating a 600 megawatt unit! I got retirement after an accident when a steam valve blew out and burned my legs from the groin to below my knees requiring major skin grafts. I miss my work but couldn't work back in a hazardous environment.
just rewind the output transformer. the defective primary winding is usually the top winding. count the turns of one layer, multiply it with the number of layers, and job done. The number of turns is not that critical.
I wonder what the impedence would be, 6k to 3.5R perhaps? At a pinch if it was mine, i would rewind it. Is that electromagnet working like a "Hum Bucking" coil as well?
The speaker I am sure is probably 16 ohm. Don't know what the turns ratio is off hand. Am still researching this. A universal audio out from an old tube radio will probably work fine. I may take the one out of the viking I fixed previously to get this one going. Sacrifice the old chassis to fix this complete radio.
If you have a similar transformer from another set, and it works with this one, you can guestimate the turns ratio pretty easily by feeding in a know amplitude signal and measuring the output. Armed with that information, you can then look for suitable substitutes, based on a rough guestimate of the power requirements (the rough wattage of the speaker).
They usually have one in parallel, but in opposite phase, to the secondary of the output transformer, which this probably does have since it's an Electrohome product which copied much of what RCA did. It would be an extra winding next to, but independent of, the field coil winding.
You never know what PCBs were used on in very old electronics. There are lots of capacitors that were oil filled in the old days, and the chance of those not containing PCBs is low because they were used everywhere.
If the primary of the output transformer is open then observe the output valve and see if the screen grid is red hot. This is an indication that the transformer is open. In this case the screen grid acts as an onode and as it's a light structure it gets red hot with the current flowing.
There is a CRT monitor on the other side of the shop way up in the corner about 20 feet away. Monitor for security cameras. When I am working, and expecting someone I turn it on so I can see when they arrive.
What about evaluating the unknown solar cap first? Solar made some fairly respectable caps. The capacitance may be near the original. I thought the SOP for radio work was check transformers and chokes for continuity,that includes IFs. Then tubes, then resistors and cap replacement. Asbestos is not so dangerous as it has been made out to be. Millions upon millions of brake shoes and clutches were made with it. Countless buildings have asbestos insulation sprayed in the drop ceilings to protect the steel framework, and mile after mile of main water pipe (cement transited) are still in use.The list is so long. Far overstated.
James Lucas I found no data on that multi stage cap, but the values were shown on the schematic. 2 of the 5 in it were already bypassed by the time I got this so I just looked up the values and changed the rest. Paper capacitors are the number 1 cause of other component failures in tube gear. Coils and transformers generally do not fail unless they are overloaded and too much current is drawn. This overheats the wire melts the insulation and a short results. When you see these Old caps don't measure them, replace them before applying power. No doubt that audio output transformer was burned out by the owner as he told me he plugged it in and it started smoking. That mistake added 100 to his repair bill as that is what that transformer cost for a new one. When I work on vintage all the caps gotta go before I plug it in and trouble shoot. I have 3 of my own pieces to look at. An old Normende stereo, a McIntosh 1500 and a Halicrafters. They will be looked at sometime soon I hope. When I get time. My wife is on my case for the Normende stereo as it was her parents that we have inherited so she wants that one overhauled so she can put it on display in the house. As far as asbestos goes as long as it is not disturbed it is fine. It is the dust that is the problem. Don't be ignorant of it. Go tell that to someone that is sick because of exposure at work. I know a mechanic that is now dying of asbestos lung cancer. He did not smoke but he was a heavy duty mechanic and was exposed daily to brake dust. The dust masks they used 30 years ago did not help him and his doctor has given him 6 months to live. He is 54 and likely won't see 55. Where I work we sometimes have to go into atics. We have to Don full respirator before going into crawl space or atic
12voltvids Thank you for your comments. Really looking forward to the McIntosh restoration. Hardly anyone doing McIntosh videos. A testament to their longevity or they are just still as costly old (may be , some appreciated vastly e.g. MC 250.). I have 3 MC2105s. One amp for bas, one for mid range and one for high. They were an amazing amp, built like a truck but have the best of the best components. Will be anticipating that and the Halcrafters. Good luck.
I tried searching for the schematic information and see this downloading site that may be this radio schematic, link: www.radiomuseum.org/r/phonolacan_662_e.html
Something I thought you would want to be aware of....I watched someone testing "brown drop" caps like the ones you installed in this set. They all had a stripe down one side like the old paper ones, and you would think that the stripe was on the outside foil end...well, half of them were, half were not. I guess the safest bet is to test all your caps, place some sort of identifying mark on each one, and when you use them, you will know which end is the correct outside foil end. Also, I would like to urge you to trace out the electrolytic caps with the diagram (schematic) and find the value of those and replace them as well. This video might also be of interest to you: ua-cam.com/video/BnR_DLd1PDI/v-deo.html
I also fully aware of "outside foil" and do test them when I buy them to identify them. I do go over this on my videos. You must be skipping ahead. I know Paul built an auto switching jig to check them but I am not that lazy. It takes no more time to switch the cap around manually. Also outside foil is not as big a deal on modern caps as opposed to the old ones just due to the physical size of the new ones. There is less surface area to pick up incidental interference than on the old paper caps.
you do not physically desolder or use loop over wire to solder the caps.... I do in these old sets and every other tuber doing these age radios and tvs curse you out if not. whats your excuse for not.
I think he meant :- fully desolder the component and replace or snip the leads at the sides of the old component and form a loop to feed and wrap the new component leads through - gives better mechanical solder joints.
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Very therapeutic to watch. I never knew mylars had a shield.
Well not a shield as to speak but there's two strips of foil separated by mylar dielectric all rolled up. Obviously one of them is going to be on the outside.
Good
When unpolarized caps actually are polarized to electromagnetic field instead of current flow...
I've never heard about that before, interesting info!
Its not that they are polarized, the outside foil acts like an antenna and picks up stray induction. That is why the outside foil needs to go the the low impedance side, either ground or supply, so that the induced current will not hot the next amplifier stage (grid of the tube) and be amplified. It will make an amplifier hum slightly if put in backwards.
@@12voltvids Ah, so the shield needs to be connected to the lowest impedance connection instead of the lowest potential?
The funny thing is, most (unbalanced)wires have the negative contact as a shield (like the shield of RCA connectors), instead of ground as shield. When I turn up my phono preamp gain real high and touch the input cable, I can hear the noise coupling into the wire.
@@QoraxAudio
Right. Usually it is the ground as it would be in a filter or bypass cap such as kathode coupler to ground. The outside foil is connected to the plate on the leading stage because in this role it is a blocking capacitor to block the high voltage from getting into the grid in the following stage. If the outside foil was connected to the grid of the following stage any noise induced on it would be amplified. When it is connected to the plate side noise will still be picked up by the foil but the ratio of it is much lower by comparison to the signal coming off that stage.
@@12voltvids Yeah, that makes sense.
But now I start to wonder how much RFI is picked up by all the metal filament parts within the tubes when they're not mounted in a metal can.
For me, there's always something to ponder or worry about when it comes to noise and accuracy while doing an electronics project haha
There were shielded tubes in metal cans. Used in Rf and if circuits. 6sc7 is one I remember but there are many others. The filiment really isn't an issue because on indirectly heated tubes the metal cathode surrounds it and that is at ground potential anyway. After the metal jacket tubes they started putting a metal screen, around the outside of the plates to stop electrons that missed the plate from flying out of the tube.
There would usually be a visual clue to an open output transformer, that is the screen grid on the output tube glows red hot.
If the plate is glowing red hot the tube is over biased. Either a bias resistor has failed or a capacitor has gone electrically leaky. This will burn out the tube and also the transformer.
Sorry, but I said the screen grid, not the plate. If the plate has no voltage the screen grid will act as an anode,( assuming it has voltage), and the screen grid will glow red hot because it can’t handle the current and over dissipates. I’ve seen this many times.
@@widecast If you loose your plate there should not be any flow of electrons as the screen grid should be negatively biased. If it isn't then you will get full flow of current to the plate which wil burn out the output transformer. If your grid is glowing hot, it is because the negative bias is lost on the screen, likely due to a open resistor or electrically leaky cap. This will over saturate the tube, likely burn out the winding of the output transformer. Then you lose your B+. If the screen is positive at this point it will get hot, but the screen should never have a positive voltage on it. It is biased slightly negative, and is modulated by the signal.
Now saying that, I would never apply power to one of these dinosaurs with the original paper caps. In all likelyhood the screen would have glowed red hot had I tried to power it up with the open transformer because the grid would have been pulled positive by the leaky paper caps, but since I replaced them all BEFORE attempting to power up, the negative bias would have been restored therefore there was no grid glow. The plate would have glowed red hot while the transformer was burning up. Since these radios are getting scarce and the parts hard to find I would never risk doing damage to one of these. I have 5 in my personal collection all restored. I don't run them much, just turn them on once in awhile and let them play for an hour or so, more to show them off to people.
Trivia: (same company listed on Cap? Hamilton, Ont.) December 1938: The Aerovox Corp., maker of condensers, announces it is moving its plant and offices to Belleville Avenue in New Bedford.
1938 to mid-1970s: Aerovox emerges as major manufacturer of capacitors and other electrical components.
Thanks for all your video ,I love the old radio stuff a lot ,you are amazing at it.
Don't see those much anymore. So you're in Canaduh? I'm in Ont-errible.
A good substitute for those multi-part electrolytics is 47 uF @ 300 VDC. 2 sections were for the B+, and one for the cathode bias on the output tube (usually). Once you find the schematic/parts-list, you can sub in values closer to the design specs. They usually range from a low of 8 uF, all the way up to about 100 uF or so, in those AA5 sets.
Great video. I recently restored a 1937 Murphy A34. To say it had Been interfered with would be an understatement! Got it working though and after some RF alignment works really well. Very satisfying.
The old beasts are fun to work on. I have a RCA and a Nordmende sitting in the shop to work on some day
great video...can't wait for the other part(s)
I wonder which is more fun to work on old radio or new ,I love the videos you do of you saving old radio s
Definitely vintage equipment. New stuff with the digital circuits and everything burried in LSI chips are almost impossible.
If you have the patience of a saint, you can carefully cut into the transformer paper to try and find the open winding and possibly get lucky where it's very near the connection points, then reconnect it.
I had to do this for an unobtanium transformer some years ago and it's been working fine ever since.
If you are a real glutton for punishment, you can rewind the transformer too. Takes a lot more effort, but it is doable. Trouble is, how much will the customer pay? They 'aint going to pay for several hours of my time to rewind that thing, even supposing I could. If, as you said, the break is near the solder tabs, you may get lucky.
Andrew Hull try Radio days or the anteak radio forum hear are the Web sites I bealeve www.radiodays.com and www.anteakradioforum.com love your videos Don Hiscock From Newwestminster British Columbia dghiscock@gmail.com
Andrew Hull I rewound a hair clipper for a barber once took about 8 hours he had a 400 dollar bill for labour a new one would of been 1500 dollars so he saved some coin and made me 425 dollars richer win win for both us
Yes did that. Did find one spot that was open, but I cleaned the enamel off to expose copper on the winding and still open. Transformer is FUBAR
Dang that sucks :(
It must have been really insulted to have multiple open windings.
i found this on that series E 662 radio. pacifictv.ca/schematics/phonola6525ldata.pdfl
back in the late 80s a friend brought an old 1969 Marshal amp over for me to look at. It had prior owner hacks i suspected were done wrong. It was or had been burning tubes out in less than a minute, but sounded really good. And i remembered 2 yrs prior i set the bias when we replaced the tubes and that didnt work he said. So i suggested recapping everything and replace all of the resistors. he agreed and had the cash.
SO we get our list of everything we needed and head to our local Radio Shack, this is way before interweb, and $50 later we're set. Now this amp hadnt been plugged in for over a yr, but i pulled a tube next to the transformer and my hand touched it...and i got one hell of a zap!! lol I was shocked(literally) that the caps or anything was storing that much voltage for that length of time not being plugged in.
but i was young and didnt know alot back then. lol It was horrible inside! Someone jumped a bunch of stuff i think they just started touching things and when it sounded good and distorted they soldered it down not having a clue wth they were doing.
Good thing Marshal put the wire diagram inside the head cabinet, so i just put it back to factory and replaced everything. It worked out great and sounded better than ever. One thing it stopped blowing tubes.
The caps turning to resistors was my guess too as to what was over driving the tubes, and several resistors and caps were blown/popped open, so i knew somewhere they had gotten some OV.
Thanks for sharing this video! i love this old stuff, they just dont makem like that anymore.
I just got a new job making potentiometers. What do you think?
Frank
Electronics was really in it's infancy when this radio was made in the thirties but they understood electronics very well back then and achieved amazing things with the technology of the time.
When I was taught to solder, I was told that you had to make a good mechanical connection and then solder it. Relying on merely solder to hold wires together, I was taught, is a no-no!
Swarf Rat
I did make a good connection. A few were tacked down to hold one side in so the other side could be soldered in and then I went back to the other side. And twisted , resoldered the first. This radio is by no means finished. The electrolytics need replacing, but I need to find that transformer first. This was an investigative look to see what exactly needed replacing.
Sorry! I didn't mean to sound like a troll. I guess I didn't see all that you were doing. I apologize!
Open wiring how did everyone make this far. Love that old time engineering.
Everything is so darn small now days. The eyes aren’t what they use to be.
That's why us old guys like working on this old shit.
Never heard of or seen jacketed wire containing asbestos and I work on old electronics all the time. Last thing I worked on which had asbestos in it was a ceramic glowbar heater from the 1940s which was used for defrosting freezers. BTW the stuff is still mined and used in certain industrial applications.
I'm not saying that the jacket has asbestos, however it might. We don't know. I haven't had it tested. I am referring to the insulation tubing that is often places on leads to power resistors that can get hot on old electronics. Since asbestor was so common it is entirely possible that a component may contain it. For that matter the water main that supplies my house is asbestos concrete. It broke last year, and when they hauled out the piece that they cut out they put it in a hazmat bag. They also kept the area wet as the worker was cutting it and he was in full PPE to make the cut.. It used to be used in many things, and unless you know for sure that insulation does not have it, then you have to assume that it does, and take the appropriate measures to avoid cutting, drilling, or disturbing it.
What a mess, this old timer probably reflects she spirit of the time. Respect.
Piotr Misiuna
I have seen worse. At least no mice have chewed all the wires and with a proper audio transformer this thing will be making noises again. There is something about these vintage pieces. Love the old tube stuff, so simple but they work and last forever. Tubes rarely fail unless over driven or mechanical shock. These ones all look to be original.
Beautiful on the outside.
Well, electric chair can get broken, but you can never run out of stones, my friend.
Another awesome radio with those vintage tubes!
I know it would be nice to be able to replace the caps with originals, however that's not that important as you can't see those parts normally anyway in normal everyday use. As long as the unit performs well. An original engine in a classic car is more desirable, but with the hood down, it doesn't matter.
Nice job, I prefer to work on Vintage kit. Much greater sense of achievement when you get a piece working, especially when you watch a customer as they hear music from a previously silent Vintage radio or record player etc.
Nice video , thanks ....
well done ...
It looks like someone took the Viking to a Philco dealer/service representative at one point earlier in it's life, I see at least two Philco branded paper caps under there. Watch out for those dogbone BED coded resistors, they are almost as unreliable as the paper caps, they love to drift upward in value. I would not worry too much about asbestos, the spaghetti tube was usually made out of a phenolic or fiberglass product. As for the wiring asbestos cost money and radio manufacturers used to cut corners anywhere they could, some even used bare rubber covered wire because it was cheaper then the cloth covered stuff. Even if the wire had a some asbestos insulation it's easy to tell, for one thing it's much thicker then normal wire, a there would be a layer of fluffy white material under the cloth jacket.
The Viking is a 1937-38 model I believe, Electrohome used to use a code in their model numbers, the first number being the year it was designed which would have been in late 1936, the second, the number of tubes, also a six, and the third the number of bands the set had, which was two. The "E" just stood for Eatons, but if it had been an "S" it would have stood for Simpsons, and if it had a "P" it would have been marketed under the Phonola brand. On battery radios they would place a letter "B" between the first and second numbers, so if it were a battery set it would be branded as a 6B62-E, AC sets had no letter between the first and second numbers, and AC/DC series string sets had a "U" placed between those numbers. It should be listed in the RCC manuals under "Phonola" but you might also have a look at the Pacific TV site for a schematic.
Nice cabinet, it looks very similar to a 1936-37 Canadian Westinghouse model, but with a much cheaper and plainer looking tin dial rather then glass. At least nobody has ruined the finish on top with a potted plant, which seems to be the fate of many console radios.
thanks good video
Where's part 2?
It is there.
they still make replacement output transformers for tube sets. TubesandMore carries them but they are expensive.
Yes I know. Hammond makes them, in Canada. Got the replacement for this one from Mouser. Transformer was about 100.00
Very good video. Lots of valve output transformers on ebay. Some cheap generic reproduction ones out there ive used in a few valve radio repairs before and had good luck with. Just need to find out what the output impedance of that 42 tube is and the speaker impedance and should be able to find something. For how much and how it mounts in the radio is a different question though. Good luck with it.
Antique electronic supply should have an output transformer that would work.
You should definitely change those electrolytics, and that box cap, they are probably already gone or are about to go, the only reason you didn't hear the loud buzz is because the speaker wasn't working right, but I could start to see ripple in that scope waveform. Those cardboard electrolytic caps are awful too, they fail often, and that would mean it would be returning for more service. I thought I saw a tiny bulge on the end of that red cap which means it's starting to spew it's guts.
P.S. you can figure out what that box cap is just by tracing it's connections on the schematic, these old machines don't care what you use as a substitute as long as it's close. If you need the space just rip it's guts out and glue the new one in the empty can.
Don't worry about the electrolytic, they will be changed. I am still trying to locate a suitable output transformer. The paper caps had to be changed before attempting to power it up. Now that I know that the tubes work, I can spend some more time and money on it once I locate a transformer that is.
I use the same multi-meter, was 35 bucks on Amazon. Works pretty good compared to my fluke that was over 200 that I didn't like to travel with. Mines a different name tho, they are re-labled meters.
Actually cloth covered wire did not generally use Asbestos.
Most of the time, when you find it in a radio, it is used in sheet form as a heat shield.
Not the cloth covered wire I am concerned about. The heat tubing that is ised to insulate quite often is asbestos or mica, and mica very often has asbestos in it.
put some liquid tape or paint on the asbestos to coat it. Use hi temp paint, or even epoxy. Once it's coared, it's safe.
yeah when i think of valve radios i don't think of 12 volts but more like 160 volts. granted the filaments use 6.3v on most tubes but still
You can make caps like described here, for saving vintage look: www.radiomuseum.org/forum/recycling_of_vintage_paper_capacitors.html
I really enjoy watching your channel. It is very therapeutic to me. I have a 1957 Motorola Tube Radio that works really well, and I want it to continue to work well. Should I take it to someone to see if the capacitors can be replaced?
I'm surprised that those caps weren't marked in some way to indicate the foil side.
They don't do that on the new ones. So you need to scope em and see where the foil shield is by looking at the noise floor.
You might be able to repair the transformer...sometimes the connections from the windings to the hook-up leads fail...you might want to peel the paper back to examine the leads.
Yes I haven't got into that yet.
I noticed that you used a variac, isolation transformer, and a current limiting device. How were these all connected? Great video!
Isolation transformer plugged into mains. Variac plugged into isolation transformer. Current limiter (100W incandescent) light bulb in series with line cord. This isolates the chassis from mains, allows me to vary the voltage, and limits the current to 800 miliamps (100 watts) which will protect things like the power transformer, tubes ect.
My current limiter might not be as sexy as paul carlson's but it works exactly the same way.
12voltvids I made a current limiter following your video and it works well. Thanks again for great info.
When I posted that the Type 42 was equivalent to a 6V6, I was in error. it is equivalent to a 6F6! All those power pentodes are similar anyway. Sorry for the confusion!
Have a good one!
Dave
Right, well the tubes all look to be OK. Once I find a sutable transformer I will be replacing the electrolytic caps. Don't know what I will do with that box cap yet. Don't know the values but with the print it may be easier to identify what it is it. Looks like a few have already been replaced, as a few wires are already cut off it..
A type 42 is a power pentode, a 6V6 is a beam power tube, the difference is that one of the grids is replaced with deflection plates in a beam power tube.
That’s like me I always get the top secret stuff with no info.
Just subscribed to your really nice channel. Seems like they didn't believe in PCB's during that time.
Luc Peeters
Pc boards had not been invented yet. They didn't actually come along until the early 60's and initially were for cheap portables transistor radios. This one is over 80 years old. It is the oldest piece of equipment I have ever worked on.
Interesting. Still feels strange opening a device and finding a mess in it. I used to work for a big company electronics company in the 90's and sometimes did work on old stuff, but this is something else.
Very nice to see someone still trying to make things work again, as I like progress I always dislike seeing stuff being thrown away.
I loved this video. I miss fault finding in my job as an electrical fitter in a power station. It didn't involve much in the way of electronics as it was mostly relays, limit switches etc in control circuitry so I'm learning loads in your videos. Anything below 50 volts and we usually got an instrument tech involved although that's changing more these days, I think! Can't wait to see this up and running. What's your day job btw?
I work for the phone company now, but it isn't just phones. Actually very little palin old telephone service (POTS) it is now more DSL / Bonded DSL, PON and IPTV work that I do.
I ran the service dept in a repair shop for 20 years, and still work on stuff, but not as much as before. I like the old vintage stuff. I am searching out the output transformer for this radio now. I have a few leads, and am going to probably go with the universal replacement option.
I had to retire early after an accident at work but still miss (some of) the work and the banter! I started doing a bit of electronics to keep my hand in on the electrical side and am thoroughly enjoying it. I particularly enjoy radio but I'm afraid it's all new to me so any hints and tips on your channel are well received! Your job sounds interesting although I know from experience that when you do it every day it can become a bit tedious at times! Keep up the excellent work
Davy
gartmorn
My day job is actually not boring because every day is different. I drive around from one customer to the next. Some installs some troubles and upgrades. Yesterday I had to configure a security system for remote monitoring and that required forwarding ports and setting static ip. Today I am upgrading service to HS 100 over copper and after lunch I have trouble on fiber for low light levels. Every day is different so the day goes by quickly.
My job was varied and involved troubleshooting and maintenance on power plant from 11 kv down to 50 v. Then I did a spell on day work doing routine maintenance which was quite repetitive! I moved onto operations after that (mistake) which was even more monotonous! Having said that I did cover in the control room which could be interesting as I was operating a 600 megawatt unit! I got retirement after an accident when a steam valve blew out and burned my legs from the groin to below my knees requiring major skin grafts. I miss my work but couldn't work back in a hazardous environment.
just rewind the output transformer. the defective primary winding is usually the top winding. count the turns of one layer, multiply it with the number of layers, and job done. The number of turns is not that critical.
I wonder what the impedence would be, 6k to 3.5R perhaps?
At a pinch if it was mine, i would rewind it.
Is that electromagnet working like a "Hum Bucking" coil as well?
The speaker I am sure is probably 16 ohm. Don't know what the turns ratio is off hand. Am still researching this. A universal audio out from an old tube radio will probably work fine. I may take the one out of the viking I fixed previously to get this one going. Sacrifice the old chassis to fix this complete radio.
If you have a similar transformer from another set, and it works with this one, you can guestimate the turns ratio pretty easily by feeding in a know amplitude signal and measuring the output.
Armed with that information, you can then look for suitable substitutes, based on a rough guestimate of the power requirements (the rough wattage of the speaker).
They usually have one in parallel, but in opposite phase, to the secondary of the output transformer, which this probably does have since it's an Electrohome product which copied much of what RCA did. It would be an extra winding next to, but independent of, the field coil winding.
Yup looks like a hum bucker the way it is wired through the voice coil and secondary of the output transformer.
Yes 2 field coils, one with the B+ supply going through it, and the second feeding into the voice coil and secondary of the output transformer.
I wish you would re-stuff the original capacitors to make the radio look original.
I really wouldn't use those things because they caused housefires
Paper caps do not use PCB's..
OIL-filled caps MIGHT, depending on their age.
You never know what PCBs were used on in very old electronics.
There are lots of capacitors that were oil filled in the old days, and the chance of those not containing PCBs is low because they were used everywhere.
what about a 110v primary +12v,0,-12v secondary
Probably better to use a 240v primary. I do have a 240 primary transformer around here that I will try to locate.
try pacifictv.ca they list electrohome and viking radios pdf schematics hope this is of use
If the primary of the output transformer is open then observe the output valve and see if the screen grid is red hot. This is an indication that the transformer is open. In this case the screen grid acts as an onode and as it's a light structure it gets red hot with the current flowing.
Do you have a CRT next to you? Holy hell that 16KHz whine...
Yup, would prefer a notch filter at that freqency
There is a CRT monitor on the other side of the shop way up in the corner about 20 feet away. Monitor for security cameras. When I am working, and expecting someone I turn it on so I can see when they arrive.
Doing it just to generate a bunch of thumbs down.
12voltvids ,hthe MM
I didn't see any lead cleaning
The still make those speakers just google it.
What about evaluating the unknown solar cap first? Solar made some fairly respectable caps. The capacitance may be near the original.
I thought the SOP for radio work was check transformers and chokes for continuity,that includes IFs. Then tubes, then resistors and cap replacement.
Asbestos is not so dangerous as it has been made out to be. Millions upon millions of brake shoes and clutches were made with it. Countless buildings have asbestos insulation sprayed in the drop ceilings to protect the steel framework, and mile after mile of main water pipe (cement transited) are still in use.The list is so long. Far overstated.
James Lucas
I found no data on that multi stage cap, but the values were shown on the schematic. 2 of the 5 in it were already bypassed by the time I got this so I just looked up the values and changed the rest. Paper capacitors are the number 1 cause of other component failures in tube gear. Coils and transformers generally do not fail unless they are overloaded and too much current is drawn. This overheats the wire melts the insulation and a short results. When you see these Old caps don't measure them, replace them before applying power. No doubt that audio output transformer was burned out by the owner as he told me he plugged it in and it started smoking. That mistake added 100 to his repair bill as that is what that transformer cost for a new one. When I work on vintage all the caps gotta go before I plug it in and trouble shoot. I have 3 of my own pieces to look at. An old Normende stereo, a McIntosh 1500 and a Halicrafters. They will be looked at sometime soon I hope. When I get time. My wife is on my case for the Normende stereo as it was her parents that we have inherited so she wants that one overhauled so she can put it on display in the house.
As far as asbestos goes as long as it is not disturbed it is fine. It is the dust that is the problem. Don't be ignorant of it. Go tell that to someone that is sick because of exposure at work. I know a mechanic that is now dying of asbestos lung cancer. He did not smoke but he was a heavy duty mechanic and was exposed daily to brake dust. The dust masks they used 30 years ago did not help him and his doctor has given him 6 months to live. He is 54 and likely won't see 55. Where I work we sometimes have to go into atics. We have to Don full respirator before going into crawl space or atic
12voltvids
Thank you for your comments. Really looking forward to the McIntosh restoration. Hardly anyone doing McIntosh videos. A testament to their longevity or they are just still as costly old (may be , some appreciated vastly e.g. MC 250.). I have 3 MC2105s. One amp for bas, one for mid range and one for high. They were an amazing amp, built like a truck but have the best of the best components.
Will be anticipating that and the Halcrafters. Good luck.
I tried searching for the schematic information and see this downloading site that may be this radio schematic, link:
www.radiomuseum.org/r/phonolacan_662_e.html
Something I thought you would want to be aware of....I watched someone testing "brown drop" caps like the ones you installed in this set. They all had a stripe down one side like the old paper ones, and you would think that the stripe was on the outside foil end...well, half of them were, half were not. I guess the safest bet is to test all your caps, place some sort of identifying mark on each one, and when you use them, you will know which end is the correct outside foil end.
Also, I would like to urge you to trace out the electrolytic caps with the diagram (schematic) and find the value of those and replace them as well.
This video might also be of interest to you:
ua-cam.com/video/BnR_DLd1PDI/v-deo.html
I also fully aware of "outside foil" and do test them when I buy them to identify them. I do go over this on my videos. You must be skipping ahead. I know Paul built an auto switching jig to check them but I am not that lazy. It takes no more time to switch the cap around manually. Also outside foil is not as big a deal on modern caps as opposed to the old ones just due to the physical size of the new ones. There is less surface area to pick up incidental interference than on the old paper caps.
you do not physically desolder or use loop over wire to solder the caps.... I do in these old sets and every other tuber doing these age radios and tvs curse you out if not. whats your excuse for not.
Fibro Dad, your comment is jibberish, what did you mean?
I think he meant :- fully desolder the component and replace or snip the leads at the sides of the old component and form a loop to feed and wrap the new component leads through - gives better mechanical solder joints.
Sasquatch, oh i see, i got a bit confused there lol.
Thankyou for making it clear :-D
Actually I generally solder to the lugs when the wire is long enough, or clip the lead, twist and solder.
I do form a loop, are you blind. Go back and look. You will see a shot of the pliers in there forming a loop. Some was cut out.
auto dyne radio