Philco 50T-1404 restoration part 2
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- Опубліковано 16 бер 2024
- Let's see if we can breathe some life into this old TV.
* Replacing roasted AC interlock
* First power up without B+
* Repairs inside the HV box
* Second power up slowly building to full B+
* Rigging up a test CRT
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The Caganer figurine aka Uncle Shitty. Haven't see one in decades. Very nice of your sis to thing of you that way! Always
a pleasure watching you get these old chassis operating again. Love those "flying by the seat of your pants" repairs.
That was a nice bulldog session Bob. Way to just get at it!
Very promising, excellent. The yoke cradle reminds me of something that Dr Frankenstein would have put on the monster's head to make it come to life 😄
Great video Bob! This old Philco is VERY similar to the 1401 I am currently working on. Great job with the initial checks and powerup before even doing anything other than getting correct tubes in the correct spots, changing the AC interlock and jumping the bad power switch. I wish I could have done that with mine. Unfortunately, my missing C5 cap and a few random broken wires kind of prevented that. I'm watching this one with great interest.
Also there's one good use for the dead picture tube: it can be swapped into an unrepairable shelf queen.
I am so glad the waiting is over, been patiently waiting for my very favorite channel. Made the long week worth the wait. Very overjoyed.
Thanks. I will be getting back to the Admiral/beginners series as soon as I can.
28:10 The HV rectifier and horiz output tube being mixed up actually explains the bright flash that can be seen inside the HV cage on first powerup at 21:48; the 1,4V filament of the HV rectifier was blasted with the 6,3V for the H-output tube and burned up.
Haha - I missed that. I was wondering as I edited the video if I might killed the HV rectifier. I'm a little surprised it uses the same filament pins as a 6BG6.
I too use Nichicon 500 volt capacitors !
13:11 Philco Yoke Girdle.
For HV rectifiers you can use Soviet equivalents. 1C1S (1Ц1С) and 1C7S (1Ц7С). They have the same pinout and same ratinga as the US tubes. There's also 2C2S (2Ц2С) it has a bit higher heater voltage ,but it would work ok.
When you joked about hitting the CRT with a hammer to get the hoop assembly off, I was thinking the same thing, but putting the whole thing in a heavy duty trash bag to contain the resulting mess. Implosion wouldn't be an issue, given what happened to the tube
I get a little antsy every time you reach over the chassis adjust the power. Especially in the dark. Especially with your t-shirt hanging just inches away from the bare rectifier plate wires. But so far, so good. Be careful, Bob.
oh yes... sweat be conductive! we're fans, but not for sake of bravado. consider who ELSE is getting cues from this. we old codgers think the next generation is stupid enough -- don't encourage them to be stupider. perhaps bob should consider having a "spotter" in the room with him. that dog cannot call 911 or cut off power, though maybe he could start howling and alert his spouse, lol.
one hazard about slight shocks is that they can startle if not also cause a spasm -- and send one into a more dangerous position than before.
(@35:28) LOL! That looks like something you would find in the old Republic serials with Flash Gordon, or some mad scientist’s “death ray”. 😂
¡Saludos desde España!
Thanks
It also makes me nervous when you reach over a Live TV Set to get to your Sencore isolation transformer... I think you should reposition the Sencore so your arm is not going over the tv set... 🙂
true, perhaps the isolation transformer/variac could be relocated to a shelf beneath the front edge of the bench? it might be slightly less camera friendly there though.
wow
Rephosphoring is relativly easy on non-aluminised monochrome tubes, some rebuilders even did it as a matter of course, It is somewhat more tricky (but doable) if the tube is aluminised and impossible on colour tubes. Air exposure will ruin the cathode however.
Relatively easy if you have the right chemicals. I've read it's difficult to mix up your own B&W phosphor solution.
@@bandersentvBarium Acetate and Potassium Silicate, I don't remember the concentrations. Solution temperature and settling time are also important. Phosphor powder has to be milled to the proper particle size, I seem to recall it was around 10 microns. The acetate causes the phoshor grains to be charged and repel each other.
the silicate glues the phosphor grains to the glass bulb
Some how when i pull a set out to work on you are restoring the same one most of time. Also my philco started with the original caps. I found two open electrolytes and one black beauty. Replaced the crt grid caps. My crt has a bit of ion burn and no emissions and tube brighter. The contrast was so bad i tried rejuvenation but i should have know better the contrast became slightly worse.
I'm surprised it has ion burn. That should not be possible unless it was rebuilt with a straight gun.
@bandersentv Let me look, it's a 12KP4A tube, chart says, well I don't know, its damaged. The set is a 50-T1403 I couldn't find the exact schematic. 12LP4 is the right tube?
@@SoundsLegit71 12KP4A is interchangeable with 12LP4. 12KP4A is also aluminized so it's impossible to get an ion burn.
@bandersentv I haven't taken off the screen cover because it looks pretty clean. Maybe there happens to be dirt in the middle. Just occurred to me the crt socket was re-soldered on so it could a different tube.
One small correction: if I'm not mistaken the traditional early flyback has a 1:1 ratio. When there's 9kv on the 1B3's plate there is 4.5kv on the BG6 plate.
I think you meant 2:1. True I forgot the HV winding is pulled off the primary like an auto-former. FLY-1 has 180 ohms primary - 240 ohms HV winding. Philco is 4:1. 97/403 ohms.
@@bandersentv 1:2 if you measure from the feed. 1:1 if you measure from the HOT plate.
2:1 measure from HOT plate. 165 ohms from HOT plate to bottom of winding. 310 ohms from HOT plate to top of winding. OK, not quite 2:1 but close.
@@bandersentv The Sams for my Emerson says 340 ohms with a tap at 175. This would mean 165 on one half and 175 on the other half. Either Sams is wrong (possible) or this TV is different than normal (also possible). Listed equivalents are A-8117 and TFB-1.
@@eDoc2020 Not familiar with that one. Don't recognize the flyback #s either.
Bob, I noticed this set appears to be missing the trap magnet on the rear of the CRT stem behind the focus coil. Does the 1404 not use it?
Depends entirely on the picture tube. This has a 12LP4 and you absolutely must use the magnet. I assume it was lost over the years.
Do you know of a source for replacement AC interlocks? I've an admiral chassis with a similar burned one.
Are all of the replacement Mouser electrolytics radial-leaded? Should I give up trying to use hard-to-find and expensive axial-leaded ones for restorations?
Depends on how you plan on mounting them. These are replacing multi-section twist-loc cans. Since I will be used adapt-a-caps and mounting them in the original position, it would actually be more difficult for me to use axial leaded caps to replace them.
Why do you have CLR on your electronics work bench?
I use it to clean chassis and other metal parts.
Going to get a 12KP4 for it?
12LP4. KP4s are rare
Bob- Is there a way to contact you? I have some items you might like, Including 1B3's. You can use part of a spring as the plate cap on the BG6.
bandersentv@gmail.com
No Octal Adapter??? That cant be possible from "The Expert" 🙂
Not for the TeleCheck test rig. It has alligator clips on the leads.
@@bandersentv OK Got It!!!!
Please don't work with electricity when tired....
Oh I'm used to it. Haven't had a good night's sleep in years.
@@bandersentv well if you can't be "good" be careful, lol. a lot of people would be very sorrowful to see this hobby unalive you before your time. i hope you go to heaven but not while there are still sets to fix for folks...
Conversely, don’t work with tired people when electrified. 😏
It's really disgusting how much useless plastic Mouser irresponsibly uses in their packaging....those plastic bags will foul the environment for 1000 years. They could just as easily pack things like that in paper, wax paper, cardboard, cotton......
The labels on the bags can be carefully peeled off and the bags re-used. The bags used by Digikey have a different glue and the bags will tear first.