I just enjoy videos like this, you really know your electronics, and what is good about this is I feel you are a very humble person, this is one reason I like to work on vintage electronics, we need to keep this alive...
Even after 6 years this video serves it's purpose to those who now have an EICO 147A and want to make it both safer to use and sensitive enough too. Going to rebuild a Heathkit probe for it properly as shown. Thanks Vern!
I recently gave one of these (actually a 147A) to Buddy at The Radio Shop here on UA-cam. He just posted a video last week on the rebuild. A truely indispensable piece of equipment on any repair bench.
Watched the video. You sent quiet the care package. Kind of what drove me to by this unit. I sold my really clean one about a year ago. Regretted it immediately after.
t his video is invaluable to me i just acquired two EICO units the 324 and the 147A i have been watching you for some time now and ALL your videos cover every thing that i did not learn in a electronics trade school THANK YOU THANK YOU THANK YOU
Hi, great video.I would love to see a video on restoring the accurate signal gen. and tracer model 153 I have one trying to get it working. thank you for your time and effort making these videos.
Those HP meters are awesome. I still have an issue with mine but have not had to time to get back at it. One day...... Keep up the great work you are doing. Good to see someone helping folks that are getting started. I recently found your channel thanks to Mike at Mikes Radio Repair. Enjoy every video I have seen so far. Been watching them since 5am this morning while in the shop doing a bit of work.
Very interesting. I actually have one of these sitting on the shelf, in the box, unbuilt. I'll be sure and replace the caps before I build it, and probably those other mods too, as resale would not be a concern of mine. Cannot wait to build it. As you might guess, I'm older than it is. I built a number of kits back in the day (tubes were my first), but never an EICO. It's a long-gone era and consider myself lucky to have just a few of the old unbuilt kits (and many modern waiting too).
Hi Milo, Thank you for watching and for the nice comment. Something very satisfying about building a kit and having a nice piece of gear after. Just think of the tubes as Thermionic FET's and it becomes modern.
Ha Ha, I'd never thought of it that way before, though I'm aware of their similar function. When the big EMP goes off (either solar or otherwise), hopefully we'll still be playing with our tubes :-), and it will be a world lost to many as it is now (tubes).
Great upgrades and video! This circuit and its intended DUT circuits are both outside of my skill set. However, I am beginning to learn about them, both. In considering building my own signal injector/tracer, I thought it might be useful to have the injected tone include a discernible beat/pulse. That way, I could not confuse it with any other tone of similar frequency produced by the DUT. My hearing is significantly diminished. Thoughts/suggestions/circuit method?
i bought a Eico 147 based on this video and some others, but i am missing the Output Selection Rotary switch, Do you know what type of switch is needed and what is wired to it???
Hi thanks for the vídeo. The process of grounding this unit would be equivalent to the swap of a 2 prong chord to 3 prong chord on an old Fender Tube Guitar Amp? Thanks again.
Dear Radio Mechanic, I own both the Eico 147A and the 324 and on the 324 when it is plugged into the power I use, when I touch the case I can feel just a small shock, is this due to a leaking power transformer? Also on the 147A that you replaced the ac wire with a ground, did you connect the green ground wire to the chassis? Thank you kindly for any input...
So, the 3-wire AC cord was something you put in (changed out the origional 2-wire cord) ? ? And added the fuse . . . right? That's what stopped the shocks ?
One other question I have, I am building the Elenco 108 AMFM kit and it tells you when doing some testing to feed a 455khz signal in at 80% modulation, are we modulating the audio to keep from distorting the 455Khz signal? Thank you kindly for any help...
Would an XY I think,,,or a Y2 cap across the ac input helped??? I am going to make a probe out of a broken AC voltage tester..the kind that lights up in the presents of AC...It is all plastic...
Very cool! I have a Conar signal generator model 280, Heathkit S3 capacitor/resistor checker and a Jackson 641 AM/FM Signal Generator I needs to rebuild and plan on swapping out and adding BNC and plan on adding 3 wire cords...thanks for the tips! By chance do you have a video where you address changing out the selenium rectifier (thumbing through your videos now)?~Jack, VEG
No, but someone ( I think it may be either Mr Carlsons lab or Mike at MIke's radio repair. You usually want to add a resistor to compensate for the Selenium voltage drop. If the Selenium is still working, measure the voltage drop across it and the current through it. Then you can replace with a diode and resistor.
Do apologize, I didn't get notification to your reply (I don't on most vids for some dumb reason), I thought the seleniums change voltage over time, so measuring what you currently have today is good enough? If its that simple, then not a problem! I've seen both videos but it wasn't made as simple as your explanation, thanks! ~Jack, VEG
The increase in voltage drop usually isn't much of an issue. The real danger with selenium rectifiers is that they produce a poison smoke if they power supply gets shorted. But if all is well I usually leave them in. If there is obvious damage from moisture I will change them. Check the schematic for the unit and see what the DC supply voltage should be. This is a good indication of how the rectifier is working.
Thank you for the great information. I just bought an old Heathkit signal tracer and would like to ground and insulate the probe. Do you recall the size of the heat shrink you used? I haven't received the unit yet so I cant measure the OD of the probe but I'd like to have all of the parts ready when it arrives. Thanks again. Rob.
Nice video! I have one of these. I'm in the process of replacing the 3.? watt speaker with a 4" 30 watt Eminence speaker and two 1/4" female guitar jacks for the black & red audio inputs. I still have to figure out the circuit mod that will give me 20~25 watts of super clean out to the speaker. Any thoughts and advice would be greatly appreciated. Thanks!
@@theradiomechanic9625 Thanks for the response! I agree. At first glance I figured "wow, three transformers" but last night I changed out the "audio in" jack to a 1/4" jack and very carefully plugged in the guitar, (I read somewhere an electric guitar puts out around 300 millivolts) so basically the guitar is a giant probe. It's not as loud as an acoustic. So it was basically a success. Nothing caught fire and no one was injured. I'm hopping, with more research, I can install a small toggle switch that will turn off the magic eye. I figured out how to add a switch without adding any holes. No vintage gear will be harmed during this project. Any advice would be greatly appreciated. Thanks!
I just bought a 147 on eBay "untested". It has a bad output transformer. What would you expect the impedance of the primary of the original transformer to be? Is the speaker 8 ohms? Thanks.
I am sending this from Thailand and have no access to my schematics. However take a look at what tube is used for the audio output, look up the specifications for the plate resistance. This will give you a pretty good approximation of what you need for the primary of the audio output transformer. That being said, this is not a high fidelity unit and is used primarily just to hear audio signals. Therefore just about any general purpose replacement audio transformer will work and I wouldn't worry about the speaker impedance. Again you're only using this to monitor the sound through the radio you're testing.
Were is, or who is: Erik den Houter ? (someone who responded, but didn't answer my question. I'd like to respond to him.) So, once again, what do you subscribe the disappearence of the "shocks" you were experiencing ? Are you implying that the addition of the fuse solved the problem ? I realize the value of adding the fuse but don't see how it would stop the "tingle". Just not clear.
When my Eico 147A gets resold I won't care or I will be dead. Heathkit test probe for a few bucks I wish. They go for $40 or $50. Update I now have two Eico 147a and two Heathkit probes
The hum is from the layout of the components in that model, they put the transformers in line and very close to the speaker. Very nice looking outside, very poor design inside.
I just enjoy videos like this, you really know your electronics, and what is good about this is I feel you are a very humble person, this is one reason I like to work on vintage electronics, we need to keep this alive...
We need more of these type videos what a great job you have done with detailing .love it.
Thanks Donnie, these kinds of responses make me want to make more vids. Appreciate your watching. Vern
Even after 6 years this video serves it's purpose to those who now have an EICO 147A and want to make it both safer to
use and sensitive enough too. Going to rebuild a Heathkit probe for it properly as shown. Thanks Vern!
I recently gave one of these (actually a 147A) to Buddy at The Radio Shop here on UA-cam. He just posted a video last week on the rebuild. A truely indispensable piece of equipment on any repair bench.
Watched the video. You sent quiet the care package. Kind of what drove me to by this unit. I sold my really clean one about a year ago. Regretted it immediately after.
Yes he sends the very best. Must be a hallmark thing lol.
Mike is the man.......
+The Radio Mechanic
Just trying to help out where I can.
t his video is invaluable to me i just acquired two EICO units the 324 and the 147A i have been watching you for some time now and ALL your videos cover every thing that i did not learn in a electronics trade school THANK YOU THANK YOU THANK YOU
Your are welcome sir, I thank you for watching and the nice comment.
Great improvements noted here. I just acquired a 147, these mods are going in it as I clean it up and re-cap it. Thanks.
You are very welcome. Thank you for watching.
Now I know how to quiet down my Heathkit T-4. Thanks!
Very nice video
Hi, great video.I would love to see a video on restoring the accurate signal gen. and tracer model 153 I have one trying to get it working. thank you for your time and effort making these videos.
Nice tips on the upgrades. Very good information. Subscribed.
HI, thanks for watching. Thought that HP meter was a 400E when I saw it. Have the 400E version on my bench.
Those HP meters are awesome. I still have an issue with mine but have not had to time to get back at it. One day...... Keep up the great work you are doing. Good to see someone helping folks that are getting started. I recently found your channel thanks to Mike at Mikes Radio Repair. Enjoy every video I have seen so far. Been watching them since 5am this morning while in the shop doing a bit of work.
Bought mine because my HP Q meter uses it for calibration. Works great and is real accurate.
Outstanding fix thank you for sharing well done. D
Thanks Dennis....
I couldn't get mine to work, so I striped it down and building into a 5F1 guitar amp. Same chassis and cabinet. For practice amp.
Very interesting. I actually have one of these sitting on the shelf, in the box, unbuilt. I'll be sure and replace the caps before I build it, and probably those other mods too, as resale would not be a concern of mine. Cannot wait to build it. As you might guess, I'm older than it is. I built a number of kits back in the day (tubes were my first), but never an EICO. It's a long-gone era and consider myself lucky to have just a few of the old unbuilt kits (and many modern waiting too).
Hi Milo, Thank you for watching and for the nice comment. Something very satisfying about building a kit and having a nice piece of gear after. Just think of the tubes as Thermionic FET's and it becomes modern.
Ha Ha, I'd never thought of it that way before, though I'm aware of their similar function. When the big EMP goes off (either solar or otherwise), hopefully we'll still be playing with our tubes :-), and it will be a world lost to many as it is now (tubes).
Russian Military kept using tubes well into the early 90's just for that reason. They forgive a lot that will kill semiconductors.
Great upgrades and video! This circuit and its intended DUT circuits are both outside of my skill set. However, I am beginning to learn about them, both. In considering building my own signal injector/tracer, I thought it might be useful to have the injected tone include a discernible beat/pulse. That way, I could not confuse it with any other tone of similar frequency produced by the DUT. My hearing is significantly diminished. Thoughts/suggestions/circuit method?
i bought a Eico 147 based on this video and some others, but i am missing the Output Selection Rotary switch, Do you know what type of switch is needed and what is wired to it???
What is the maximum AC voltage the RF input can handle on your 147? I was looking at a 147A to buy..
Hi thanks for the vídeo. The process of grounding this unit would be equivalent to the swap of a 2 prong chord to 3 prong chord on an old Fender Tube Guitar Amp? Thanks again.
What type of Coax is usually used on the RF test probe? RG-59?
Dear Radio Mechanic, I own both the Eico 147A and the 324 and on the 324 when it is plugged into the power I use, when I touch the case I can feel just a small shock, is this due to a leaking power transformer?
Also on the 147A that you replaced the ac wire with a ground, did you connect the green ground wire to the chassis? Thank you kindly for any input...
So, the 3-wire AC cord was something you put in (changed out the origional 2-wire cord) ? ? And added the fuse . . . right? That's what stopped the shocks ?
I refurbished an eico 324 & calibrated it using an am radio. When I put it back into the case the signal is gone. Help.
One other question I have, I am building the Elenco 108 AMFM kit and it tells you when doing some testing to feed a 455khz signal in at 80% modulation, are we modulating the audio to keep from distorting the 455Khz signal? Thank you kindly for any help...
Would an XY I think,,,or a Y2 cap across the ac input helped??? I am going to make a probe out of a broken AC voltage tester..the kind that lights up in the presents of AC...It is all plastic...
Very cool! I have a Conar signal generator model 280, Heathkit S3 capacitor/resistor checker and a Jackson 641 AM/FM Signal Generator I needs to rebuild and plan on swapping out and adding BNC and plan on adding 3 wire cords...thanks for the tips! By chance do you have a video where you address changing out the selenium rectifier (thumbing through your videos now)?~Jack, VEG
No, but someone ( I think it may be either Mr Carlsons lab or Mike at MIke's radio repair. You usually want to add a resistor to compensate for the Selenium voltage drop. If the Selenium is still working, measure the voltage drop across it and the current through it. Then you can replace with a diode and resistor.
Do apologize, I didn't get notification to your reply (I don't on most vids for some dumb reason), I thought the seleniums change voltage over time, so measuring what you currently have today is good enough? If its that simple, then not a problem! I've seen both videos but it wasn't made as simple as your explanation, thanks! ~Jack, VEG
The increase in voltage drop usually isn't much of an issue. The real danger with selenium rectifiers is that they produce a poison smoke if they power supply gets shorted. But if all is well I usually leave them in. If there is obvious damage from moisture I will change them. Check the schematic for the unit and see what the DC supply voltage should be. This is a good indication of how the rectifier is working.
Thank you for the great information. I just bought an old Heathkit signal tracer and would like to ground and insulate the probe. Do you recall the size of the heat shrink you used? I haven't received the unit yet so I cant measure the OD of the probe but I'd like to have all of the parts ready when it arrives.
Thanks again.
Rob.
HI Rob, the probe measures 7/8" ( .875" ) or 22.25 mm. Heat shrink was from a bundle of clear heat shrink I purchased years ago.
Sounds like 1" should be about right if it's 2X shrink factor but I'll see if I can find some 7/8" online as well.
Thanks so much.
Rob.
Nice video! I have one of these. I'm in the process of replacing the 3.? watt speaker with a 4" 30 watt Eminence speaker and two 1/4" female guitar jacks for the black & red audio inputs. I still have to figure out the circuit mod that will give me 20~25 watts of super clean out to the speaker. Any thoughts and advice would be greatly appreciated. Thanks!
Going to take a whole lot more power supply than this thing has for that kind of wattage.
@@theradiomechanic9625 Thanks for the response! I agree. At first glance I figured "wow, three transformers" but last night I changed out the "audio in" jack to a 1/4" jack and very carefully plugged in the guitar, (I read somewhere an electric guitar puts out around 300 millivolts) so basically the guitar is a giant probe. It's not as loud as an acoustic. So it was basically a success. Nothing caught fire and no one was injured. I'm hopping, with more research, I can install a small toggle switch that will turn off the magic eye. I figured out how to add a switch without adding any holes. No vintage gear will be harmed during this project. Any advice would be greatly appreciated. Thanks!
Collector value means nothing except that the owner wont use or enjoy the unit. Its your thing so change it to be useful to you.
I just bought a 147 on eBay "untested". It has a bad output transformer. What would you expect the impedance of the primary of the original transformer to be? Is the speaker 8 ohms? Thanks.
I am sending this from Thailand and have no access to my schematics. However take a look at what tube is used for the audio output, look up the specifications for the plate resistance. This will give you a pretty good approximation of what you need for the primary of the audio output transformer. That being said, this is not a high fidelity unit and is used primarily just to hear audio signals. Therefore just about any general purpose replacement audio transformer will work and I wouldn't worry about the speaker impedance. Again you're only using this to monitor the sound through the radio you're testing.
so did you really try touching both piece of equipment again to see if you fixed it?
Absolutely......
Were is, or who is:
Erik den Houter ? (someone who responded, but didn't answer my question. I'd like to respond to him.)
So, once again, what do you subscribe the disappearence of the "shocks" you were experiencing ? Are you implying that the addition of the fuse solved the problem ? I realize the value of adding the fuse but don't see how it would stop the "tingle". Just not clear.
When my Eico 147A gets resold I won't care or I will be dead. Heathkit test probe for a few bucks I wish. They go for $40 or $50. Update I now have two Eico 147a and two Heathkit probes
The hum is from the layout of the components in that model, they put the transformers in line and very close to the speaker. Very nice looking outside, very poor design inside.
What is The Magic eye for?
The manuals claim it is to indicate relative signal strength. Mostly it is window dressing.
@@theradiomechanic9625 wow, do you have a link for the manual with schematics?
so by window dressing you mean aesthetics?
@@itrstt66 just search for EICO model 147, OR HEATH KIT IT 12
@@theradiomechanic9625 thank you
My magic eye is very dim ...