First of all, I want to tell everyone how much I enjoy AAC! This website is one of the best internet discoveries I've made in the past year. I especially relish the featured teardown articles! I've been doing that sort of thing since I was a little kid, and I'm thrilled to see that other people are just as inquisitive as I am!

I have some vintage shirtpocket/coatpocket transistor radios from the late 1960s that were responsible for piquing my interest in electronics/radio/tv/broadcasting, so much so that I made it my career. These radios aren't performing too well anymore, probably because they need to be recapped and realigned. I just don't have the time to troubleshoot, source new components, and repair these devices.

Can anyone direct me towards people who might be able to repair these for me?

Thanks for any guidance you can share.

Bobb
73 de KB3ZIM

 

Let's see your collection. Crack a few open so we can see the circuitry.

And welcome to AAC.

 

Don't attempt to align the 455kHz IF transformer cores unless you have the know-how and a sweep generator.
Also most transistor superhet receivers will have trimmer caps to adjust the RF tuner and the local oscillator. Don't fiddle with those without the right knowledge and equipment.

As a ham, you should have an idea of how these things work.

I would make a guess that these radios do not need recapping.

Start with one radio at a time. Show us the guts and tell us what's wrong with it.

73.

 

Don't attempt to align the 455kHz IF transformer cores unless you have the know-how and a sweep generator. Also most transistor superhet receivers will have trimmer caps to adjust the RF tuner and the local oscillator. Don't fiddle with those without the right knowledge and equipment.

As a ham, you should have an idea of how these things work.

I would make a guess that these radios do not need recapping.

Start with one radio at a time. Show us the guts and tell us what's wrong with it.

73.

 

Let's see your collection. Crack a few open so we can see the circuitry.

And welcome to AAC.

See below.

 

Don't attempt to align the 455kHz IF transformer cores unless you have the know-how and a sweep generator.
Also most transistor superhet receivers will have trimmer caps to adjust the RF tuner and the local oscillator. Don't fiddle with those without the right knowledge and equipment.

As a ham, you should have an idea of how these things work.
I
I would make a guess that these radios do not need recapping.

Start with one radio at a time. Show us the guts and tell us what's wrong with it.

73.

Indeed. I don't have all of the necessary equipment needed to test/align. Yes...as a ham, I do have an idea of how they work. What I don't have a lot of is time to do it (see initial post), which is why I posted the question.

No need of recapping? Your reason to suspect that is???? I'll note that there is no physical damage or obvious mechanical issues (broken traces/wires, battery leakage, etc.).

As per requests, here's a look...........

 

There are 10 types of people in the world: those who understand binary and those who don't.

73.

BTW: Your signature line is hysterical! Thanks.

 

After you clean the battery holder and put in fresh batteries ... Does it work?

 

After you clean the battery holder and put in fresh batteries ... Does it work?

Yes. It works. Very low audio output and very low RF sensitivity. Only 1 AM broadcast station can be received: transmitter just a mile or two away.

 

I have 50+ year old tube equipment that still work and never been recapped. I usually will not go about changing capacitors unless I know they need changing.

For low voltage transistor equipment, that is stronger reason not to recap.

 

Did you clean the volume control with contact cleaner or another solution?

 

I suppose you are really looking for someone to work on these for you. Too bad I was near Trenton not too long ago. There are some other AAC members in PA. Maybe they might be willing to lend a hand, example, @OBW0549 .

 

I suppose you are really looking for someone to work on these for you. Too bad I was near Trenton not too long ago. There are some other AAC members in PA. Maybe they might be willing to lend a hand, example, @OBW0549 .

Me? I'm as dumb as a box of wet hair when it comes to radio; the only experience I've ever had with it was building a crystal set back in the 1950's, and the only reason that thing worked at all is we lived just a couple of miles from the antenna tower of what was then the most powerful transmitter in the Northeast- WABC in New York.

I'd offer to help, but I'd just be lost.

 

Give it an easy but sharp rap. Hammer action can be very effective.

They are not all like that are they? I mean they all don't have low volume do they?

Check for insect infestation in speakers. Stuck or warped speaker voice coils? What conditions were they stored in?

I would have expected that most (if not all) would play fine.

 

Give it an easy but sharp rap. Hammer action can be very effective.

They are not all like that are they? I mean they all don't have low volume do they?

Check for insect infestation in speakers. Stuck or warped speaker voice coils? What conditions were they stored in?

I would have expected that most (if not all) would play fine.

Thanks for the suggestion. I should have been a bit more precise: not ALL of the radios I have are experiencing these issues....just the one Bulova in particular. Yes...I've "rapped" firmly, touched many components to determine if a lead was broken or a circuit board trace was cracked...stuff like that. Component failure due to aging is my best guess.

 

I would go along with BR-549. There is a good chance that most are working fine.

I like his suggestion about testing for a bad speaker. I never thought of that.
Get an 8Ω speaker that you have tested as working. Replace the suspect speaker in the radio with low volume and test again.

Or conversely, verify that the suspect speaker is working fine.

 

Headphone jack? try that. Speaker may not be 8 ohm. I've seen some with 40 ohm speakers.

Check the bias voltages on the transistors and see if they seem reasonable. Germanium transistors will have base biases in the 300 mv range. Your more likely to have a transistor that has gone leaky than bad caps.

 

I would still suspect a mechanical fault first. Clean battery contacts with pencil eraser. Check voltage at power switch.

As you advance volume.....rock pot perpendicular to pot travel.

Make sure speaker cone moves freely.

Look for insect cocoons on board.

After that, follow a signal thru.

I don't know of a company that does this type of work anymore. It's the time. Circuits/devices can be replaced a lot cheaper than being repaired.

I seriously doubt, anyone does component repair/replacement now days. It's a skill that is being lost.

Try a mom and pop tv store. They still have them, but you have to search. You might find an old geezer that knows how to component level repair.

 

I would still suspect a mechanical fault first. Clean battery contacts with pencil eraser. Check voltage at power switch.

As you advance volume.....rock pot perpendicular to pot travel.

Make sure speaker cone moves freely.

Look for insect cocoons on board.

After that, follow a signal thru.

I don't know of a company that does this type of work anymore. It's the time. Circuits/devices can be replaced a lot cheaper than being repaired.

I seriously doubt, anyone does component repair/replacement now days. It's a skill that is being lost.

Try a mom and pop tv store. They still have them, but you have to search. You might find an old geezer that knows how to component level repair.

Have been doing some of that already, but will investigate more. I'm in no hurry. It has, without any doubt whatsoever, and RF sensitivity issue. The very low audio output does not account for the additional fact that only one MW broadcast station can be received because the transmitter is about two miles away. Living in a market with several 50KW stations nearby, I'd think I'd be able to receive them, albeit with low audio output. Fact is, I can't, regardless of audio output power.

What you say about this day and age is absolutely true: most stuff isn't repaired anymore, just replaced. However, believe it or not, there are some people out there doing repairs on this sort of stuff, though they're hard to find (which is why I posted the question here) and charge a lot of money (which is okay if it's worth it to someone).

Thanks for sharing your thoughts.

 

You might find a competent tech at your local ham club. Your only problem seems to be time.

kb7wg