I wonder if people get this from their expectation of medical doctors: I have this symptom - skin rash, yellow eyes, etc. - now, what disease do I have, and how do I cure it? Or maybe we like the idea of modern auto mechanics hooking up our misbehaving cars to a computer, and telling us what's wrong.

But when it comes to old tube-type radios, describing symptoms like "no sound" does not offer much help in the diagnosis. There are more possibilities than you can throw replacement parts at.

What's needed is systematic troubleshooting, which is difficult to lead people through over the Internet. One approach is to start at the back (audio) end, and work toward the front. But whatever approach you choose, it needs to be systematic with a schematic in hand, not grasping for straws, replacing tubes willy-nilly, etc.
Doug

Absolutely ...certainly and of course!!!... but you are preaching to the choir.. Dougie....lol
I think perhaps the "tube swappers" (maybe beginners) simply lack the fundamental block-diagram functional understanding of a basic radio and that without that perspective are not able to do "logical" functional trouble shooting.

By the way... there is a school of thought in trouble shooting that reduces the number of steps by always starting in the middle of the circuit ... then based on the results will jump ahead 1/2 again or back 1/2 again and so on..etc, etc..... very effective.

Peter.
I suspect that the subject of Doug's post involves neophytes, looking for quick answers (21 century instant gratification syndrome), and not at all trained in the fine art of logical troubleshooting.
I never (have never) powered an old set first, but do test tubes as a first step, and take notes as to the meter readings, then store them (wrapped) w/notes for the final product. A complete cleaning/drying of the chassis is next (with appropriate cleaning agent and water) Next step always starts at the heart (power supply) where conclusive measurements of transformers are made, then power up with no load (tubes/electrolytics) to verify all voltages are within unloaded range of values. Then all caps and bad wiring are replaced. Now I have a stable platform on which to perform final alignment/testing with tubes.

marv

:Absolutely ...certainly and of course!!!... but you are preaching to the choir.. Dougie....lol
:I think perhaps the "tube swappers" (maybe beginners) simply lack the fundamental block-diagram functional understanding of a basic radio and that without that perspective are not able to do "logical" functional trouble shooting.
:
:By the way... there is a school of thought in trouble shooting that reduces the number of steps by always starting in the middle of the circuit ... then based on the results will jump ahead 1/2 again or back 1/2 again and so on..etc, etc..... very effective.

:Peter.
:I suspect that the subject of Doug's post involves neophytes, looking for quick answers (21 century instant gratification syndrome), and not at all trained in the fine art of logical troubleshooting.
:I never (have never) powered an old set first, but do test tubes as a first step, and take notes as to the meter readings, then store them (wrapped) w/notes for the final product. A complete cleaning/drying of the chassis is next (with appropriate cleaning agent and water) Next step always starts at the heart (power supply) where conclusive measurements of transformers are made, then power up with no load (tubes/electrolytics) to verify all voltages are within unloaded range of values. Then all caps and bad wiring are replaced. Now I have a stable platform on which to perform final alignment/testing with tubes.
:
:marv
:
::Absolutely ...certainly and of course!!!... but you are preaching to the choir.. Dougie....lol
::I think perhaps the "tube swappers" (maybe beginners) simply lack the fundamental block-diagram functional understanding of a basic radio and that without that perspective are not able to do "logical" functional trouble shooting.
::
::By the way... there is a school of thought in trouble shooting that reduces the number of steps by always starting in the middle of the circuit ... then based on the results will jump ahead 1/2 again or back 1/2 again and so on..etc, etc..... very effective.

At Delta Air Lines, the powers that be hated to see us do regular troubleshooting, as we could change a bunch of IC chips at about a tenth of the cost of changing one, due to our pay vs. the price of chips. I hated to do it that way, but the best of chips(airline quality)were very cheap compared to the tubes of forty or fifty years ago, back in the days when the tech was getting a dollar or two and hour, and a tube could cost five. Shotgunning a board fixed it, but the fun of the hunt was no longer there.

Lewis L.

Hi
I'm a neophytes, looking for answers and the 21 century gratification of repairing an old radio without having to go back to school for 2-4 years. I don't know about you but at age 53 I don't have the time, or money to go to school to become an electronics technician in order to repair a few old radios. I find that there are some very professional and helpful people, like yourselves, who provide some great advise and ideas on how to do this type of work. Like most neophytes, or 21 century syndromers, as we are called, I too am looking for ways to do the repairs and actually use the radio before I die. (which at the rate I'm going that might not happen. So to you guys and gals please be patient and keep providing the great and insightful help you have, we appreciate it. And Mary, in behalf of all the neophytes, "cut us some slack", thank you.

Dave

:Hi
:I'm a neophytes, looking for answers and the 21 century gratification of repairing an old radio without having to go back to school for 2-4 years. I don't know about you but at age 53 I don't have the time, or money to go to school to become an electronics technician in order to repair a few old radios. I find that there are some very professional and helpful people, like yourselves, who provide some great advise and ideas on how to do this type of work. Like most neophytes, or 21 century syndromers, as we are called, I too am looking for ways to do the repairs and actually use the radio before I die. (which at the rate I'm going that might not happen. So to you guys and gals please be patient and keep providing the great and insightful help you have, we appreciate it. And Mary, in behalf of all the neophytes, "cut us some slack", thank you.
:
:Dave

Sorry, It's Marv, not Mary, forget the gal part. Thank you :

::Hi
::I'm a neophytes, looking for answers and the 21 century gratification of repairing an old radio without having to go back to school for 2-4 years. I don't know about you but at age 53 I don't have the time, or money to go to school to become an electronics technician in order to repair a few old radios. I find that there are some very professional and helpful people, like yourselves, who provide some great advise and ideas on how to do this type of work. Like most neophytes, or 21 century syndromers, as we are called, I too am looking for ways to do the repairs and actually use the radio before I die. (which at the rate I'm going that might not happen. So to you guys and gals please be patient and keep providing the great and insightful help you have, we appreciate it. And Mary, in behalf of all the neophytes, "cut us some slack", thank you.
::
::Dave
:
:
:Sorry, It's Marv, not Mary, forget the gal part.

Dave:

When I was a neophyte (new guy) at Delta, a lead mechanic at work had this sign over his desk:

"I would rather answer your stupid question,
Than explain your stupid screw-up."

I liked that guy, he had been training us newbies for a while. When I got to be an "old guy", training my own newbies of my own, I always tried to answer more than I was asked. That way, I didn't have leave our air-conditioned shop and go out in the hot sun and fix a newbies screw up as often. Ask anytime, If I don't know i'll tell you. Someone here will know.

Lewis L.

Lewis:

Thank you I appreciate your understanding and insight into the matter. Like others we have come across this hobby of old radio repair and want to enjoy it as you do. A few helpful words from people like you go a long in our efforts to repair these radios and to learn the trade. Again thanks.

Marv:
In the last year or so I've fully restored or repaired about 75 radios... about 2/3 are AC/DC sets so I don't have a hard-to-find transformer to protect with those sets.
So..I can afoord to be .... and in fact I am ...a bit more cavalier in my approach with those.

I know this will probably rub most of you cautios guys the wrong way ... big time... but this is how I do it:

For me, I don't expect the restoration project to be a long drawn out affair where I'd spend an hour or two on it for a couple nights a week for casual relaxation. (not that there is anything wrong with that approach)...

But to me I enjoy the trouble shooting (de-bugging) stages and then also a good feeling that the whole project is done ..save cabinet painting or refinishing.
.. so I can restore an AC/DC radio completely in about six hours or one evening's time. That includes all electronic testing, troubleshooting and capacitor/resistor replacements as well as removing and washing the tuning condenser, replacing all the rubber gromets and dial restringing as needed and wire brushing or sanding the entire metal chassis. When I'm done it almost looks new.

I am always interested in getting a quick general sense of the "state of health" ( a quick assessment) of the radio..
So when I first put the new "victim/patient" on my bench I give it a good visual inspection first... but then I simply connect my volt meter to B+ and with my finger on the power switch of the isolation transformer for a quick kill... I power it right up. Full power. ZAP!
After all without the fear of damaging a power transformer... how bad can it really be? ...lol

Usually... what?...the worst is maybe ..a shorted filter cap sucking hard on the rectifier?

In all my repair experience... so far ...with AC/DC sets the most common problems are found in:

1.) the electrolytic filter caps... then
2.) the audio coupling cap to the grid of the output, and
3.) the audio cap to the detector and the tone cap on the output plate.
4.) the cathode bypass cap

None of the above are ever catostrophic failures when you are watching the B+ meter and listening carefully.

95% of all these radios came up with merely a severe hum indicating bad filter caps.

So then the next thing I always do is clip out the old filter caps and temporarily tack solder in new ones and re-power ...always watching that B+ meter...
Usually by this time there is very little left that needs extreme caution.

If the B+ looks good but no audio I start my signal tracing and may find a bad paper cap here and there or an open IF transformer or such.
So I then go about replacing all the paper caps and checking resistor values, checking plate voltages etc... and so on.

After I've replaced all components very neatly and I know that everything works well... then I pull all the tubes and remove the tuning condenser.... scrub or sand the chassis, wash that tuning condenser and slap it all back together knowing that it was working fine before that last step and if it does have a problem after cleaning it's usually something obvious I've done or mis-wired when replacing the condenser.

Everyone has their own approach... some more careful and deliberate ...others less so..
I am just a bit more bold in my approach that's all.
But it works well for me.
lol

OK, Peter, my point exactly. There are many ways to skin a cat. I might go crazy watching you go through your approach, and Thomas would most certainly go crazy watching either of us.

But here's the thing: None of us would like to see a totally random approach based on hunches or off-hand tips. There needs to be some logic and structure applied to troubleshooting, and it has to begin with reading the radio's schematic. (Well, maybe, if it's a simple AA5 or 1920s TRF like you've seen before, no need for a schematic - it's in your head.)

Nobody was born with the skills to troubleshoot a tube-type radio, but you don't have to go away to school either. Nobody learned those skills by just asking how to fix their radio if it has no sound. Still, it's not quite as overly simplistic as asking, "My car won't start, how do I fix it?"

Books are important. And so is learning to use a volt/ohm meter.

Year's ago, many neophytes learned electronics by assembling kits, lashing together experimental circuits, reading hobby magazines, or working on junk radios found in the alley. Those days are long gone, so maybe it's now the Internet or nothing. Still...there are books.
Doug

:
:In the last year or so I've fully restored or repaired about 75 radios... about 2/3 are AC/DC sets so I don't have a hard-to-find transformer to protect with those sets.
:So..I can afoord to be .... and in fact I am ...a bit more cavalier in my approach with those.
:
:I know this will probably rub most of you cautios guys the wrong way ... big time... but this is how I do it:
:
:For me, I don't expect the restoration project to be a long drawn out affair where I'd spend an hour or two on it for a couple nights a week for casual relaxation. (not that there is anything wrong with that approach)...
:
:But to me I enjoy the trouble shooting (de-bugging) stages and then also a good feeling that the whole project is done ..save cabinet painting or refinishing.
:.. so I can restore an AC/DC radio completely in about six hours or one evening's time. That includes all electronic testing, troubleshooting and capacitor/resistor replacements as well as removing and washing the tuning condenser, replacing all the rubber gromets and dial restringing as needed and wire brushing or sanding the entire metal chassis. When I'm done it almost looks new.
:
:I am always interested in getting a quick general sense of the "state of health" ( a quick assessment) of the radio..
:So when I first put the new "victim/patient" on my bench I give it a good visual inspection first... but then I simply connect my volt meter to B+ and with my finger on the power switch of the isolation transformer for a quick kill... I power it right up. Full power. ZAP!
:After all without the fear of damaging a power transformer... how bad can it really be? ...lol
:
:Usually... what?...the worst is maybe ..a shorted filter cap sucking hard on the rectifier?
:
:In all my repair experience... so far ...with AC/DC sets the most common problems are found in:
:
: 1.) the electrolytic filter caps... then
:2.) the audio coupling cap to the grid of the output, and
:3.) the audio cap to the detector and the tone cap on the output plate.
:4.) the cathode bypass cap
:
:None of the above are ever catostrophic failures when you are watching the B+ meter and listening carefully.
:
:95% of all these radios came up with merely a severe hum indicating bad filter caps.
:
:So then the next thing I always do is clip out the old filter caps and temporarily tack solder in new ones and re-power ...always watching that B+ meter...
:Usually by this time there is very little left that needs extreme caution.
:
:If the B+ looks good but no audio I start my signal tracing and may find a bad paper cap here and there or an open IF transformer or such.
:So I then go about replacing all the paper caps and checking resistor values, checking plate voltages etc... and so on.
:
:After I've replaced all components very neatly and I know that everything works well... then I pull all the tubes and remove the tuning condenser.... scrub or sand the chassis, wash that tuning condenser and slap it all back together knowing that it was working fine before that last step and if it does have a problem after cleaning it's usually something obvious I've done or mis-wired when replacing the condenser.
:
:Everyone has their own approach... some more careful and deliberate ...others less so..
: I am just a bit more bold in my approach that's all.
:But it works well for me.
:lol
:

Hummmmm.....now let's do the math, either using Reverse Polish Logic or Boolean Al-gee-bra.
That's 75 X $500-1000 = $37,500 <----> $75,000 in the till for mass overseas purchase
shipments of 'zistors and 'pacitors...even some 'ole toobies thrown in !..but wait I forgets to
factor in the IMRON, CENTARI, and Poly-you-ree-thane Enamel finishes, they don't come cheeep.

ROTFLOL...wabogomf!

73's de Edd

:Hummmmm.....now let's do the math, either using Reverse Polish Logic or Boolean Al-gee-bra.
:That's 75 X $500-1000 = $37,500 <----> $75,000 in the till for mass overseas purchase
:shipments of 'zistors and 'pacitors...even some 'ole toobies thrown in !..but wait I forgets to
:factor in the IMRON, CENTARI, and Poly-you-ree-thane Enamel finishes, they don't come cheeep.
:
:ROTFLOL...wabogomf!
:
:73's de Edd
:

EDD... you are 2 phun-knee...

I didn't put all 75 up for $ale...lol
only 12 or 15.
But I've sent Thomas boxes filled to overflowing with old paper caps...
and I've got another good sized box chock full again now.... (anyone want 'em?)
So..Nope.. most of my repairs are still sitting around here on every possible inch of shelf space I have left... and I've been buying more shelves...
I'm definately going to HAVE to start divesting myself of these... if only to make room for more broken ones to have fun fixing... y'know?

Hey, all: I think that we need to cut some slack with the new folks who are just learning (and people like myself who have learned enough to know just how much I don't know!). Reading up on radio repair and educating yourself is necessary, but for someone just starting out, it can be overwhelming. I agree, some problems can be too vague, like a dead radio, but let's give them some direction about where to start looking and some good references to use. My main interest is in keeping my collection of radios up and running, so I don't do nearly the number of repairs that some of you do. My reason for learning more is the result of coming up against a problem that I can't solve. If all my radios kept on working and never needed repairs, I almost wouldn't have a reason to bother learning any more. But, at least one thing is sure with an old radio, it eventually needs a repair! Mark from Kalamazoo

In keeping with all the above, I heartily reccommend the following on the... All American Five ...basic radio theory and repair tips and training outline information.

I studied basic radio theory in US Army Signal Corps school way back in 1963. So last year as I got back into all this as a hobby I reviewed the following text as a healthy refresher.
It will do wonders for all beginners and almost anyone interested in the repair of AA5 radios.

http://www.angelfire.com/electronic/funwithtubes/AA5-1.html
http://www.angelfire.com/electronic/funwithtubes/AA5-2.html
http://www.angelfire.com/electronic/funwithtubes/AA5-3.html
http://www.angelfire.com/electronic/funwithtubes/AA5-4.html
http://www.angelfire.com/electronic/funwithtubes/AA5-5.html
http://www.angelfire.com/electronic/funwithtubes/AA5-6.html

http://www.angelfire.com/electronic/funwithtubes/How_AM_Works.html

Peter;

Thank you, great sight and information.

MMAKAZOO'S

Thanks for your comments they really sum the issue up.
Like others I want to make these radios work again. I have my first radio on the bench now for five months and it still does not work, but you know I understand more now than I did five months ago and in part it because people like you and others took the time to help us instead of kicking us in the mouth like some others. Please continue your efforts.

Dave