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Philco 37-610 tombstone restoration
#1
Hi everyone, my name is Manuel and I am from Spain, I like to restore old things but never tried with a tube radio, in one of my trips to the USA I found a 37-610 in poor condition, chasis full of rust, missing knobs...it made all way to Spain and now I am restoring it, hope to make a good job and bring it to life and that you can help me to do it since is my first radio restoration. I will post Photos soon, I think it was recaped at some point parcially with aerovox wax caps, the schema I have is correct I think by the code but also I found an extra bakelite cap that Does not show in the schematics, this is usual?
Best regards from Spain
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#2
Hi Jeepeto and welcome,
A good pic or two of the bottom of the chassis will tell the tale of what's been done to it. It's a relatively simple set to service however it does have chassis in chassis design along with just about all of other 1937 and 38 models.

GL
"Just because the microphone in front of you amplifies your voice around the world is no reason to think we have any more wisdom than we had when our voices could reach from one end of the bar to the other"     Ed Morrow

Terry
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#3
Hola Jeepeto y bienvenido a nuestro Phorum!

As Terry just said, illustrating your questions with pictures always helps.
if you have never restored a VERY old tube device, the first rule is: don't plug it in and see "if it works". Chances are, it doesn't, worse yet, it might go up in smoke, and there's a little chance it still might "work" but it is very dangerous to use it that way.

The single unpleasant thing in these radios is the RF subassembly, but this is a simple radio and so the RF sub is simple too.

Mike.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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#4
Thank you for the advice, never pluged it as it had the power cable cut, and the electrolytics cans were looking nasty and leaking some kind of acidic stuff that corroded the chasis. Not a plug and play radio indeed Icon_smile
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#5
Testing photo upload...


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#6
This is the "insulation" of the transformer, many wires are like this or are like glass when I bent them


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#7
I bought here some meters of cotton braided wires of different colors to replace all wires, also I have some NOS URSS film capacitors, resistors... The rule of 20% tolerance is for all components or just for resistors? Also I have some new MKT capacitors but with voltage rating in AC (275vac) the old wax ones are 600v in DC I think, The guy in the electronics show told me that equals to 600dc volt rating, is true or I have to search 630v capacitors? Thanks and sorry if I ask something stupid
Cheers
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#8
Let me see what a can answer for you.

<I bought here some meters of cotton braided wires of different colors to replace all wires

Good move. Two things to consider. Rating of the insulation as your set has about 300vdc running around in it. On the power transformer the two hv wires have about 700vac between them. The other consideration is the gauge of the wire. Needs to be able to pass enough current for the heater circuits. General recommendation is 20ga. I just mention these in passing your probably fine with what you have purchased.

>The rule of 20% tolerance is for all components or just for resistors?

When the set was made 20% was what used. Now days resistors 5% or better. The foil/paper caps I wouldn't both to test just replace. Micas I would leave alone unless there is a problem.

>The guy in the electronics show told me that equals to 600dc volt rating, is true or I have to search 630v capacitors?

The AC rating is about 1/2 of the DC rating so you should be ok.

<many wires are like this or are like glass when I bent them

Generally I don't go out of my way bend wires as they are brittle. On the later Philco models (1939-42) and a lot of other models rubber covered wire was used. The rubber coating turns to dust when looked at funny or touched. These set usually require a good bit of rewiring to get them back in good order.
When rewiring be carefully about wire placement as some wires don't get along being near others. In other words layout can be critical. It can cause some circuits to not function or oscillate. Take pics and notes on the original wiring. Some folks will try to "neaten up" the wiring by rerouting some wires only to have caused problems in the end.

> electrolytics cans were looking nasty and leaking some kind of acidic stuff that corroded the chassis.

Some will have a white powdery stuff at the top and or bottom. As far as I know it's not particularly caustic washes off with a little soap and water.

GL
"Just because the microphone in front of you amplifies your voice around the world is no reason to think we have any more wisdom than we had when our voices could reach from one end of the bar to the other"     Ed Morrow

Terry
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#9
Thanks Radioroslyn, this hobby is new for me, any help is much apreciated, never heard about the rule of Ac/DC capacitors, very good information! The gauge of the wires is 20, is used in vintage tube amplifiers, should work fine, and every wire I remove I measure it and cut new one same lenght, and route it same place of the old, but I think some Were changed of place because of the recap, hope not and will work fine. I am starting with the tunning condenser sub assembly to remove it and let me clean and give me more space. The electrolytics are dry but one I removed from the sub assembly is half with liquid, hope this is normal and this not mean has been submerged in water Icon_smile the mica I have been checking are within value but many resistors not, can I change the watts from 1/2w to 1 or 2w without issues? 1/2w looks very small and "modern" and want to make it as close as possible in my possiblities to original.
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#10
> can I change the watts from 1/2w to 1 or 2w without issues? 

Yup not a problem just not the other way not lower in wattage.
Typically after a major overhaul like this when you get it done you'll need the realign the various stages. It's not hard but you will need a rf signal generator to do this job. It can make the difference from a set barely working to work great.
"Just because the microphone in front of you amplifies your voice around the world is no reason to think we have any more wisdom than we had when our voices could reach from one end of the bar to the other"     Ed Morrow

Terry
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#11
Thanks, all resistors I have new are 1/2w and up, the old ones have a strange color code, philco had own code?
Today I will keep cleaning tunning assembly, I am going to paint chassis after derusting, hope this way will look close to zinc platting and preserve it for future restorers.
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#12
Philco resistor color code explained:
http://www.philcoradio.com/phorum/showth...?tid=14966
--
Ron Ramirez
Ferdinand, IN
Я этого не понимаю
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#13
Today I removed the power transformer, I must re insulate all with Heat shrink and glass fiber jacket, the bakelite capacitor have a sprague that looks suspicious, maybe for simulate the twin bakelite? By the way Ron, Thanks for the link, now make sense the resistors Icon_smile


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#14
Transformer done, new insulation and a light coat of varnish to preserve it, also I applied liquid tape where the wires come out just in case, hope is correct to do this.


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