#1
While I was on vacation at my river house, I found this thing hiding in a corner under a bunch of stuff. I was amazed at it and I figured I'd try to bring it back to life. I plugged it in and it didn't work, so I took it all apart to see what was wrong, and I'm under the impression all the caps are bad, along with the transformer(s).

I figured I'd upload pictures so you guys could gawk at a piece of tube history.












And these are the tubes I pulled out of it, MADE IN AMERICA TUBES!!!!




So, anybody know where I should start in getting this thing to work again?
#2
If it doesn't work at all (no lights, no heaters) you need to start working backwards from the wall plug. Get out your voltmeter and figure out where the power stops.

If you get lights but no sound, tubes are a good guess.

Those orange drop caps are replacement parts, that's a place to give some extra attention.

Looks like a nice radio. I always like working on tube radios, they just feel old and warm like your grandpa's old leather shoes. Plus, they sound great.
#3
Quote by Roc8995
If it doesn't work at all (no lights, no heaters) you need to start working backwards from the wall plug. Get out your voltmeter and figure out where the power stops.

If you get lights but no sound, tubes are a good guess.

Those orange drop caps are replacement parts, that's a place to give some extra attention.



That's what I was thinking as well, I don't think they had sprauge orange drop caps in the 30's. But they look kinda, naturally molded to the original wire, it kinda makes it look original.

Well, first I gota figure out the order that the tubes went in there, cause they are all just slightly different, and then I know I need a new on off switch for it, cause the original one ceased to continue moving.

Also, the wires going into those tall metal towers next to the speakers, the insulation is all broken and the wire is exposed...
#5
That radio needs a lot of work to make it safe. The rest of the paper capacitors and cloth-insulated wiring should be replaced. As far as figuring out what tubes go where, you need to determine which sockets are for the power, audio, and RF. Don't start a fire or zap yourself!
#7
don't EVER just plug in an old radio like that. if it has an internal problem (extremely leaky filter caps, shorted power transformer, etc) then you can destroy it pretty much beyond repair, and you could hurt your test gear or yourself. you need one of these things (read the heading "Other interesting stuff") :

https://www.ultimate-guitar.com/forum/showpost.php?p=17568094&postcount=6

Other than that, replace all the caps except for the mica and ceramic ones. You might have some bad tubes. If you have a tube tester you could check, but don't go buying one. you'll probably just get screwed unless you know what to buy and what it's worth (and for some reason tube testers hold so much voodoo with guitar players, go figure).
#8
^ Sorry Jim, I actually just plugged it in, after putting in the new tubes, and flicked it on, I had my multimeter out, and I got voltage readings in a few places, but then I started to feel alot of heat so I unplugged it. The three tubes near the speaker and towers were hot, and the two near the channel controls, or the two slots visible in the pics, were dead cold.

I'm not really sure where to start with this thing, it's such a mess on the inside, and I don't know where to find most of these components. I have a bunch of old vintage new parts, like caps, and resistors, but idk if they are the right ones.

I don't think the tubes are bad cause none of them look like they've been used. And I don't' have a tube tester either, just my multi meter.

Should I attempt to replace all the paper caps first?
#9
the "towers" are RF transformers. as for where to start, replace all the paper and lytic caps. basically all caps except any ceramic or mica types, as these rarely go bad. looks like there's at least 1 multi-section cap in there (probably the supply filter cap). this DEFINITELY needs to be replaced. you can use individual discreet caps. you dont have to track down another multi-section.

and don't use old caps. the less you use lytic caps, the faster they go bad (this is why you should let your vintage gear sing for an hour a month). modern replacements will work just fine provided they are close enough to the original ratings (cap values in particular are non-critical). as for the PSU, watch out for the filter cap rating. it is usually around 20uF and that is all you need. this isn't like SS circuits where you can just slap in the biggest value you can find. too high a value puts stress on the rectifier tube. bad filter caps also put stress on the tubes.

also check to see if the tuning cap is shorted anywhere. use an ohm meter on the rotor and each individual stator and rotate the cap along its full travel. it should show an open circuit the whole way. you may want to check the padders too (they are the screws on the sides) to see if the mica insulation is broken or open anywhere (it probably wont be).

another thing you should do is check the resistors. see if they are out of tolerance. those old carbon comps are real bad about drifting. and they always drift upward. if any are over or under 10% of their rated value (read the color codes) then replace them.

lastly, you'll want to rewire the mains input. this set has no power transformer so that means this is an AC/DC set (it works on 120v AC or DC). as a result there is no isolation between you and 120v in the wall (hence the plastic case and plastic knobs). you'll want to at least rewire it for a polarized line cord and modern switch/fuse wiring. those old things have a non-polarized cord and one wire is fused while the other is switched. this is very unsafe. even better, you could see about getting an isolation transformer for it (you may not be able to fit it in there though).

for more info about electrical safety and grounding and such, head to the wiring thread and re-read the post i linked earlier.

and if you trust me, you can ship me the tubes and i'll test them for you, free. i have a tester (link) and it can save you a good bit of money on tubes if these turn out to be good.

obviously it's a bit of work but that's why we do it. it's fun.
Last edited by Invader Jim at Jun 7, 2011,
#10
This looks pretty cool. I, too, will be keeping an eye on this, and I wish you luck.

Can't give you any advice because I'm useless with electronics and following any of my advice will probably kill you, so sorry. But I'm interested in this nonetheless.
LOOK

Call me Neutral.
Quote by da_
I wonder if you get more out put if you wire a battery to your penis.
#11
Mmm, I see vintage paper and oil caps
Last edited by Seref at Jun 7, 2011,
#12
I don't mind shipping you the tubes Jim, I'll PM you about it it a little bit. But your going to have to point out in the picture what all the different caps are, cause I'm not sure. I'm guessing the multi wire cap is the big paper one with several wires coming out of it.

I think the RF towers are bad, cause all the insulation on the wires are gone, and the wires look like they are...well, rusted. I'm guessing I'm going to have to remove and replace everything one thing at a time as to not mix anything up.

Know any good places to get parts for something like this?
#13
Quote by ethan_hanus


And these are the tubes I pulled out of it, MADE IN AMERICA TUBES!!!!


Where are they usually made? I love the look of this old radio. It's interesting the way the dial gives you frequency and wavelength at the same time lol (well interesting if you're a sad git like me)
EH


"Show me war; show me pestilence; show me the blood-red hands of retribution..."
#14
Quote by eddiehimself
Where are they usually made? I love the look of this old radio. It's interesting the way the dial gives you frequency and wavelength at the same time lol (well interesting if you're a sad git like me)


Modern cheap ones tend to be Chinese. For older tubes, it's usually easier (and cheaper) to find Russian ones. Old American tubes can cost quite a lot.
#15
Quote by eddiehimself
Where are they usually made? I love the look of this old radio. It's interesting the way the dial gives you frequency and wavelength at the same time lol (well interesting if you're a sad git like me)


Russia or China, there are several custom home made tube makers, but those are mainly like, local things.

I think they stopped making tubes in America in the early 70's or something like that. America doesn't make anything anymore, we just buy other peoples stuff.
#16
Quote by ethan_hanus

I think they stopped making tubes in America in the early 70's or something like that. America doesn't make anything anymore, we just buy other peoples stuff.


How do you think the UK feels. actually speaking as an Engineer i would say that we do make more stuff than people give us credit for here in the western world. Sure we can't really compete with the cheap labour rates of china and taiwan but there are still a surprising amount of products that can still viably be made in the US and western europe. Just not valves.
EH


"Show me war; show me pestilence; show me the blood-red hands of retribution..."
Last edited by eddiehimself at Jun 8, 2011,
#17
Quote by eddiehimself
How do you think the UK feels. actually speaking as an Engineer i would say that we do make more stuff than people give us credit for here in the western world. Sure we can't really compete with the cheap labour rates of china and taiwan but there are still a surprising amount of products that can still viably be made in the US and western europe. Just not valves.


I've always found that anything made in the US, the UK, Japan, Germany, Netherlands, Switzerland, and the such, have always been great products that last and last and last.

The US no longer processes steel, which has practically destroyed our independence from other countries like China and made us dependent on other countries who do make steel. Not to mention it killed alot of jobs. Soon light bulbs will no longer be made in America simply because they think they are outdated.

There's not much made in America, but what is still made in America tends to be 10 times better than what's not made in America or any other western country.

I have a vacuum cleaner from the 1950's that still works like new. Also have one of those old push mowers, with the blades, that you push and it cuts grass, rusted all up, but still works perfectly and smoothly. That's how good we used to make stuff.

/rant.
#18
^ I agree. I have plenty of old stuff lying around that is still as good as it was when new.

anyway here are the labled pics.

http://i51.tinypic.com/9tiwkk.jpg
http://i54.tinypic.com/dddmh0.jpg

Quote by Seref
Mmm, I see vintage paper and oil caps

Paper caps are utter garbage. they are much less reliable than even electrolytics.

Quote by ethan_hanus
I don't mind shipping you the tubes Jim, I'll PM you about it it a little bit. But your going to have to point out in the picture what all the different caps are, cause I'm not sure. I'm guessing the multi wire cap is the big paper one with several wires coming out of it.

I think the RF towers are bad, cause all the insulation on the wires are gone, and the wires look like they are...well, rusted. I'm guessing I'm going to have to remove and replace everything one thing at a time as to not mix anything up.

Know any good places to get parts for something like this?

if the RF transformers are bad then you'll have alot of trouble finding replacements unless they are spec'd on a schem somewhere (the schem is usually on the cabinet somewhere). they are wound with enemelled magnet wire so they probably have insulation, but it is clear so you cant really tell. you can use an ohm meter to check for continuity in the coils.

doing it one part at a time is a very good idea.

this site should help alot for parts.
http://www.radiodaze.com/

looks like they are in the process of moving it here:
http://www.radiosupply.com/
Last edited by Invader Jim at Jun 9, 2011,
#19
That one little cap that you pointed out near the transformer on the right, that looks kinda hidden, idk if that's a cap, cause it's hollow tube, with that black ring around it looking like a wrap of wire or something.

The RF transformers do have some markings on them. The small one reads 8PT 586-9 And the big one reads 8PT 587-9.

I think I'll start with the multisection cap since that site you provided actually sells them. So I'll just snip the wires in half so I can remove it while knowing where each wire still goes.
#24
ah, i see it now. if it was an aux in, that'd be kinda cool. but turning a radio into an amp is pretty much impossible without rebuilding it. i had an old table radio (pics in my profile) but i got crazy with improvements on it and it broke so i built basically a pentode-based Champ out of the parts and stuck it in the same cabinet. Never got it to fully work though. But i kept the clockworks. those old synchronous motors last forever and have better long-term accuracy than crystal oscillator-based clocks of today.
Last edited by Invader Jim at Jun 11, 2011,
#26
the transformer is physically attatched to the speaker? then un-attatch it

it's not hard to remove the OT if it is part of the speaker assembly. if it is connected with tabs, bend them up. if it is rivetted, drill out the rivets.

you'll figure it out.