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I've been fiddling a bit w/ 3 TF radios over the holidays to see if something might be done here
first I had to get a power source happening - a friend gave me an antique battery charger awhile back that had been the "base station power" for the search radios on the ski hill for ages, so I overhauled it , and it works [Nix may recognize it ] - radio manual sez current draw is 2.5 amps and fuse should be 7.5amps, so I figure a 5 amp charger should do perfect! I'll consider it a Christmas present from Andy

next scrounged the parts stash and found an original speaker w/ the wires, complete w/ original connectors, that need fixin - ok ....

for you TF guys, this pic shows the wires , this one shows the guts front and back , with tubes labeled - here's one of the 3 vibrators I\'ve got - the 'original' came from a radio I'm almost certain has never been opened, the 'replacement' came from #2 which was from the radio repair shops panel truck, which has obviously been messed with, the solid state one I bought years ago to get the 3rd radio working [all it took until I let the smoke out]

got the first radio hooked up [unmolested original], and the vibrator vibrates, tubes light, speaker up to the ear gives the faint hum of the vibrator - no antenna handy [2, but on the trucks] - should still have some noise even w/o an antenna??

on to number 2, the one from the radio truck that I was hoping might work - seems to have been smucked on the volume switch [prolly dropped ] which pushed the switch back out of the threaded piece and broke 2 wires loose! - got the switch back together and it feels like it still works - need to figure which terminals the wires go to and solder them back [vibrator from this radio vibrates installed in #1 and 3]

# 3, the one I smoked some time ago, vibrates, but most tubes are so black [internal] that they may be fried - only saw any glow in one, tho I will let it cook awhile later to see which get warm - don't see any obviously fried components, but there hasta be, as it did quit in a cloud of smoke

so what's next Nix? I think the best bet is to fix the wires on #2 and see what it does - do I hafta have an antenna hooked in? maybe just a coat hanger? seems to work on some ratmobiles ya see around whose antennas have gone on to being zip guns

red58,
those are great shots. I think that the battery charger looks familiar, good ol Canadian tire! We now have our first radio bench photo!

To start with, we have a radio that has all lit up tubes, speaker hooked up and a running vibrator. (It is a good idea not to use a solid state unit for troubleshooting a radio that may have other problems)

It is usually necessary to provide some antenna input. This can be done with a length of maybe 2' of hookup wire, any convenient gauge. Bare about 1/4" and insert the bare portion into center of the antenna socket. If the radio is going to work right off, this should make a difference.

Failing success, the next step is to see if the power supply in the radio is producing DC power. From the circuit diagram, we see that there should be +250 V Dc from pin 8 of the OZ4, to ground. Now to measure this, set your meter on DC, full scale of 300 V Dc or more, clip one lead on the chassis and touch the other meter lead (not your finger!!) to pin 8. Now, when looking at a tube socket from the bottom, you will see a set of pin contacts around in a circle. There is always one space in the circle. The first pin from the space going counter clockwise, is pin 1. The pins are counted off counter clockwise from there.

I will wait to find out what results you have from these two steps.

For a little explanation here, pin 8 on the OZ4 is shown as "K" for the Cathode. This tube is a rectifier, also known as a full wave rectifier. The output of the power transformer presents a sinewave across the "P" pins, 3 and 5. For one half of the cycle, pin 3 goes positive and the cathode emits current across to it. On the other half of the cycle, pin 5 goes positive and current flows from the cathode to pin 5. At no time does current flow in the opposite direction. Because current flows on both halves of the cycle, this is a full wave rectifier circuit. This current is also charging the capacitors 18A and 18B, that are connected off of pin 8.

I went to visit my parents this weekend and took the old TF radio with me that I got cheap off eBay (guy had no idea if it worked). My dad is an electronics guru and I figured it would give us something to do. Thanks to red58 I was able to get the wiring diagrams and figure out that I was missing the OZ4 tube. My dad knew someone that had a colleciton of tubes so we drove out into the sticks to see him (and to look at his 1916 Commerce truck under restoration - cool truck). Anyway the guy had a complete set of tubes for the radio (but no vibrator). He wanted $9 for the lot so I gladly paid him $10 and off we went.

Back at my dad's I swapped out all of the tubes and we hooked it up to a fused car battery. Also hooked up an old speaker and 6" attenna wire. Unfortunately we got no sound. Next we made few checks of the pin voltages here and there. Everything looked fine. Then as I was moving the tuner around I thought I heard the faintest of voices on the speaker. My dad held onto the end of the attenna wire and presto! out came Johnny Cash with "A Boy Named Sue". I couldn't have been happier.

Now with a longer attenna wire I've been lsitening to the radio all weekend! I can only bring in two stations but I am in rural Arizona where two is probabaly all they've got.

Can't wait to get it into my truck.

Greg

great news Greg! what a treat nice to know about the antenna, and ya caught a good tune to warm that thing up!
now if I can find someone around my area w/ a stash of tubes ....

gotcha Nix - it's been pouring all day here and I don't feel like gettin soaked goin out to the shed to get the rest of the electrical collection but I'll do some more tomorrow and get back - I'm tryin to get a collection of pics 'for posterity' - maybe there can be a tech tip eventually for the TF radio

Bill

groselle,
doesn't it feel great to revive one of those? I find it hard to turn it off and walk away after! Sometimes there is quite a big difference in reception between a piece of wire and the real antenna. Also if you are working in a basement, the signal strength may be greater on the first floor.

That's a great story, Greg! And what a perfect "first song" to hear ... Johnny Cash is the greatest.

PS - And I dated one of his daughters when I lived in Nashville, too!

well, did some more - tried the 1st one again and let it sit on for a few minutes to warm up - must not have let all the smoke out before, but did this time!

unplugged it and removed the cover on the underside of where the power transformer is [where the smoke came from], and found a large capacitor that seemed to have been dripping it's wax on things, one small resistor pretty black, and a larger one w/ an end that may have gotten overheated - pic here - ok for that one, found the smoke hole, hafta refill it!

next I moved to fixing the broken wires on #2 - turned out all 4 wires on the bottom were off as well, looking like they'd had cold solder joints so just 'popped' when the the thing got pushed back - got\'er fixed up , and took off that power section cover to check, and it looked ok

so hooked it up and tried it - same with vibrations, slight speaker hum, no sound - checked the voltage on the OZ4 and found about 250V on 3 pins as per the book - didn't go further because that was about the 5th time I thought "I'm really glad I decided 40 years ago I didn't wanna spend my life doin this!"

this one had a couple tubes that didn't look lit, so I think I need to find a tube checker next, which might not be found nearby - did find a few xtra tubes in a bag w/ the rest of the radios shown in another post here, will look at'em tomorrow

Bill

Bill,
it sounds like we are making some good progress. Let's talk about the radio that almost works, first. Because you have several radios, you can probably come up with one set of working tubes. All five tubes except the OZ4 have heaters and they should be warm or hot to the touch. To check the heater in each tube, pull the tube out first. Next, look at the circuit diagram and locate the two pins marked on the diagram as "H". Using your ohm meter, take a reading between the two pins. You should get a low reading of a few ohms. If you get an open reading, the tube is burned out. You don't need a tube checker for this. There are some more tests that we can do after you have five tubes that light up.

Regarding the radio with the smoke, this is typical of what happens when the capacitors get old and start to short. Not only will they sometimes leak, they will also cause resistors to burn or fail. The normal procedure in restoring radios is to replace all the capacitors from the start. Here is a link to the supplier I use for capacitors, and also schematic diagrams.
http://www.justradios.com/

ok - checking that site I suppose I should get up a list of the paper capacitors and replace'em all - maybe even all 3 radios seeing I have 3 trucks any CDN scources of tubes? are any of the tubes even still made? not too interested in dealing w/ ebay, but I guess I could look there for a supplier

I checked the bag and it turns out there's 4 OZ4's and another vibrator - don't recall where they came from but I must have gotten them w/ one of the non-TF radios I picked up

Bill

Bill,
as far as the capacitors go, if you are going to replace them, you should do them all, and that supplier handles them all. They have a little guide section that talks about the different types that are available. I can help you out with the selection.

Tubes: I normally shop on Ebay for tubes. If you do a search for each tube number on Ebay, you will get results for each one. If you scroll down past the list you will see Ebay stores that carry them. These stores have a fixed price and there is no bidding involved. The tubes seem to sell for very reasonable sums, some less than $2.00 . If you prefer to buy elsewhere, doing a Web search for "radio tubes" brings up a long list of suppliers, some with NOS tubes, some with new tubes and some with used tubes.

In my opinion, an NOS tube is no better than a used tube that is in working condition. An untested NOS tube may have lost it's vacuum and would then fail immediately. Used tubes that test out to be working properly are a good buy. However a tube tester does not tell you whether the tube will perform properly in the circuit.

There are some tubes being manufactured new, but these are mostly for the amplifier market. There are tubes being made in Eastern Europe, so I understand. For me, I'd rather buy several used tubes at a low price than one NOS tube at a higher price. I have not tried to buy new tubes.

Alan,
and that is a great story! To have dated the daughter of such a legend is really something. I always enjoy his music and it carries great memories of the man performing. He never got "reinvented" like modern artists sometimes do when their managers think they aren't making enough money.

When I was working on radios in my early teens, one of the checks was to adjust the trimmer using a station in the upper part of the band. For me that station was CFGM, 1310 and it was all country music. I got a good grounding in that style of music, at the time.

well I got one step further along - checked w/ a shop here that has been around since about 1960 - knew that the sons of the original owner still ran the shop and they still work on modern TV and stereo equipt as well as marine stuff

got the resistors and half the capacitors off the shelf [new style, correct voltage] and the "kid" [in his 40's] is gonna dig thru the boxes in dad's basement where the stash of tubes and other seldom used parts are for the rest on the weekend

he also sez dad has some old car/truck radios, and they'd like to sort some of the parts & stuff and weed out a bunch, so I foolishly offered to take the lot if they don't want too much for it

gonna pick one of the 3 to do for now, and if it get's goin might get the parts to do the rest - the project continues!

Bill

I pulled the front and back of my radio off. I hooked up the battery to it to see if there would be a hum. Yep, got a hum. That was good to hear.

Maybe this old radio will come to life.

The problem I found was the volumn control is broke. I was messing with the center and it pulled out of the body. And it took a little playing with to get the on/off snap. I may need a new one.

Does anyone have a parts radio that I could get one from? Or a source to buy one from? I noticed that there was one on ebay about a year ago but did not take advantage of bidding on it. Darn.

oldbluetruck,
what year of truck radio do you have there? I do have some parts radios and I may be able to fix you up. Are you saying that the shaft pulled out the front?

By the way this is not a sales attempt. I hope that we can demonstrate here how to fix a common problem.

Truckernix,

I am trying fix a radio. Like you said - this is not an attempt to break any rules or get in trouble with the forumn police. Please, take that into account.

I have a 55-59 chevy radio.

And yes. The shaft pulled out the front. on the back side of the shaft it is square. If I get a new control I would like to take it apart and see if the shaft broke or if it is loose by some other fashion.

Thanks for the reply.

oldbluetruck,
I will look at my collection when I get home tonight. From the schematic diagram, I cannot tell the resistance value of the tone control section. If you have an ohm meter, please measure the resistance between the outer two tabs on both sections. I will look at some of my other references to see if I can determine the value.

Fred

Dennis - from my experience w/ a damaged control on one of the TF radios I'm dealing w/ I'd say yours is toast - would advise NOT trying to take a good control apart to that point, as it's likely you'd not get it back together to be functional - of course if you open the can on the one you have you may find that it is fixable, but you'll have to unsolder it and remove from the radio to try that

Bill

Bill - I am with you on this one. I think the volume/tone control is toast. The center shaft snapped and will only work to turn the radio on/off with major monkeying around.

Not good on a bouncy truck.

I need to find a good used one or new. I wonder if the guys that buy these old radios for the carcasses save the AM guts? That would be a good source for us restorers.

Dennis

oldbluetruck,
I have a control that is a match electrically but the shaft length is different. Now, if you would like to try replacing the shaft and bottom end with the same from this one, I can mail it to you and then I can guide you through the procedure. These controls are quite simple to work on. The ones in the AD truck radios are a little bit harder to work on.

Basically each stage is attached with several little tabs. To take it apart, once the control is removed, you just start from the front and disassemble it. It goes together in the reverse order and the tabs are good for about two or three repetitions. In an emergency, JB Weld does a great job!

Let me know what you think.

Fred

Fred,

If it is no trouble I would like to take you up on your generous offer. I would like to replace the volume/tone control. From there I can move on to possibly checking the electronical guts of the radio. Or the radio may just work and life moves on.

Thank you very much.

Dennis

Dennis,
I think that I struck gold tonight. I found what I would describe as a perfect replacement for your control, on one of my old parts radios. The shaft length and everything else appears to be correct. So, what I would like to do is mail it to you, no charge and when you have it installed, you can mail me your old one. Then I will do a photo essay of the repair of the control. If you Email me your address, I can send it off within the next few days.

Fred

Fred,

You have an email coming. Thank you.

It would be nice if you could repair the control. We could all learn from the experience.