Beemon

1956 Sonomatic Restoration

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I think I've bit off a bit more than I can chew here. I've seen some threads indicating that some of you have done work on these in the past, so here goes.

 

Before I did any troubleshooting, I did a lot of research and replaced all the wax and electrolytic capacitors with modern replacements. I checked all capacitors before installing and all were good. The only difference in soldering is that I routed one capacitor to a different ground state. I then went through the circuit and checked every 1/2W resistor to 10% of their resistance values based on the schematic in the shop manual. Everything checked out. One 360 ohm resistor broke so I made a new one from a 100 ohm and 270 ohm resistor and routed them in series. The electrical difference between the two read 360 ohms after soldering. I even checked all mica and ceramic capacitors, which checked out via shop manual.

 

So here's where I'm stuck. My next step, I fired it up. Nothing. Unplugged and pulled the vibrator. I crimped the can back so I could pull it out. Contacts are free, but very cloudy. I used a burnishing tool to clean the contacts, hoping it would work. Put it back in, fired it back up, nothing. This time I took the multimeter and traced the schematic. All heaters check 12VDC, both connectors on the vibrator dock check 12VDC, and two of the three connectors on the OZ4 dock read 12VDC the two pins for the OZ4 that read 12V come straight from the transformer - the third goes to the electrolytic capacitors. The vibrator is still also silent. I then checked for AC current at the vibrator - nothing. AC current at the OZ4, nothing. No surprise because the vibrator didn't want to fire, but wanted to make sure it wasn't just quiet.

 

I should note here that the tubes seem to be ok - they all light up, are a soft glow and there is no indication of damage or loss of vacuum (I was told they would be a hazy gray).

 

So what's my next step here? I'm really a novice, the extent of online tutorials go so far as "replace wax caps, you're good to go". I want to say the vibrator contacts are oxidized to the point where they are not working properly, but I'm also curious about the OZ4 tube. is there a surefire way to get the vibrator vibrating again (a way to clean out the oxidation)?

 

Enjoy some pics of my sub-par soldering attempts:

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15540817_10155810508725830_4698107915085

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17 minutes ago, Beemon said:

The vibrator is still also silent.

 

Thats your problem. The vibrator should buzz. If it doesn't, you don't have AC, and current has to alternate for transformers to work, so you have no high voltage as a result. 

 

Vibrators are touchy. They are the weak points (HA!) in these radios. Starting the car with the radio on can cause them to seize up. 

 

There are solid state alternatives. If you really love AM radio that much, at least convert the vibrator to solid state.  Then you can troubleshoot from there (although shotguning the caps first probably fixed any other issues downstream).

 

http://www.tech-retro.com/Aurora_Design/Accessories.html

Edited by SpecialEducation
Added link to solid state vibrator. (see edit history)
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Only 2 out of the 11 caps tested positive so they needed to be replaced.

 

That's what I thought about the vibrator, but when I opened it up, it was covered in some type of rubber sheath so I thought it was silent running or something. Where can I find the solid state vibrators? I'm a bit iffy on solid state anything really because the last two solid state products I tried left me stranded somewhere.

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Did I ever share photos of the last Sonomatic I worked on?

 

Still having upload issues, but here's a few...

 

IMG_0689.thumb.JPG.aeeb72c2ab45829f7ac74dfd27e57af3.JPGIMG_0691.thumb.JPG.cb4ba2db7f8ab350e9dc3f0e65d4880e.JPGIMG_0698.thumb.JPG.b046b02d1453691eb4aa7929ce500653.JPGIMG_0774.thumb.JPG.b0db752eb06ed00f7bae937edcfd3d72.JPGIMG_0784.thumb.JPG.bb50b8b5c6bdcb59d84f92bec93d2971.JPGIMG_0821.thumb.JPG.86447fb763a71f2959a6ec2d690286c5.JPG

 

Don't fret too much, we still have 2 with tubes in them...

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Pretty interesting setup, how did you set the tuner dial? Or do you do that from under the car?

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36 minutes ago, Beemon said:

 I'm a bit iffy on solid state anything really because the last two solid state products I tried left me stranded somewhere.

 

Oh, no. Mechanical vibrators are junk. Watch the video on the page I linked to above. He goes through all the things that would toast an old school vibrator, and the VBx-1 doesn't miss a beat.  It's the only thing I'd consider buying. 

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Oh yeah, I did some reading on the Aurora products - you can only buy them from vendors, and the vendors I've talked to have said "we'll convert it for $150 assuming it's already working".

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18 minutes ago, Beemon said:

Pretty interesting setup, how did you set the tuner dial? Or do you do that from under the car?

 

I feed it with my iPhone. I'm using the power switch in the left knob to turn it off & on. I was going to wire in the volume control, but ran out of time before nationals and haven't pulled it out to finish it yet. I just control the volume with my phone. 

 

8 minutes ago, Beemon said:

Oh yeah, I did some reading on the Aurora products - you can only buy them from vendors, and the vendors I've talked to have said "we'll convert it for $150 assuming it's already working".

 

$25:

http://www.vintagecarradio.com/accessories/accessories/vbx-1-electronic-vibrator/

Edited by SpecialEducation (see edit history)

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Thanks for the link Matt, I guess I was just looking in the wrong place. Going to go ahead and order it later tonight if I can't get the oxidation off the vibrator points. I'm still a bit skeptical, but I have seen the videos. I guess that's the difference between made in the USA and used to be made in the USA.

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 The gentle buzz of the radio vibrator while you are waiting for the radio to warm up......................Priceless!

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Thanks EmTee, been hiding this from the girlfriend since I've had the radio out.

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18 minutes ago, Bhigdog said:

 The gentle buzz of the radio vibrator while you are waiting for the radio to warm up......................Priceless!

 

I have a friend who bought a '57 Chevy back in the '80s. He was going through everything, figuring out what worked & what didn't.  He turned on the radio, and it hummed but played no music. He cranked it all the way up; nothing. 

 

He turned his attention to something else for a moment, then POW!  He was blown away with music!  

 

He felt kinda silly not thinking about the fact that it was a tube set. 

 

By the way... those OZ4s are usually pretty solid, but after you start making AC you find that you aren't converting back to DC, you can easily make your own low cost replacement solid state rectifier with a resistor and a couple diodes. 

Edited by SpecialEducation (see edit history)

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31 minutes ago, EmTee said:

OK, once you have the vibrator sorted you can graduate to the following thread.

 

Which is EXACTLY why I clearly said "RADIO" vibrator in my post. .............Bob

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so hey, neat little trick. I took a spare wall outlet plug, connected one wire to a light bulb socket with a 40 watt bulb and ran that to the small pin on the vibrator, while running the other wire straight to the large pin on the vibrator. Read about it on a radio restoration forum. The vibrator came to life and started lighting up the bulb! I guess you need to run it for about 30 minutes or until the brilliance of the bulb is the same if you just wired it in by itself. This destroys the oxidation on the points and I guess rejuvenates the vibrator. I'm curious, however, as I would think both pins would work but only one of the two large pins activates the vibrator.

 

After an hour, with no improvement, it's safe to say the vibrator is dead. I've ordered a solid state chip, so we'll have to see how that goes. Was kind of hoping the vibrator would work, was looking forward to the hum.

Edited by Beemon (see edit history)
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8 hours ago, Beemon said:

was looking forward to the hum.

 

Well, you could always reinstall your old differential...  :wacko:

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12 hours ago, Beemon said:

so hey, neat little trick. I took a spare wall outlet plug, connected one wire to a light bulb socket with a 40 watt bulb and ran that to the small pin on the vibrator, while running the other wire straight to the large pin on the vibrator. Read about it on a radio restoration forum. The vibrator came to life and started lighting up the bulb! I guess you need to run it for about 30 minutes or until the brilliance of the bulb is the same if you just wired it in by itself. This destroys the oxidation on the points and I guess rejuvenates the vibrator. I'm curious, however, as I would think both pins would work but only one of the two large pins activates the vibrator.

 

After an hour, with no improvement, it's safe to say the vibrator is dead. I've ordered a solid state chip, so we'll have to see how that goes. Was kind of hoping the vibrator would work, was looking forward to the hum.

Have you checked the transformer?  Or substitute a known good 0Z4.  You demonstrated that the vibrator needs a load to work.  Most good working vibrators will give trouble free service if used regularly.

Years ago I heard of the now common electronic solid state vibrators.  I forgot the name and terminology when I asked a friend where i could get a vibrator substitute.  After a long puzzled look he said that a vibrator IS a substiute. :D 

If you want I can look in my 'pile' for serviceable parts.

 

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The vibrator circuit with the AC wall socket at 40W bulb energizes the coil, not the contact points, so it forces the vibrator to vibrate. They say you should run it for about 30 minutes or until the light bulb shines as bright as a complete lamp circuit. That's when the contacts are clean. My vibrator never got bright after an hour, which is usually indicative that the points are too far gone. I consoled with my uncle, who drove the car from 75-78 to and from college, and he said the radio had stopped working somewhere between there. So at some point, the original vibrator eventually wore itself into the ground. The radio guys say it either works or it doesn't. I would like to have an original vibrator to run the radio, but I've already ordered the solid state unit. In the vast amount of 55s, a 56 and some 57s in the junkyard close to me, I don't remember the radios being pulled out, so maybe I'll go salvage some tubes and vibrators from those old radios.

 

The vibrator in the radio, based on the wiring diagram, has the coil grounded to the case and is energized by the contact points. It's energized by the on switch, so I can't test the 0Z4 until after the vibrator is replaced. If I get the vibrator installed and the 0Z4 doesn't work, you can make a solid state unit by using two 3W 220 ohm resistors in series with two 1N4007 diodes rated at 1A 1kV, where you wire both diodes and resistors from the 3 and 5 pin respectively to the 8 pin, while the 1 pin is grounded to the shell (in this case, the 0Z4 can).

(3)---/\/\/\/----|>|---(8)---|<|----\/\/\/\---(5)

(1)---[shell]

 

like that. I got that off another website, so credit is not mine on the schematic, but it seems to be the go to setup.

 

I'll take you up on your offer, Willie, if the solid state vibrator lasts just as long as my solid state ignition system, or if all the vibrators at the junkyard don't work out. Thanks for offering! I guess my progress will be updated in 3 business days.

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Might want to give Alan J Kriss a call. He's always happy to talk and help when able...........Bob

Alan J. Kriss

416 Norris Brook Road

Middlebury Center, PA 16935

(570) 376-3952

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Reading through this thread...feels like I am in Japan all over again trying to break through the language barrier:blink:. When I removed my radio from my car a few months ago, I hooked it up to my battery and got nothing.  Of course, not understanding these old radios need time to warm up, I just assumed my radio didn't work.  How much diiferent are the radios between the 55 and 56?

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I'm thinking I need to go out to the garage and throw a battery in my '56 Bel Air which has been sitting idle for the last 25 years.  The radio always worked great -- now I wonder if it still does...  :huh:

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6 minutes ago, Kosage Chavis said:

Reading through this thread...feels like I am in Japan all over again trying to break through the language barrier:blink:. When I removed my radio from my car a few months ago, I hooked it up to my battery and got nothing.  Of course, not understanding these old radios need time to warm up, I just assumed my radio didn't work.  How much diiferent are the radios between the 55 and 56?

 

Internally, the basic tubeset radio principles are the same. In 1956 alone, there are 3 different circuit designs, but the need & method to make high voltage AC (225-250v) and rectify it back to DC is the same.  The vibrator should buzz loud enough to be heard, because it's a mechanical device that converts 12vdc into square wave AC. It should take 30-45 seconds for the plates to warm up. 

 

Also, the capacitors don't last long if they sit unused. Replacements are cheap & easy, but a shorted cap can damage other things.

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8 minutes ago, SpecialEducation said:

In 1956 alone, there are 3 different circuit designs

 

The shop manual only shows 2 - one for the sonomatic and one for the selectronic. Is the third maybe a 55 or 57 retrofit? I would think the chassis would be the same, just the face is different.

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1 hour ago, Beemon said:

 

The shop manual only shows 2 - one for the sonomatic and one for the selectronic. Is the third maybe a 55 or 57 retrofit? I would think the chassis would be the same, just the face is different.

 

No, 3 different circuits for the 1956 Sonomatic.  They aren't even the same number of tubes.  My book has 2 different models, but I'm pretty sure one of the Sonomatics I have is neither.  The one I gutted was a rusty '707 that we actually only bought for its knobs. 

 

 

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981707

 

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981708

 

Yours looks like a '707, too..

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Edited by SpecialEducation (see edit history)

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