Electrola RE-57: First look and some pictures

[PaulOF]

So, my brother-in-law and I drove out to bring home my "new" RE-57. That thing is HEAVY. I pulled the tubes and packed them in a tube carrier for the trip home, Removed the radio chassis to lighten the weight a tad, and wedged the tone-arm in place with a small soft pillow. Everything arrived intact. The tubes all test good (so its already worth more than it cost). Here are a couple pictures and then a few more questions.

It was nicely refinished by a previous owner.
Front with doors closed
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Front with doors open
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Turntable and tone-arm
DSC_0126.jpg The felt is a little ratty around the edges.

Tuner chassis. The round thing in the middle is the contraption that simultaneously tunes all the trf sections.
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Amplifier and power supply chassis
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Tag riveted to the amplifier. Anybody know what the SUV means? This thing is heavy enough to be a sport utility vehicle, but I doubt that it is.
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Now on to the questions: This is the oldest thing I have undertaken (16 years older than I am) and I feel somewhat daunted.

I. To recap or not to recap the filter caps. I have not yet powered this thing up, but the previous owner tells me that while the radio does not work, the phono has been in regular and recent use. I've read a fair bit on some other boards and with respect to Victors of this era there seem to be three different points of view.

a) "Fuse it and use it," the idea being that the paper caps from this era are particularly rugged so just make sure the 80 and the transformer are protected by fusing the 80's plates and keep your fingers crossed.

b) Hide some 600V caps (electrolytics or, better, polys) under the chassis, disconnect the old cap box and just let it sit there looking pretty.

c) Melt the tar, clean out the old cap box and hide modern caps inside it.

If, in fact my filter caps are in decent condition, I lean towards option b) for for two reasons... it does no damage to anything original, and it feels safer than a) Anyone following me can undo what I have done and the original caps are still there. But, I would like to hear others' points of view.

II. I have the Riders (thanks BANDERSEN) schematic. It lists C-10 (a part of the tuned circuit connecting the 2nd RF amp to the 3rd RF amp) as 10 uF. Surely this is a misprint. Is it, perhaps 10 uuF (pF)?

III. The wooden volume, tone, and tuning knobs are not original. Does anyone make repros of these?

IV. The power switch is new. What should the original look like?

V. Just a matter of curiosity - when (why) did condensers become capacitors?

Thanks as always for your expertise. I'll try to keep you informed of my progress.
Paul

[Sandy G]

I'd go w plan "B", too. That is too nice of a specimen to trust to 80-yr old caps.

[Reece]

Beautiful set. Grandpa had an RE-45. I like plan B too. Also what Zenith suggested when 6X5's were taking out transformers, was to put ordinary dial pilot lights in series with the HV leads off the transformer, to act as fuses. Any surge would pop the bulb. Haven't heard of it done with Victors, but oughta be OK, belt and suspenders, treating old xfrmr gently, as it deserves. Be a pain to have to yank the chassis to change bulbs if they were underneath. Maybe they could be in a little metal handibox with cover off to the side where there's space in the cabinet.

The Rube Goldberg tuning arrangement, which works very well, BTW, is supposed to have a cover: do you have it?

[PaulOF]

Thank you both for your responses. I think plan B is gonna be it. I love the idea of putting panel bulbs in the plate leads of the 80. No, I don't have the cover for the tuning thingee. Dang, something else to look for. Got the microphone though.

Now I just gotta get my Zenith porthole chassis off the bench and back to make room for this new project. I've had it working for a while now with my little repair crt, but I've been avoiding re-instaslling the real picture tube 'cause frankly it scares me a bit. The whole front half of the tube is metal and runs at 15K volts, and the centering adjustments and beam bender are not that far away from the high voltage. Ah well, the new project motivates the completion of the old. My wife will be happy to see the porthole back together again.
Paul

[Reece]

Maybe the tuning cover is kicking around at the seller's place. I believe it has Nipper in relief on it.

[PaulOF]

I pulled the two chassis and took them to the bench for a better look. The amplifier is really heavy. From the front

you can see that someone has placed some sort of clear plastic over the speaker cone and taped it in place. Attempting to remove the tape pulls the fuzz off of the fuzzy brown surround, so for now I am leaving it in place.

Things look pretty good underneath.
Two nominal 8K resistors each measure 10K, and the nominal 70K comes in at 50K. The other three resistors are all spot on. I am thankful that I have the pictorial as well as the schematic since the wires are mostly in a harness and the colors have so faded that is impossible to trace them directly.

However, the pictorial and schematic as printed are too small for my old eyes to read even with my reading glasses, so I blew them up to double size, printed them on four sheets each, and taped them together.
My wife's stuffed bunnies enjoy trying to make sense of them.

So now to work.

I finally decided to disconnect the old filter caps even though they test ok and leave them in the can in case someone coming after me wants to undo what I have done. I really like the idea of trying to make reversible changes. So first I disconnected all the wires and resistors connected to the filter caps.
All the wires are tagged with the numbers assigned to the connectors on the filter cap can.

Then I mounted the new metalized polypropylene caps on a piece of perf board and on the other side, I re-created the layout of the connectors on the original cap can.



Here it is installed.

I mounted it on four metal standoffs which I epoxied to the underside of the chassis. I didn't want to drill new holes. This way someone later can undo what I have done.

Today's quiz: Can you find all 6 resistors in this picture?

Turning the chassis right side up, I check to make sure the fuse in installed in the correct place.
Installed to the right, it connects to the 120V tap on the power trans. To the left, it connects to the 110V tap.

I added a label to the now disconnected cap can so that anyone coming after me can see what I did.


So here we are,
ready for the smoke test.

I put in the rectifier and the power supply voltages were about 5% above nominal. Put in the rest of the tubes and connected the radio chassis. The plate and screen voltages again are about 5% above nominal. I get a satisfying hum on touching the grid of the first audio amplifier, but no radio sounds. So it looks like the power supply and amplifier sections are working ok. Decent progress for the weekend. Tomorrow I'll start messing around with the radio.

[bandersen]

That's some mighty nice, respectful and thoughtful work Shame about the speaker.

I only count five resistors including the big wirewound ones

[PaulOF]

There is a third "big wirewound" at the top of the terminal board to the right of the perf board. It is hard to see in this view, so I will give you full points. It's a 35 ohm resistor across the filament supply for the tuner chassis and center tapped to ground.

I suspect that the speaker will end up sounding fine. If not, it doesn't look difficult to recone if I can find someone with the expertise and supplies necessary.

Thanks for the kind comments.
Paul

[VintagePC]

Your best bet for that speaker might be to carefully cut the tape along the edge of the plastic and remove the plastic, leaving little bits of tape on the perimeter.

[Reece]

You didn't just fall off the turnip truck, did you Paul? Great and thoughtful work on that condensor bank (we will continue to call them condensors in homage to the old girl RE-57.). Just think: in another life somebody else could have got this set and turned it into a wine cabinet or a fish tank or put an LCD TV inside of it or some other horror.

[VintagePC]

Originally Posted by Reece

... turned it into a wine cabinet or a fish tank or put an LCD TV inside of it or some other horror.

Please don't bring that up... I just ate!

[PaulOF]

see next post

[PaulOF]

Back from a couple weeks of vacation and through my first week of classes, so I've had a little time to get back to the Electrola. When I left off, I had the power supply and amplifier working but no sound from the radio.

I cobbled together a little AM signal injector from my son's ancient Radio Shack "100-in-1 projects electronics lab," applied the output to the grid of the detector and, woohoo, heard a tone from the speaker. Moved back to the grid of the third RF amp and nothing. Stuck the scope on the grid of the detector and saw this eensy little AM signal, way less amplitude than I was pushing into the grid of the 3rd amplifier, so it was attenuating rather than amplifying. First and second stage RF amps were doing the same.

At this point, I had checked the plate and screen voltages and they were sort of reasonable, so it occurred to me that perhaps I should see where the cathodes were living. Turns out they were only about 15 volts below the plate and real close to the screen voltage. Oops.

So I took another look at the schematic. Here is a stripped down version of the first RF amp.


The volume control is a part of a voltage divider from B+ to ground that sets the cathode voltage for all the RF amp stages.

A bit of messing about with soldering iron and ohm meter revealed that the negative end of the 1K pot was open, leaving the cathode at nearly screen potential.

My first thought was to buy a dual gang 1K pot and a dual gang 50K pot and do some surgery to make a Frankenpot with 1K and 50K. But curiosity overcame me and I decided to drill out the rivets and see what was in the original and why it had failed.


The coppery thing on the left half is a spring that pushes the silver arc of metal against the carbon layer beneath it at one point. The problem is that on one end, the carbon layer does not come all the way to the rivet that holds the solder lug. It looks like a bit of the carbon was scraped or dissolved away. Not sure how, because the rivets were intact before I drilled them out.

Anyway, this got me thinking that if I could get some conductive paint, perhaps I could fix the thing. I found this web page:
http://www.instructables.com/id/Cond...nt-and-Conduc/

which I used as a starting point. Instead of Liquid Tape I used Barge Cement, a contact cement used in shoe repair. It is sort of like industrial strength rubber cement. I have used it in the past to lay HO rails onto ties without needing to spike them. Stands up well in my experience. I used acetone instead of toluene as a thinner because I had it on hand. My final mixture was 3 parts powdered graphite, 3 parts acetone, 2 parts barge cement. Let me remark in passing that this is an outdoor activity. Acetone should be used with good ventilation and powdered graphite is annoyingly difficult to clean up if you spill it.

Anyway, I mixed it up, painted on 3 layers, and let it dry. Here is before



and after



Next morning after drying overnight, the resistance had gone up about 100 ohms more. Here it is reassembled:


I just finished soldering it back in, powering it up, and I am now listening to KYW. I will be interested to see how well this holds up. I am optimistic.

Tomorrow it's time to put it back into the cabinet and make sure the record player portion still works.

[bandersen]

Once again, I'm very impressed with your handiwork. I recommend others crack open a pot before tossing it too. If nothing else, I think it's interesting to see how they are constructed.

Did you draft that schematic ? If so, what program did you use ? That's a great idea for cleaning up those often hard-to-read schematic scans.

I've used PADS and AutoCad Lite back in the day. They've probably changed so much, I'd need to relearn them

[Sandy G]

I never cease to be amazed & in awe of people who can do what you've done...