My Attempt at Predicta Restoration

[PredictaNoob]

Hi Dave,
I've thoroughly read through your restoration thread (several times). Yours was the one that convinced me that this was something I wanted to attempt.
As of now, after corresponding with Sonny "The Radiola Guy", I'm still planning on pulling the board. I am apprehensive (because of the 'cons' you listed), but I'm determined to nug through it.

I can't seem to find solder braid / wick here locally, but I did pick up a very nice German-made solder sucker, it is very long and very slender, about the diameter of a fat writing pen, with a nice long, slender point. It will reach into some pretty tight spaces. And I've got several thin 40W solder irons, as well as a big honkin' antique iron for soldering grounds to chassis, and a good old Weller gun.

I've tested the tubes, and all are OK except for the 6BZ7 on the tuner, which is gassy. Ordered the replacement from ETE tubes.

I am following your advise about powering up via Variac without the HOT, then again with it. I was lucky and learned about "just plug it in and see what happens" on my very 1st antique radio. A nice little inexpensive Admiral that went up in a cloud a acrid black smoke as the transformer turned into a skillet full of molten tar.

I definitely don't want to do any harm, but from the looks of this chassis, it has been the victim of a motel TV repairman's 'gitter-done' attentions, so I'm not taking any chances. I'm just replacing all caps & electrolytics, and touching-up every solder point.

I offer these two pics to support my idea of Motel Joe's hack job:


and this:

I don't know, since I've never seen one, but this CAN'T be a fused resistor, can it?

Since I don't have a television signal generator, I intend to use a VCR for the signal. Is this an OK idea, or worthless?

[DaveWM]

wow, some one has been re-engineering that one. Not sure what the heck the big sand resistor tack on is for. Yea the fusistor is gone. I have a fusistor in mine, but if it ever goes my plan is to replace it with a 10 ohm power resistor,1/2 amp fast blow fuse and maybe a thermistor to soft the blow on startup.

Hopfully your deflection control pots are ok. I would not mess with them, just hope they are in the right spot. some of them are wirewounds and I had one that was toast, wire busted inside, all cruchy etc.


I do like predictas the module approact make them easy to work on.

[Phil Nelson]

Originally Posted by PredictaNoob

Since I don't have a television signal generator, I intend to use a VCR for the signal. Is this an OK idea, or worthless?

If you just want to check operating voltages or eyeball things, a VCR signal is as good as any. To adjust things like linearity & centering, it's better to use a pattern generator that will give you a crosshatch pattern, cross, dots, etc. B & K made some Dynascan generators (1230, 1245, etc.) that are small enough to hold in your hand and often sell very cheap on eBay. Search for "color generator" or "pattern generator." For test gear like this, I'd generally avoid a vintage device, which will need the same kind of service as any old tube equipment and may also need calibration that you're not equipped for.

Phil

[PredictaNoob]

Originally Posted by Phil Nelson

If you just want to check operating voltages or eyeball things, a VCR signal is as good as any. To adjust things like linearity & centering, it's better to use a pattern generator that will give you a crosshatch pattern, cross, dots, etc. B & K made some Dynascan generators (1230, 1245, etc.) that are small enough to hold in your hand and often sell very cheap on eBay. Search for "color generator" or "pattern generator." For test gear like this, I'd generally avoid a vintage device, which will need the same kind of service as any old tube equipment and may also need calibration that you're not equipped for.

Phil

I found a post tonight where a guy described using a test pattern card that he printed, taped to a wall and shot with his video camera. He then fed his video camera into the television he was working on. Sounds like a pretty simple 'poor boy' solution. Not the perfect solution, but perhaps good enough?

[Phil Nelson]

Originally Posted by PredictaNoob

Sounds like a pretty simple 'poor boy' solution.

Caught red-handed! That was my po' boy solution when I did my Predicta 1,000 years ago and didn't own a pattern generator. I had forgotten all about that scheme until you mentioned it.

http://antiqueradio.org/philc12.htm

Phil

[PredictaNoob]

Originally Posted by Phil Nelson

Caught red-handed! That was my po' boy solution when I did my Predicta 1,000 years ago and didn't own a pattern generator. I had forgotten all about that scheme until you mentioned it.

http://antiqueradio.org/philc12.htm

Phil

That is great Stuff! You're a legend, Phil (AKA Phil's Old Radios)
I love reading about your projects! I don't how many people you've helped, but you've sure helped me! Thanks.

[PredictaNoob]

Originally Posted by Phil Nelson

If you just want to check operating voltages or eyeball things, a VCR signal is as good as any. To adjust things like linearity & centering, it's better to use a pattern generator that will give you a crosshatch pattern, cross, dots, etc. B & K made some Dynascan generators (1230, 1245, etc.) that are small enough to hold in your hand and often sell very cheap on eBay. Search for "color generator" or "pattern generator." For test gear like this, I'd generally avoid a vintage device, which will need the same kind of service as any old tube equipment and may also need calibration that you're not equipped for.

Phil

OK, I said the heck with it and bought a Dynascan 1245 from a guy on eBay for 10 bucks. I hope it actually works...