![]() |
another great job Bob. Now on to the Princess!
|
Not so fast!
First off, I got a new tripod and better lighting on my workbench :) https://farm4.staticflickr.com/3750/...118a9880_c.jpg Next, I wasn't really happy with having the electrolytics scattered around the chassis. So I found an old cap of the proper size, restuffed it and restored the original wiring. I also added another 10 ohms to the filament dropped to compensate with the higher line voltages encountered today. https://farm4.staticflickr.com/3775/...87f4e368_c.jpg I also rebuilt the old dual diode assembly with modern diodes. https://farm4.staticflickr.com/3725/...fbae873d44.jpg https://farm3.staticflickr.com/2909/...db2437e7a7.jpg Then the "fun" process of installing the chassis. Remember I was just sent the chassis. The cabinet and CRT are from my set. https://farm6.staticflickr.com/5536/...befd68c2_c.jpg It played fine for a few minutes then the horizontal collapsed to a vertical line then disappeared altogether :( The sound is still good though. I pulled the chassis back out and wiggled some wires. That seemed to fixed the problem at first, but after about 30 seconds it collapsed again. I pulled the chassis twice more with the same result. So it seems to be an issue with a loose yoke connection or possibly over heating. I'm not so sure about heat though because once the problem occurs, letting the set cool down does not help. https://farm3.staticflickr.com/2922/...cf6749e0_c.jpg |
It was a pain to pull the set apart again, but I think I found the problem.
When the picture goes out, it collapses to a vertical line then quickly fades away. So I figure it must be an issue with the horizontal circuit. https://farm3.staticflickr.com/2928/...11321622_z.jpg Sure enough. A scope confirms that although the hor. oscillator is running just fine, there's no signal on the 12DQ6 HOT grid. After a little poling around, I discovered that putting slight pressure on the K5 hor, network in just the right spot restores the raster. I figure there's a cracked PCB trace or bad solder joint under that network. I wedged a bit of foam against the network and the sets has been running fine for a bout 30 minutes now. Next, I'll pull the board out and fix it properly. https://farm4.staticflickr.com/3899/...fb484866_z.jpg |
Quote:
Phil Nelson Phil's Old Radios http://antiqueradio.org/index.html |
It helps if you remember to actually solder the leads :sigh:
https://farm4.staticflickr.com/3914/...d257940a_z.jpg |
I know this already but sometimes forget and then have to "re remember", but I am adding to my check list is a good magnifying glass and strong light, and just go over the pcb/wiring as part of my normal check out.
|
I recently added some Xenon under cabinet "puck" lights. They get kinda hot but do kick out a lot of light and they're cheap :)
https://farm6.staticflickr.com/5113/...759771d0_z.jpg |
Based on his performance of the miracle of healing upon a severely stricken chassis, I believe Bob should be canonized henceforth as Saint Predictia IV. :sing:
|
Well I don't know about all that :o I still have several Predictas to restored so we'll see.
I soldered up that open joint and reinstalled the board. The task was made easier because I happened to have another 9L37 chassis nearby for reference. https://farm4.staticflickr.com/3865/...49b65b48_z.jpg Viola! It works and has been running for 30 minutes without any more problems popping up :) https://farm4.staticflickr.com/3900/...f37148fe98.jpg https://farm6.staticflickr.com/5553/...05603edabf.jpg |
Bob,
Would you be interested in selling the round bezel + dial glass from your extra RCA 222 cabinet? I sent you a email. Thanks |
https://farm6.staticflickr.com/5113/...759771d0_z.jpg[/QUOTE]
That's a nice bench setup, Bob.:thmbsp: Tim |
I recently received this photo from the owner showing the restored Predicta running in his office :)
https://farm4.staticflickr.com/3949/...3b4b9857_c.jpg |
1 Attachment(s)
Looks great, but I definitely prefer the factory stand.
|
Hopefully he doesn't leave that test pattern on all the time.
|
| All times are GMT -5. The time now is 02:04 PM. |
Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2026, Jelsoft Enterprises Ltd.
©Copyright 2012 VideoKarma.org, All rights reserved.