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#1
03-15-2006, 07:44 PM
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RCA 630TS maiden voyage -- sploosh!
Finally replaced the last cap in my RCA 630TS and powered it up. All good/new tubes, including CRT. Rewarded with a faint ghostly blur on the CRT which I could somewhat move around by fiddling with the ion trap and focus coil.
No sound, or any semblance of picture. Then . . . nasty spitting noise from the HV area, followed by instant power-off. Rats! Ideas? I'm taking a break until tomorrow, but would appreciate any tips about known weak points in this set. 
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#2
03-17-2006, 12:26 AM
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Did it have a bright raster before it went Ppphhhht!
I hear peaking coils can give problems on those sets. Some folks have been saying the Mica caps in the 621's & 630's are having problems too after 60 years. I haven't had the pleasure of working on a 630 yet so I don't have any specific ideas. Hopefully you'll be able to see what let go, maybe a cap hooked to the wrong place. Seems like I always get at least one wrong on every set!  BTW, I have a junk chassis if you find you need a part.
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#3
03-17-2006, 12:32 PM
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Well, it had a moderate raster before the poof. See http://antiqueradio.org/art/temp/RCA630TS16.jpg .
That's a little hard to judge when you have absolutely no signal, a problem I traced down to a failed 6J6 in the RF section. (It tested OK before, but nothing lasts forever.) I spent a long time checking my work and poking around. Found one last paper cap that I had overlooked before -- and discovered that one end was not soldered! The lead was just lying in the terminal. In another area I had found a pair of resistors "connected" in the same fashion, so some sloppy serviceman had his hands on it once, but what else is new. I then remembered that I had seen evidence of arcing from a h-v lead to the chassis, so I disconnected one end and slipped spaghetti tubing over the lead. I also did more cleaning of things in & around the h-v cage. Oh, and also cleaned the picture adjustment pots on the back panel, something I had skipped before. I brought it up on the variac and it looks like we're back on track. Raster is back and no spitting, at least for the time being. After some fresh 6J6 tubes arrive in the mail, I'll be able to do some more intelligent diagnosis. Good to know there's a junk chassis out there -- you never know what odd unobtanium part you might need one day! Reminds me of my Hallicrafters 505, which was complete except for three little coils that someone had "borrowed" once upon a time.
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#4
03-21-2006, 05:00 PM
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Hi Phil,
Do yourself a HUGE favour and replace the filament winding on the flyback transformer with new wire. If one point was willing to arc over to the chassis, there's sure to be others as the wire insulation has broken down. Make sure you round off the solder joints on the 1b3 socket to discourage corona discharge and potential arc over. Bob
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#5
03-23-2006, 12:01 PM
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#7
03-23-2006, 02:59 PM
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I gather this is the two or three turns of white wire pointed to by the red arrow in the photo at http://antiqueradio.org/art/temp/RCA630TS17.jpg ?
I tried to attach the same photo to this message, but haven't done that trick before, so my apologies if it is hosed somehow. Is the type of wire critical? It looks like a fair amount of work to pull things apart to replace that wire. I think I will bring up the TV one last time in the dark, in hopes of (quickly) spotting the arcing source. Meanwhile, I need to do more detective work to find the no-signal problem, which did not improve as hoped with the substitution of 3 new 6J6 tubes in the RF section. One of the coupling caps in that section is mica, so perhaps that's the culprit. The others are ceramic, which I am assuming (ha-ha) is very reliable.
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#8
03-23-2006, 03:24 PM
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#10
03-23-2006, 10:31 PM
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Phil,
Your symptioms of diminishing brightness with advancing brightness control sound like either inadequate high voltage, or low B+ to the HV section. Check the B+ at hte damper. Try unpluging the high voltage capacitor, sometimes they can fail and overload the high voltage. Disconnect the CRT anode an measure the high voltage, then reconnect it and measure it as you advance the brightness. Try replacing the damepr and hv rectifier tubes. One of these things should lead you in the right deriction.
__________________
John Folsom
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#13
03-24-2006, 02:47 PM
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I don't have any 3.3 ohm resistors in the house, but perhaps a 3.0 ohm will do here. If anyone votes for using a 4.7 ohm in place of a 3.0 ohm, speak now or forever hold your peace. That's all I've got on hand, and I don't feel like waiting 3 days to order one resistor thru the mail :-)
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#14
03-24-2006, 11:55 PM
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Hybrid Mode
