|
|
|
#1
03-06-2021, 07:39 PM
|
||||
|
||||
|
RCA 630TCS sudden failure (set was recapped few years ago)
RCA 630TCS was working so good. Key word . . . WAS!!!
After a few hours of playing today I turned it off. It sat for a few minutes and then I decided to turn it back on. I got zero audio or picture. I got a faint raster that only appears in the center of the brightness control range. Turning that control to the right blacks out the raster and turning it to the left extreme - it almost acts like a focus control. Moves the raster off center at little. Also the contrast control has zero effect. Set is rated for 2.5 amps at 117 volts. Drawing 1.9 amps. Same as when it was working normal. I have 10kV at the CRT anode, so that appears normal. Tested the rectifier tubes and all tubes in HV cage and they are all ok. So what failure, that happened suddenly (with no bad smells, smoke, clues), would kill the picture and the sound signals, kill the contrast control, and only give me a faint raster at the center point of the brightness control even though I have 10kV at the anode? Typical vintage TV puzzle. Who can solve or give me hints?? Thanks fellas.
__________________
-Al 
|
|
#2
03-06-2021, 08:04 PM
|
||||
|
||||
|
Also wanted to mention that I replaced the resistor network in the black box at the back of the set when I recapped it.
__________________
-Al
|
|
#4
03-06-2021, 09:05 PM
|
||||
|
||||
|
My FADA was was a clone of the same and they can be a bitch, and since you lost both video AND audio, since these things have separate IF for both split off at the tuner, it may be a tuner problem, or you lost a voltage someplace.
Its unlikely that both video and audio IF failed at the same time.
__________________
=^-^= Yasashii yoru ni hitori utau uta. Asu wa kimi to utaou. Yume no tsubasa ni notte. いとおしい人のために
|
|
#5
03-06-2021, 09:58 PM
|
||||
|
||||
|
Perhaps the focus coil has gone open ?
|
| Audiokarma |
|
#6
03-06-2021, 10:23 PM
|
||||
|
||||
|
[QUOTE=bandersen;3232063]Perhaps the focus coil has gone open ?[/QUOTE
easy enough to check, should be about 247 ohms, and if it was open it would throw the balance of the voltages all out of wack, if it is open you could hook in a 250 ohm 2 watt and see if the sound comes back.
__________________
=^-^= Yasashii yoru ni hitori utau uta. Asu wa kimi to utaou. Yume no tsubasa ni notte. いとおしい人のために
|
|
#7
03-08-2021, 06:36 AM
|
|||
|
|||
|
Always check tubes before digging into it , I made that mistake a couple times and hunted and searched and it turned out to be a tube , after that check focus coil .
Sounds like a resistor gave up ?
|
|
#9
03-09-2021, 09:27 PM
|
||||
|
||||
|
The CRT voltage levels should be easy enough to measure.
The heaters should be on, because they are tied to all other tubes. Cathode. Pin 11 is ground. So zero volts there. Grid one . Pin 2, SAMS says should be 1 volt, but I assume this will change as you adjust brightness, you do not need video here to get raster, or at least this is what I have seen on my set. Grid 2 pin 10 is tied to main bias (275v) via 150k and should be somewhere close to that. Even with a dead tuner, you should be able to get raster, but from the way I understand the way this thing works, if you DID lose the focus coil, will throw the balance of the power supply all to hell, especially the negative voltages. But I do agree with what the others say check all tubes first, then voltages, especially the negative voltages, if the -100 is way off, it's a good sign the focus coil is hosed, cause it is sitting right there on than line. I spent 5 months rebuilding FADA (RCA 630ts clone) so it's still fresh in my head.
__________________
=^-^= Yasashii yoru ni hitori utau uta. Asu wa kimi to utaou. Yume no tsubasa ni notte. いとおしい人のために
|
|
#10
03-10-2021, 12:26 AM
|
||||
|
||||
|
Picture AND sound missing points to a bleeder resistor chain issue. Remember this is a split sound set with the sound take off at the tuner. Then it could be the tuner. But the listed faults points to a B+ issue and the bleeder.
|
| Audiokarma |
|
#11
03-10-2021, 05:41 AM
|
||||
|
||||
|
Quote:
thus i mentioned to check the CRT voltages, to try and spot a problem with that. but a am puzzled by when he said... "Also wanted to mention that I replaced the resistor network in the black box at the back of the set when I recapped it. " "the resistor" ? there are 2 in there... the HUGE ceramic one that gets DAMN HOT!, and a candohm resistor. did he overlook the candohm resistor perhaps?
__________________
=^-^= Yasashii yoru ni hitori utau uta. Asu wa kimi to utaou. Yume no tsubasa ni notte. いとおしい人のために
|
|
#12
03-11-2021, 07:50 PM
|
||||
|
||||
|
I replaced the resistor “network” (more than one resistor). The multi-section candohm and the multi-section ceramic have all been replaced. Making sure proper wattage resistors were used to match the original specs.
I have not gotten back to the set yet, but plan to do so next weekend hopefully. Thanks to everyone for the clues and suggestions. Much appreciated!! I will update when I get back to the set and investigate. Looking forward to figuring out what failed. Quote:
__________________
-Al
|
|
#13
03-11-2021, 09:04 PM
|
||||
|
||||
|
may I ask why they were replaced? were they ALL bad? on mine, only one of the candohm sections was about 30% off, so i bypassed it, i prob did not need to, but did anyway, the values and powers are VERY hard to find... and I would think only replaced if you REALLY need to.
__________________
=^-^= Yasashii yoru ni hitori utau uta. Asu wa kimi to utaou. Yume no tsubasa ni notte. いとおしい人のために
|
|
#14
03-11-2021, 09:22 PM
|
||||
|
||||
|
Quote:
__________________
-Al
|
|
#15
03-11-2021, 10:41 PM
|
||||
|
||||
|
Quote:
__________________
=^-^= Yasashii yoru ni hitori utau uta. Asu wa kimi to utaou. Yume no tsubasa ni notte. いとおしい人のために
|
| Audiokarma |
 |
|
|
Linear Mode
