1971 Sony Trinitron KV 1201

[Airedale]

Well I can't find a chassis code on this. I've looked at it a half dozen times, even had a friend go over it too, there is nothing. Every label has been read, nothing is stamped on the metal. Perhaps it HAD a label and its missing.

[zeno]

KV1201
Different Sams manuals are
#1309-2
#1389-3
#1493-3
#1698- SED

Those tags do get lost. Good chance it fell down between the CRT
& the shield. The 330 number you found is the CRT number.
If the serial number is still on the back post that & I can try
that. In any case all are SCC-17 but with different letters at the
end. They may be all very close BUT sometimes they are totally
different.

[DaveWM]

those are nice sets, I have one as a daily watcher. sounds like the CRT is being biased off, turning the set off releases the bias as the residual HV pulls the electrons thru.

check HV anode voltage 19kv

check the voltages at the 3 cathodes of the CRT IIRC should be around 100v-110v. These are driving by the collectors of the 3 video out transistors.

The grids all get voltages from boost voltage, so if you lost that, then you will have cut off the tube. boost is about 500v check pin 5 (common screen grid) on the crt should be upper 400's the common control grid also from the boost is upper 90's (pin 7)

My guess is you lost the boost.

[Airedale]

Thanks for the help. I'll pick up a HV probe and look into acquiring a manual.

This is a cute set, I'd love to add it to my living room for occasional watching.

[MX70]

I have the same set with " wood" cabinet , KV1212 ( the one in my avatar pic ). It works like a champ but has pincushion issues ( any ideas? -- thanks !) This set was the one in the Sony print advertisement where it was set up in a bank branch and left running for a year and a half with no servicing needed

[dieseljeep]

Originally Posted by MX70

I have the same set with " wood" cabinet , KV1212 ( the one in my avatar pic ). It works like a champ but has pincushion issues ( any ideas? -- thanks !) This set was the one in the Sony print advertisement where it was set up in a bank branch and left running for a year and a half with no servicing needed

Mine had a problem with the pin cushion corrector circuit. IIRC, it was on a small board near the flyback.
The set was about six years old at the time. That's all that went wrong in the time I had it. I sold it cheap when the CRT was starting to look tired.
Too many years ago.

[dieseljeep]

Originally Posted by dieseljeep

Mine had a problem with the pin cushion corrector circuit. IIRC, it was on a small board near the flyback.
The set was about six years old at the time. That's all that went wrong in the time I had it. I sold it cheap when the CRT was starting to look tired.
Too many years ago.

I meant to state that it was a small electrolytic on the board.

[MX70]

Originally Posted by dieseljeep

I meant to state that it was a small electrolytic on the board.

Thanks dieseljeep , I kinda knew there was no actual adjustment for pincusion but couldn't for the life of me remember how it was done on this set ! i picked up this set from a second hand store for a song and was a daily use set for about ten years, it had this issue for all that time but never seemed to get any worse. Iv'e had it for about 22 years now and run it every now and then, still works the same!