KV-1222RS Trinitron Vertical
 

Hello All,
I acquired this trinitron recently. It should clean up pretty good and I have the remote to go with it but I am weary of getting into a really involved project. Generally speaking are these TVs simple to service?

Turned on with nothing connected i would expect to see a full screen of static and certainly the audio works. As I change chanels you can see the singly horizontal sweep change brightness so something seems to be working :).

I'm hoping this is a common problem for these sets and you folks can give me a pointer where to check first ... an i'm hoping its an easy fix.

This TV is a perfect match for my Atari 800XL computer and i'd like to get it going again.

Thanks
Steve

You'll need a schematic of this one. No vertical sweep. You could do visual check on PCB for bad solder connections. But a schematic will be a must on a Sony set. Good luck.

Should be able to fix this with a good meter, schematic & a little
knowledge. Nothing comes to mind as far as common vert
problems on this set. Looks like the CRT is strong but dont
run it like that. Turn down the G-2 until you barely see a line.

73 Zeno:smoke:
LFOD !

ok... thanks guess I'll need to see about getting a service manual.

The remote dosesn't seem to work and I can't seem to figure out how to program the channels without it. :)

Steve

Sony made a few sets that needed an OEM remote to add
& delete channels. They were all subbed to a big combo remote that
dealer net was abt $65 !! The manual will have an RM number
for the origional. Look on e-bay then.

73 Zeno:smoke:
LFOD !

You may need to take your remote apart and clean the contacts. Some mysterious grunge gets on the PC board and the switches no longer work reliably. Rubbing alcohol and Q-tips work just fine. I've resurrected many an OEM remote with balky keys that way. Also be sure to clean off the back side of the polymer keyboard as well with the alcohol.

Here is a video od a remote control ( How to ) you'll have a good idea . On Youtube


https://youtu.be/yWpMcXWlhBE

No vertical is usually the vertical IC and some capacitors connected to it. The caps cause the IC to run hot and fail. A sure sign caps are bad, once the IC is replaced is a foldover at the top of the screen.
I remember that I had to add to the heat sink to keep the IC alive. Apparently towards the end of that IC's popularity, seconds were being sold. I had the same trouble with Zenith power supply IC's when the sets with all the shorted CRTs came along. The seconds always ran HOT!

Thanks all..

I'll give the remote a cleaning and see if it it helps.

Looks like the vertical IC is UPC1378H . Pretty cheap on Ebay. I'll order a couple to have on hand to swap it out. Sounds simpe enough.

if it fixes it then i'll shut it back off quickly and go for a recap.

Steve

With those Sonys, the chip is rarely bad - it's usually 1) the 22uf/50V cap off the yoke return - it's open, and ESR will be >10 ohms or so 2) Solder connections at the chip itself 3) Bad 24V or 28V source feeding the chip 4) the 10uF boost-up cap, also in the vertical area.

With lightning strike sets, the chip will usually short, taking out the 24 or 28V source - replacing the chip fixes that, but you wouldn't have a picture with the chip shorted. Two different versions - the UPC1378 and the UPC1488 - you have the earlier, and the caps are usually the culprit.

OP, have you checked the solder on the chip, and the presence of the 24-28V source feeding the chip?

You might be able to find the service manual online for free, do some googling.

My later model Trinitron gave me hell with cracked solder joints. I'll bet if you completely remove the PCBs and go over them with a magnifying glass, you'll spot plenty of problems. Warm up that soldering iron!

Ok so i finally had time to try and do something with this TV. After getting the dust out of it ... the I checked and the IC is not getting any voltage to it. Should be 24V on pin 6 but it reads zero. TP96 also reads zero. I'm trying to wrap my head around this schematic and figure out how the 24Volts is generated but not having much success.

Here is a link to the schematic, Its to big to upload here.

https://drive.google.com/file/d/1bTd...ew?usp=sharing

Steve

Here is what I have been able to deduce / theorize what is happening.

1. The flyback transformer has secondary windings on it that are also used to supply +15 and +25 volt dc source via rectifier diodes D514 and D508.
2. Checking the +15 volt supply confirms it is working.
3. Checking the +25 volt supply indicates it is NOT working.
4. D514 test good.
5. Resistance from pin 11 to pin 6 of the FBT indicates very low resistance as expected.
6. Resistance from pin 11 to pin 8 of the FBT indicates about 11 Meg and indicates an open winding on the FBT and this is what supplies the 24 volt supply.

Conclusion... I doubt a FBT could be found and I have a 1983 curb prop.

Let me know what you think :).

Steve

Did you go over the boards with a fine-tooth magnifying glass?

While it's on try some percussive maintenance. You know, the caveman method. What we mechanics call the wiggle test. Just hit the thing and move stuff around, and see if anything changes. I'd still put my money on a cracked solder joint.

No but you but I did where the flyback transformer is. The coil is definately open.

More steps taken.

7. After giving some thought i figured I could always rig an external source of 24v if I have the parts laying around to do it.
8. Hooked up my bench power supply to the 24 volt TP and gave it a try.
9. I now have virtical deflection and its drawing about 100 ma (less that the spec sheet call for on that chip.
10. Now to get a universal remote to program .. all it need to be able to do is set the channel and I can set it to channel 3 and test with an vcr or something.

More to come.

Steve