trinitron kv-1722

[thomashjr]

Hello I found old thread from 2014 and tried to revive it but maybe that is not possible. Has anyone succeeded in resurrecting one of these attractive TVs? This has blown 4A fuse but 5A one still intact. Won't pull any current from wall other than degausser I suspect. I have new PS board electrolytics on the way. A 608 thyristor also on the PS board but is it a regulator or the H out or what? Trying to get right documents for it which might take a while. Thank you for any advice.

[vol.2]

Originally Posted by thomashjr

Hello I found old thread from 2014 and tried to revive it but maybe that is not possible. Has anyone succeeded in resurrecting one of these attractive TVs? This has blown 4A fuse but 5A one still intact. Won't pull any current from wall other than degausser I suspect. I have new PS board electrolytics on the way. A 608 thyristor also on the PS board but is it a regulator or the H out or what? Trying to get right documents for it which might take a while. Thank you for any advice.

Any Sony from that time period is going to be absolutely riddled with bad electrolytics. I just finished restoring (more or less) a KV-9200 from around the same time and I had to replace every single one of them. They were all either completely open or had turned into a resistor.

It sucks to do (I usually suggest against if at all possible), but the best first steps are to

1) replace all the bad caps. you can either test every single one of them and write down the bad ones, or just do the whole thing. it can be quicker to just do the whole thing

2) clean every single contact point in the whole set thoroughly and with the correct fluids. that means taking apart all the tuners and washing them out with electronics cleaner and then treating them with deoxit. It also means cleaning every single pot (and testing them all) and then lubing them with fader lube or something similar

3) reflow all the solder joints in the set. at the very least, reflow every single phyisical connector and large component and anything that might see heat

Once you do all that, then you can troubleshoot stuff

If you don't want to recap it first, at least do the other stuff, but recapping is going to be necessary to a large degree, so it will save you time to do it first

Of course, none of this stuff is even meaningful if the tube is too worn or the flyback is toasted, so it's all a risk, even if you can test them

Best place to start from is a set that is at least partially functional, that way you can at least know certain things work

[klofback]

I can help you along with this, Iv'e done many of them. There are 2
versions of the KV1722. One with a conventional power supply and one with a chopper power supply. Which one do you have? See SCC chassis number on
tag upper left CRT shield. Make sure you get Sony GCS thyristors, ECG, NTE
wont do. SG613 is the newer version of the SG608 and may be easier to find.
If you dont use a systematic method of troubleshooting, you will destroy those
expensive thyristers immediately. The chopper version has 2 of them. I have some excellent troubleshooting documents and some I developed myself
to prevent this. Electrolylitics.. All of them in the power supply and any that rectify scan derived sources should be all you need to do at this time.

[zeno]

Originally Posted by klofback

I can help you along with this, Iv'e done many of them. There are 2
versions of the KV1722. One with a conventional power supply and one with a chopper power supply. Which one do you have? See SCC chassis number on
tag upper left CRT shield. Make sure you get Sony GCS thyristors, ECG, NTE
wont do. SG613 is the newer version of the SG608 and may be easier to find.
If you dont use a systematic method of troubleshooting, you will destroy those
expensive thyristers immediately. The chopper version has 2 of them. I have some excellent troubleshooting documents and some I developed myself
to prevent this. Electrolylitics.. All of them in the power supply and any that rectify scan derived sources should be all you need to do at this time.

Thomas has the early chopper version. I worked at SFS when these sets were new. Absolutely the hardest sets even back then ! Labor was $125 so an SG job ran $175 +. You could buy a good winter car for that. No shops
would touch the.

73 Zeno

[klofback]

I worked in a large service department at a place
called Economy TV in St Petersburg FL in 1979.

I remember a poor tech that had a bowl full of SG613s
that he had blown troubleshooting one.

After that, no one was allowed to work on one unless he received
theory and training.

I think the circuit was amazing for its time. I unload
the sweep board from the power supply and substitute
2 100W bulbs in series for the load. A nice stout 20v
power supply to get the osc running. No harm done
even if the GCS locks on due to a fault. Just 2 bright bulbs.

[vol.2]

Also FWIW, Shango did one of these on his youtube channel a couple years back now. https://www.youtube.com/watch?v=AhM-uwKZQJQ

Should be worth watching to get an idea of the thing

[DavGoodlin]

I suffered too but after my first bench lesson (use only Sony transistors 2SC867 & SG613) while my boss grimaced, then commenced with the "training". If there was ever a TV that should never be serviced without a dim bulb tester, this is it!