1982 Sony KV2201 - Breaking my 20" rule (again)

Apart from the grey scale there appears little wrong with it.

It indeed looks very good, a few minor adjustments perhaps only being required.

In case you've not got the data to attempt purity & grey-scale, the data book states the 2201 uses the same method as the 2040

I had the Sony on the bench last night and whilst checking the CRT drive voltages I noticed a wisp of smoke from the PSU board.

Switch off quick, disconnect the mains and put my heat sensitive finger to use.

I unexpectedly burnt said digit on C641, which was hot.... very hot.

C641 looks like the reservoir cap for the 200V  HT to the RGB transistors on the CRT base. A replacement was fitted and the set was left to run for the evening.

Looks a lot worse underneath

Thanks for the info Chris, I'll take a look with a view to setting the grey scale.

The picture is too wide, I'm hoping it's just a simple adjustment of the width pot....when I find it.

Just in case you need it I've scanned and uploaded the circuit for the KV-2201 to the data library ?

Snippet

Ooh I noticed the Pin out active device is the dreaded (expensive!) SG264A gate controlled switch, thankfully it looks to be OK in this instance, with just the width and not the Pin out as well being slightly out.

great tv, i have one similar for years ago, it also still works fine, but as the other mention, yours have a little colour ajust issue, 🙂

Hello again,

Well the Sony came up good after fettling.

The excessive width was simply a dirty pot, which responded to some Servisol, being of a similar type I also cleaned the HT, width & pincushion pots.

A grey scale setup followed and it was noticed the picture lacked punch, the brightness control having little effect.

I checked the tube on my BK467 it read 90% on all the guns so obviously a low mileage tube. Voltage checks on the tube base revealed nothing untoward so a circuit diagram was acquired.

Armed with said diagram I was still getting nowhere, so I started checking components in the ABL section (Sony's take on the beam limiter).

On the D board there was an old style carbon resistor (R531) which read nearly 3meg should be 150k. replacement brought a nice bright picture.

My photography skills don't do it justice & I'm not happy with the pincushion correction, but for now it has pride of place as my bedroom telly.

This set uses the YE2 chassis, apart from the expensive GCS (SG264A) which can cause pin cushion correction (PCC) troubles I have in the past had one of the various inductors  associated with Q902 being faulty in some way causing poor PCC, all L8XX, there are a few 3.3uH ones dotted about that circuit, plus a 12 mH one, I cannot recall which one in the end was the cause of the problem as I had a scrap chassis and just substituted (swapped them) one at a time until the fault cleared ? , fault finding at its finest ?