Re-acquired my Sony KV-1204A...
 

So a bit under two years ago I posted a thread here about a non-working Sony KV-1204A Trinitron TV from 1977, and mentioned I gave it to a friend. Well, said friend was cleaning out his garage and...I've got the KV-1204A back, and now with a bit more knowledge under my belt, I'd like to try again to resurrect it.

I'd like to start by probing around with a multimeter to see if voltage is getting into the set, what are some good places to do that?

If you go to the anode of the horiz output (assuming an SG613), you should get over 100VDC. If there's nothing, check anode to ground for short. If it is (common), you'll need the SG, the 867A regulator, a damper diode, and maybe a low value resistor. I can't remember if these used circuit breakers or fuses..

John

Is the anode marked somehow? I don't have a schematic, and seemingly the only way I can get one is to pay Sams 22 dollars, and I'm not sure I want to do that.

Did some probing inside the set, the two TO-3s I could find (marked SG-246A and C867A) both only gave 0 volts. I also measured a fuse I found on one of the boards for continuity and it has continuity, so I don't really know what to check next.

You will NEED OEM only
1) SG246A IIRC subs to a SG613
1) 2SC867A
1) damper diode. It has been updated with new part number.
1) resistor in the hoz drive usually burns. Need manual to get value.
1) manual with MATCHING chassis number.
Change it ALL AT ONCE !

One of 3 things will happen
1) everything will blow again in one microsecond.
2) set will work perfect then usually withing a week blow everything
without any warning.
3) the set will work for years more.

HINT most Sony color sets between apx 1975 & 1980 used the
SG613 & 2sc867. If you get one with a bad CRT but the set works
pull those parts, they are not cheap. Dont reuse the damper.

73 Zeno:smoke:
LFOD !

The KV1212, CA 1972 uses two 2SC867 for the horiz output, IIRC.
The newer models that used the SG613 were a rather big headache. I did everything by the book, the set failed a year or so later. I checked the set out and it seemed like the same failure. I told the owner it wasn't worth repairing, as I cant see the picture. Those CRT's didn't fair that well.

Before the SG sets Sony wasnt that hard to deal with except getting parts.
The set with 2 HOT's used one for sweep & one for HV. Panasonic also
tried it. It worked good. 2SC867 were also used for vert outs. In the
day they net abt $8 & SG613's abt $25.
The first SG set was a 17" with all the controls along the bottom. Early
runs had an SG in the power supply & another for the HOT. That was an absolute nightmare ! Its in Sams if you want to see one. I took one look
at it & ran like hell ! Having one was like a cloud of doom hanging
over the shop. NOT for the faint of heart:nono:

73 Zeno:smoke:
LFOD !

Sounds like I need to pay 22 bucks for the Sams after all.