Sony KV-1746R

[Popester]

Not that I need another project but here goes. Was at the Early television convention and picked up a nice Sony. Has raster and sound. Retrace lines with no response from brightness control or G2 screen control. Yeah, I need a schematic but don’t have one and I’m just looking for a starting point. Convergence, color, and tint, all working good. Just need to drop the drive down. Don’t have a test adapter to test the jug, and was wondering if that’s my issue. I don’t think so, but looking for ideas. I couldn’t get iPhone to take a decent picture with the set on.any ideas?

[damen]

On the CRT socket board, check R721, a 1.2 meg resistor. Also, R722, a 120K resistor while you're at it.

[zeno]

Originally Posted by damen

On the CRT socket board, check R721, a 1.2 meg resistor. Also, R722, a 120K resistor while you're at it.

Ditto. The G-2 should be @400 VDC and the R,G, & B output collectors
130 ish. The lower they go the brighter the pix gets with retrace lines.
I would NOT jig this chassis especially if it uses a SG613 hoz output.
AND dont slip !

Zeno
LFOD !

[Popester]

Checked collectors of the output. Running all at about 168V. The wiper of the G2 pot is at 945V. R722 and R721 seem to check okay. I found a schematic on eBay and ordered it. So at this point I’m still going at this blind till I get a schematic.

[damen]

Did you disconnect one lead of each resistor before checking them ?

[Popester]

Thanks damen, I got the service manual yesterday and the R721 1.2M ohm screen resistor was indeed open. I do not like the pots on this set. The screen and drive controls are a square and I didn’t have anything I could adjust them with. Luckily my neighbor, who has tons of tools had what I needed to get a proper white balance and grey scale from those pots with the square. I can now finish this and put it up for sale.

[zeno]

Diddle sticks come in a a few square sizes. You can also make
your own out of a plastic stick. Trick with these JA pots is lightly
use them. If you jamb it in too far when you take it out you can
rip the guts out of it.
73 Zeno