View Full Version : Sony KV-1922 pincushion distortion


ComboCompact
10-19-2016, 12:07 AM
I have a late-70s KV-1922 Trinitron with geometry issues... Looks to me like pincushion is at or near its extreme. Not sure of the circumstances of the failure; was like this when I got it.

Hadn't ever run into this on a solid-state consumer set before, but I've encountered it with commercial RGB monitors and it's never an easy fix. My hunch is that adjusting the pin amp pot won't have any effect, though to be fair I haven't cracked it open yet.

Before I attempt to mess with pin amp/phase (and potentially start tearing my hair out) has anybody fixed this on a similar set before? Any general hints, or a quick checklist of things to look at?

Jon A.
10-19-2016, 02:57 AM
I wouldn't be surprised if it's full of bad caps. I have a KV-1921 with the same problem. I never fixed it though.

zeno
10-19-2016, 08:32 AM
Was a common problem on 80's Sonys.
A small 'lytic off the pin amp control IIRC.
Also looks like it may have jail bars. If so another
'litic in the 200V supply for the video outs. Very
common on ALL brands with in line jugs.

73 Zeno:smoke:
LFOD !

Findm-Keepm
10-19-2016, 12:57 PM
With a bad:

C810 (Cap On Deflection Board) 100uf 25V - Picture has a Pincushion Error (Bow Tie Pix) (15V pincushion supply filter)

C816 4.7uf/250v (also On Deflection Board) - Picture Has 1/4 Missing On Left Side Of Screen (Not Compressed)

C819 4.7/160 (also on deflection board) Arcing At Hv Anode

We would recap with new caps - all the 160V and 250V caps on the power supply board and the deflection board.

ComboCompact
10-19-2016, 04:11 PM
Jon / Zeno / Brian -
You guys are awesome, thanks for the advice. This gives me enough confidence to start digging into it over the next weekend or two.
Hadn't noticed jailbars in-person, even with a DVD source hooked up... figured that was a trick of my crummy camera. But maybe I just tuned it out visually. Since I'll have the chassis out anyway, will probably go ahead and do a full recap as suggested. I keep forgetting this thing is almost 40 years old.