Sony KV-35S36 - is the tube shorted?

[William Buchholz]

When I power it up the screen is bright blue with retrace lines. The
picture is barely visible except for some faint outlines. The
voltages on the CRT are the following:
Blue Cathode: 139V
Green Cathode: 206V
Red Cathode: 206V
G1: connected to ground on socket
G2: around 500V but the voltmeter is probably loading this down
Heater: 6V

I tried using my B&K 445 tube tester to see if the tube it shorted. It
tests OK but I don't know if it works properly on Trinitron tubes. I
used an isolated heater supply but it made no difference in the
picture. Switching the red and blue cathodes resulted in a slightly
purple picture but still mostly blue. I would like to know how to
confirm if the blue gun is really shorted out. Thanks.

 

[kc8adu]

pull the socket and measure the blue cathode again.it being low is causing
the bright blue.
if it returns to normal its the tube.

 

[Shoreline Electronics]

I had this exact same model in the shop with a small crack on the CRT board
causing the exact symptom.

Try flexing the board....if not look closely with magnifying loop in bright
lighting.


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
[email protected]
========================
"If you push something hard enough it will fall over."
Fudd's First Law of Opposition - Sir Sidney Fudd

 

[Wild Bill]

I'm not sure about the model 445 tester, but the 466 (and maybe other BK
units of that era) had an external accessory for checking different gun
designs. I think the adapter had 2 settings, normal/direct, maybe. Directly
heated tube designs were marked in the tube charts.

Sony guns were made differently than most others back then, directly heated
or some other peculiarity.

WB
................

 

[kc8adu]

the only direct heater cathode sony tubes i have seen are in the kv-5xxx
sets.some of the old b&k testers need a special adapter to do common g1 g2
inlines.