Toshiba CRT projection TV chassis TAC9855

[zeno]

Originally Posted by radiotvnut

OK, I checked some voltages and it's not looking too good. I have 204V on the input of the collector resistor on each video output transistor; which, seems OK. When I move to the collector side of the resistor, I have 7 volts; which, is not good. This voltage is present on all three video output collectors, regardless if the socket is plugged into the CRT or not. Moving to the base of each video output transistor, I measure about 8 volts; but, when I check the resistance from the base of each video output transistor to ground, I read around 212 ohms. In direct view TV's of this age, I seem to remember the base of the video output transistors getting their drive directly from the jungle IC and I don't believe I should be getting that low of resistance reading from the bases of the transistors to ground. At this point, I'm leaning towards a leaky/shorted jungle IC. I even tried turning down the three master G2 controls, in hopes that it would dim the CRT's enough that it wouldn't trip the protection circuit; but, no luck. The way I measured voltages was to clip my meter to the desired test points and then I powered up the set. I'll probably end up scrapping the set if it turns out to be the jungle IC.

Look up the jungle ( TA????). Find the VCC pins & measure them.
There are prob. 3 or 4 of them. Check both DC & ohms.
Maybe a B+ line is out from FBT or main supply. Usually when
a jungle shorts you will see it on one of the VCC's. (ohms).
It will also get HOT not pleasantly warm. If you can prob.
keep the set running by pulling all 3 CRT skts.
Shut down circuit is seeing too much beam current.
IC prob. cheap, if your pal wants to gamble.........

73 Zeno