B50M88W Zenith projection tv follow-up

[method]

Hello to all,

Some of you may remember my posts about this TV (which is based on
Hitachi ZP88R chassis).
The TV does not power up. When plugged, a hissing sound is heard for 2
sec. and then disappears and TV is dead.
I changed both STK packs along with main processor, but still nothing.
Now I have found that the power supply tranformer seems to be goign
bazooks on the secondary side : the +27 and -23 lines are giving out
low voltages at around 4 V. All the other lines in and out of this
transfo are fine. What do you think is the problem :

1- Short between one of the lines to the GROUND line
or
2- Faulty secondary

NB : both coils (+27 and -23 lines)in transfo's secondary are at 0.7
Ohms.

See link below for picture of schematics.


http://us.f1f.yahoofs.com/bc/2c47a5c5/bc/Share/Zenith_tv_power_transformer.jpg?bfIMS3_AJxh_ONcJ

 

[Lew]

Disconnect the secondaries, Then check the voltages from the Xformer. if they
are right then something in the circuit is pulling the voltage down. If they
are still not right you may have a bad Xformer.
Lew

 

[method]

I disconnected D915 and D914 diodes (see http link) and checked the 2
lines' voltages and got around 4V.
This means it's a bad transformer ?
Would someone be able to give the Part number and manufacturer of this
transformer ? (the part number I found is for the magnetic core only)

Thx.


lewisnov@aol.comnospam (Lew) wrote in message news:<20031214223023.12223.00001041@mb-m05.aol.com>...

Disconnect the secondaries, Then check the voltages from the Xformer. if they
are right then something in the circuit is pulling the voltage down. If they
are still not right you may have a bad Xformer.
Lew