On 28 Dec 2004 00:38:54 GMT, (John Del) wrote:

Subject: RCA CTC169 B+ Problem?
From: "Sam Pzapht"
Date: 12/27/04 1:37 PM Eastern Standard Time
Message-id:

I have got a 46" RPTV RCA CTC169 chassis that has the proper B+ voltage in
Stand-By: 143.5V. However, when I turn the TV on the B+ drops to 114V. The
audio is fine and I have OSD but the convergence is not right and I do not
have full vertical or horizontal deflection.

You can unload the sweep section and use a 100 watt light bulb as a load on the
140 volt line. If the voltage is normal, you have a load on the supply. If
the voltage stays low, the power supply is the problem.

Monitor the raw B+ during run; I've run into bad solder on the bridge rect that
will cause a severe sag under load.
John Del
Wolcott, CT

CTC169 has two regulator feedback circuits. One for standby mode via
this IC (burst mode) and cold side feedback in run mode. You have
problem with run mode feedback circuits, it is made up of few
transistors and few resistors, some has precision resistors, sealed
pot (do not adjust this!) this run feedback monitors the B+ output.

Cheers,

Wizard