On Mon, 23 May 2005 01:12:04 -0230, "Rono" wrote:

You guys are missing the info!! These units will not run
with high standby B+. Scopes & EEPROM changes won't
fix it. I tried everything I could think of. Just read again. Rono.

RCA 25" M # 25GT536, chassis # CTC177AG. Unit was dead,
replaced STK-730-010 (shorted), R104 1.5 meg ohm (gone high),
C4105 10UF @ 250 Volt (gone leaky), checked/replaced CR4108
(130 volt line), changed C4402 (warped), 12 volts, & 5 volts standby
is fine, 5 volts to EEPROM, & tact switches, but 130 volt line is +146
volts dc. B+ to LA7610 main jungle IC +7 volts. B+ to horizontal output,
& drive is + 146 volts, & unit won't start. What did I miss? Rono.


Rono, 146V in standby is normal. These chassis usually run between
130 to 140V B+ depending on models using this chassis.

Unsolder the transformer and measure all the resistors to be sure,
replace 10uF 63V in two locations; both are on both sides of that
STK-730, one for SMPS, one for horizontal area. I find them bad nearly
80% of time.

BUT, that can be caused by bad solder in tuner & micro grounds and
that means eeprom can be corrupt. Chipper check will fix this up by
reiniting the eeprom or replace the eeprom but that will be more
involved setting up other settings. UGH, that why I use chipper
check. and maybe have to align the tuner (57 of them for 19 channels
settings in groups of 3). Service manual is a must for consulting
when setting up eeprom contents.

By the way, get the horizontal driver transformer out and scrape pins
on it clean get waxy stuff out of holes, reinstall & resolder.
Carefully check that 2.4K off the emitter of the small SMD transistor
in the horizontal driver circuit.

Cheers, Wizard