On Fri, 8 Aug 2003 14:53:07 -0700, "Sofie" wrote:

Vince:
Other than expensive flybacks, you should check the B+ regulation circuitry
to verify that it is indeed regulating at the correct voltages. Also, with
a variac on the AC line, vary the line voltage +/- 10 volts or so to see if
the B+ holds steady.
Check all the pcb solder connections around and near the high heat producing
components such as power resistors, diodes, semiconductors, ICs mounted on
heatsinks, and the flyback xfmr.
I would also ESR check all the electrolytics in the PS and in the Flyback
area and flyback derived B+ circuits..... no ESR meter?.... then the only
alternative is the more time consuming task of substitution and replacing
electrolytics.
--

In this Daewoo, good news for you, problem isn't flyback, I know this
well CN-200a and 200i, fixed so many of those chassis...Replace three
100uf 35V caps. Two near vertical IC heatsink, one in middle of PSU
between rows of ceramic axial resistors.

There two more which is really responsible for shutting down after 1/2
hour or killing the HOT is two 1uF 160V caps in H. driver circuit.
Replace both with 1uF 160V or 200V. All caps preferably 105C
temperature rating.
Fly on daewoo wasn't the problem actually. The heat building in there
is excessive because chassis is tiny, crammed so tight that hot
components are cooking these caps to death and browning the PCB.

Zenith, you might have a bad tube overheating that STR-53041. Check
the two small capacitors in that hot side of switching power supply
first.

Get ESR meter if you're repairing for a living.

Cheers,

Wizard