So i've had a Samsung LE32R86BC tv brought in the other week.
Symptoms: an odd sort of "hiccup" of the power supply every few seconds, with an associated "pop" in the speakers.
Service manual's too big to attach, but here it is:
Stand-by voltage was a stable 5v, and all the big SMD electrolytics i used as test-points showed the voltages i was expecting, during the few seconds the thing stayed on, before turning off and rinse-and-repeat (mainboard power input is on page 70 in the service manual).
Since i didn't like the hissing & fizzing noises coming out of the power supply, i went ahead and replaced all five of the small electrolytics on the PSU board (3x 47u and 2x 22u).
The result: the "hiccup" is gone; the hissing is not, but that's irrelevant.
Power LED's lit solid as soon as i plug in the mains. For 10-15sec after the first post-recap power-up, there was a pretty constant scraping sound out of the speakers, but it went away and has yet to return.
Trouble is, backlight's off (a mere 40mV on the inverter power-on line), and the TCON isn't getting any power either. The former is controlled by the sub-micom (page 74, bottom left) via an NPN transistor (which has about 700mV on its base, so pulls the signal down - middle-right on page 76 of the service manual). The latter is also controlled by the sub-micom, but via a MOSFET (middle of page 70, PANEL_VCC).
The "lovely" part is that the sub-micom is under the CI card slot, so i have no real access to it.
I'll gladly welcome any ideas / hints / tips you guys might have...
Symptoms: an odd sort of "hiccup" of the power supply every few seconds, with an associated "pop" in the speakers.
Service manual's too big to attach, but here it is:
Stand-by voltage was a stable 5v, and all the big SMD electrolytics i used as test-points showed the voltages i was expecting, during the few seconds the thing stayed on, before turning off and rinse-and-repeat (mainboard power input is on page 70 in the service manual).
Since i didn't like the hissing & fizzing noises coming out of the power supply, i went ahead and replaced all five of the small electrolytics on the PSU board (3x 47u and 2x 22u).
The result: the "hiccup" is gone; the hissing is not, but that's irrelevant.
Power LED's lit solid as soon as i plug in the mains. For 10-15sec after the first post-recap power-up, there was a pretty constant scraping sound out of the speakers, but it went away and has yet to return.
Trouble is, backlight's off (a mere 40mV on the inverter power-on line), and the TCON isn't getting any power either. The former is controlled by the sub-micom (page 74, bottom left) via an NPN transistor (which has about 700mV on its base, so pulls the signal down - middle-right on page 76 of the service manual). The latter is also controlled by the sub-micom, but via a MOSFET (middle of page 70, PANEL_VCC).
The "lovely" part is that the sub-micom is under the CI card slot, so i have no real access to it.
I'll gladly welcome any ideas / hints / tips you guys might have...