Hi. I am looking to repair a 42" Samsung plasma tv that has had intermittant problems up until now, which is now a permanent problem.
Model: SP-R4212, Type: SR42S5
Possible defects: Ysus (LJ41-03424) Ybuffer(LJ41-02249, LJ41-02248)
Symptoms: No video, good audio. With bevel removed (exposed PDP) you can see white snow (very dim) occasionally while the set warms up. Completely dark after 60 seconds or so. The no video issue started intermittently: the set would go dark, then come back online, and off again. Sometimes it would stay dark for a few minutes, then other times never go bright again. The set is now permanently dark (but with audio).
Resources: digital multimeter, 100 Mhz. scope, time and patience, empty wallet.
Based on online forums and service manuals for a similar model, I think that the ysus board is toast. I can't tell for sure, and based on the components, I would think the board can be repaired. The buffer chips are all cold to the touch, and I see waveforms at the OUTL and OUTH test points, but I don't know if they are good.
The voltages out of the SMPS are OK.
I am looking for information on how to test the overload circuits, possibly a schematic for the Ysus board, or suggestions on which components fail on these boards. I can buy a rebuilt Ysus, but I don't know if that is the problem....
Any suggestions ???
Model: SP-R4212, Type: SR42S5
Possible defects: Ysus (LJ41-03424) Ybuffer(LJ41-02249, LJ41-02248)
Symptoms: No video, good audio. With bevel removed (exposed PDP) you can see white snow (very dim) occasionally while the set warms up. Completely dark after 60 seconds or so. The no video issue started intermittently: the set would go dark, then come back online, and off again. Sometimes it would stay dark for a few minutes, then other times never go bright again. The set is now permanently dark (but with audio).
Resources: digital multimeter, 100 Mhz. scope, time and patience, empty wallet.
Based on online forums and service manuals for a similar model, I think that the ysus board is toast. I can't tell for sure, and based on the components, I would think the board can be repaired. The buffer chips are all cold to the touch, and I see waveforms at the OUTL and OUTH test points, but I don't know if they are good.
The voltages out of the SMPS are OK.
I am looking for information on how to test the overload circuits, possibly a schematic for the Ysus board, or suggestions on which components fail on these boards. I can buy a rebuilt Ysus, but I don't know if that is the problem....
Any suggestions ???
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