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Sharp Aquos LC-26P70E

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OldLes:
Yet another Sharp has come my way, and has me scratching my head again. This initially simply went straight to a red LED. Having heard of problems with the touch panel, we looked at that first. The prog and vol controls are the normal tact switches, but the on-off switch looked odd, and it did not pop out when button released. Pulling it out, then pressing it and pulling back again brought up the sound of a relay operating, but after about 5 seconds, back to red LED with relay off.
I removed the switch, and found I could dismantle it, only to find (well, NOT find) a tiny compression switch which had gone AWOL. Somebody had been there and obviously lost it! I must have more than 1,000 springs, but no compression spring that small; by chance I found a tiny tension spring, so a bit of stretching had something to fit.
I located a copy of the service manual, and found all the supplies were present and correct for the duration of "relay ON" period. No light from the CCFLs, but checking them with my tester had them all lighting up OK.
Not surprisingly, I now suspect the inverter board, but wonder if there are any suggestions from anybody here.
Les.

In_Focus:
Yes, the on off switch was a cheap and nasty affair on this model.

It sounds like the lamp error count has reached its limit. Try putting the set in "K" mode by applying power whilst holding down volume- and AV then pressing volume- and channel down.

Hopefully should get you some sort of display, look for the usual Sharp problem of one or more of the lamps coming on pink for the first few seconds.

OldLes:
In Focus, we tried getting into the factory menu, but no sign of anything on screen. There is no CCFL activity at all as far as I can tell.
Les.

In_Focus:
Were you able to get the front LED to go green? If not you could a have corrupt eeprom which may not be recoverable. If I remember the inverter is similar to the earlier P50, you could try some resistance checks on the many optos on the inverter.

Not easy to fault find these Sharps.

OldLes:
Hi, In Focus. Let me clarify.
Plug in mains cable. Nothing. Press "ON" button, hear relay, then very brief Red LED, and then Green LED for between 4 and 5 seconds, hear relay open, and all LEDs OFF.
If "ON" is pressed again, relay, red, green (4-5 secs) and relay sequence exactly as above.

During the Green ON period, ALL power rails are present, and all decay slowly after relay opens.
The +24v is present on inverter board, but no visual response.
No optos on inverter board, but I guess you meant on the PSU board.
The inverter board is No.  RUNTKA213WJZZ (5X).
I did all the simple checks there without power. All seven transformers had identical resistances, both fuses OK, no visual problems. I think I will next see what happens if I power the inverter from my bench PSU, when I can access both side of board, and maybe hang a few spare CCFLs to see if any activity to show. There certainly is no activity from the CCFLs in the set.
Les.

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