Mulja tv repair portal
Equipment Repairs => LCD TV forum => Topic started by: OldLes on March 02, 2013,11:44:25
-
Some time ago, I had a quick look at a 26" sharp. Plug in, wait a few seconds, relay clicks and green LED lights up. Nothing else at all. It was in rather tatty shape, so I pulled the boards and junked it.
Today a pal brought me the 32" equivalent set, with identical fault. I recall problems with touch buttons, so unplugged the lead to the panel, but it still did the same with no response from remote.
I searched here, and found an apparently identical fault reported under LC-32AD5E, with "fault found, F404 O/C".
Needless to say, F404 on both this and the board pulled from the 26" set were OK.
I shall try to get to the bottom of this one, as the set is very tidy, but it does seem to be a common symptom, so has anybody got any suggestions to point me in the right direction.
OldLes
-
hi les here is the service manual for you
regards
shaun
-
Isn't this the same if not very similar to the Orion set that had so much trouble playing dead ? Sure there's a couple of threads about what to replace on them might be worth a read
-
Press and hold Volume + and Program - together,then plug in the unit.
Check:
C-435 (1000uF/25V)
C-446 (470uF/16V)
IC-401 (MP2A5060)
IC-404 (KIA431)
R-533
D-424
-
Hi Les,
Is the inverter working?
This when you need a ccfl tester!
Failure of sharp ccfls is or was common, some sets also have an error count which stops the set working and needs to be reset in the service menu. It has been a few years since I have seen a sharp so a search on the net may throw up some info.
Keith
-
My pal came around today (Monday pm is our playtime), so we did a few checks on the Sharp. The main control IC (IC401, MP2A5060) is obviously not driving the T401 trannie. There should be a 19V supply on pin 10 of IC401, but we only get about 12 V. Does IC401 need the 19V to start up, or should it start with 12V. The start up voltage would appear to come via a chain of 82K resistors (all OK) and various circuitry, but it seems as though there is also a supply from winding 7-8 of T401. This can only be supplied when T401 is being driven.
If 12V is OK for start up, this suggests I need to spend £10 for a new control IC.
I just don't want to spend the money (impecunious, miserly old pensioner, you understand).
We checked various associated components (Rs, ZDs etc) and can't see any reason for instant failure if I replace the IC. Just trying to be certain.
Les.
-
hi les, just thought i had a fault like this after a thunderstorm no burnt parts i did change ic401 stlll didn't work so just returned it to the customer still scratching my head now, did you check the fuse on the main board soldered type?
shaun :33:
-
I have just been studying the data on the IC401, and it seems that the supply voltage must reach a minimum of something over 15. Since I only have around 12v, I will concentrate on the line from the 300v circuit up to pin 10. That includes a capacitor C407 which will be my start point. May not touch it for a day or so, but will report back.
Les.