Thanks to the forums and my prior electronic repair history, a co-worker has asked that I perform some magic on bringing back the picture on her 1 1/2 year old LCD tv. The picture will come on if I unplug everything (power & inputs) and replug it all back in after many tries. Come back a while later leaving everything plugged in and you get sound but no picture. I have not taken it apart to look for burnt picos or anything at this point. I have not found much info on this problem other than other models require replacing the tcon board. I have not found that for this sanyo model. It is a Sanyo DP26647. Any help is appreciated. Point me to a direction to start. I recently repaired my Pany 47 projection (IC chips and 1 pico) and Sony 57 projection.
Regards,
Bob
Power board (DPS-102HP) looks good - capacitors show no signs of failure - need advice as to where/what to test for...
I take that back - further inspection found 6 capacitors blocked together - 1 is definitely bubbled out. I'll pick up a few and replace 1 by 1 and update as I go...
The capacitors came in - can I replace a 680uf 35v VZ(M) to replace a 680uf 35v - PW(M)?
Make sure you use 105 degree rated caps. The originals may be lower rated and they tend to fail prematurely.
They are rated at 105 degrees (smaller in size from the originals) - I replaced 5 out of 6 just in case but the repair was not successful on the power board. I just don't know what to look for????
Update on this repair as I was just about to toss the tv to craigslist - free for the taking. I went over the board with the 6 blocked together capacitors and replaced the 6th with a capacitor I had in another board. Put it together and it powers on as it did prior with sound but no picture - then after a few minutes, the bright screen (with no colors) starts to transform with some colors then suddenly the picture comes in clear. Shut it off and the next day, same thing - picture does eventually come on... I got the capacitors fro fleabay so is it possible, they are poor quality and a better quality would solve this issue? Or, am I looking on the wrong board - possibly not a problem on the power side?
Throwing bad money at this, I picked up a t-con board with no positive results. Question - should I just re-cap the entire power board or is there a testing procedure for fuses? I did see 3 pico fuses that are hidden under an aluminum tray. Sometimes when I power on - the picture appears and freezes before going blank with just the backlight. Used to change colors but no longer does.
You can test the fuses for continuity or with the diode setting on your DMM -Digital Multi Meter.When you turn it on is the back light present?if not since you already replaced the T-Con board on it,it may have a bad inverter board or bad/no power going to it.Locate the Baclight Inverter board and trace the wires from it back to the power board there should be some voltages marked next to the connection test these for proper voltage.
Thanks for the advise - To answer your question, yes when I power on, I have backlight. Sometimes a picture will even display and freeze before it goes out (backlight remains on). I was looking for a direction to go with what board to check and what to look for. I have pictures https://picasaweb.google.com/118427240330650835149/20110823 and one is of the inverter board. I will look closely at voltages. I don't have a service manual for this so I am not sure if I will be able to confirm "proper" voltages. I removed the purchased caps thinking they were not correct due to size - I believe 10mm as opposed to 12mm but they were 680 35v 105c - and popped in 1000uf 35v for testing just as a fyi...
The size doesnt matter,If I understand right the original caps were 680UF?and you replaced them with 1000UF?if so you are choking the flow of electricity to the other components in the circuit which could have caused those components to go bad.On the last picture there are 3 shields can you take a clos up picture of the cap under the shield on the far right,or remove the shield?
Ok - I will remove the shields - I tried in the past and gave up due to me being able to set the caps in without removing it. I had originally replaced 5 of the 6 caps under the shield in the middle. Just 1 seemed bulged. I then found a 6th cap and replaced the final 1 under in the same cluster. The replacements were the 10mm but were 680uf 35v 105c. When it didn't correct the problem, it sat for a while. A neighbor's lcd went out and brought it to me for repair and it was a simple 1 cap replacement and he was back working. This got me inspired to repair this. I picked up the t-com board and it still was no change - it was at that time I tried 3 of the 1000uf 35v caps to remove 3 of the smaller 10mm caps. No change with any of the attempted replacements - which is why I am appreciative of the diagnosis procedures as opposed to throwing parts at it in hopes of repair... IIRC under the shield on the right, there are 3 pico type fuses and 1 capacitor +. I had tested for continuity for those and did have it - I did not test for voltage when powered.
I found the removal of the shields more difficult than needed. I poster more pictures showing the caps underneath the shields. I am testing continuity and not sure where I should or shouldn't have it. I guess I am not sure what are fuses... I recognize the pico fuses and diods and I will test for voltages and post back my findings as the board does show what should be 5v 12v 24v. https://picasaweb.google.com/118427240330650835149/20110823#564715260914...
On the cap under the shield I thought it looked bubbled from the other pictures you had of it. Capacitor C245 looked funny on the picture,it may just be the way the camera is angled. The only way to test capacitors is with an ESR meter,not cheap.About the only thing you can do is see if your power supply board is the problem by seeing if it is putting out the correct voltages to the other boards,via the marked connection points.
Thank you. I will report back the voltages in the next few days. As simple as your advice is, it is greatly appreciated. I think some of the caps appear slightly bubbled due to the angle although I have removed and replaced the 12mm ones with 10mm ones and back and then to the incorrect ones and always seem to have the same results. At this point instead of recapping the entire power board, I shall follow the advice and check voltages to identify where the problem is.