Samsung LE40M87BDX resets very 15 seconds

[andytw]

Samsung LE40M87BDX powers on OK.
I don't have the remote.

Display is OK but no channels are tuned as yet, menus can be selected and navigated from the buttons on the side.
After being on for a few minutes the TV will reset, PSU relay clicks, and the TV powers back up to where it was.
This then repeats every 15 seconds or so.

I have replaced all capacitors on the PSU though none were 'domed'.

I am happy to replace all the SMD caps on main board but wonder about eeprom too, though others seem to have had various results with the latter.

Problem persists with IR and control cable removed from main board.

Does appear to me to be a hot fault so am thinking the caps under the DTV screen as this does warm up quite a bit.

Don't have access to a capacitor tester, just multimeter and a scope.

Any thoughts ?

andytw

[Andrew F. Ali]

Re: Samsung LE40M87BDX resets very 15 seconds

I don't think you have a capacitor overheating problem. What I do suspect though is a software issue, EEPROM on the Main Bd.

[andytw]

Re: Samsung LE40M87BDX resets very 15 seconds

OK thanks, I'll go for that first.

[andytw]

Re: Samsung LE40M87BDX resets very 15 seconds

It wasn't the EEPROM. New one fitted, fault remains.

[sordids999]

Re: Samsung LE40M87BDX resets very 15 seconds

Have u tried going into service menu and setting ready to on ?
Had this before on the same version of tv

[andytw]

Re: Samsung LE40M87BDX resets very 15 seconds

I have read about that. Don't have remote to do this, but from what I have read does this not turn off digital TV though ?

[andytw]

Re: Samsung LE40M87BDX resets very 15 seconds

Well, we move on. I started to replace ALL of the caps on the control/system board.
There are about 35 and are all SMD. I started with the larger ones 4 x 1000uF and 2 x 220uF and then did some others but to be honest did struggle. I found difficulty with my Weller iron and pointed tip getting the contacts to come clean off the pads and actually lifted a couple of pads. In the end I gave up, refitted the tin screen and refitted the board in the TV. Result....TV now stays on and does not have the 15 second re-cycling fault any more.
Problem now is that it will not tune in any digital stations. I suspect the digital tuner is off so I am looking to do a factory reset. As previously stated I do not have a remote so unless I can borrow one then I am stuck as I do not think I can access the service menu without a remote.

[andytw]

Re: Samsung LE40M87BDX resets very 15 seconds

Problem now is that it will not tune in any digital stations. I suspect the digital tuner is off so I am looking to do a factory reset. As previously stated I do not have a remote so unless I can borrow one then I am stuck as I do not think I can access the service menu without a remote.

Now sorted, used 'Source' button on side of TV to select DTV then retuned, all fine now. I was previously searching for ONLY analogue stations.

[dick_barton]

Re: Samsung LE40M87BDX resets very 15 seconds

It wasn't the EEPROM. New one fitted, fault remains.

New pre-programmed EEPROM or blank?

[andytw]

Re: Samsung LE40M87BDX resets very 15 seconds

New pre-programmed EEPROM or blank?

Blank

[dick_barton]

Re: Samsung LE40M87BDX resets very 15 seconds

Have you tried the following and it also mentions a problem with two capacitors in the power supply.

[Andrew F. Ali]

Re: Samsung LE40M87BDX resets very 15 seconds

Excellent point there dick barton.

[andytw]

Re: Samsung LE40M87BDX resets very 15 seconds

Not sure where this is going guys....
I changed all the caps on the PSU...no effect
Changed the EEPROM...no effect
Changed some caps on the control board..fault fixed but no digital stations
Found source button on side of tv, put it to DTV now have digital stations
So....all sorted. See posts #7 #8
Now getting asked about eeprom !! And resetting it.
I'm fine

[dick_barton]

Re: Samsung LE40M87BDX resets very 15 seconds

Sorry for the confusion. Missed your earlier reply. Glad you got it up and running.

[andytw]

Re: Samsung LE40M87BDX resets very 15 seconds

...and I managed to borrow a remote locally so I could get to the service menu and give it a reset.
The owners are dropping by today to Somerset and picking it up and taking it back to Carmarthenshire, so the TV will be passing close to you tomorrow Dick Barton !!!

I did mention earlier that I had struggled getting the SMD caps off the control board. I kicked myself when I found this yesterday. Looks brutal but the legs have no strength so I am sure it would be fine.

https://www.youtube.com/watch?v=X8N9O3a9jiM

[vinceroger69]

Re: Samsung LE40M87BDX resets very 15 seconds

can you remember what capacitors you changed on the main board it may help other people out with this issue

[andytw]

Re: Samsung LE40M87BDX resets very 15 seconds

I think the likely candidates were the 4 x 1000uF under the tin shield of the 2 x 220uF.
These were the 6 physically largest caps on the board.
The others that I changed were small like 1uF as I was going to change everything but gave up in the end due to difficulty getting them off the board.

[andytw]

Re: Samsung LE40M87BDX resets very 15 seconds

Couple of images of the capacitors I replaced. One of which would have been the faulty cap.