Maxent MX-50HPT52 Powers on, blinks, then off.

[T2Steve]

Maxent MX-50HPT52 - when i turn the set on, it powers on, blinks, and then powers off with an audible click sound.

I followed a few troubleshooting steps, disconnecting the X and Y boards and the issue still happened. I then disconnected the logic board and the X and Y boards were still connected. with the logic board disconnected, the TV will power and LED will stay lit up. The Y board has two caps that are visibly bulging (25v 660 iirc). the Logic board is a LJ92-01371C. it has three caps and it feels like one or two might be bulging. they are surface mount and i cannot read them.

So my first question - is the logic board the problem here? it seems like the TV powers fine when the board is out, but im not familiar with the order of operations here. Do the X and Y work because they arent connected to the logic board? or is it just the logic board that is the problem? I'm going to replace the caps on the Y board because i can read the values on them, I'd like to replace the surface mount caps on the logic board and then see if that fixes it... if the logic board is the only thing wrong (aside from the Y caps) then i might just replace it altogether.

thanks in advance for any help.

[dick_barton]

Re: Maxent MX-50HPT52 Powers on, blinks, then off.

Post some pictures of the circuit boards and of the caps you think may be bulging. Good pictures are worth more than words.

[T2Steve]

Re: Maxent MX-50HPT52 Powers on, blinks, then off.

The two caps are pretty obvious for bulge/leak but arent the worst I've ever seen. the two surface mount caps I cant tell if they are shot or not. That's why i'm trying to figure out if the Logic board needs to be replaced or not, since the TV appears to power without it...

[dick_barton]

Re: Maxent MX-50HPT52 Powers on, blinks, then off.

Perhaps if you fist replaced the faulty electrolytics with some decent 105 deg Panasonic caps and then see if that cures your problem. If not we can move forward from there. It may be that there's an error signal being fed to the logic board to shut down the power.

[T2Steve]

Re: Maxent MX-50HPT52 Powers on, blinks, then off.

that's kind of what i was thinking. I just wasnt sure if the caps on the logic board looked lifted and if i should replace them at the same time or not..

any way we can figure out the values on those? It's an hour's drive to the nearest cap store so I may as well get the caps for those as well in case i end up needing them..

[dick_barton]

Re: Maxent MX-50HPT52 Powers on, blinks, then off.

Remember to buy low ESR capacitors which is why Panasonics are often suggested and of course the temp rating.

Edit
How about Mouser, Digikey, Farnell, RS and then no driving.

[maxvalutech]

Re: Maxent MX-50HPT52 Powers on, blinks, then off.

Yes obvious cap problems to fix first. Samsung boards by the look of it and set about 10 years old? When testing with either Y or X disconnected you also need to disconnect main board from power board and jumper the power board on as set out in several recent posts. Doing that helps in pinpointing the board at fault.

[T2Steve]

Re: Maxent MX-50HPT52 Powers on, blinks, then off.

bad news gang. I replaced the two 25v 680 mF 105 caps with a pair of 35v 680 mF caps rated for that temp or higher... was a piece of work getting the Y panel off as it had a couple of sticky pads adhering it down. Finally got it off, replaced the caps, plugged the logic board and everything else back in and turned it on. green light goes on, flashes ten times, and then the green light stays steady for 1-2 sec and then goes back to stand by. The first time it does this after plugging in there are two audible click sounds, after that it only clicks when it is told to power on...

disconnecting the X and Y board doesn't change the results. There is some sort of board that is part of the power board with a green LED on it. That LED flashes 7 times, so whatever error message that is, that's probably what is happening..

not sure where to go next.

[T2Steve]

Re: Maxent MX-50HPT52 Powers on, blinks, then off.

also - when i turn it on the first time after a discharge the logic board has two LEDs that light up, and then turn off, and additional attempts to power dont bring the lights back on.

So now the question is, is this a logic board issue or Y board issue? from almost every troubleshooting guide i read it says the y board tends to go, but the only real troubleshooting guide told me that when the y board was disconnected it should power on and stay powered on with no picture...

[T2Steve]

Re: Maxent MX-50HPT52 Powers on, blinks, then off.

Yes obvious cap problems to fix first. Samsung boards by the look of it and set about 10 years old? When testing with either Y or X disconnected you also need to disconnect main board from power board and jumper the power board on as set out in several recent posts. Doing that helps in pinpointing the board at fault.

sorry for my question on this, but by main board are you referring to the board with all of the various inputs or the logic board? can you link to where it talks about these steps? I didn't see them when i looked earlier. the guide i was following online simply stated to disconnect X and Y and check but the only time that i get power on and staying on is if the logic board is disconnected.

[T2Steve]

Re: Maxent MX-50HPT52 Powers on, blinks, then off.

bump on this - anyone got any suggestions? or any troubleshooting guide i can follow?

[maxvalutech]

Re: Maxent MX-50HPT52 Powers on, blinks, then off.

A good picture of whole set from rear plus individual boards would help. The main has signal inputs. Usually you disconnect lead from power board to main then jumper pson lead on connector to gnd and vson lead to 5v lead similarly. Turn on and check voltages. If none disconnect y lead and if voltages OK that indicates y side problem. If no joy then do x side disconnect. If neither works PSU problem. If all voltages did come up though this indicates main board problem. For the logic board it is usual to see a led blinking about one second intervals indicating normal operation.

[T2Steve]

Re: Maxent MX-50HPT52 Powers on, blinks, then off.

thanks for the response it's nice to see one after getting nothing. I'll take some pics and post tomorrow (hopefully). Im at the point where even just knowing what board to replace in total would be fine by me. I'm good with a soldering iron, but want my TV back in a bad way.