Possible purchase - Proscan 55 LCD 55lc55s240v69

[martyparish]

Hi badcaps members,

I'm wondering if you could give some advice on this. I have this info from the seller:

I have a 3 yr old Proscan 55" lcd - 55lc55s240v69 with remote and owners manual.
The T V repair guy said the screen needed replacing but he can not get them.

Then I asked what exactly happens when he turns it on:

It looks like it going to start normaly, then it shuts down after a small flash.
The TV guys unpluged the screen connections (one on each side) and it stayed on.

So, do you think it's bad panel, or could this be inverter board(s)? And would it be worth buying?

Thanks in advance!


Marty

[tom66]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

This is probably a single failing poly film capacitor on the power supply - C352 if memory serves right - worst case would be failing bulb in set or bad inverter, unlikely to be the panel itself.

[martyparish]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

Thanks Tom! I can probably get it for $50. Good deal?

[martyparish]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

I just read this thread:

https://www.badcaps.net/forum/showthread.php?t=17613 (Proscan 55LC55S240v69)

Looks promising! A few people who fixed them chimed in and most were C857 cap and one other was "V801 was shorted and F801 was blown".

Thanks again, and if anyone else has any opinions they would be appreciated.


Marty

[tom66]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

I got one digit of the capacitor number right!

$50 is a great deal, I would struggle to get this for anything under £60 (if they sold it here) or about $100. Just make sure, when it flickers, that the screen doesn't show obvious cracks.

[martyparish]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

That's music to my ears Tom thanks again. I'll be sure to post back.

[martyparish]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

Alright, I got it and guess what??? C857 is obviously burnt

Good call Tom!!!

Parts are ordered. I also ordered the three mosfets and three Schottky Power Rectifiers that are nearby...just in case.

Oh yeah, I got the TV for $40 instead of $50. He wanted to keep the base??? I had to ask and he said he was going to make a fantasy football trophy with it LOL.

I'll post back with results when I get the parts in


Marty

[martyparish]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

Hey guys, did I get the wrong cap??? See attached image.

I bought this one since it was recommended from another thread about the same tv and same problem. You can see the damage on the old one.

Here's the link to the cap I ordered

http://www.digikey.com/product-detai...1922-ND/502702

Hopefully it's compatible! Just worried since it's different construction.


Thanks!

** Edit: Well, it is the exact same one that a couple successfully used, so I'm gonna install and report back!

[tom66]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

It is just a different shape, probably more expensive construction than that one, should work OK.

[martyparish]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

Well, the cap alone did not fix it... I did also order three mosfets and three schottky diodes just in case, since I heard the cap could take out the mosfet and they are in very close proximity.

The screwed up part is, I got the part number off of the one mosfet that I could easily see. There are three on this heat sink. I assumed they were identical

There are actually two different types:

FQPF3N80C (1)

[I ordered 3 at digi-key ]

STK1625F (2)

[ I thought one had a short but retested a bit later and now no short, must have been charged??? ]

I doubt the ones I have are interchangeable with the stk1625f. I cannot find it on digi-key but found this.

I attached images that show the bad cap area and also a heat discolored area. Gotta step out briefly but will be right back.


Thanks!

[tom66]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

OK, have you checked if you get good 24V from PSU? May be bad inverter or bulbs.

[martyparish]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

Hi Tom,

Sorry I left info out. Here's exactly what happens and what I have tested:

When you plug in the AC main power, the tv automatically tries to power up. Then it shuts down within 2-3 seconds. You hear "click" and the red LED lights up, then it goes out(with another click I believe).

I have not done a jumper test yet but did test the 24 volt pins during the initial power cycle that happens when you plug it in. It does have 24 volts during that brief period, then slowly drops out.

I also tested the "on/off" (same as plon?) and it read 3 volts during the power on cycle.

Neither the remote nor power switch on tv do anything.

I was hoping for the simple solution that I saw a few others have(the cap that was obviously burnt), but no such luck. This is a massive tv, hope to see it on my wall


Thanks again!

[tom66]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

Let's have a look at the inverter then.

[johnboy1313]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

If the inverter is in fact bad, couldn't the PSU be forced on with the inverter unplugged? Ruling out a PSU issue? If the PSU won't force on, or forces on with an issue of some sort (like on the Sceptre X460BV that I've been working on), wouldn't that then point to a potentially good inverter?

[martyparish]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

Cool, here are both inverters. Both fuses check are ok. (the one labeled inverter_left1.jpg is the actual on on the left when look at the back)

Thanks again

[tom66]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

Some inverters have a feedback ERROR signal which will turn off the TV.
However I am more suspicious of the PSU myself.

[martyparish]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

johnboy1313, good point I suppose, yet I am new to this. I DID however, try to power up the set with inverters unplugged and same exact thing happened. (did not force psu, just unplugged inverters)

[martyparish]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

I agree Tom, especially with the obvious heat discoloration and burnt cap. I guess it's gonna be a goose chase but will be good experience for me.

Thanks guys, this forum is really the most helpful I have seen!

[martyparish]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

Can you guys help me out with the PSU "force on" procedure please?

I attached an image of all connector labels. I need to know which ones to jumper to test this thing.

I assumed it should be "S5V" to "on/off". Can you guys confirm or add any advice?

** when jumping "S5V" to "on/off" I get constant relay clicks.


Thanks!

[tom66]

Re: Possible purchase - Proscan 55 LCD 55lc55s240v69

S5V should go to PSON, using 100~470 ohm resistor. ON/OFF is probably for backlight.