Samsung HPT5054, HUGE PAIN IN THE ASS

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Added 60mm fan to it and heatsunk buffers, going to be doing a good video on how to repair these Ydrives and keep em lasting. You seen my PS50C96 repair video explains a little about these Ymains ?

[mmartell]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

It's customary to draw air over heatsinks instead of blow on them to reduce dust accumulation buy I'm sure you already knew that Reecey

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

I did, but they get soo hot which as you know heat = bang especially in these Tv's

I did that as it will keep them fets which all together dissipate 180 plus watts on to a crappy heatsink which gets soo hot to the point where it burns your hand, I normally put fans to extract air but this time did it on the heatsink. Just to help the set last longer.

Also the gap between the fins on the heatsink is big so it would take many many years to even get close to blocking that up matey

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Psu will have Vg. Y main is failed, I have the same set here to fix same issue Will be doing video on it. Theres 5 transistors on the lower smaller Ymain heatsink that normally fail test them.

Thank you, Reecey. I will pull the Y-main and test those fets, but this is a board I already replaced, but I suppose it could be a bad one. I'm still mystified as to how the TV could maintain full VS and VA voltage and not go into shutdown with shorts on the Y-Main. I will report back.

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Okay, so I pulled the Y-Main and the fets you mentioned all test good, no shorts. I tested everything on heatsink, too and still found no shorts. How should they read? Dead short or...? I tried different combinations and no shorts in diode check and in resistance they all seem to be 10k ohms to 230k ohms depending on which pins I'm checking. They don't need to be desoldered to be tested, right? Also, this is a board that I got from a distributor who obviously had rebuilt it as those fets have been resoldered (likely replaced) and that capacitor in the corner (common failure) has been replaced. The soldering on some of this stuff was pretty sloppy, so I redid it, but doubt that's the issue. I DO have a logic board on the way, to rule that out, but...

You are sure that solid green LED on the Y-Main indicates a problem with it? What should I do next?

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Right do you know how to test the buffer ? I have the set I mention yesterday (not the one I did the fan mod on) Ymain shutting down top two buffer Ics are shorted causing Ymain to lock out.

[mmartell]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

If the green led on the ymain is lit even without buffers connected then yes you still have an issue with your ymain.

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Right do you know how to test the buffer ? I have the set I mention yesterday (not the one I did the fan mod on) Ymain shutting down top two buffer Ics are shorted causing Ymain to lock out.

Well, I did repull the buffers when I repulled the YMain and tested them again. I wanted to make sure that the upper buffer that I had had repaired was good and not shorted (had sent it into an ebay repair service because I don't do the chip replacements; it's very inexpensive to have one done with an ebay repair service).

I think I know how to test them correctly. Find a good ground for the buffer ICs by probing between the bottom of the board, right under one of the ICs where they are attached to the large ground trace and find one side of a capacitor on the topside that connects to that ground, then test between that ground point and all the pins of the connectors in diode check to see if any pins are shorted. I tested both buffers and didn't find any shorts that way.

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

If the green led on the ymain is lit even without buffers connected then yes you still have an issue with your ymain.

Any suggestions?

[mmartell]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

The greed led is lit WITHOUT either of the buffers connected ?

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

The greed led is lit WITHOUT either of the buffers connected ?

I will check that and get back to you.

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

The greed led is lit WITHOUT either of the buffers connected ?

Okay, I unplugged both of the buffers (completely removed them from the TV) and then the green LED on the Ymain board DOES NOT light. If the buffers are installed and connected, the green LED on the Ymain lights and stays solid.

What do you think this means? Thank you so much for the help!

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Shorted buffer.

[mmartell]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

+1

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Shorted buffer.

A shorted buffer? Really? Well, can you help me determine where the short is or which buffer board? As I said, I had the upper one repaired by an ebay repair service, but I've retested both of them and didn't find any shorts. Can someone verify my testing method or help me out here? Thanks!

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Well, I rechecked the buffers AGAIN and AGAIN, talking with another tech about my meter and testing method and I found that I had somehow skipped over a pin and missed a short on the lower buffer board. The problem was me assuming that chirp from the meter was just another diode junction that are common on these boards, when this particular one was actually a short; I just didn't leave the meter there long enough!

So, sure enough, you guys were right, a buffer was bad after all! Thank you for the help! I am going to get a lower buffer and I will report back!

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Right plug the set back in now and check them Ydrive voltages ! They are:

VSC
YUP
YDN

[mmartell]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

On this set you can run with upper buffer so give that a go. If your upper is good then no green led on ysus.

[Truncatedhose]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

TV works with a new lower buffer, thanks all of you! Thanks so much!

Reecey, I didn't check those voltages, but thanks for all your help!

[ReeceyBurger123]

Re: Samsung HPT5054, HUGE PAIN IN THE ASS

Awesome work