Dude is bringing over a Hitachi P50S601 (plasma 1080)

[Paul678]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

Check and replace any startup caps on the primary side.

Ok, did that. All the caps look good.

This meter is great. It seems very accurate. Unfortunately
for this case, the truth is a bit disappointing! haha

I'm tempted to use the o'scope to trace the voltage
from the Va and Vs back into the transformers, until
I find where the voltage is dropping. 89 Volts isn't
terribly huge, and my scope can handle it.

Problem is, I'll have to hang this huge power supply
board off the back of the TV, because not only must
I connect the main board and 120AC, in order to
turn-on the PS, but I need to be able to probe the
backside of this board.

Not going to be fun....... haha

[Paul678]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

Those 100v 3300 uf caps are bad on every one of these power supplies and very common failure.

the secondary voltages are running at 85 volts at these caps.

I have not had any other cap issues on this power supply other than these two large caps.

These are narrow caps and you have to watch when ordering replacements.

The buffers fail on these and can take out the y drive.

The best way to check these tvs is to unplug the upper or lower buffer board.

If the tv power supply was going into protect mode you can unplug one buffer at a time.

You can not check these like the l/g tvs, that, is you can`t unplug the y or z and have the tv power up. It won`t do anything unless all the boards are plugged in.

You can unplug the buffer boards and the tv will still power up.

I have found these in China on feebay for around 120.00 for the pair new.

These tvs have a great picture. (you have a good panel with multiple buffer ics)

This tv is very much worth repairing.

Yeah, as I've mentioned, I have already tested that my lower
buffer board is bad. Hopefully the Y-sus is still good. And
again, the two big caps (as well as pretty much every cap
on the board!) still tested good out-of-circuit.

Here's the only place that had this PS in stock:

http://www.iccfl.com/product_info.php?products_id=11166

What my fear is, is that I will order this, and it will show the
same symptoms, because there is some sort of missing
"turn-on" voltage that needs to come from another
board which is the real culprit.

But it seemed like there were healthy voltages going to
and from the other boards, so I'm not sure.

I just don't want to plunk down $126, plus some huge
shipping and handling fee from China to the USA, plus
another $67 for this:

http://www.ebay.com/itm/270950963043...84.m1438.l2649


....just to find out the bitch still doesn't work!

If I knew for certain that a $250 repair would
result in a working $450ish TV, then I'd do it.

OTOH, even if it didn't work, I could always
resell on Ebay, and get most of my money
back, but what a Goddamned pain the ass!

[leo_the_noob]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

[QUOTE=cadiman;230658]Those 100v 3300 uf caps are bad on every one of these power supplies and very common failure.

the secondary voltages are running at 85 volts at these caps.

I have not had any other cap issues on this power supply other than these two large caps.

These are narrow caps and you have to watch when ordering replacements.

The buffers fail on these and can take out the y drive.

QUOTE]

Cadiman I was just given one of these sets by a friend at work. I checked both upper and lower buffer boards and found 2 bad buffer ICs in each board plus the swollen 100v 330uf caps on the power supply. The cost of the buffer ICs is 10$ each so I figured it wouldn't cost much more to replace the entire boards vs. time and money to replace individual IC chips. I've replaced the bad caps on the power supply and powered up the TV with buffers removed. I'm getting good Vs and Va voltages but they only stay up for about 1 minute before going down. I wasn't sure if this was due to protection mode or not. I tried connecting a good upper buffer board and powering up. The TV showed a picture on half of the panel but every other line was black and the part of the screen that was lit was just a green snowy mess. I quickly turned it off before I blew a buffer board. I removed that buffer and installed the good lower buffer. Same thing, half of panel lights up with every other line blacked out and remainder of image just green snow. I checked these new buffer boards and I know they aren't shorted. The power supply voltages seem to be ok . What can I check on the Y SUS board to make sure it didn't get damaged when the buffers shorted initially? If anyone else has experience with this please chime in. Thanks.

[leo_the_noob]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

I was just looking over that Y sus board and checking the MOSFETS for shorts. I did come across a diode D44F which is a FCU20UC30 fast recovery diode. The diode checks Ok with meter , infinite resistance in one direction and practically nothing in the other but I noticed the 2 anode legs on the diode both short to the heatsink the diode is mounted to. Is this normal? I know it's badnews when a MOSFET shorts to it's heatsink but not sure about diodes. YES I AM A NEWBIE. Trying my best guys and learning a lot here but any help is welcome. Thanks

[cadiman]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

Don`t worry about being a newbee. I am still a newbee to everything and always learning. (to:leo the noob) I make alot of mistakes and I invest in items to learn on.

I can accept a loss on anything I am repairing as long as I learn something. It has always been my career to learn and gain knowledge on everything. The problem is the more I learn the dumber I feel and that just makes me try harder. I guess that is a good thing.

The heat sink is most likely also part of the circuit and should be a few hundred ohms.

Pending your meter setting, 000 is not good unless you are checking for continuity.


I have repaired 4 of these tvs and I don`t feel I have learned much. The last two just needed buffers and the two caps and it was fine.

If all the boards are plugged in and one is bad the power supply will power up for about 2 seconds (on these models) and go into protect mode. (failed y board, x board or buffers)

The bad caps don`t kill the buffers. The buffers kill themselves. (heat sinks needed)

I have had these tvs with just bad caps (100v 3300uf). (power supply will go into protect mode)

If the power supply does nothing then you have mainboard or power supply issue.

You said missing stand-by power possibly.

Again these are a bit tougher to troubleshoot than most tvs. Similar to Pioneer.

The original or beginning post doesn`t make any sense. I have never had these tvs with sound but no video, only l/g and samsung.

This tv is worth fixing and a new 499.00 plasma is not the same tv.

I am sure of at least that much.

[leo_the_noob]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

Thanks for the encouragement cadiman .I've only been doing this for a while but I'm hooked on this forum and the thrill I get when I succeed in a repair. I've spent lots of time reading and have managed to fix a few things (stumbling and asking for help along the way) but this is only my second plasma tv and I think this will be tougher to repair than the first which had a Samsung panel.

The buffer boards were bad on this Hitachi (Model P50H401) but now that i have the replacement buffers I'm still getting a bad image. The Vs voltage was almost 10 volts over what it should be but that is back to normal since replacing the Caps on the power supply. I'm pretty sure i have a problem on the Y sustain board but nothing obvious sticks out. Is there any other common failure on these sets besides buffers and power supply caps? If the buffers do take down the sustain board then where might the damage most likely occur? With the buffers removed the set does power up and stay on for a minute or 2 and I can take good voltage readings during that period, then the blue power light turns orange(standby) and the voltages drop down to about 3 volts. I don't think it's protection mode, maybe just standby because it doesn't detect a video source?

[Paul678]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

Thanks for the encouragement cadiman .I've only been doing this for a while but I'm hooked on this forum and the thrill I get when I succeed in a repair. I've spent lots of time reading and have managed to fix a few things (stumbling and asking for help along the way) but this is only my second plasma tv and I think this will be tougher to repair than the first which had a Samsung panel.

The buffer boards were bad on this Hitachi (Model P50H401) but now that i have the replacement buffers I'm still getting a bad image. The Vs voltage was almost 10 volts over what it should be but that is back to normal since replacing the Caps on the power supply. I'm pretty sure i have a problem on the Y sustain board but nothing obvious sticks out. Is there any other common failure on these sets besides buffers and power supply caps? If the buffers do take down the sustain board then where might the damage most likely occur? With the buffers removed the set does power up and stay on for a minute or 2 and I can take good voltage readings during that period, then the blue power light turns orange(standby) and the voltages drop down to about 3 volts. I don't think it's protection mode, maybe just standby because it doesn't detect a video source?

I obviously feel for you Leo, as I have the same
model.

As others have pointed out here, plasmas are more difficult
and expensive to fix than LCDs, with buffer boards and Y-sustain
boards being rather pricey.

Your situation is actually why I decided not to order a new
power supply and a new lower buffer board....I wasn't sure
these were the only problems. If I had to order yet another
board, probably the Y-sus, it would have been too
expensive to be worth it. I decided to just Ebay the parts.

Based upon the Magnavox plasma that I worked on, you
should check the heat-sinked MOSFETs on the Y-sus
first. Typically, when the buffer boards go out, they
take the Y-sus out too.

Check for shorts.....you may have to unsolder
the leads, and check them out-of-circuit to be certain.

Good Luck

[cadiman]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

If the tv is powering up that is a great thing.

If the panel lights up that is a great thing.

If you just have issues with the picture I would go after the y drive board and you may find one on feebay. They don`t fail as often as the l/g or samsung, mostly really just the buffers.

The failure on these happens more from poking around in them.

I had one out of four that I ended up selling because it needed a power supply, a y drive board and an upper buffer.(that means both)

These have the mosfet y drives that hold up better then the ipm driver boards that l/g and samsung used around this year. (p50h401)

The 720 version of this seemed to hold up better.

[leo_the_noob]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

Thanks for the tips cadiman. I'll remove the Y drive and check the ESR on all caps plus I'll check all diodes and MOSFETS. If I can't find any faulty components then I'll have to make a call on whether or not to gamble on a new Y drive. I already have a TV though and I enjoy this more as a hobby so I was interested more in repairing the Y drive rather than board swapping. These are very complicated devices and the service manual doesn't have schematics for the sustain boards so it really is a but futile. I prefer the Samsung panel because if the buffers go the IC chips are only $3 each and usually only one IC will go at a time. These Hitachi buffers are pricey even if you replace the IC chips($10 each) and I had 4 bad on this set between the 2 boards.

[easy2know]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

Paul, I have a Hitachi P50S601 with exact the same issue as you stated in the first post. Did you fixed or find a solution?

Thanks

[mvalent000]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

I am in dire need of some Hitachi go-ru's. I have a p50s601 and a p50h401 that are both not working right. Long of the short, caps replaced, both buffers are replaced (or fixed) and are working. I am either getting a solid blue light in the front or a 4 blink code....not 3. The tv's will both run if the CN68 plug is unplugged from the power supply. If plug the CN68 back in I get a high pitched sound, I believe coming from the power supply, and the unit shuts down with a solid blue light. I am at wits end trying to figure this out and nobody out there has posted anything like this.
Any advice besides taking the tv's to the shooting range?

[tom66]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

Test across YSUS CN68 for a short.

[georugby]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

I will start on that Hitachi P50H401 project next week, replacing them two caps on the power supply, and I'll try replacing the two ic chips burned on the upper buffer board.

I will keep you updated on the project. First step - test voltages and tensions and this leads to second step: order the pieces!

Cheers!

Jeff

[kc8adu]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

those are shot on every one of those hitachi plasmas.
replace them first.
sometimes they short.

The three caps next to the heatsink on the right side all look bulged. Definitely replace them. Those are Chemicons, but this is an older set and it's likely they have simply reached end of life given their position.

[colorless]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

Got one of these with a smashed screen let me know what you need and I will give to a quote.

[freakaftr8]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

I bet you have shorted buffers and in turn loaded down the ysus and shorted some discreet components.

[freakaftr8]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

When you replace those buffer ics you could have some funky interlacing look to the screen with alot of mal discharge. If so the ics will overheat instantly. Be careful for this. There is a small 6 pin ic on the ysus directly located above and under each buffer boards connection. Also with this a small 3 pin ldo regulator. They like to short when a buffer shorts. Check them before installing the buffers.

its been a few minths and don't remember the proper labeling. Take a pic of the top and bottom of the ysus and ill tell you what to look out for.

[georugby]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

When you replace those buffer ics you could have some funky interlacing look to the screen with alot of mal discharge. If so the ics will overheat instantly. Be careful for this. There is a small 6 pin ic on the ysus directly located above and under each buffer boards connection. Also with this a small 3 pin ldo regulator. They like to short when a buffer shorts. Check them before installing the buffers.
its been a few minths and don't remember the proper labeling. Take a pic of the top and bottom of the ysus and ill tell you what to look out for.

Hi freakaftr8, i took two pictures that might get what you want to show. I'll check them for sure before I replace the buffer board. If you want the pictures to be more close to the board, tell me and i'll try to take some more.

[freakaftr8]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

Cant read the location but on the bottom it right above the stamping FCVV4 on the top same ic. Its the 3 pin one with one pin on the opposite side. Check in ohms Range center pin to each end for shorts.

[georugby]

Re: Dude is bringing over a Hitachi P50S601 (plasma 1080)

Would that be FVCC4?