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Discussion Starter #1 (Edited)
Hello everyone.

I found this forum after my plasma would't come back on after dinner a few nights ago.
The blue led light blinks twice which i have found (thanks to this forum) means there is something wrong with the XSUS board.

I have combed through this (and other forums) looking for some insight about this error but most problems with these Hitachi Plasmas seem to circle around the buffers on the SDRs and the caps on the power supply.
Jason76's thread "Hitachi P50H401 led flashes 3 times" discribes the problem and solution so effectively that i almost which my led was blinking 3 times.

I have read that in order to test the xsus board i can simply unhook it from the Ysus board and if the tv screen powers up i know the xsus board is the problem. [Please correct me if i am wrong about that]

My question is: if the xsus board is the problem (or one of the problems) can it be repaired like the power supply or SDRs? I have not read where anyone sent this board out for repair. I have only read where people bought a replacement board.

Thanks for your help and i will keep this thread updated until the very end.

A little history on the tv...
Bought it refurbished from EUCweb over 3 years ago. Opted not to get the extended warranty and glad i did... the tv died a few weeks after the 3 year mark. And i believe 3 year was the maximum serive length they would give you. IIRC, that 3 year coverage was over $500! I would have been REALLY mad.

TV has been wall mounted and untouched for the most part.
Installed in wall power comditioner at the time of purchase just in case. No loud pops, problems or signs of trouble since day of purchase.

Well about a year ago the tv wouldnt come on and and the led was flashing. I dont remember if it was the blue led or red but i unplugged it for about an hour and everything has worked fine since.

I also updated the firmware as of a year ago courtesy of Hitachi customer service.
 

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Discussion Starter #3 (Edited)
Last night I got the TV down off the wall and began taking the back panel off.
As someone stated before there were a lot of screws.
Luckily I have the repair manual which gave me confidence that i would not be left with a handful of screws after the deed was done.

Taking the back panel off was straight forward enough.
In all there were only 3 different types of bolts/screws but they were many (50-60 or so).

Here's what she looks like with the back on & off.
You can see where everything is from the layout diagram in the previous post.
 

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Discussion Starter #4 (Edited)
First thing I noticed (even before I pulled the back off) were the huge fans planted on both sides.
Some members on another forum installed fans on the back of their 50 inches to keep things cool as they say these TV generate a lot of heat. I actually had planned on doing this myself but was happy to see the engineers cut on corners on the P60. Needless to say the back was pretty dusty.

So with the back off I stepped away and took in the whole thing.
What struck me was the enormity of the the boards I was dealing with.
These boards are HUGE. Think small and medium sized pizza box huge!

After a few seconds I went straight to the XSUS board to see what I could see.
Being a circuit board novice, the only thing I knew to look for were scorched and puffy components and maybe even a leak but everything looked fine. I don't think there is anyway to eyeball a nonviolent short so I kept it brief. What I did do is take lots of high resolution photos (1944 × 2592) so i could come back to my desktop and scan over them in hopes of catching something I might have missed on the scene…

Here's what the XSUS board looks like from afar.
Sorry about that bar being in the way but I didn't want to take them off just yet.
 

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Discussion Starter #6 (Edited)
Before I moved on to the power supply I wanted to test the XSUS board.

As I mentioned in my first post that I read where some were able to test the XSUS board by disconnecting it from the other boards and looking to see if the TV powered up. If it powered up then the fault lied in the XSUS board. I wasn't sure this applied to my model but I figured it couldn't hurt anything to try.

So I disconnected the 2 cords (1 from the YSUS and 1 from the PSU) and the ribbon cable from the logic board and fired it back up.

This time instead of 2 blue LED flashing; I got 4.

According to the PDP self diagnosis sheet from the second post this indicates an error with the X-SUS, Y-SUS, SDR and/or PSU. Apparently the P60 didn't like what I just did. Thinking about it now I should have just disconnected the cord from the YSUS instead of all 3.

I reconnected the 3 cables/ribbons and powered to TV and got the 2 flashing blue LED again.

Now On To The Power Supply.
 

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Top 3 transistors on the last picture? Can't tell from the picture, but those look to have blown. If not, check the whole row of transistors for shorted components.

Jim
 

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Discussion Starter #8
Top 3 transistors on the last picture? Can't tell from the picture, but those look to have blown. If not, check the whole row of transistors for shorted components.

Jim
Thanks Jim!
I noticed that too but upon further inspected (I went back to the board) I figured it was a lighting issue.
Here's another pic of the same spot but at a different angle. It looks better but I will still test this out for a short.
 

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Discussion Starter #9 (Edited)
POWER SUPPLY UNIT

The first thing i noticed about the power supply was how much different it looked from the more common P50 PSUs. Not only is the layout different (and the board seems much bigger) but the PSU seems to be split into two connected only by a few wires.
 

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Discussion Starter #10 (Edited)
While the layout is different from the P50s PSU I was able to find a suspect CAP.
All the largest caps present on this PSU are either 450v-330µF (35 mm dia), a 220v-1600µF (35 mm dia) or 100v-3300µF CAP (30mm dia). There is only one 100v-3300µF CAPy and it was the one that's was bulging out a bit.

If you are looking at the pic of the main board I posted above its the one that's circled in yellow.
Here's a closeup at a different angle. Its not flagrant but its definitely puffed out.

All the other CAPS look fine.
 

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Discussion Starter #11
ON TO THE SDRs

This was the easy and fun part.

First off I found a pinhole (or shall I say crater) in my upper SDR almost immediately. It was the 8th (or last) IC on the SDR-U. No doubt a result from that sole 100v-3300µF CAP. All the other ones looked okay, but I have read looks can be deceiving so I took the trusty multimeter out and started to measure the mini caps next to each IC.

The first thing I noticed was instead of 2 mini caps, as seen in most of your P50s (see Jason76's pic), mine had was only one.
 

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A problem like this is "usually" not a visible problem. You will need to check to voltages to the XSus.

A voltage pulled very low that should be high is usually indicative of a short down line from it. Vs comes from the power supply, at around 200vdc. I usually check Vs then Va / Ve. Y and X sustain boards are waveform driven, but checking voltages can lead you to a problem on them. Check the voltages and take it from there. I always do a visual inspection, usually looking for burns and the obvious. Also look for pico fuses on the X, if one is open, there ya go.

I don't think that cap is the problem, it may be a little low, but not enough to kill a drive to the Xsus. Capacitors in recent years will vent, meaning the top splits open venting the electrolyte.

Jim
 

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Discussion Starter #13 (Edited)
Nevertheless I started testing to see what I would get.

All the mini caps seemed to have around the same resistance.
They were close but it wasn't until I finished testing them all that I started to see a difference.

Take a look at the picture and the resistance readings to see what I mean.
The mini caps on the SDR-D all read between 1608-1616.
Now the mini caps on the defective SDR-U board read anywhere from 1612-1648.
I didn't make much of it at first until I notice the pattern…

What was really interesting (as you can see below) is the resistance for every other IC on the defective board (starting with the visibly bad one) was about the same (~164X) while the other 4 had the same resistance as the ICs on the good board.

Again, I don't know any of this for sure but its seems any IC reading the same values of the visibly defective chip is bad. If I am wrong on this please feel free to let me know.
 

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Don't know why those pictures didn't show when I last posted. Problem solved.

Why that gave a 2 error, I have no idea.

Sometimes electronics theory, is, well just a theory.

Jim
 

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Discussion Starter #15
Don't know why those pictures didn't show when I last posted. Problem solved.

Why that gave a 2 error, I have no idea.

Sometimes electronics theory, is, well just a theory.

Jim
Yeah... or one of the problems!

As you said this stuff can seem like all theory but would anyone care to hypothosize on why the ICs are giving such strange readings. Strange as in every other IC is bad. That can't be a coincidence.

And more importantly, what might have caused it. It was just mentioned that the lone puffy cap may not be bad but I have not read of any other causes of blown SDR boards.

Would love to get a list going of thing I need to check or do (preventative) before I pop this repaired board in.

I contacted the guy Jason76 mentioned (FIXNEX) and he let me know that he has the ICs on hand to get the job done. I usually shop around but the other contacts I have found on these boards haven't gotten back to me yet so I don't really know...
 

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I have not read of any other causes of blown SDR boards.
I would tend to lean towards heat. Hitachi never built any sort of heat dissipation into the design of these boards. Caps could cause it. As could a ramp being too high.(the waveform driving Y sustain). Checking capacitors is ALWAYS a good practice, so don't take that as meaning not to check them.

Jim
 

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Discussion Starter #17
I would tend to lean towards heat. Hitachi never built any sort of heat dissipation into the design of these boards. Caps could cause it. As could a ramp being too high.(the waveform driving Y sustain). Checking capacitors is ALWAYS a good practice, so don't take that as meaning not to check them.

Jim
That's some good insight Jim.
Thank you.

I have read about heat being a BIG problem.
That's why I was happy to see those 2 large fans on the back of this unit.
Maybe this TV could use 2 more! :T

I'll have to read-up on this waveform driving the Y-SUS business you are referring too.
Sounds like there isn't much I can do about it though.

Also, there has to be a more precise way of checking/testing these caps.
All I have read is people eyeballing them for chips and bulges.
But I haven't seen anyone hook leads to them and getting a figure out of them.
I'll be reading up on them for clarity but there has to be a way to do this.
If anything this is done after production for quality assurance....

Then again I hear the art of repairing boards at at the component level is going away.
Even the really good technicians simply replace the boards if anything smells funny.

Jim, do you know of a good website where I can get more info on this stuff?

Thanks in advance!
 

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Discussion Starter #18
Today I ordered the replacement capacitor for that slightly puffy 100v-3300µF CAP from Digikey.
The replacement isn't the Panasonic that Jason76 used on his post.
He was kind enough to give me a little insight on the reason why he choose that specific cap (basically size, cost and life rating).

Since I am not constrained for space on the P60 I went with the CDE brand 381LX332M100K052 which is just about the same but it has a higher lifetime at operating temperature (3000 hrs @ 105°C vs 85°C), lower ESR (75 vs 90) and lower ripple current rating (3.2 vs 4.06). Everything I have read indicates that this cap will handle heat better than the original cap I have in now. The only other difference is its 10mm taller and costs twice as much as the Panasonic ($8 vs $4).

I also got the name & number to the guy from FIXNEX TV replacement parts. He says he'll be out of town for a few days so I will give him call to see what he can tell me about this defective board (alternating bad ICs) and what's involved in fixing it. I want to learn about the parts & process as much as I want it fixed (and that's pretty bad). Plus I think we will do better on the phone as I was having problem conveying my situation and getting answers via email. Hopefully we can make a lot of headway and I can get this board on and off of his bench in no time.


By the way, Digikey is amazing. I ordered the part and within an hour the item had shipped.
I have never seen such a turn around time. AND they gave me more than 12 shipping choices ranging from USPS First Class Mail (the cheapest at less than $2) to Same Day Service.

Now I have to get myself a descent soldering iron this week. The one I have a a cheap one with only a high/low setting. Reading through Jim's (74f100) TV repair information link I saw that I definately needed a unit with temperature control. I think I am going to get a Weller WTCPT.
Then I'll practice on an old alarm clock I have sitting around here.

Should be fun!
 

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For ripple current, higher is better. Ripple current is the ability to pass a.c. current. You want a cap that can deliver the most power, and that requires more current for a given operating voltage.
 

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Discussion Starter #20
For ripple current, higher is better. Ripple current is the ability to pass a.c. current. You want a cap that can deliver the most power, and that requires more current for a given operating voltage.
Thank you Leonard.

I realized this after writing that post but figured it was an acceptable trade-off for the other pro's.
Especially being able to handle higher temperatures better.

Am I mistaken?

Is the difference in ripple current ratings (3.2 vs 4.06) more important than the other factors?
 
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