Hitachi P60X901(60" not 50") led flashes 2 times (not 3)

lcaillo said:

My guess would be a cap with bad DA or a reset circuit that is malfunctioning. DA is also known as "battery effect" and will result in a cap voltage RISING after it is discharged. It can create some unusual effects and is not uncommon, even in new caps. A DA of over 15% is considered bad, but I have tested caps at around 10% that would not work in some circuits.

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Thanks for the input Leonard.

Can you elaborate more on the diode array issue?
Are you referring to the diodes in the bridge rectifier arrays I mentioned before?
I also don't understand how a faulty array could result in a caps voltage rising after discharge.
Does it have anything to do with the faulty array preventing current from flowing?
And how would unplugging the X&Y-SUS from the PS correct this problem?
I have tried to find reading material but have found none (regarding diode arrays and battery effects).

There is a section in the SMPS Repair ebook about Over-voltage, Over-current and Over-temperature protective circuits on power supplies. While I understand the concept I am having a hard time finding it on this circuit board. Maybe because these protections are built INTO other components (I've read) and I don't know what to look for.

Also, if I read your last sentence correctly, you are saying that you have seen caps that read +/- 10% of their target rating and still failed to work properly in some circuits? I find that astonishing since most caps I have seen state that +/- 20% is acceptable.

I have been doing a good amount of research on DA (and other parasitic effects in capacitors).
I even emailed Jestine Yong (the author of the SMPS repair ebook I read) about it and asked how common it was in his experience (since it wasn't mentioned in the ebook).

He replied:

HI,

Actually to test a cap we need to test the capacitance value, ESR and the DA. But since there is no cheap or affordable meter that can test DA thus i do not have the real percentage of the capacitor failure due to bad DA. I have personally encountered few caps that tested good using the capacitance and esr meter and yet failed when under load. The only tester i known of that capable to perform the full test on capacitor is Sencore LC103 capacitor and inductor analyzer.


Jestine
http://www.JestineYOng.com

Click to expand...

*He did not object to me relaying the message on the forum.

Since I had already checked all the caps with a capacitance and ESR meter and they seemed okay it now seems that other parasitic effects seem unlikely. It is more likely that I have a protection circuit or reset circuit malfunction as Leonard said. I'm not knowledgable enough (yet) to look at this board and figure out where those circuits are or what they would look like.

So for now the TV is back up and running.
And while I am glad I was able to get it in the state it is in I still worry about future failures.
Especially with a partially faulty power supply.

But for now this is the close of this chapter of the P60's repair.
I hope I don't have to come back for chapter 2 for years to come!

Hope this was (or will be) helpful to readers (future readers).
Your comments and suggestions are definitely welcome.
I won't hesitate to take it off the wall and fix the power supply if a working solution presented itself.

Blackshirt!

Sorry to hear about your Hitachi going down.
But I'm glad you found this forum so (at the very least) it will remove the fog of mystery around the repair.

First off, you did the right thing by unplugging it first.
I would leave it unplugged overnight and start it back up in the morning.
This will give the electronics more than enough time to discharge or reset.

If that doesn't solve the problem right off the bat then you have a few choices.
The easiest one is to take advantage of these great post-Black Friday deals that are going on.
The whole month I was fixing my unit my contingency plan was 70" Sharp LED-LCD TV.
(I even had the mount picked out on mono price).

If you are going to go the repair route, you can save your save yourself a lot of time by setting your sights on the SDR boards (for any defective ICs) and the Power supply (for any budging capacitors).
Removing, testing and replacing/repairing a SDR board is pretty straight forward and only requires a multimeter and a good repair service. SMPS (switch mode power supply) testing and component replacement is pretty difficult for a newb (well it was for me) but the good news is these power supplies are built tough for the most part and the weakest link seems to be the e-caps. You could remove the power supply and take it to a TV or Computer repair shop (or a buddy who is handy with a soldering iron) and tell them that you want all e-caps replaced.

Note: Usually we replace only the ones that has tested as bad or that are bulging, which is what I did, but if I had it to do over again I would have replaced them all because the older ones can go bad at anytime and toast your SDR board again... or worse. These caps cost $4 and less so replacing them all is very cheap insurance.

I have no idea how much a shop will want to charge but removing and replacing less than 12 caps on this board shouldn't take long at all.

You should start trying to find replacement IC chips or a whole SDR board. As you've read, its cheaper to replace a bad IC than buying another board. You can check with FIXNEX to see if they can get the ICs you need. The reference numbers on the ICs are 740101 / R2A20282AFT / JAPAN.
I know when I sent my board in to them there was a problem sourcing these ICs in the US.
It maybe better these days.

Once your SDR board(s) are fixed and your power supply is inspected and/or refurbished all you need to do is get it put back together and powered it up.

I'm pretty confident that this will solve your problem (with the symptoms you mentioned).
You maybe saying "that's easy for you to say!" but the members of this forum are pretty knowledgable and helpful. And you have as much as my time and assistance as you need if you decided to go forward with the DIY.

No matter which route you go, you should keep the wife and kids pacified by getting one of your bedroom tvs and setting it up for them in the sitting room. Don't worry... after 3 days they will be used to that 32" screen and this will give you the peace of mind to focus on the repair. I know all too well to dagger-like stares from the wife as the days and weeks rolled by! LOL

Thanks for the quick response. really apprecaite it. So this morning, I unplugged the unit completely and when I got home a few hours ago, plugged it back in. I told myself if this worked, you were getting a christmas present alas no. same blinking lights so the long shot easy fix is out. I shared you comments about the 70 inch LED with my wife and she liked that idea - for the most part because she doesn't want me to spend 3 months trying to fix something myself that she believes probably still won't work, I'm very ADD as it relates to technology - yes the microwave in the basement is still flashing "12:00" so there is history here.

I'm leaving for out of town for a few days so the the fam will be congregating in the basement. I think my game plan is going to be to buy a 60/70 inch LED/Plasma/LCD - really need recommendations. . I LOVE The image on the plasma, not so much the LCD in the basement and I really don't know much about LEDs.


So I'll replace the Hitachi, then start working on it so that when it's fixed (I say "when" because I'm determined) it's be the upgraded TV in the basement and the 40 inch LCD will replace my old sony trinitron, yes I still have one of those lddude:

So, for now I'm buying a new TV - since I have :T from the wife. And then move the Hitachi to the workshop and start the surgery. I'll keep everyone posted on my progress. in the meantime, I'll take reccomendations for the replacement.

thanks again for your thoughts. really apprecaite it.

Erf

Okay folks i feel the need to report back on the last couple of months.
Everything was chugging along all fine and dandy until 1 month ago when the Tv powered on with a black screen (no blinking lights though). I tried to fix iit right while it was on the wall with my little procedure of unplugging the power supply from the sustains and power cycling it but it didnt take.

So we removed it from the wall and laid it along the wall in the next room. The next day, i removed the back and did my procedure again and the Tv initiallied. Everything worked fine.

Not the one to let an opportunity pass me by, i ordered all new caps for Power Supply 2 from Digikey. A few of them were custom made by Chemicon for the P60 and were never commercially available but tech support at Chemicon were good enough to send me replacement samples.

After replacing all the caps (~$50) i expectected the Tv to behave as it should but it didnt. Since i had already tested almost every little diode and array on the power supply i felt in my bones the problem lied with the Y-sus (due to the fact that the chips SDR boarsds blew). But i could not visually detect anything and the symptoms indicate a charege/discharge problem of sorts. I figured since i had resucetated the tv once again i would put it back on the wall and tackle the problem the next time it goes on the fritz.

About a month later (yesterday) it happened again. Black screen with no blinking lights or should i say solid blue lights. Like last time my attempts to disconnect the power supply from the sustains and power cycle it while up on the wall proved futile. I tried to revive the patient a few times that day....but it was no use. So we pulled it off the wall again and set it against the wall in the other room.

This time i am fresh out of ideas. I will pull the back off again to see what i can see but i have already come to the realization that it may not go back up on the wall. To be honest i was not happy. Not just at the thought that i would have to buy another set but at the idea of owning an LCD TV again. To me the picture quality on a plasma is head and shoulders above any LCD tv i have seen.

But after some reading and research i realized i didnt have to settle for an LCD. Plasmas have come a long way since 2008. They can be very light weight, have energy star ratings and as ultra slim as any lcd tv out there. I wouldnt mind owning anothe Hitachi but i they got out of the PDP game. So tonight i placed an order for a Samsung PN64D7000.

While i should be happy with my new purchase I just cant take my mind off of My Hitachi. Its an amazing beautiful machine. Heavy as an engine block but a beaty to look at. It just ran out of track (no more after market parts).

I'll take the Y-sus out and start testing it as much as i can but IIRC the service manual didnt have anything in the way of troubleshooting that component.

I'll keep you guys informed of what i find out.

Ever since I had the P60 sitting in the next room collecting dust, the new Samsung Plasma has arrived and is mounted.

That set is a beauty.

Ultra thin and amazingly light compared to the P60.
It lays as flat on the wall as a picture frame.
Picture is what you expect from a Plasma (awesome) and I even watched a few of Dtv's 3D channels.
I'm still a firm believer that 3D at this stage is gimmicky but its a nice feature to breakout whenever you are bored.

Anyway, tonight I decided to take the back off the P60 to see what I could see.
I was half expecting to come across a pitted IC but everything looked okay.
I went through my routine of unplugging the X & Y-Sustains while power cycling trying to get the TV give me a few blinking blue lights but I got nothing but a solid blue light.
Fan cut-on a second then back off again and the PDP (screen) refused to initialize.

By now I kinda know what not to waste my time on so I decided to disconnect the bridge between PSU1 and PSU2 and power cycle the TV. I did this because the PSU was the components I have been spending the most time with and all other components down stream look good.






The status light turned on (blue) then turned back off again (red) and wouldn't come back on. I unplugged the TV and when I reconnected the bridge I got a small discharge (pop) from the stored up juice in the capacitors. Then I replugged the TV with the wires to the sustains still disconnected and and WHALA.... I got my familiar 3 flashing lights. I unplugged the set again and reconnected the Sustains. Upon plugging and powering the TV up the screen initialized and I got a picture again. From removing the back cover to getting a picture again took about 10 minutes.

I smirked and shook my head.

Seems I have (or still have) a power supply problem that came (or was never solved) by the replacements of all the caps on PS2. Whether this strictly a PS problem I cannot know without a replacement PS to try to replicate these behaviors. My earlier suspicions about a sustain problem is looking less and less likely now but it may very well be a combination of the two.

I'm at a loss of what to do now.

I have a finicky TV that goes brain-dead every 2 months like clockwork.
Meaning I can't give it to someone as they would be inheriting my problems.
I really love this TV but its too big to go anywhere else.
I have no stand to sit it on and I'll be damned if I try to mount it on any wall again.

Interestingly I have been seeing a few parts for it popping up here and there but now power supply (Part number HA02001).

There is something funky about this power supply but I am not experience enough to diagnose it.
Back when I was trying to get it to work I tested every component I could with the tools I had available and everything "seemed" fine on a component level.

I'm taking votes on what you guys think I should do with it:
Keep it and make it in my pet project endlessly trying to make it as good as new?
Or part it out leaving the best parts of it (the plasma screen) to rot in a landfill?

74f100, you might be onto something...

I decided to find a stand for this TV because I was not going to wall mount it again if I decided to keep it and having it on a stand would make it more practical for a buyer if I wanted to sell it.

Since this TV didn't come with a stand (a $400 optional accessory) and there weren't a lot of these TVs out there to begin with I figured I would have to go with an aftermarket stand that could support the weight.

There were a few out there but I happened across the original stand by chance and talked the owner into giving it to me for $50 plus postage. It was sitting in his warehouse for years anyway and at that price it was too good a deal to pass up.

The stand itself is about 40 lbs :gulp: and uses two 2-3" thick solid steel beams to support the TV. But having it for this repair is a good thing because I was never really comfortable with the TV leaning agains the wall like it was.


So once I got the TV on the stand I plugged the TV back in and got the solid blue LED with no picture (as expected).

I went straight for the wire that connects Power Supply Unit 1 and Power Supply Unit 2, unplugging it instead of the wires to the sustains.
When I reconnected the wire (got the loud pop) and plugged the TV back up again the TV came on and I got a picture.

So its definitely a power supply problem.
Since I already changed all the caps on PSU2 I'm going to take your advise and have a look at the caps on the other power supply (PSU1).
Lucky for me there aren't a lot of caps on PSU1 so I'll start testing the obvious caps which are in plain sight first.





Hidden caps sound like a full blown nightmare.
I'm not sure I can even get my heat sinks off without hot air because they look like they are soldered in with molten aluminum.

.