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  #16  
Old 04-30-2017, 09:52 PM
user181 user181 is offline
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Quote:
Originally Posted by rcaman View Post
the last i got from encompass was junk and went up in a fit of sparks. and encompass would not warranty them i no longer buy ANYTHING from encompass.

Is there another supplier you'd recommend?
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  #17  
Old 05-03-2017, 11:00 AM
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Quote:
Originally Posted by rcaman View Post
the last i got from encompass was junk and went up in a fit of sparks. and encompass would not warranty them i no longer buy ANYTHING from encompass.

248 dollars of parts (mostly 2SC4834s, MX0841s, and one lamp ballast board for aDLP set) from Encompass so far (since 2012/3), and all are genuine, but even genuine parts will fail if the original problem isn't fixed - whatever caused the original part to fail will take out any replacement.

What genuine Sony replacement source do you suggest, or use? Hard to find any Sony parts in North America anymore, much less genuine without going with Encompass - expensive they are, but original and genuine.
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Last edited by Findm-Keepm; 05-03-2017 at 11:01 AM. Reason: 248 vs 348 - correction..
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  #18  
Old 09-26-2017, 12:44 PM
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I'm following-up on this issue that I originally posted in April (Sony KD-34XBR970, having trouble starting up).

The issue first occurred in April, then again in early August, and yesterday (late September), and each time I was able to resolve things by briefly unplugging AC power to the set.

I have read everything you guys have posted about the MCZ3001DB chips being the likely culprit, and I've also taken note of the fact that there are counterfeits out there to beware of. Way back in April I preemptively purchased some chips from Encompass Parts, as well as proper sockets for them. So, I'm prepared to replace them when the time comes.

However, part of me has a nagging feeling of wanting to be certain this is the correct thing to do.

Are there any measurements or tests I could do (without specialized/proprietary equipment) to verify if the chips are good/bad? Is there a typical separate root-cause for these chips to fail, or is the problem the chips themselves?

Also, since I'm able to get by -- for now -- by power-cycling the set, I'm hesitant to risk making things worse by messing with it. What general advice do you guys have for making such a repair? I'm relatively proficient with soldering/desoldering, but I have never worked on a CRT TV. Do I need to discharge the CRT before proceeding to work on the D board? I'm sure the answer is 'yes,' but I could sure use some guidance on that.

From the service manual for this particular set, it seems that some of the boards can flip or hinge for service access. Is that the case for the D board, or is it best to completely remove the board from the set and do the chip replacements on the bench?

I know I've asked several questions, and I sincerely appreciate your patience and bearing with me.
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  #19  
Old 09-27-2017, 08:56 AM
zeno zeno is offline
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There are 2 power supplies. One is always on & supplies
the micro & on/off relay ( if it has one.). Second one supplies
B+ for horz/HV. Its on/off is via a relay or other method.
You will need a schematic for at least the power supplies
to check them & see if one isnt working.

Use care changing the IC's the board is double sided & you will
probably lift some top etch. If you have very small dikes
you can try nipping off the IC pins & saving the etch. Otherwise
you will need jumpers.

We were a authorized Sony dealer / warranty station at that time.
Never seen a bulletin on the problem & Sony TA changed the subject !
It was common, I had the 30" & went through 3 sets in abt 5 yrs.
Shame of it is the 30 & 34" widescreens were the best CRT sets
ever made pix wise.

good luck Zeno
LFOD !
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  #20  
Old 08-06-2018, 04:34 PM
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Looks like I'm in the bad MCZ3001DB boat now too...My KD-34XS955 is now clicking twice (used to only be once) on power up then giving the 7 blink error code. It started a really dumb way: it was on but the computer it was monitoring was asleep so I turned it off thinking it was on then turned it on again which is when it failed...

Can anyone recommend a legit supplier of good chips? (I notice F-K recommends Encompass and rcaman says their parts were bad.)

Also is there any other preventative maintenance (aside from socketing the chips) that could help prevent this problem from occurring in the future?
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  #21  
Old 08-06-2018, 09:53 PM
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I purchased a few sets of chips from Encompass Parts, per Findm-Keepm's guidance. They seemed legit, per the attributes that folks have said to watch for. I have been limping along so far, and have not tried installing them.

Are you able to get your set to start after pulling the power cord for a short time?
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  #22  
Old 08-07-2018, 12:10 AM
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So far I have tried 2 hours unplugged and it still completely refuses to light the screen or complete power up. I plan to try it again tomorrow and see if it will stay on.

This is my main TV for HD content (which is most of what I watch) and main monitor for my wannabe HTPC so it needs to be able to power up on cue...Even if it comes on as is again it can't be going into error mode where I have to wait hours to days...Unless I just leave it on 24-7 (which I don't want to do since I don't want to use up the CRT prematurely). It probably gets 1-10 hours of use a day and power cycled as much as 10 times.
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  #23  
Old 08-07-2018, 03:37 PM
user181 user181 is offline
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OK. Then it seems like you'll need to replace the chips. What's never been clear to me is what the exact failure mode is; whether some other problem causes the chips to fail, or if they just go bad on their own. So, there's no guarantee that new chips will solve it.

I've bought other things from Encompass Parts with success as well, so I wouldn't discourage you from buying from them.
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  #24  
Old 08-07-2018, 05:46 PM
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I guess Encompass it is. After ~20 hours off it still does not power up. I even tried running it off the variac, and the only thing it did differently is continuously try and fail to power it's self on when fed around 70VAC...Above that it failed as it was yesterday and below that it is stone dead.
https://encompass.com/item/5932375/S...1/Ic_Mcz3001db
Two pairs of those chips at $25 a chip is a stupid steep investment for a BPC set, but I like it enough to want to keep it going long-term (meaning I should grab a spare set of OEM chips to have on hand while I can).


I have half a mind to also buy a pair of these cheaper non-OEM chips to test out. https://encompass.com/item/7894629/J...i_s/MCZ3001DB/

I wish there was a detailed datasheet explaining the function and design of the chip and outboard circuit better (all I can find is the pinout and block diagram). Part of me wonders if I could put two of those chips in parallel with each other to reduce strain.
Also, it seems to merely be a feedback controlled combined osc./gate driver for a switch mode power supply there are a lot of such ICs on the market so I wonder if a more rugged equivalent exists that could be built in with no or minor circuit modifications...Hard to evaluate with limited info on the original.
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  #25  
Old 08-07-2018, 07:51 PM
zeno zeno is offline
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Our shop at the time was a REAL Sony franchise & warranty station.
Although I am sure Sony looked into it there was never a "fix" or explanation
of what was killing them. They drive FET's in a switch mode power
supply ( SMPS ). Either the FET or the IC needs a start circuit to turn on/off
& my best guess is thats what fails. MOST fails were the run supply
( press on/off 20 times & it starts). A few were the standby ( STBY) or
"always" supply ( dead set). The only thing I have never seen tried was
adding a heat sink to the IC's.
These sets were the biggest example of the new "just junk it" mentality by
builders that started in the 90's & peaked with flat screens. You buy the
best CRT TV ever built IMHO & if you get 4 yrs if you are lucky. Damn shame
as they absolutely blew away all the new displays at the time & most
made now.

73 Zeno
LFOD !
Quote:
Originally Posted by user181 View Post
OK. Then it seems like you'll need to replace the chips. What's never been clear to me is what the exact failure mode is; whether some other problem causes the chips to fail, or if they just go bad on their own. So, there's no guarantee that new chips will solve it.

I've bought other things from Encompass Parts with success as well, so I wouldn't discourage you from buying from them.
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  #26  
Old 08-07-2018, 08:10 PM
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Heat sinks are a good idea worth trying (IIRC I have some DIP heatsinks on hand).
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Last edited by Electronic M; 08-07-2018 at 08:55 PM.
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  #27  
Old 08-08-2018, 10:33 AM
user181 user181 is offline
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Quote:
Originally Posted by Electronic M View Post
Two pairs of those chips at $25 a chip is a stupid steep investment for a BPC set, but I like it enough to want to keep it going long-term

Bite your tongue -- I don't think these sets deserve the BPC moniker. ;-)

They're a few levels above the garden-variety BPC.
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  #28  
Old 08-08-2018, 10:55 AM
zeno zeno is offline
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Very true. These were the last of the "all out" TV's built &
with quality. They do deserve respect.
BTW Samsung & others used the wide tubes, probably the same one.
Had a 3 yr old Samsung 30" come in with a bad FBT. Guess what ??
Part NLA. It was everyone doing this shit not just Sony.

73 Zeno
LFOD !




Quote:
Originally Posted by user181 View Post
Bite your tongue -- I don't think these sets deserve the BPC moniker. ;-)

They're a few levels above the garden-variety BPC.
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  #29  
Old 08-08-2018, 12:49 PM
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You have a point. They have the best picture I've ever seen on any CRT resolution wise, and are very good on most other fronts (round screen colors, especially my 1954 models, do seem to have slightly better color).

There is just something about spending 2X what the set cost me used for 4 little DIP chips (that probably cost well under $1 a pop to make) that does not feel right to me...Especially when the replacements are about as failure prone as the originals. If I were paying that price for a pair of chips designed to last longer than the CRT I'd feel better.

I ended up buying 3 genuine and 2 of the cheaper compatible part from Encompass. I'm going to install sockets, try the genuine and the cheap ones and test the originals (if one is good and de-soldering don't kill it may as well have another spare).
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  #30  
Old 08-08-2018, 01:27 PM
user181 user181 is offline
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Sony XBR Questions

Personally, I would not be too worried about the dollars-and-cents of it. There's more to it than just the "book value" of the set; that is, what it's worth to YOU & how much you like/want it. Keep in mind that the average person would not consider all the $$ that we spend on antique & vintage TVs to be worthwhile. We all have different things that we value differently, and that's fine.

For what it's worth, I've stocked up on a few sets of genuine chips myself.

It's obviously your choice to make, but I would only be comfortable using OEM chips. I'm not knowledgeable enough of the circuit in the set to know the risks of causing cascading failures, but I wouldn't want to take the chance.
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