Sony XBR Questions

[user181]

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.

[zeno]

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 !