Samsung PTV STK392-040 replacement caution notice

[[email protected]]

I went on a call last week on a Samsung Proj. model PCN5425R which had
a dynamic convergence problem. I just received the two new STK's which
I ordered, and they came with the following notice:


IMPORTANT SAMSUNG STK392-040 REPLACEMENT INSTRUCTIONS
Instant failure of the new device will happen when replacing this
device on ALL Samsung projection televisions unless the following
precaution is taken.
Before installing your new STK's we recommend clearing any erroneous
data from the convergence memory that may damage the new parts before
installing the new parts.
Using the OEM remote, for the TV, power on the TV and press <MUTE>
1-8-3. This will reset the factory convergence data. You should see a
cross hatch on the screen verifying that you are in convergence mode.
Then press the <ADD/ERASE> button to save the reset data, then press
<SMODE> button to exit.

During that first service call I removed the convergence board,
brought it to the shop and removed the two IC's in preparation for
installing the new ones when they came in. The preceding notice
suggests that perhaps I should have performed this "reset" procedure
with the suspected bad IC's before I removed the board from the set.
Does that sound right? If so would I have to reinstall the old chips,
take the board back to the customer's home and perform the reset
procedure and then replace the parts? I can do that if necessary
however, now I don't know which chip went in the left or right
position. Would that matter? So I'm somewhat confused. Can anyone shed
some light on this? Thanks for any help. Lenny.

 

[Dani]

I never heard of that, with any brand TV. Where did you get the IC's
from? Dani.

 

[[email protected]]

Maybe in some cases scrambled PROM data caused / could cause some wild
scan/convergence scenario that would overstress the new devices?

I doubt that the devices require a specific location unles some
special markings exist.

I went against Panasonic factory advice and installed OEM devices in
my PT51DX80A. That was two years and many hundreds of hours ago.

If you want to be 100% safe install the old devices and go back to the
customer and do the reset provided the old devices worked well enough
for you to view the setup and were not endangering other components.- Hide quoted text -

- Show quoted text -

The replacements came from Prelco. Lenny

 

[Leonard Caillouet]

Disregard the wise crack, sorry

Doesn't really matter where they came from. You asked what to do about
the reset I advised to be 100% safe, do it with the old devices if
safely possible. My addition of the PT51DX80A was just an example to
confuse you further.

You can run the set with the power to the output ICs removed or with them
out completely. It will not change the reset proceedure which just wipes
the data in the EEPROM for the convergence generator.

I have fixed dozens of these sets and you are unlikely to blow the new chips
instantly unless there is a large d.c. offset on the inputs. If that is the
case the DCU is likely bad and a reset will not solve it. The real reason to
reset these is that sometimes they have corrupt data that causes the chips
to run hot due to exagerated correction waveforms. They won't blow
immediately but you will find it hard to align and the chips will run even
hotter than normal. The run hotter than most sets that use them anyway.

I have a good discussion of convergence repairs in general in the first 10
posts here:

http://www.hometheatershack.com/for...based-rptv-convergence-repairs.html#post43725

Leonard