On Thu, 7 Oct 2010 23:49:25 +0900, "Michael Kennedy"
wrote:


"Mark Zacharias" wrote in message
eb.com...
"Michael Kennedy" mike@com wrote in message
...
Sorry if this is a bit of a novice question...

I have a SMPS in Plsama tv which upon powering up starts clicking... It
seems to do it as it warms up or the load changes on the psu (screen
going dark or getting light)

As far as I can tell it isnt any relay doing this, even though It sounds
like a relay.

Ticking alone I could live with, although a bit annoying but the PSU also
occasionally shuts down when cold. I am not 100% sure what is clicking..
The clicking noise seems to be coming from different locations at
dfferent times, even possibly the X or Y sus boards.

I have sprayed the whole thing down with freeze spray to no avail... It
is built with PBF solder, so I guess bad solder joints are likely issue
also.

I have changed the obvious capacitors near heat sources excpet the two
large 400v 250uf filter caps.. Removed and checked the filter caps and
they checked good on my ESR meter.

Any Idea what would be clikcing? Here is the board layout
https://sites.google.com/site/chibamikey/PSU.JPG



I have seen similar issues on Samsung plasmas resulting from bad solder
connections at some switching transistors near the middle of the board.
The eyelets are too small and need to be scraped a bit to enlarge them
before resoldering. The board does look similar to yours. Maybe you'll get
lucky.
If not solder connections in there somewhere, failing capacitors would be
the likely culprit, although this problem has been much more common on LCD
sets. Plasmas I've seen don't seem to use the really cheap caps.

Mark Z.


Thanks you suggested that before.. I will get a closer look at the
transistors and check out those eyelits.. I havent doent that yet, and
probably would have forgot had you not replied.



About the ticking.. It doesn't stop even with the power removed. It is
almost if something is expanding and contracting, but makes the sound
equilivant of a relay?!

The really strange part is it doesn't seem to come from one consistant
place..

Power removed or TV turned off? If it continues long after the set is
turned off (but still connected to AC power) it is something in the
standby power section of the main power supply.

If it continues for hours after the set is unplugged, it's probably a
cricket.

PlainBill