I'm working on a Pioneer Model SD-P55A3-K Projection TV. Initially,
you can turn on the power for standby. However, when you apply main
power, the unit goes into shutdown. When I removed the board assemblies
from the light box, I discovered that the fuse (4 A) from the SMPS
transformer for the -25 and P-25 lines was blown. This line feeds
directly to the convergence board with the notorious STK392-110
convergence amps. After resoldering ring cracks on the power supply/
deflection board as well as the convergence board, I replaced the fuse
and fired up the unit. Now you can apply main power. However, a hissing
sound is heard from the flyback area. I am suspecting either the flyback
or the high voltage splitter. After talking to my secondary supplier
who supplies me with both Sharp and Pioneer parts, he indicated to
me that is very rare that the flyback or the splitter fails. When I
asked the customer what he witnessed when the tv failed, he told me that
the unit went blank with a rushing sound. I need to get this right as
my supplier tells me that the high voltage splitter can be replaced
separately but the complete power supply/deflection module with the
flyback has to be replaced completely.(Flyback cannot be replaced
separately). The module is quite ewxpensive. I will return to the
customer to perform the flyback unloading test (disconnect high voltage
splitter) that I performed initially. Has anyone encountered this
situation before. Any help would be appreciated. Thanks in advance. Ron


--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

It is rare that the flyback and splitters go, but I have seen a number of
them before. The only way to really properly test this is to try them.
Otherwise you will be guessing around for many hours.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Ron Novini" wrote in message
news:41d7c25937de2b55ae8a43a9cebdc513.123933@mygat e.mailgate.org...
I'm working on a Pioneer Model SD-P55A3-K Projection TV. Initially,
you can turn on the power for standby. However, when you apply main
power, the unit goes into shutdown. When I removed the board assemblies
from the light box, I discovered that the fuse (4 A) from the SMPS
transformer for the -25 and P-25 lines was blown. This line feeds
directly to the convergence board with the notorious STK392-110
convergence amps. After resoldering ring cracks on the power supply/
deflection board as well as the convergence board, I replaced the fuse
and fired up the unit. Now you can apply main power. However, a hissing
sound is heard from the flyback area. I am suspecting either the flyback
or the high voltage splitter. After talking to my secondary supplier
who supplies me with both Sharp and Pioneer parts, he indicated to
me that is very rare that the flyback or the splitter fails. When I
asked the customer what he witnessed when the tv failed, he told me that
the unit went blank with a rushing sound. I need to get this right as
my supplier tells me that the high voltage splitter can be replaced
separately but the complete power supply/deflection module with the
flyback has to be replaced completely.(Flyback cannot be replaced
separately). The module is quite ewxpensive. I will return to the
customer to perform the flyback unloading test (disconnect high voltage
splitter) that I performed initially. Has anyone encountered this
situation before. Any help would be appreciated. Thanks in advance. Ron


--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

Actually on that set the HV block is matched with the deflection board at
the factory. Here is a note from Pioneer's tech tips:

Symptom: Horizontal instability during brightness change after Power
Supply/Deflection Board replaced.
Cu Must replace Anode Distributor supplied along with replacement board,
they are a matched set. Note other Tip regarding proper removal of cables
from block.
Models Covered: SDP50A3, SDP50A5, SDP55A3, SDP55A5, SDP62A3, SDP62A5
Tip Date: July 21 1998

When replacing either unit you replace the other also. The FBT IS available
as a service part, P/N ATK1108, retails for $45.20. When replacing the FBT
it is not advised to change the dist. block unless it is defective as you
will need to change the deflection board also if the dist.block is bad, they
are matched. If you feel like studying the service lit and finding the HV
adjustment you could re-match them I suppose. Also, on the fuse blowing to
the amp assembly, there was a run of DAC boards that cause excessive DC
bias on the convergence IC's thus causing that fuse to blow after a period
of time. For warranty Pioneer's FSE told us to replace the DAC and the Amp
Assembly. Here's the tip on that.

Symptom: SYMPTOM: UNIT SHUTS DOWN. RESISTORS ON AMP ASSY OVERHEATING.
Cu CAUSE: DEFECTIVE CONVERGENCE CONTROL ASSY AND OR AMP ASSY.
Models Covered: SDP50A3, SDP50A5, SDP55A3, SDP55A5, SDP62A3, SDP62A5
Tip Date: February 06 1998

Check all your anode connections and make sure all leads are firmly snapped
in. Make sure you slide the gray rubber boot up the wire when removing or
reinstalling the anode leads, it sometimes interferes with seating the
cable.

And last, here's a link to Pioneer Parts for that model.

http://parts.pioneerelectronics.com/...elNum=SDP50A3K

--
Jammy Harbin
J & J Electronics, Inc
227 S. 4Th St.
Selmer, TN 38375
731-645-3311
"Ron Novini" wrote in message
news:41d7c25937de2b55ae8a43a9cebdc513.123933@mygat e.mailgate.org...
I'm working on a Pioneer Model SD-P55A3-K Projection TV. Initially,
you can turn on the power for standby. However, when you apply main
power, the unit goes into shutdown. When I removed the board assemblies
from the light box, I discovered that the fuse (4 A) from the SMPS
transformer for the -25 and P-25 lines was blown. This line feeds
directly to the convergence board with the notorious STK392-110
convergence amps. After resoldering ring cracks on the power supply/
deflection board as well as the convergence board, I replaced the fuse
and fired up the unit. Now you can apply main power. However, a hissing
sound is heard from the flyback area. I am suspecting either the flyback
or the high voltage splitter. After talking to my secondary supplier
who supplies me with both Sharp and Pioneer parts, he indicated to
me that is very rare that the flyback or the splitter fails. When I
asked the customer what he witnessed when the tv failed, he told me that
the unit went blank with a rushing sound. I need to get this right as
my supplier tells me that the high voltage splitter can be replaced
separately but the complete power supply/deflection module with the
flyback has to be replaced completely.(Flyback cannot be replaced
separately). The module is quite ewxpensive. I will return to the
customer to perform the flyback unloading test (disconnect high voltage
splitter) that I performed initially. Has anyone encountered this
situation before. Any help would be appreciated. Thanks in advance. Ron


--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG