[TechAssist] Sony KV27FS100L, BA6 chassis +135V source short. dead. fix
- From: Phil Bader <tjanphyl@xxxxxxxxxxxxxxx>
- To: "techassist@xxxxxxxxxxxxx" <techassist@xxxxxxxxxxxxx>
- Date: Tue, 15 Feb 2005 14:20:12 -0500
Submitted by another shop I was offering tech assist to.
Said the HOT showed dead short from collector to ground.(was Good)
Unsolder the B+ pin to the flyback supplying the +135volts to the HOT
and HOT short gone.SMPS short... Back at the SMPS, found the source.
SMPS transformer T603,pin 17, to rectifier diodes D624 and D611
produces the +135VDC. On down stream, zener D614 is across it to ground.
part: # EZ0150AV1. I assume it's a protective avalanche diode rated at
+150 volts. It shorted. Tech replaced Diode D614 and set is running
several hours now. He inherited this repair from another shop that
seemed to be in the right area and replaced the associated IC's,"error
amp" IC604 (DM-58) and opto-iso (PC123FY2) IC PN602.
I would have changed these as well had they not already been so.
Something had to cause the B+ to rise and cause this zener to short.
Possible those IC's.Seems the previous shop stopped just short of
discovering shorted D614.
Phil Bader
--
Philip Bader
Jan Phyl TV Inc. (estab. 1976)
3420 Recker Hwy. Winter Haven, Fl. 33880
Fax (863) 299-8821
email: tjanphyl@xxxxxxxxxxxxxxx
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