V
Vector Viper
2) Sony 32" KV32XBR37 Chassis SCCF84VA
Came in dead, had the classic blown power regs (C4834)+blown output
(C4927)
Replaced all+the black vdr, found bad connection on 'E' of hor-out,
thought it fixed
after soldering everything....
Horout will now run MAYBE 1 min before blowing; gets hot pretty
fast....can't see pix
before this happens. Did sub a D1880 for hor out to get this
time;original
C4927 blows in SECONDS. For each horiz pulse at HOT, the trailing edge
is lifted off the
baseline (not sharp) tried swapping flybacks with a known good one with
no change.
disabling pincushion by pulling link coil WILL allow set to run with
bowed picture,
but HOT still gets too warm....What could the problem possily be?! bad
yoke???
The yoke is a 8-451-315-41. The hor winding measures 713uh on mine, if
someone has a listing
on specs for this part, let me know? I'm really stumped on this one...
-----------------------------------
Fix::
I feel so stupid....when it came in, it had a huge burn/arc mark on the
Emitter of the
Hor out transistor; this was a clue. It turns out the horizontal drive
transformer was BAD,
probably a fried secondary. The hor out shorted C to B, sending +135V
through the
transformer back to the emitter coil...
The bad xformer measured 238mh primary, 5.4 uh secondary. (with 1 or 0
rings)
A good one was 1 think 150 mh on the secondary...
This also proves a D1880 will run with lower drive, a bit higher gain, I'd
suspect.
Here's a big hurrah for keeping spare part boards!!! HURRAH!!
Aaron H.
Came in dead, had the classic blown power regs (C4834)+blown output
(C4927)
Replaced all+the black vdr, found bad connection on 'E' of hor-out,
thought it fixed
after soldering everything....
Horout will now run MAYBE 1 min before blowing; gets hot pretty
fast....can't see pix
before this happens. Did sub a D1880 for hor out to get this
time;original
C4927 blows in SECONDS. For each horiz pulse at HOT, the trailing edge
is lifted off the
baseline (not sharp) tried swapping flybacks with a known good one with
no change.
disabling pincushion by pulling link coil WILL allow set to run with
bowed picture,
but HOT still gets too warm....What could the problem possily be?! bad
yoke???
The yoke is a 8-451-315-41. The hor winding measures 713uh on mine, if
someone has a listing
on specs for this part, let me know? I'm really stumped on this one...
-----------------------------------
Fix::
I feel so stupid....when it came in, it had a huge burn/arc mark on the
Emitter of the
Hor out transistor; this was a clue. It turns out the horizontal drive
transformer was BAD,
probably a fried secondary. The hor out shorted C to B, sending +135V
through the
transformer back to the emitter coil...
The bad xformer measured 238mh primary, 5.4 uh secondary. (with 1 or 0
rings)
A good one was 1 think 150 mh on the secondary...
This also proves a D1880 will run with lower drive, a bit higher gain, I'd
suspect.
Here's a big hurrah for keeping spare part boards!!! HURRAH!!
Aaron H.
