[TechAssist] Hitachi 60sx1k -AP 14 chassis. Big Pix Bending, poor sync
- From: <damon101@xxxxxxxxxxxxxx>
- To: "TechAssist" <techassist@xxxxxxxxxxxxx>
- Date: Tue, 9 Oct 2001 08:24:09 -0500
Hello everyone,
Recently worked on a Hitachi PTV ap14 chassis with darker than normal picture,
no or erratic vertical sync and horizontal bending only at the bottom 1/3 or
top 1/3 (not at the same time).
I tested the sync signal at the vertical output and horiz drive using the NTSC
generator and found that they were locked to the generator. Also tested the
power supply and found about 2 volts of ripple on C952, C957 & C958. Gonna
replace those caps...
I checked the PIP and here is my concern: The small Picture is not present
using video 2 (Pip's main source is only Video 2) and is replaced by a green
field. Video 2 is present on big picture so the failure point must be in the
PIP. The customer doesn't care to have the PIP replaced unless it fixes his
scrambled Big Picture. Has anybody seen the Big Picture lose sync in the Pip?
Yet the horiz/vert outputs are locked to the sync. Slightly weird set of
symptoms, I would have guessed bad sync at the outputs and looked at power
supply, or the video jungle IC for starters. Any help would be appreciated, I
only get 2 or 3 Hitachi units a year.
Thanks in advance,
Damon Brunger
damon101@xxxxxxxxxxxxxx
Telrad Electronic Services
Ft Wayne, IN 46815
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