[TechAssist] Re: Zenith PRO851, 9-700, no video, aux muted.
- From: "Damon" <DAMON101@xxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Wed, 28 Nov 2001 20:31:11 -0500
Jim,
Read from "OH MY GOD!" to the bottom before doing any circuit tracing
Yeah, most likely. Pin1 of 2A9 is the video input from the front panel, goes
to q2206-base, out of emitter thru c2218 to pin 37 of Ic2201 (ad/da
converter ic). After that it's "digitized back and forth between ic2201 and
ic 2202(comb filter/video processor). Ic 2701 is also connected to the
databus but is the deflection processor (data bus is pins 2 thru 8, and pin
36 on Ic 2201, 5 thru 11 and pin 1 on ic 2201) (Blah, blah, blah).
Anyways here's something more basic:
Video 2 input: 2a9 pin 1 to q2206 base to pin 37 of Ic 2201
Video 1 input: 2C1 pin 2 to q2208 base to pin 35 of IC 2201(same route as
Vid 2 above)
Next: output is on pins 26, 27, 28 of IC 2201 (B, G, R) and exits the 9-700
module on plug 2c5 pins 1, 2, and 3 (red, grn, blu). Next it goes to 9-678
board (if it's used in this unit) and........
OH MY GOD! Prehistoric IK sense board!!! Flintstones....Meet the
Flintstones....
And now it's time for the EPIPHANY......I remember one of these projos I
worked on had a bad CRT BOARD which caused a weak picture. At this point
it's better to bring the schematics to you so you can isolate which board is
at fault. Anyways, this IK sense circuit keeps the sense signal separated so
it's easier to identify which crt signal is bad.
I'll drop this off tomorrow, I doubt the 9-700 board is the failure point,
either the crt board or the Ik Sense board is the likely culprit.
Damon Brunger
damon101@xxxxxxxxxxxxxx
Telrad Electronic Services
Ft Wayne, IN 46815
----- Original Message -----
From: "Jim Myers" <jr.myers@xxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Wednesday, November 28, 2001 12:21 PM
Subject: [TechAssist] Zenith PRO851, 9-700, no video, aux muted.
> Zenith PRO851, 9-700, no video, aux muted.
>
> Set has no video with video connected to the aux input and display says
AUX MUTED, menu's are ok. Is this problem likely to be on the 9-700 module?
>
> Jim Myers
> jr.myers@xxxxxxxxxxx
>
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