PROSCAN CTC169 OnScreen Display Sync Problem
Same problem I didn't work on since a year ago!
(I didn't want to take the set apart until I had the replacement transistor in hand.) Helped by this group, I replaced Q4402 (H-Sync emitter follower/buffer) but no change. Now I have looked at emitter & base of Q4402, as well as Pin 23 of Controller U3101. All waveforms agree with the service manual. Any further suggestions? My original post was as below: The ProScan 27" set with CTC 169 [AJ] chassis is over ten years old. Recently onscreen display started tearing; after an hour or so of "warmup" it would be OK. Now it never displays properly. Video modulation comes through. Horizontal sync is the problem; vertical is OK. I have the Field Service manual, which says "The OSD horizontal position is phase-locked with the H-SYNC signal at Pin 23. . . . Components external to the micro at Pins 25 and 26 set up the characteristics of the OSD PLL." Pins 25 and 26 go to 2 resistors and one cap to ground. This set is a mess to work on. If I am sure that it's one of these three parts, I'll do it. (Otherwise I'll just forget about the OSD!) Any suggestions? Thanks - Matt Baum Expert in the obsolete! |
All times are GMT +1. The time now is 06:23 AM. |
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 DIYbanter