View Single Post
  #7  
Old 09-22-2018, 11:16 PM
Popester's Avatar
Popester Popester is offline
VideoKarma Member
 
Join Date: May 2012
Location: Lakewood, CO
Posts: 392
So, checking all three R,G,B drive transistors Q701,Q702,Q703 I seem to have 4.5V video signal P-P on my scope at the base of the transistors. I'm suppose to have according to the Sony schematic 6.3V P-P. I've included pics of the schematic so I hope you can follow along. The collector of all three of these is reading source voltage which is 126Vdc. The collectors should be at around 100 Vdc. It's like the transistors are biased off. All three emitters are about 4.63Vdc and should be about 5.4Vdc. The base voltages are low too they are reading 3.05Vdc and should be 5.0Vdc. I replace the following lytics in the video circuit to no avail. C441,C442,C404,C405,C406 and C301. I've checked transistors tonight in circuit and injected video which didn't help from the B/K analyst. I didn't see video. I have very very faint color bars on the screen. It's basically color without luminance. When I'm on the color bars if I vary brightness, and picture controls I see slight changes. If I vary color and hue I notice intensity from no color to very slight color. And hue I see a shift in my bars changing phase. I wish I could just figure out what is effecting my bias turning these outputs off. I hope the pics are helpful to someone out there. Attachment 197700
Attached Images
File Type: jpg image.jpg (111.8 KB, 16 views)
__________________
Sony Trinitron is my favorite brand.
My wish list:
Sony KV-7010U
Sony KV-1220U

Last edited by Popester; 09-22-2018 at 11:22 PM. Reason: Spelling
Reply With Quote