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MS9-29A 15khz Sync(?) Issue

FPJ

FPJ

Student
Joined
Jun 3, 2019
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Location
Richardson, Texas
I have two MS9-29A's in a Vs City and I did a cap kit on both because they were both looking pretty dull. One is great now, the other seems to no longer want to sync. When I hook up the TPG, you can see something for a split second and then I lose image entirely and there's that telltale high-pitched noise like it won't sync. This is only on the 15khz signal. If I switch to a 24khz signal, at first I had an image but it was wonky and then adjusting the HH24 pot got it solid. So whatever is happening is only affecting the standard res.

I have triple checked to make sure I didn't put any caps in wrong, they're all in the right positions. I've tested a bunch of parts along the horizontal line, comparing to the good chassis and haven't found any bad transistors or resistors yet. I went ahead and tried replacing the LA7853 at U550 and it changed nothing. I've checked the HOT, Q508 and a bunch of other stuff. B+ is good, it's right at 76v for 15khz.

Any ideas on what else I could take a look at that would only be affecting the sync on 15khz?
 
Did you check the HH15 pot as well? To adjust and actually measure to make sure didn't accidentally break or something.
 
Yeah, I should have mentioned that, I thought about the fact that I didn't mention it after I went home. I tested the pot and it is good and no amount of adjusting will get an image to sync. It changes the pitch of the noise, but nothing visible happens. I also checked all over thoroughly for bad solder.
 
This monitor is not auto sync, are you switching the 15/24 header on the board too? Maybe obvious.. but you never know..
 
You didn't state it in the post and i cannot see the relay in my crystal ball. Autoswitching 29A isn't common, so i had assumed you didn't have one.

Does the relay click at all when you change the tpg from 15 to 24? You didn't tell us this. Maybe post a pic of the chassis.
As 15K was working before, check your caps and work. Did you buy the 'kit' online or replace caps as you pulled them?
I never buy kits, who knows how old they are and how long they were in the bag. I hate how these are now known as 'magic bullets fix all' when in reality they don't.
 
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