Nanao MS-2930 issues after recap

[Doop]

I started off by recapping everything except for the daughter board and the large B+ and filter caps. When I powered it on I got an enlarged image with overdriven red and bad side pin cushions (not pictured here). Tested it with a properly set up Mistercade (was outputting an image to this very same Blast just fine before recap) and then with a Taito-Gnet board just to make sure. Same issue on both.

Here it is after I messed with size controls on the remote board and R cuttoff on the chasis. Picture is still off.

After inpsecting the chasis for broken traces I found and (jankily) repaired a broken trace at C406 using some 30AWG wire. Ugly as shit I know but continuity is solid (goes all the way back to the vertical linearity pot!) and I threw some kapton tape on top afterwards. Don't mind the lint I used too many q-tips doused in isoprophyl while cleaning.

Plugged it in again after and the good news was that the image size and side pin cushion issues were fixed.. Also the image is no longer enlarged. But now the horizontal and vertical hold appear to be collapsing?

https://imgur.com/a/zhBk4ze

I tried messing with the horizontal hold 15kz and it only seemed to make things worse.

https://imgur.com/a/4PnpfUM

After this I went back and double checked continuity on every cap installed; everything seemed fine. Anyone have any ideas? I spoke to some of y'all on discord/twitter was told to start looking around the Mitsubishi video amplifier IC (M51387P). What pins should I be tracing the path on? Pin 17? (blanking pulse). I guess what I'm trying to understand here is a) what this issue is called and where to start looking first.

Thanks in advance!

 

[Doop]

Update: Found a cap was installed backwards at C957. Fixed it. No change.

 

[advans14]

Fixed as in your replaced it with a new cap?

 

[Doop]

Fixed as in your replaced it with a new cap?

I used the same cap but installed it correctly this time.

Edit: Just measured the ESR&DCR with an in-circuit tester (GME 236).
1.5% loss on the 10uf 35v cap @ C957. Doesn't seem blown?

 

[Doop]

Replaced C957 just to be on the safe side and reflowed U951. No change.

One thing I noticed is that if I mess with the horizontal hold pot there is still an audible change in frequency and a slight change in the image (but no improvement). Here is a picture of what it looks like running 240 test suite menu... Picture size osscilates sightly but stays at this height...

FWIW I have a replacment 7852 on the way...

 

[Doop]

- Tidied up and rechecked all bodge work. No change.

- Replaced LA7852 (Sync Deflection circuit IC) with LA7853. No change.

- Replaced M51387P (Video Amplifier IC). No change.

- Replaced LA7837 (vertical deflection output IC) with LA7838. Verified proper installation/continuity. Lost output picture completely except for a few brief speckles of blue onscreen when powering up for the first time. Tube still has neck glow.