Wow, that's quite a bummer if it can't be adjusted out. Paging MS9 guru @Hatsune Mike to enlighten us
- Thread starter BuddyC
- Start date
Hmmmm.. I swapped to a MS9 in September last year and have had zero issues after that. No pinched center. Great geometry and convergence + awesome color since I find the MS9 was easier to calibrate. My Impress has been running perfectly with no issues. I was in luck and found a NOS MS9 and got some custom cables done for a drop in replacement. Will not be going back to the old chassis.
This because there are some variation on MS9 chassis, ms 29su drive hitachi tube with less curvature than Toshiba tube and have different S correction capss due to this. Do you know what MS9 chassis chassis model is inside your cab?
What's the PCB type ?
- PCB-MAIN: 05A00675D1 (red C101, green wire over U550)
- PCB-MAIN: 05A00675C2 (red C101, green wire over U550)
- PCB-MAIN: 05A00675C1 (red C101, green wire over U550)
- PCB-MAIN: 05A00675A1 (red C101, black wire over U550)
- PCB-MAIN: 05A00585D1 (black C101)
The most important is find the perfect compromise in S correction, on MS9 the caps wich are responsible are c519 0.68uf and c531 0.47uf , so c519+c531 have a total capacitance of 1.15uf if this capacitance is increased we have a slow scan at side of the screen (more large square on left and right side of the grid) if capacitance decrease we have a more fast scan on both sides of the screen so we will have compression on the sides. It is possible to modulate the s correction also when there is no adjustment pot on chassis. I have not done on my unit because my hitachi chassis just looking better than ms9 (wich I love too). Some ms9 chassis have a modified s correction caps due to the slight diffence of the tubes used since the entire h scan circuit is a resonant circuit wich can be modulated. Some others variations are on the neck board, all ms9 chassis are still interchangeable but some could be better than others for a Capcom impress tube/yoke set.
I thought the wide / narrow jumper will affect S-correction on a MS9. EDIT: nevermind, you mentioned it.
Also, co-sign on GMK29FS looking amazing and better than a MS9. I have one, but it doesn't stay on for whatever reason? I threw new caps on it and a tried a different HOT, but it's still shutting down after a 20 seconds or so. Something's breaking down, but I don't know what.
Yeah, it's perfectly fine.
Do you have any idea what the B+ voltage on these is supposed to be?
I have to pull out one chassis from a cab to test it on bench to offer you a proper answer since its impossible to work on it when is inside the impress cab., I think I will do this for you just tomorrow and report. Have you already tested Q902 (FN651)? But most likely your chassis PSU switching is not good, we have no scheme, the good news it is a very easy chassis. The only downside is the flyback wich like Toei chassis is not as strong as the Nanao.
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Yeah, I bought a replacement just to be sure the original wasn't breaking down under stress. Same issue unfortunately.
OK was too busy with a weirdo BVM 20F1 with faulty PA board this little board was sending the monitor itself in overload protection without any picture and HV, some GMK are on my bench I hope to working on them tomorrow. They are just spares ones and all working, as you can see the black frame one is the GMK29FS3 Super Neo 29 normally drive an Hitachi tube but it is working just fine on Capcom Impress Toshiba tube, to test them all I'll use a nanao MS9 yoke/tube or a Toshiba D29CR55...
