Nanao MS9-29S - 15khz not working

[l33der]

I've managed to get past all the other stumbling blocks getting my arcade set up, and I even played it for a week or so... but I wanted to switch to 15khz (from 25khz) and I found that the monitor just won't turn on in that mode. It clicks as if though it were going to turn on, but I get nothing. I had it on in this mode when I was first testing the monitor, so I know I'm not doing something wrong in my setting it up... does that mean I need new caps? I can't get it to turn back on in 25khz after trying in 15khz until I let it sit without power for a while.

It also takes a long time to "warm up" in 25khz mode, the picture flickers as though the hold is way off until it warms up and then stops, is that also a symptom of needing new caps?

On that note... can anyone give me a list of the caps I need to buy? My chassis is here: http://www.jomac.net.au/Nanao%20MS9-29A-T-SU.JPG

[grantspain]

you do know you have to manually switch the freq on these monitors using the jumper plug on the chassis?

[l33der]

Yeah, I moved the plug from 25 to 15. When I turn the monitor on in 15, it doesn't even start up. But when I turn it on in 25 it works fine.

If I run it in 25 for a few minutes, then turn it off and quickly switch to 15, then it turns back on, but it powers off after a couple minutes.

[arcadecup.com]

I wonder if its going into shutdown for some reason.. otherwise maybe there is an open in that particular plug circuit.

[l33der]

Just a little bit ago when I tried to turn it on (in 25) it came up for just a moment then shut off. What could be causing it to shut off? I got it to come on by trying a few more times with a few minutes in between, and now it seems to be staying on (in 25) but I still have no luck with 15. It just won't come on at all, and if it does (because I warmed it up in 25 first) it won't stay on for long.

Is it like some kind of safety shutoff, or is there something in there that is dying and it's only tripping occasionally?

[arcadecup.com]

ok so its going into shutdown.
either you have corrupted diodes tied into the shutdown circuit or your b+ regulation is not working.
or your b+ is not set correctly.. to high.
the correct b+ is 96v dc..
use the ground off the emiter of HOT on the nanao as common ground.

[l33der]

Where can I find the b+ to adjust it? This is not my first electronics project but definitely my first monitor.

[l33der]

I found the B+ pot, but no matter what I set it to I get the same shutoff effect. I can't find where to measure it, though, so I can't say what voltage it's getting.

What kind of things can trip the protection circuit? Is there something else that could be causing it that I could try adjusting? Voltage on the power supply itself? It's only doing this in 15khz, and only does it in 25khz after I recently try 15khz...

[grantspain]

frame ic can cause ms9 to shut down,otherwise if you hear a clicking or chirping then look towards the HOT-caps are also an issue