MVS monitor problems

Hey,

I've got a Big red 6 slot MVS with a 26" display. Within I've identified a Kortek chassis and a Sharp picture tube.

The monitors display seems to be fine apart from a minor problem which is a little hard to explain. The monitor seems to "twitch" at the sides corresponding to flashes of brightness.

Only some games are affected where its really noticeable on the screen: e.g. like in strikers 1945 plus you don't notice there's any issues with the monitor until you destroy/blow up ships close to the sides of the monitor making that area twitch and then return back to normal till the next bright flash of light makes it happen again. The "twitched" video doesn't last too long but long enough to be annoying. A game like super sidekicks 2 that doesn't use any sudden flashes for effects doesnt distort the monitor at all.

Any ideas as to what maybe causing this would be appreciated.

Welcome to the forum Trenal
I think you have the same cab as mine, the twins also use Kortek monitors, which are standard in Australian L&A MVS cabs.
Maybe a cap kit for the monitor pcb would help.

Hey ttooddddyy,

I have the exact same one thats in your pic (just the 1 though), as far as I'm aware its original including the monitor and the manuals for the machine are dated from 1991. I hope its not the crt going bad with age? Everything else with the monitor display seems sharp including the colours.

I havent used any official cap kits, just replaced the 25 or so electro caps according to the manual. This fixed another problem that I used to have where a small part of the bottom display was cut off, but didnt help the above problem.

Other suggestions Ive read on here about are raising the 5v and adjusting the V.Hold which didnt work. Something I havent tried is replacing the machines power supply but I doubt it would fix this problem.

Just managed to get the ribbon cable needed for the coin mech; getting the game select and start buttons to light up now which is keeping me amused

So youve done the cap kit.

It may be a psu issue, does yours have a Peter Chou psu. Whats the 5 volts, measure it at the board not the psu as there will be drop in the harness.
Low 5 volts would more likely cause intermittent boot up, the green screen.

The pots for vert/horizontal hold are on a sub pcb and easy to get at.

As a matter of interest do your mini marquee lumi panels work ?

Yes those illuminated buttons do look rather cool

Hey,

Iv'e got a pic of the power supply if I can email it to you? Anyway I checked and it's got a Leisure & Allied Industries sticker on the side but has ENTRON imprinted on the top.

I don't have a multimeter yet so I need to get one to test the voltage. All the MM's light up but the third one is a lot dimmer then the others (You can only notice it illuminate in the dark).

As you said low 5 volts doesn't allow the neo to boot up or to keep resetting, which is what happened when I lowered the 5v on the PS. Don't think it would cause the issue with the screen, adjusting the 5v higher made the colours bleed.

have you tried degaussing ?

Hey,

Ive tried the inbuilt degauss which gets rid of discolourations but not the problem I'm having. Ive read about more powerful external degaussers but would need to know if this problem of mine is related. I dont think I could find such a degausser locally I would have to order one in and would only do so if I'm certain the problem relates to this.

I'm yet to take it in to this local arcade repairer to check it out, but I would want to try everything else before I do that.