Blast City screen going dim, certain boards seemingly not booting

[Jonmkl]

So after some years of growing family stuff and moves I finally had time to dig my blast out of storage and it is a bit worse for wear.

It first I was getting no picture and some of the boards I was plugging in weren't getting power lights etc, till I plugged in a Neo Geo 1 slot board and finally got picture, but the picture is super dark even with the contrast and brightness cranked. Audio sounded fine.

Could a power supply issue explain the dimness on the monitor? Insufficient power would definitely explain why the 1 slot might run and not some of the other boards. Mostly wondering if this could all be one problem or if I am looking at several simultaneous ones.

It's a Nanao tri-sync, but it isn't automatic. It has the daughterboard with the dip switches. I also noticed a few flickers on the monitor when picking up and handling the daughterboard.

Any input or direction to helpful resources would be huge.

 

[Ajax]

I would start be replacing the caps on the chassis.

You could also test the output of the PSU to ensure that everything is in order there.

 

[skate323k137]

I would check and consider recapping the PSU if it hasn't been done. Boards not booting potentially means the 5v is very weak. Audio is driven by 12V amplifiers usually, but logic ICs (which can drive video) are 5V TTL devices which can and will malfunction if 5V is too low. Causing a dim image, however, not a certain outcome.

The AC mains connect to the fluorescent fixture, monitor, and PSU, so interference from any of those can affect the other.

Normally an aging PSU can show in the way of soft video interference which clears up when clean power is applied. However it's certainly not out of line to be suspecting the monitor too at the moment.

 

[radiantsvgun]

Recap the psu, those blast psus have been run into the ground. I’d recap the sound amp while you’re in there too.

As far as the monitor, if you have a 2930- you probably want to service it while it’s still working. On those 2930x series, once something goes down it usually takes something else with it.

 

[Jonmkl]

Thanks guys. I think I am going to give this a shot.

Are there any guides on-line that are particularly good? A preferred place to grab cap kits?

If I have only done minor soldering before is this something I can pull off without ruining my stuff?

 

[skate323k137]

A preferred place to grab cap kits?

If I have only done minor soldering before is this something I can pull off without ruining my stuff?

Not sure if console5 stocks a kit for it but they're a good spot. There is also a cap list on Arcade Otaku which I originally submitted.

The Circiut board for the PSU is not too bad, you may struggle with the large filter capacitor but it's not the worst work. The sound board may be a littler more difficult but neither are rocket surgery.

 

[NEgO MANIAC]

Both cap kits here. Its an easy install even with minimal soldering skills. Give it a good cleaning and consider replacing the fan.

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