Blast City – Monitor 2930

Originally posted Oct 8, 2020

So this post will be about the 2930!

As mentioned in the previous post, when I plugged in the 2930 all I got was a blue image, I couldn’t get any Red or Green bias dialled in. When I reached out to Joey who said check the transistors which I did and couldn’t find anything obvious. Rather than sending it back to Joey, I thought, I’d try my luck with changing the neck board with the other two spare 2930’s.

Simple enough mod, desolder two wires from the flyback and unplug a couple JST connectors.

When I fired her up, I was greeted with a red and green! Of course there’s no blue!!

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So I tried my luck with the third and final neck board….

VOILA!! WE HAVE COLOUR

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Whacked on a game and she came out all good, obviously needed to dial in the horiztonal/vertical size and positions.

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So 15khz is now running perfectly, I thought I’d try my luck with getting 31khz…

First attempt at using a DC didn’t go down too well.

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As you can the image is waaay too narrow and my horizontal pot was already maxed out.

Reached out to a few people I knew that had the blast city and a 2930 who don’t seem to have this issue. So I had to trawl the interwebs further :)

I found a jumper on the chassis that stated “narrow” and “wide”, so I tried swapping it around

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That didn’t work. I then tried the 2931 to see if it was experiencing the same issue with 31khz, no such issue as I was able to adjust accordingly.

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I then read a post on Arcade otaku about changing a horiztonal limit. After looking for about 5 minutes on the board, I tried changing “H.S.L” and saw it improve so I maxed it out to get full screen. I later found out this pot stood for Horizontal Size Limit

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Working perfectly with a Naomi! Look at that buttery image! :)

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Monitors are now working, so it’s time to work on the cab itself, test for power and what not as they haven’t been tested at all yet.

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