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(SOLVED) MS-2930-S (blast city) No R and B gains.

erdrick1980

erdrick1980

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Hey guys.. yes, another blast city monitor issue.

So I started my cab today and noticed no red, so I tried turning the red gain on remote board and nothing. The blue worked. So after reading on here to similar issues I took neck board out of tube and started to reflow almost everything, after I did that, now the blue is gone and messing with the B pot did nothing either. And ended up with this images now.

20230410_213040.jpg
20230410_213036.jpg
Here are some pics of the neck after reflow. Could it be I accidentally burned out the transistor?

20230410_213259.jpg
20230410_213335.jpg
20230410_213343.jpg
20230410_213416.jpg

Thank you for looking.
 
Do you have a desoldering iron like the Hakko FR-301? A troubleshooting method for these types of issues would be to swap the color drive transistors around and see if the problem follows.

Before doing that, though, I would recommend checking out the cables that connect the neckboard to the main chassis. I've had issues in the past (lacking certain colors, no sync) because of those cables. Try reseating them, and also reflow them on both ends. Check those headers on the neckboard for any corrosion and clean them up with some deoxit if needed.

Also maybe check the CRT socket on the neckboard to see if there's corrosion there, also the pins on the CRT, and clean up if needed.
 
benime said:
Do you have a desoldering iron like the Hakko FR-301? A troubleshooting method for these types of issues would be to swap the color drive transistors around and see if the problem follows.

Before doing that, though, I would recommend checking out the cables that connect the neckboard to the main chassis. I've had issues in the past (lacking certain colors, no sync) because of those cables. Try reseating them, and also reflow them on both ends. Check those headers on the neckboard for any corrosion and clean them up with some deoxit if needed.

Also maybe check the CRT socket on the neckboard to see if there's corrosion there, also the pins on the CRT, and clean up if needed.
Click to expand...
Thank you, I have tried most of that, maybe I can wire brush pins gently or something they seem dirty.
 
erdrick1980 said:
Thank you, I have tried most of that, maybe I can wire brush pins gently or something they seem dirty.
Click to expand...
Just be careful using a wire brush like that.

If you don't have a fiberglass scratch pen, it might be worth looking at getting one. They're cheap and great for this application (I use one to clean corrosion off JAMMA edges all the time).
 
benime said:
Just be careful using a wire brush like that.

If you don't have a fiberglass scratch pen, it might be worth looking at getting one. They're cheap and great for this application (I use one to clean corrosion off JAMMA edges all the time).
Click to expand...
Glad you gave me a heads up. I'll look into it.

I'm going to start checking all the transistors on the neck board for continuity and see if I find something. I'm in this rabbit hole and it's actually kinda fun. If all else fails I'll ship it to sharp or PNL as previously stated by some awesome forum members.

Once again thank you man.
 
This happened to my monitor except i could only display blue and it was waaay overblown. Transistor on the neckboard was the culprit.

@GeekMan1222 did the work on it and may have some input. But yea… check that green transistor on the neckboard
 
JSN_ said:
This happened to my monitor except i could only display blue and it was waaay overblown. Transistor on the neckboard was the culprit.

@GeekMan1222 did the work on it and may have some input. But yea… check that green transistor on the neckboard
Click to expand...
Thank you brother. But, I gave up and sent it out SHARP to get fixed.
 
UPDATE:

So I got the chassis back from SHARP REPAIR. Unfortunately after hooking it back up I now don't have red, blue works. I have 2 controller boards and both red pots did nothing. Sucks because they send me a video of it working perfectly.

The repairs were:
Board repair
Capkit
New flyback

I'm starting to believe maybe my tube red gun capped out?

Anyways will contact them tomorrow and take it from there.
 
JSN_ said:
This happened to my monitor except i could only display blue and it was waaay overblown. Transistor on the neckboard was the culprit.

@GeekMan1222 did the work on it and may have some input. But yea… check that green transistor on the neckboard
Click to expand...
I think theres like 3 total transistors per color gun. Your main color amp transistors are heat sinked but it seems from what from some people that some of the smaller transistors near by can actually burn out. If you can try to check those to
 
GeekMan1222 said:
I think theres like 3 total transistors per color gun. Your main color amp transistors are heat sinked but it seems from what from some people that some of the smaller transistors near by can actually burn out. If you can try to check those to
Click to expand...
Thank you GeekMan1222.
 
I pulled mine ff a cursed parts board that killed a tube (the only time I ever seen that happen) but not everyone has that luxury but iirc I did look those up and they are online somewhere.
You might also want to search other parts vendors if there is no equivalents sold by people like Digikey.

I have used a site called Quest Components in the past for NOS obsolete ram chips and some other IC for a board I had and couldnt find the parts for unless it was from some questionable chinese seller on ebay. They might have an order minimum I cant remember anymore but it came professionally packed and quick too. Probably not needed for these but its useful info none the less.
 
GeekMan1222 said:
I pulled mine ff a cursed parts board that killed a tube (the only time I ever seen that happen) but not everyone has that luxury but iirc I did look those up and they are online somewhere.
You might also want to search other parts vendors if there is no equivalents sold by people like Digikey.

I have used a site called Quest Components in the past for NOS obsolete ram chips and some other IC for a board I had and couldnt find the parts for unless it was from some questionable chinese seller on ebay. They might have an order minimum I cant remember anymore but it came professionally packed and quick too. Probably not needed for these but its useful info none the less.
Click to expand...
Thank you.

But gave up, and sent it back. Hopefully it's not another 2 month wait...
 
erdrick1980 said:
Thank you.

But gave up, and sent it back. Hopefully it's not another 2 month wait...
Click to expand...
Wait which transistors are you looking for? I did buy some up... have a big pack. I'll post a pic of them shortly
 
JSN_ said:
Wait which transistors are you looking for? I did buy some up... have a big pack. I'll post a pic of them shortly
Click to expand...
It's cool, don't worry about it. Shipped it back to repair. I'm assuming red transistor but who knows. I'll just let them figure it out since I paid already.

But, thank you brother.
 
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So little bit of update.

Just got a call back from SHARP REPAIR and told me chassis is working perfectly. So they will be sending it back. I'm wondering if it has something to do with sega I/O pcb or some bad wiring connections. Soon as I get board I will disconnect everything back out and check all wiring,connectors, and hope I find something.
 
tripple check the rgb wires from start to finish. I found a blast like last year that had a loose red terminal for the connector that goes to the monitor and you have to push on it to make sure it has a positive connection
 
GeekMan1222 said:
tripple check the rgb wires from start to finish. I found a blast like last year that had a loose red terminal for the connector that goes to the monitor and you have to push on it to make sure it has a positive connection
Click to expand...
Good idea. Will definitely check that for sure. Thank you geekman.
 
Update:

So I was checking all the wiring and found this wire that looked like it broke off the jamma harness.

20230709_150249~2.jpg



and guess what? It's number 12 pin (RED!!) so I'm certain for sure that was my issue. It didn't look like it was at first but when I was moving the wires around it moved out easily. The only thing is the other half is inside and there seems to be nothing left to soldered too.

Unfortunately I haven't received the chassis back yet to test but soon. Maybe I'll just get a knew loom. I guess loom1 is the one correct? Or maybe they buy those types of pins? And I can probably try to crimp it, if I manage to be able to pull out the old one.
If that turns out to be the issue... me looking like an idiot will be an understatement.
 
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