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Sharp Image Repair (CRT Repair service in Las Vegas, USA)

From the PM I got, it sounds like his geometry stuff is off. As long as you stick to the pots that don't have epoxy on them, you should be fine. He also bought some strips to get the corner convergence as best as possible.
 
DecepticonZero said:
From the PM I got, it sounds like his geometry stuff is off. As long as you stick to the pots that don't have epoxy on them, you should be fine. He also bought some strips to get the corner convergence as best as possible.
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Sounds like he has to adjust the pincushion settings, ugh. It makes life a lot easier if he gets someone else to help- another set of eyes works wonders.
 
Page 52 and 53 of the Bass Fishing Manual describes the function and location of each of the Adjustment Pots:
https://wiki.arcadeotaku.com/images/6/65/Sega_Blast_City_Bass_Fishing.pdf

On the Remote board:
VR282: Contrast
VR280: Red Gain
VR281: Blue Gain
VR283: Brightness
VR284: Horizontal Size
VR285: Horizontal Position
VR286: Vertical Size
VR287: Vertical Position

On the Chassis:
VR201: Red Cut-Off
VR202: Green Cut-Off
VR203: Blue Cut-Off
VR452: Pincushion Distortion
VR451: Trapezoidal Distortion
VR286: Vertical Linearity

^those last 3 are what you're looking for if you've got "geometry issues" beyond size and position.
 
Be very careful adjusting those, you can easily make things worse. If it's corner convergence issues they will probably need to be fixed with convergence strips instead of those pots.
 
kuze said:
If it's corner convergence issues they will probably need to be fixed with convergence strips instead of those pots.
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not "probably".. convergence issues have NOTHING to do with geometry.

honestly if the chassis has been capped and convergence issues remain you probably need to reconverge the tube. strips shouldn't be needed on a modern crt that's been recapped and properly adjusted.
 
I think we should make sure that 8bits chassis has been recapped- especially on a blast, they should be checked out. @8bitforlife do you know if that chassis has been recapped yet?
 
DecepticonZero said:
8bitforlife said:
probably not it came from kc
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maybe send it out for a kit first, then start messing with the geo settings. That way you can "set it and forget it."
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^ This right here. Cabinet is 22 years old now and if there are no signs of it being recapped or no date marks stating it was recapped, I would send it in to get recapped.

These cabs have had a lot of hours thrown at them. Electrolytic Capacitors are literally rated by Hours and they do break down over time. Recapping is overlooked by many in the hobby and just ignoring it can lead to potential permanent dmg to otherwise perfectly working components. Especially when it comes to 2930 and 2931 chassis.
 
I wanted to bump this thread to share my recent experience with Sharp Image Repair.

I bought a Nanao MS2930 from Yaton as a backup a few months back. The chassis was pretty gross and the picture quality was ok at best. Well fast forward I decided to send it in to Sharp Image to fully service the chassis. It took about 2 weeks to get it back in my hands and cost about 155 + shipping for the repair. Well one of my Blast city's was having a little issues with some colors near the top of the screen, so I decided to take it out and replace it with the serviced one to see if there's a huge difference. Well I got the old chassis removed and the repaired one in, but I noticed that the screen pot on the flyback was a little off because the screen was hella bright when first powered on. Fiddled with the screen pot and adjusted the contrast and brightness and damn...the picture is absolutely stunning compared to the old chassis. I couldn't be any happier with the quality of the service and the decent turn around.

Oh and they cleaned it up really well :)

Pics of the chassis below:

Chassis before service

wRJo0Fs.jpg


Chassis After Service


SQox9SE.jpg



h1ogV3B.jpg


Fully Assembled:

gZMVkkP.jpg

 
my only suggestion as i have got chassis repaired and bought from them is to look over the chassis. I had a couple cap legs floating around under stuff that could cause shorts. Nothing bad just check for cap legs they snipped and missed.
 
Please don't take the following as gospel.

Some of the caps look "wrong". Replacement caps should be more or less same size. If the can size is noticeable smaller, then something is possibly off. I can spot C912, 47uf 200V right off the bat.

I'd be interested in what they put in C703, 6.8uf 250V, because it's something I had trouble finding a replacement for.

https://wiki.arcadeotaku.com/w/Nanao_MS-2930-S

Lower right in the cap map.

Actually, here it is. I found one in my pile of junk.

caps.jpg

Left is what is in originally in this chassis, right is just something I had on hand. Capacitance matches, voltage is equal or higher. What's the problem? Left reads 0.2 ohms for equivalent series resistance (ESR), right reads 3.9 ohms. That's orders of magnitude greater. Higher ESR causes more ripple.

So if I replace it with the one on the right, how will that ripple manifest in this case? Possibly in no discernible way. However, I like to think the cap is low impedance for a reason.

Food for thought!
 
here is my 2931 from them They should be getting my 2930 i shorted trying to get moonwalker to work today.

GSlcQ4Y.jpg
 
Moonwalker - that is not jamma.. I think it is a system 16 and you need the adapter to jamma.. that's how I use my Shinobi board
 
nem said:
Please don't take the following as gospel.

Some of the caps look "wrong". Replacement caps should be more or less same size. If the can size is noticeable smaller, then something is possibly off. I can spot C912, 47uf 200V right off the bat.

I'd be interested in what they put in C703, 6.8uf 250V, because it's something I had trouble finding a replacement for.

https://wiki.arcadeotaku.com/w/Nanao_MS-2930-S

Lower right in the cap map.

Actually, here it is. I found one in my pile of junk.

caps.jpg

Left is what is in originally in this chassis, right is just something I had on hand. Capacitance matches, voltage is equal or higher. What's the problem? Left reads 0.2 ohms for equivalent series resistance (ESR), right reads 3.9 ohms. That's orders of magnitude greater. Higher ESR causes more ripple.

So if I replace it with the one on the right, how will that ripple manifest in this case? Possibly in no discernible way. However, I like to think the cap is low impedance for a reason.

Food for thought!
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When I was comparing and contrasting the old chassis with the serviced one, all the caps looked identical. I know the original one has never been serviced and all the caps are original. I'll double check again and look at the cap values when I get home. But if the cap values were off, wouldn't the picture be somewhat off or something of that nature?
 
BlinG said:
I'll double check again and look at the cap values when I get home. But if the cap values were off, wouldn't the picture be somewhat off or something of that nature?
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He's not talking about the cap values such as farads and voltage, he's talking about the ESR, which is something that most people don't look at when replacing caps.

it's also rarely printed on the cap, you'd have to look up the model number of the original cap (which you don't have) and the model number of the new cap (which you don't know), or test the ESR of the original cap (which you don't have) and compare it to the measured ESR value of the new cap (which you'd have to remove from the PCB to test).
 
twistedsymphony said:
BlinG said:
I'll double check again and look at the cap values when I get home. But if the cap values were off, wouldn't the picture be somewhat off or something of that nature?
Click to expand...
He's not talking about the cap values such as farads and voltage, he's talking about the ESR, which is something that most people don't look at when replacing caps.
it's also rarely printed on the cap, you'd have to look up the model number of the original cap (which you don't have) and the model number of the new cap (which you don't know), or test the ESR of the original cap (which you don't have) and compare it to the measured ESR value of the new cap (which you'd have to remove from the PCB to test).
Click to expand...
just FYI in almost all cases you can ESR test in circuit without removal capacitor.
 
twistedsymphony said:
BlinG said:
I'll double check again and look at the cap values when I get home. But if the cap values were off, wouldn't the picture be somewhat off or something of that nature?
Click to expand...
He's not talking about the cap values such as farads and voltage, he's talking about the ESR, which is something that most people don't look at when replacing caps.
it's also rarely printed on the cap, you'd have to look up the model number of the original cap (which you don't have) and the model number of the new cap (which you don't know), or test the ESR of the original cap (which you don't have) and compare it to the measured ESR value of the new cap (which you'd have to remove from the PCB to test).
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Ok, but I do have the original cap info from the original chassis that I pulled. However, I don't think I am going to go the extra lengths to test the ESR values and purchase new caps when the chassis is running fine the way it sits right now. Maybe it'll go out in a week, month or year...I dunno, but if it does I'll just put the old chassis back in.
 
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