Help w/ Nanao MS8-26SG

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Help w/ Nanao MS8-26SG

Post by NoAffinity »

Fellow otakus, your help is urgently needed.

It seems for every successful project I take on, there's a nightmare project soon to follow. Welcome to the new nightmare. I did a cap kit on my Aero City's MS8-26SG, including the filter cap. I was meticulous, pulling the caps, confirming ratings as they were coming out, ensuring proper orientation going back in, re-checking all my work. Re-flowed a couple headers, too, as well as a couple other solders that looked questionable.

Put it all back together, and the monitor isn't even powering.

Took the chassis back out. Went over the cap list again, verifying against what was installed. Re-checked all orientations. Reflowed a few more things. Rinse and repeat a couple more times. Still no life at the monitor.

Checked the 120V power cable that the monitor plugs into within the cab, and there is good 120V AC there.

What next?

:edit: and the game plays blind.
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Re: Help w/ Nanao MS8-26SG

Post by thegreathopper »

First of all make sure you have power on the chassis, you have probably missed the obvious,,, I know I do it all the time.. 8-)
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Re: Help w/ Nanao MS8-26SG

Post by PrincessPrinPrin »

Weird, aren't cap kits supposed to fix all monitor problems? I've heard that on a forum that starts with K...

So... was it working before the cap kit? 8-)

You should connect a light bulb to the B+ line and see if it lights up and meter the voltage. You can remove the b+ fuse (F902) and connect the bulb to the fuse holder and ground (an *actual* ground point). If light off/no voltage then check things before the fuse, especially bridge rectifier and voltage regulator (2SC3306).
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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity »

Thanks guys! Yes, it was working before capping. I should have just left it be. The image looked very good, but there was some curling at the top of the screen and I couldn't expand fully vertically to fill up the screen. That's what prompted me to do the cap kit.

Of the few other sources of information I've found on this particular model, one was by a fellow collector on the KLOV forums who had picked up (4) aero cities, (3) of which were working, and after capping all of them, only (1) was working. :mad:

I do have power connnected to the chassis, and as said, I measured 120V at the cab's power connector that the monitor plugs into. There is also a yellow-orange 2-pin cable that is grouped with the power cord. Does anybody know what this connector does? It lands at the chassis just above the AC power cable, and looks like it runs back in the general direction of power coming into the cab, the utility outlet on the back of the cab, etc...although I didn't follow the wires all the way. All lines re-connected, if anyone wants to double-check that I'm not overlooking something:

2-prong AC power cord
2-pin yellow-orange (?) cable
3-pin connector for RGB2-pin connector for ground and sync
1-pin connector for ground at neckboard
anode cap
2-pin degauss cable

I will try the other suggestions.
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Re: Help w/ Nanao MS8-26SG

Post by PrincessPrinPrin »

The yoke??
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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity »

PrincessPrinPrin wrote:The yoke??
Oh no, I left that dangling, is that important? It's good when it's sparking and arcing to the cabinet right? :lolno: Just kidding, yes of course I connected up the neck board.
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Re: Help w/ Nanao MS8-26SG

Post by nem »

The yoke is the funnel like thing infront of the neck board. You're missing the 4 pin connector that connects the yoke from your list. Red, blue, yellow, brown IIRC.
NoAffinity wrote:Of the few other sources of information I've found on this particular model, one was by a fellow collector on the KLOV forums who had picked up (4) aero cities, (3) of which were working, and after capping all of them, only (1) was working. :mad:
I have capped two. Both of them are running fine (although I didn't touch the filter cap).
There is also a yellow-orange 2-pin cable that is grouped with the power cord. Does anybody know what this connector does?
That's probably for the degauss switch.
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Re: Help w/ Nanao MS8-26SG

Post by Asure »

Black wire from the tube GND reconnected to the correct spot? Fuse(s) ok on the board?
The black wire from the tube should probably connect to the neck board, it looks there is a big pin for it there. I do not have this monitor, others should comment pls.

Caps replaced with the correct matching new cap?
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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity »

^^haha, right... yes, I have reconnected the 4-pin connector. Tried it on the "normal" header and on the "reverse" header. Same result either way.

Fuses are good - 2 on the chassis and one by the main cab power supply.

Installed caps have been gone over at least 5 times now - all correct, all correctly oriented.

Black wire from tube connected at ground pin (only available pin) on the neck board. I reflowed the pin, too.

Ah yes, probably the degauss switch at the front of the cab goes to that yellow/orange connector. Good call. The funny thing is, I pressed the degauss button while the cab was playing blind, and you could hear the degauss "bump", but not followed by the usual static sound. As anyone should, I always discharge the monitor after every power-up attempt, and there is no charge on it.

nem - was it this exact model...SG, not SU? Do you happen to have a cap list? I was verified all caps coming out against what was going in, but it's possible I could have overlooked something. And, of course, I threw the caps in the trash as soon as I was done...with a pile of caps off a WG K7000 that I had done the night before. I am not above fishing them out of the trash, but they are now all intermingled along with the 30-40 earwigs I've killed in my man cave during that same time :crazy: (that's another story).
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Re: Help w/ Nanao MS8-26SG

Post by nem »

Ahh, you're right, I double checked and mine are indeed SU.

I just recently recapped a MS8-28. Just to make sure, you don't have any neck glow, do you? Because with the -28 I initially had a black screen. I needed to turn up the voltage on the flyback for the raster to appear. Naturally you shouldn't do this if you don't have any neck glow.
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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity »

nem wrote:Ahh, you're right, I double checked and mine are indeed SU.

I just recently recapped a MS8-28. Just to make sure, you don't have any neck glow, do you? Because with the -28 I initially had a black screen. I needed to turn up the voltage on the flyback for the raster to appear. Naturally you shouldn't do this if you don't have any neck glow.
Okay, thanks for checking. Hey, if you still have any papework or cap list that came with that kit and wouldn't mind sending it, it could be another data point I can check against the installed cap kit. If not, no worries.

Correct, no neck glow. And actually, I did turn up the voltage on the flyback, but no change/no signs of life.

I've been tinkering with a WG K7000 out of my big blue, which had serious convergence issues, needed a yoke adjusment (image slightly rotated), and needs a rejuve, so haven't gotten to pulling the MS8 and getting it on the bench yet. Need to get the stupid K7000 behind me so I can start working on the stupid MS8. :cry: I hope to free up the bench tonight. Both of my "committed" fighting game cabs are down right now! :cry: :cry:
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Re: Help w/ Nanao MS8-26SG

Post by nem »

http://arcademonitor.com/arcade-monitor ... o-ms8-26su

I'm pretty sure this is correct for SU.
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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity »

^thank you! I will check that against the list that came with my kit.

Interestingly, the -SG has no c579, at least not that I can find and I scoured the board. It definitely does not exist where it is identified on this pic (there are no electrolytic caps within the flyback cage).
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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity »

Well, in positive news, I wrapped up the K7000 out of my big blue. Man, that was a beast...but I tell you what, if you ever want to really learn convergence and color balancing, remove the balancing wedges and convergence strips, and completely loosen the yoke and start at square 1. :ugeek:

(This is NOT the MS8)

Image
Image

Okay, that tangent aside, I compared the list I got with my cap kit, which is labeled "for Nanao MS8-26SG", with the one linked above, and there a handful of differences. So, I don't think I can trust the comparison. Starting tonight after work, I will pull the monitor and starting poking at it, in hopes it comes back to life.
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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity »

All right, starting the process here.

Powering the monitor with an iso tap, plugged in on the isolated side, getting around 102-103V AC through fuse F901. I've read these can are okay at 120V, and I was clearly running it on 120V for the few months I've had it so far, with no problems. But, nonetheless, I'm going with what's marked on the tube sticker for testing.

Soldered a wire to the negative side of the filter cap for my ground. Getting 93.8V DC at F902. I put the isotap up one tick, to get around 108V AC, and still 93.8V DC at F902.

Also hear a very very light hum from the neck area of the tube, but no glow.

Moving on to some other checks...if anybody sees anything fishy so far, please speak up.
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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity »

Had to cut my efforts short last night. got back to checking voltage at the IC on the vertical board and there was nothing there...at least not on pin 9, which is supposed to be VCC. I started desoldering, and unbeknownst to me, was doing it with the monitor still plugged in. :-o I got to I think the 4th or 5th pin, sucked up the solder, and instantaneously the monitor came on. Scared the crap out of me.

I immediately unplugged and discharged, and got that beatiful POP from the discharge. I then resoldered and checked for shorts, figuring I must've had a short, and found 2 pins shorted, which are continuous via the vertical board, and 2 pins shorted that are continuous on the chassis. Re-powered and nothing. :wtf:

Then I looked closer, and the connection at the board that goes to pin 9 is floating. It is a through hole with no connectivity. And there's no way I'm installing the vertical board backwards. It will not physically fit if rotated 180 degrees. :cry:

Any suggestions? I'm not crazy...the pin I'm point to below is pin 9, right? And pin 9 is supposed to be VCC?
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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity »

Also checked Q901 - 94.1 on the base, 93.9 on the emitter
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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity »

I discovered that pin 9 is labeled on the board, and it seems the pins get numbered counter-clockwise, with 1 being at the top right of the notched end of the chip. Pin 9 is measuring around 10.7V DC.

Checked voltage across the filter cap - 133.8V
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Re: Help w/ Nanao MS8-26SG

Post by PrincessPrinPrin »

NoAffinity wrote:I discovered that pin 9 is labeled on the board, and it seems the pins get numbered counter-clockwise, with 1 being at the top right of the notched end of the chip.
The pinout is:
Immagine2.jpg
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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity »

Wow, this is a tremendous help. Thank you, PPP! I had started documenting, but I would have never guessed the pin number on the IC jumps all over the place. Maybe that's explained or implied on the data sheet, but I don't read Japanese. :crazy:

So, I've got 3.5V DC on pin 4 of the vertical board (V VCC), and 12.6V DC on pin 12 (H VCC). Any idea if these are correct...or should they be the same?
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