Help w/ Nanao MS8-26SG

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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity » April 29th, 2017, 3:47 pm

I also started poking around on the neckboard. I confirmed that grounds are continuous and good, from the tube through the neckboard and to the flyback. None of those, however, are continuous to the filter cap '-' side. Is that right?

I'm also not finding any voltage at the neckboard. Is that also right?

Lastly, 4 pins of the flyback have 3.7V DC on them.

Not sure if any of these are useful clues... :think:

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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity » April 29th, 2017, 5:36 pm

Checked the HOT. The base and emitter have continuity. Is that right?

http://www.datasheetspdf.com/PDF/D1880/606258/1

93.4V DC on the collector. No voltage on the base or emitter.

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Re: Help w/ Nanao MS8-26SG

Post by PrincessPrinPrin » April 29th, 2017, 6:11 pm

If you don't have heater voltage and 180v for video amps on the neckboard, the flyback isn't working. If the flyback were working the HOT would be working too and on the collector you would have over 1000v. Now you just have the B+ going through the primary side of the flyback to the HOT collector. It seems you don't have horizontal drive. It goes like this: IC103 daughterboard (pin 11)--->H drive transistor (Q532)--->H drive transformer (T530)---> HOT (Q533). If something isn't working in this chain the flyback will not work.
Im running games with a vga to tv converter on my Shangai Novel, with composite and it looks amazing, Im not interested in RGB or Scart.

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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity » April 29th, 2017, 8:12 pm

Well maybe the issue is more in my measurement currently. My multimeter only goes up to 600V DC. Any good suggestions for continue the troubleshooting with a standard multimeter, or do I need to start thinking about investing in higher voltage rated test equipment?

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Re: Help w/ Nanao MS8-26SG

Post by PrincessPrinPrin » April 30th, 2017, 3:10 pm

The HOT collector pulse is checked with an oscilloscope not with a multimeter. When working it's a waveform like this:
coll.jpg
But clearly it's not working. I would check if the H drive transformer is getting power (this comes from the B+ through R543A and R543B), if the H drive transistor is good and if the HA11423 is getting power and if the soldering on that vertical daughterboard is OK (you said the monitor came up when you were tinkering with that).
Im running games with a vga to tv converter on my Shangai Novel, with composite and it looks amazing, Im not interested in RGB or Scart.

- anonymous

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Re: Help w/ Nanao MS8-26SG

Post by grantspain » April 30th, 2017, 3:20 pm

what is the value of your cap at c560?

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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity » April 30th, 2017, 4:42 pm

c560 is 47uf 250v. And I checked it three times, including confirming the polarity is correctly oriented.

Unfortunately, I haven't invested in a scope yet. For the cost of a scope (or less), I'm contemplating taking it to a local repair shop with glowing reviews including a few customers reporting their arcade monitors fixed. :think: I would like to invest in a scope, but also just want it fixed at this point.

Yes, there is power at the 11423: 3.5V DC on pin 4 of the vertical board (V VCC), and 12.6V DC on pin 12 (H VCC). Do these seem right?

I will check those resistors. Yes, it came up one time when I was accidentally desoldering the daughterboard with power on. It's nice to know it's capable of working, but honestly I think it's more frustrating getting a glimmer of hope and then nothing since. The best I could deduce from that is either I inadvertently heated up a cold solder joint, so I reflowed everything on the daughterboard and in the immediate area (no joy). Or I shorted something which should or shouldn't be shorted normally, but produced a positive result. :whoa: I was so excited, though, I figured it was just a matter of resoldering and cleaning up and it would all be working again, that I didn't note which pins caused the glimmer of hope. :palm:

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Re: Help w/ Nanao MS8-26SG

Post by grantspain » April 30th, 2017, 4:52 pm

pretty sure that value is completely wrong for c560
I need to check to be certain but I am sure it should be 0.47uf 100v,i am quite sure its the start up cap for the power supply section

let me double check on one of my chassis and get back to you-just in case I am talking ****

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Re: Help w/ Nanao MS8-26SG

Post by PrincessPrinPrin » April 30th, 2017, 5:40 pm

Yes, it's definitely 0.47uF/160V. People mistaken it for 47uF because they're not used to such a low capacitance for an electrilytic cap:

https://forums.arcade-museum.com/showpo ... ostcount=6

See also the schematics:
cap.jpg
I don't think it has to do with the power supply (the more so as he has B+) as it's connected to an output of the flyback. It's on a line that goes to the horizontal oscillator in the HA11423 on the daughterboard. A problem in that line would definitely cause the H oscillator not to work so there would be no horizontal output to the H transistor, etc. that I mentioned above.
Im running games with a vga to tv converter on my Shangai Novel, with composite and it looks amazing, Im not interested in RGB or Scart.

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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity » May 1st, 2017, 12:15 am

If C560 is the issue, you guys will be my heroes for life. I had put the monitor back in the cab temporarily, as I needed space on my bench. It's coming back out now! I still have the original caps. Hope to be reporting back with amazing news in a bit.

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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity » May 1st, 2017, 12:42 am

It's....fu**in'....alive!!!!! :-o :mrgreen: :-o :mrgreen:

Gotta get it back in the cab and test with a signal.

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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity » May 1st, 2017, 12:58 am

Boo effin' yeah! Oh my goodness, I am so happy right now. Thank you both so much. omgomgomg :D

And the curl at the top of the screen is gone, which is the whole reason I even undertook this endeavor. :slowclap:

Image
Image
Image

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Re: Help w/ Nanao MS8-26SG

Post by grantspain » May 1st, 2017, 1:02 am

so was it c560 then?

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Re: Help w/ Nanao MS8-26SG

Post by grantspain » May 1st, 2017, 1:36 am

so seriously take note people, cap kits are ****-some bloke says somewhere this bunch of caps will fix your chassis,well here is the truth and I am telling you(not asking you) -you put in what you take out

cap kits= I don't have a clue what I am talking about

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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity » May 1st, 2017, 1:40 am

Haha, yes I forgot the critical detail, it was c560. Put the original .47uf 160V back in, and it came right on.

I don't fault the seller in this case. I've gotten many kits from him, always with no problems. He said his kit was put together from a list put together by someone he enlisted to document their 26SG. I've notified him of the needed update to his kit, and I am confident he will make the update. Heck, I went over every cap that came out, and checked it against the list I received with the cap kit, and didn't catch this one discrepancy. :oops:

Either way, I'm off to play some super turbo! :D

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Re: Help w/ Nanao MS8-26SG

Post by grantspain » May 1st, 2017, 1:44 am

btw with c560 I stick in a 0.47uf 100v poly cap

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Re: Help w/ Nanao MS8-26SG

Post by PrincessPrinPrin » May 1st, 2017, 4:10 am

NoAffinity wrote:I don't fault the seller in this case. I've gotten many kits from him, always with no problems. He said his kit was put together from a list put together by someone he enlisted to document their 26SG. I've notified him of the needed update to his kit, and I am confident he will make the update.
The fact is that C560 isn't always an electrolytic cap. On some MS8-26 version it's a 0.1uF poly cap:
C560.jpg
Im running games with a vga to tv converter on my Shangai Novel, with composite and it looks amazing, Im not interested in RGB or Scart.

- anonymous

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Re: Help w/ Nanao MS8-26SG

Post by gusmoney » May 1st, 2017, 5:45 pm

Glad to see you get this sorted NoAffinity. Saw you posted it on NG this weekend and was thinking you must be frustrated. Good call grantspain.

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Re: Help w/ Nanao MS8-26SG

Post by NoAffinity » May 1st, 2017, 6:34 pm

gusmoney wrote:Glad to see you get this sorted NoAffinity. Saw you posted it on NG this weekend and was thinking you must be frustrated. Good call grantspain.
Oh yeah, I was at my wit's end. In fact, the monitor was back in the cab, sidelined until I could find a local repair shop to take it to. Had a thread going on KLOV, NG and here, and wasn't getting any good help elswehere. It was certainly more trouble than I was bargaining for... :palm:

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Re: Help w/ Nanao MS8-26SG

Post by frsj8112 » June 20th, 2018, 6:54 am

Ok now it’s my turn to get worried.

I took the Ms8-26SG out of my Aero City to give a good clean up and had a cap kit lying around from Ian. Yes i know it’s lazy and not ideal with some of these kits, but most caps were correct except C560 and C321.
I didnt replace those two.

Checked polarity of the caps that I put in the chassis and connected the monitor back into the cabinet.

Started the cabinet and......nothing
Found that F902 had blown.

So I must’ve made a mistake somewhere.

I will go over the caps again in regards to orientation and also the reflows I did. But after I have done that, can I replace the fuse and start again or will I make matters worse?

Thanks

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