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Nanao MS-2933 Issue after taking it in for Repair at PNL

tacobell

tacobell

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Took my Sega Blast City for service to PNL as it had some brightness and convergence issues. John from PNL ran some tests and noticed the monitor was losing focus and said the flyback and chassis needed to be repaired. He spent the whole day on this. Took it back home only to find out there is now this weird scanlines and black spacing on the top, which fixes itself after a few minutes. This is on 31khz. There’s still convergence issues. Not sure how this happened. Disappointed that I’ll need to haul this monitor back in as I paid over $200 with more issues than solutions.


Anyone know how this could have happened and what I can tell John specifically what to focus on? Thanks in advance.


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Looks like retrace lines. Change all the capacitors in the vertical section on the chassis. This usually fixes the problem, but there could be other issues generated after you had it “fixed”.

Some info regarding white/grey retrace lines:

White/gray retrace lines​

Where all colors are involved - the lines are essentially white or gray (or with a slight tint due to slight unequal settings of the color adjustments), look for something common like an incorrectly adjusted screen (G2) or master brightness/background/bias control or a problem in one of these circuits, a defective power supply or a problem in the blanking circuitry:


  • Screen (G2) or master brightness/background/bias control - mark setting and then see if a slight adjustment removes the retrace lines. See the chapter: "Monitor Adjustments". Of course, if this happened suddenly, the problem is not due to a misadjusted control though a dirty pot is possible - turn it back and forth - this might clean it and restore normal operation.

  • Power supply or connection to CRT neck board - insufficient voltage will result in the CRT never totally blanking. Check (usually scan derived) power supply components (from flyback).

  • General power supply - check B+ for correct value and ripple. A main power supply fault might result in these symptoms (and usually many others).

  • Blanking circuit - this may be a part of the video/chroma chip or separate. Check waveforms to determine if the blanking pulses are making it to the video output.
https://www.repairfaq.org/sam/monfaq.htm#monwgrl
 
Caps for the vertical foldover.

Corner (ie. dynamic) convergence is not a chassis issue, but a yoke issue. I would be surprised if any repair shop wanted to tackle that.
 
BuddyC said:
  • General power supply - check B+ for correct value and ripple. A main power supply fault might result in these symptoms (and usually many others).
Click to expand...
I once had this exact same problem and it was the B+ with wrong values.
 
BuddyC said:
Looks like retrace lines. Change all the capacitors in the vertical section on the chassis. This usually fixes the problem, but there could be other issues generated after you had it “fixed”.

Some info regarding white/grey retrace lines:

White/gray retrace lines​

Where all colors are involved - the lines are essentially white or gray (or with a slight tint due to slight unequal settings of the color adjustments), look for something common like an incorrectly adjusted screen (G2) or master brightness/background/bias control or a problem in one of these circuits, a defective power supply or a problem in the blanking circuitry:


  • Screen (G2) or master brightness/background/bias control - mark setting and then see if a slight adjustment removes the retrace lines. See the chapter: "Monitor Adjustments". Of course, if this happened suddenly, the problem is not due to a misadjusted control though a dirty pot is possible - turn it back and forth - this might clean it and restore normal operation.

  • Power supply or connection to CRT neck board - insufficient voltage will result in the CRT never totally blanking. Check (usually scan derived) power supply components (from flyback).

  • General power supply - check B+ for correct value and ripple. A main power supply fault might result in these symptoms (and usually many others).

  • Blanking circuit - this may be a part of the video/chroma chip or separate. Check waveforms to determine if the blanking pulses are making it to the video output.
https://www.repairfaq.org/sam/monfaq.htm#monwgrl
Click to expand...
The problem was, and I forgot to mention, that he recapped the chassis and cleaned the black goop. I’m sure I’ll need to bring it in.
 
are you sure he recapped the entire chassis? They very rarely do that. Just change a caps. Post a picture of the chassis and we cant ell you right away if there is some original caps..
 
I brought the whole tube as I’m not comfortable removing the chassis myself. I highly doubt that he replaced all the caps as well considering I found out after I brought it back home. Kinda at his trust since I have 0 knowledge of arcade monitor repair and he’s been doing this for decades.

It’s just transporting the bulky thing in a sedan, making sure to secure it properly, then driving it an hour away through LA traffic that gets annoying. And since he doesn’t work on weekends, I need to take work time off to do it.

Sure, it’s better than shipping this from the other side of the country, but I don’t trust myself with older monitors, especially ones that don’t get made anymore.
 
Wait, so he had the tube and it worked fine or you didnt test it upon pick up?
 
tacobell said:
I brought the whole tube as I’m not comfortable removing the chassis myself. I highly doubt that he replaced all the caps as well considering I found out after I brought it back home. Kinda at his trust since I have 0 knowledge of arcade monitor repair and he’s been doing this for decades.

It’s just transporting the bulky thing in a sedan, making sure to secure it properly, then driving it an hour away through LA traffic that gets annoying. And since he doesn’t work on weekends, I need to take work time off to do it.

Sure, it’s better than shipping this from the other side of the country, but I don’t trust myself with older monitors, especially ones that don’t get made anymore.
Click to expand...
Sounds like you need to take the plunge like the rest of us and learn to discharge a tube (fairly easy and safe as long as you follow the simple steps)

You can build your own discharge tool with a BIG flat head screw driver, thick gauge wire, alligator clips and lots of insulated electrical tape. Literally all you need.

We can make a video for you on discharging if you'd like. Would make it easier for you to mail him your chassis for like $5 or less through pirate ship than lugging a heavy ass tube and losing money taking time off work. Trust me. I used to be petrified handling monitors and did the same once but it's easy just gotta be careful every time and you'll be fine.
It's OK to be afraid as that's what keeps you safe. You'll be very apprehensive for a while but it goes away.
Plus it's a disservice to yourself not learning if you're gonna get into this hobby. It's the equivalent to being a car guy and not knowing how to turn a wrench it just has to happen
I'll be more than happy to walk you through it and can posts videos.
Not all discharges are violent or loud, and removing a chassis once the anode cap is off and discharged is relatively safe. You just want to be careful not to touch caps immediately after discharge but those "shocks" won't kill you, they just smart lol 😆
 
Anselmo said:
Wait, so he had the tube and it worked fine or you didnt test it upon pick up?
Click to expand...
We tested it and I did see the test signals, but this was after the unit was powered on for a while so I didn’t catch the retrace lines until AFTER I got home. Also, the test signals were a bit blown out and didn’t catch the corners. It was a bit of both exhaustion as Covina/West Covina is such a depressing city to kill time at, and waiting for rush hour traffic to die. Dropped it off at 10:30 am and picked it up at 6:30 pm.

Kidkaos said:
Sounds like you need to take the plunge like the rest of us and learn to discharge a tube (fairly easy and safe as long as you follow the simple steps)

You can build your own discharge tool with a BIG flat head screw driver, thick gauge wire, alligator clips and lots of insulated electrical tape. Literally all you need.

We can make a video for you on discharging if you'd like. Would make it easier for you to mail him your chassis for like $5 or less through pirate ship than lugging a heavy ass tube and losing money taking time off work. Trust me. I used to be petrified handling monitors and did the same once but it's easy just gotta be careful every time and you'll be fine.
It's OK to be afraid as that's what keeps you safe. You'll be very apprehensive for a while but it goes away.
Plus it's a disservice to yourself not learning if you're gonna get into this hobby. It's the equivalent to being a car guy and not knowing how to turn a wrench it just has to happen
I'll be more than happy to walk you through it and can posts videos.
Not all discharges are violent or loud, and removing a chassis once the anode cap is off and discharged is relatively safe. You just want to be careful not to touch caps immediately after discharge but those "shocks" won't kill you, they just smart lol 😆
Click to expand...
Yea, I’ll take it in just because there should be some warranty as I spent that cash and came back with more problems. But future me will start getting shocked.

Gonna plan another visit and report back. Hopefully sooner than later…

A friend of a friend works at a sake distillery in that plaza so I might just kill time there.
 
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PNL does normally offer a 60 day warranty and for the most part they have always done right by me in times where I needed it. I dunno about the corners, thats not a chassis issue. Its a tube issue and you need to throw some convergence strips under the yoke to dial it in. Look on the bright side, at least you are within driving distance. Most people have to remove the chassis, pack it, ship it out, wait a couple weeks, reinstall and cross our fingers it works...
 
Anselmo said:
PNL does normally offer a 60 day warranty and for the most part they have always done right by me in times where I needed it. I dunno about the corners, thats not a chassis issue. Its a tube issue and you need to throw some convergence strips under the yoke to dial it in. Look on the bright side, at least you are within driving distance. Most people have to remove the chassis, pack it, ship it out, wait a couple weeks, reinstall and cross our fingers it works...
Click to expand...
Surprisingly, I brought a monitor a couple years ago and he fixed both brightness and convergence issues the same day in a couple hours using convergence strips for $50. That’s kinda why I’m surprised the recent job was kinda done haphazardly. I’ll see what he says in terms of bringing it back in.
 
Here are images of the chassis. Hope these help.
 

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Yea, I thought that looked like a 2933. The obvious orange cap is still orange, so that tells you not all caps were done. Still, that's a good chassis.
 
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