Neo Candy 25 - Toei TC-A252K Chassis - Toshiba A59JMZ90Z Tube

mikemann

mikemann

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Feb 9, 2014
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So I just got the Neo Geo 25 Candy in a trade with a guy about 5 hours away. Got home with the game and plugged it in. The monitor seemed to be acting funny, like it was loosing sync. It would sometimes switch to like a super zoomed pixelated view and then back to normal picture.

After about 5 minutes, the screen went dark and all I'm not getting is a constant whine which sounds to be coming from the Flyback.

So here's all the data I have -

Neo Geo Candy 25
Toei TC-A252K Chassis
Toshiba A59JMZ90Z Tube.

The neck is a 10 pin connection.

I tried to take yoke readings but my meter would not fit into the yoke connector. And it did not appeart to go into any winding posts that I could meter off of? I tried to improvise and was getting 9.6 and 1.4 ohms

What are my options? I cannot find anything on this Toei chassis. I've googled a ton tonight and am striking out.

Does anyone fix them? Are flybacks even available?

Is there another chassis I could be using as a substitute?

Kinda desperate at this point.

Thanks for looking....
 

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L

LegoSlug

Over Top Auto Mechanic
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Dec 10, 2012
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Dis it work fine prior to bringing it home? Did you see it running for a while before you traded?

Is the screen always black now or do you get an image after its been sitting cold for a while?
 
mikemann

mikemann

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Kinda of a complicated deal there. Seller said it worked prior to use doing a trade. I traded a fully restored Nintendo Mario Bros cab/game for this. I received pictures of it on and showing an image, but I don't know *when* they were actually taken in hindsight. I did not drive to socal myself to do the drop off and pickup. I sent an employee of mine to do it and gave him some store credit for making the run. So really even the transportation part was on me. The guy I sent has done this before for me, and he's incredibly careful about moving games. He wraps them in blankets and shrink wrap, uses pool noodles over the ratchet straps, etc. He brought this game and another back for me this weekend. Both arrived in great shape and still all wrapped up nice.

He did not turn it on and test before pickup and that is my own fault. I forgot to tell him to and I think I just trusted the guy/situation. It was a deal consummated on another site where I am a pretty established member and he more recently is as well.

The game did turn on, twice when I got it home. I was testing out all the slots on the MVS board want to make sure they worked. The seller only owned a 161-in-1 and never did anything more/less with it. I populated the board with carts and turned it on. The monitor came on but was in a weird mode I've never seen a CRT mode do before. It' was basically like looking at a 15khz image zoomed in 50%. The Neo Geo Logo was oversized and heavily pixelated and same with the game. It made a clicking noise a couple times and then corrected itself. I assumed in the moment, it was like a "sync" issue. It then ran long enough to cycle through the attract on three games. I turned it off and had to go back to work. The second time was when I got home later in the day. It did the same thing and then after about the same amount of time of being on it just clicked off, no image and started making the whine. Now, no matter what happens when I power on...there is no image and just the whine..

Crummy video from that night -



And additional pics as well of the chassis -

http://s1106.photobucket.com/user/mann0mann/library/Toei - TC-A252K Monitor
 
Last edited:
jambitboom

jambitboom

Cham Cham's Banana
Joined
Mar 10, 2012
Posts
161
mikemann said:
Kinda of a complicated deal there. Seller said it worked prior to use doing a trade. I traded a fully restored Nintendo Mario Bros cab/game for this. I received pictures of it on and showing an image, but I don't know *when* they were actually taken in hindsight. I did not drive to socal myself to do the drop off and pickup. I sent an employee of mine to do it and gave him some store credit for making the run. So really even the transportation part was on me. The guy I sent has done this before for me, and he's incredibly careful about moving games. He wraps them in blankets and shrink wrap, uses pool noodles over the ratchet straps, etc. He brought this game and another back for me this weekend. Both arrived in great shape and still all wrapped up nice.

He did not turn it on and test before pickup and that is my own fault. I forgot to tell him to and I think I just trusted the guy/situation. It was a deal consummated on another site where I am a pretty established member and he more recently is as well.

The game did turn on, twice when I got it home. I was testing out all the slots on the MVS board want to make sure they worked. The seller only owned a 161-in-1 and never did anything more/less with it. I populated the board with carts and turned it on. The monitor came on but was in a weird mode I've never seen a CRT mode do before. It' was basically like looking at a 15khz image zoomed in 50%. The Neo Geo Logo was oversized and heavily pixelated and same with the game. It made a clicking noise a couple times and then corrected itself. I assumed in the moment, it was like a "sync" issue. It then ran long enough to cycle through the attract on three games. I turned it off and had to go back to work. The second time was when I got home later in the day. It did the same thing and then after about the same amount of time of being on it just clicked off, no image and started making the whine. Now, no matter what happens when I power on...there is no image and just the whine..

Crummy video from that night -



And additional pics as well of the chassis -

http://s1106.photobucket.com/user/mann0mann/library/Toei - TC-A252K Monitor
Click to expand...

Hey Mikemann,

I don't know if this will help you out or not, but I think it's worth trying to turn down the pot labeled "screen" on the flyback transformer. My experience is that when that get turned too high, weird behaviour, blackouts, and high pitched whining result.

Let me know how it goes for you, and good luck.
 
mikemann

mikemann

Quiz Detective
Joined
Feb 9, 2014
Posts
85
jambitboom said:
Hey Mikemann,

I don't know if this will help you out or not, but I think it's worth trying to turn down the pot labeled "screen" on the flyback transformer. My experience is that when that get turned too high, weird behaviour, blackouts, and high pitched whining result.

Let me know how it goes for you, and good luck.
Click to expand...

Thanks for the advice. I should have added a few more details in that, I've got good voltages coming out of the power supply and proper AC to the monitor. But no neck glow. I've lost HV.

Good news is I did find a place that had serviced them before and felt comfortable taking on the job. So we'll see where that leads.
 
L

LegoSlug

Over Top Auto Mechanic
Joined
Dec 10, 2012
Posts
864
mikemann said:
Thanks for the advice. I should have added a few more details in that, I've got good voltages coming out of the power supply and proper AC to the monitor. But no neck glow. I've lost HV.

Good news is I did find a place that had serviced them before and felt comfortable taking on the job. So we'll see where that leads.
Click to expand...

Sweet, hope it works out. I was wondering if you had many any progress. Mind if I ask who is servicing your monitor? I am in the bay as well.

I had monitor troubles recently, and being inexperienced, it took me at least 5 hours... and it made me think it would be worth paying someone to do it.
 
RetroTechRewind

RetroTechRewind

Crazed MVS Addict
Joined
Jun 2, 2015
Posts
141
Are you plugging this in without using a step down transformer? I'm assuming the monitor has a isolation transformer inside, but as far as the initial AC in, that cab is rated for the Japanese 100v. I'd try using one. You risk the potential of under powering the whole unit, and that can cause a whole host of issues.

If the whole image is "zoomed in", I'd think (maybe) the horizontal and vertical circuitry may be to blame. There's large polypropylene/film caps that are in series with the inductor coils on the chassis. With age, they tend to fail, or lose their ability slowly to hold a charge. Could also be the HOT, or the IC's that control the horiz/vert sync.

Are you able to get the chassis out safely to get some pics? Make sure you discharge the tube first!
 
mikemann

mikemann

Quiz Detective
Joined
Feb 9, 2014
Posts
85
Appreciate the help and advice. My OP probably sounded a little desperate and I really was. It was the heat of the moment.

I actually have quite a bit of experience working on monitors and have rebuilt plenty of WG 19" and 25" chassis in all my classics. The Toei was a whole another beast though. And the biggest thing I was freaking out about was, there appears to be zero documentation on this monitor and no schematics online. That really puts a guy like me who would want to work on this on my own in a bit of a pickle. Hence the panic in my first post.

In regards to the power. Honestly the AC is fine. Yes it is 100V monitor, but it does have it's own ISO on the chassis/board. Everything else is not an issue. The Power Supply in the cab accepts 120V with no issue and is putting out the correct voltages to to the harness and while I haven't looked at the Fluorescent tube/ballast yet. It's working with no issues either.
 
K-2

K-2

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1,047
Yeah, as you said I've had a Neo 25 plugged directly into my wall socket for a couple of years now and have had zero issues.

I don't have any schematics, but if you would like me to try and take some photos of my chassis just let me know.
 
mikemann

mikemann

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Posts
85
Thanks guys. It's off to try its off for service, so hopefully I'll be taken care of. But I did take pics of the chassis before shipping it -
 
Last edited:
mikemann

mikemann

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Feb 9, 2014
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So new issue/question....

I sent this monitor off for repair. Got it back installed a few weeks ago, Monitor looks great. Good color, working well with the exception of one minor issue. I feel like with the knowledge I do have of monitors I would describe it as like a ground issue or something? I'm seeing like almost refresh lines that oscillate from bottom to the top of the screen. It's really only noticeable when you are up close or on very bright screens.

I recently grounded the cabinet on the AC power line as it was the original plug and I was getting a small shock when working on the CP. I was really hoping that after grounding the power cord I was gonna see an improvement. But nothing.

A friend told me that he's seen similar issues arise and it was Power Supply related. I'm pretty positive looking at this chassis that the Toei has an Isolation Transformer on the pcb. In fact unless there is one buried in these neo geo power supplies there is not one in the cab. AC power comes in...goes through a line filter and then to the power supply.

I'm just wondering if it would be safe for me to test his theory and plug this monitor directly into an extension cord and into the wall? It would remove the power supply from the equation and quickly tell me if that's the issue. Thoughts on this? I am hesitant because I'm not a 100% sure it's safe and the fact it's a 100v monitor to begin with and only has a 2 prong plug on it.
 
mikemann

mikemann

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Well back to the drawing board anyways. I supposed it still could be power supply related as I'm sure the 6-slot is a bit power hungry. But I swapped in a cheap multi-board tonight to test and that runs fine and exhibits none of the monitor funkiness.
 
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