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mmmmaerk

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A couple days ago it would sometimes not come on, taking the cab a couple switches off and on before the monitor would come on with it. Now the monitor never turns on. When it first started happening I figured it was a sign it needed a recap, but I don't actually know if recapping is what would help because I don't know anything. Any troubleshooting steps I should take or should I look into getting it recapped ASAP? Thanks.
 
recapping usually has nothing to do with full on power no power issues in most cases, unless its in HV shutdown which can be other things. is this a new to you cab? are the marquee lights coming on when the monitor doesn't or is it all dead? if all dead, could be an interlock issue.
 
New to me. I've only had it for about a week and in that week I only really used it twice. it was the second time using it that I noticed it wouldn't come on sometimes. The marquee lights always come on.
 
you should always cap an import cab at least at some point, as its most likely not been done. but its also good to understand the issue before you go shotgunning. i would open the back panel and see if you hear any chirping sounds or pulsing like sounds when you flip the on switch. this would indicate some sort of hv shutdown.
 
When it first started happening I heard some popping and clicking sounds but when I was trying again later I didn't hear any. I'll listen again for chirping.
 
could be lots of things. sometimes my speakers pop a little on my blast cause they are shitty and need replaced upon power up. what type of game are you running? sometimes different frequencies and portions of a chassis can shit out and only 15khz will work etc.
 
It has a Netboot Naomi hooked up. I tried using my MiSTercade at 15khz and had the same problem.
 
Could also be a flyback issue. DIscharge the monitor and then you can safely search for cracks, etc. on the flyback itself. Also did you check the fuses on the chassis?

ASAP = Always Start At Power. Take a multimeter to the monitor's AC inputs. What's it reading?

Del
 
Honestly with a 2931 chassis, I would just send it to someone who knows how to fix it. It’s a known problematic chassis and very difficult to troubleshoot.

If you have never done any CRT monitor work, this is not the chassis to start on imo. It’s the reason why people suggest not getting a blast city as your first cabinet.
 
the blast city is boss. the reason why they recommend not getting one is they want them for themselves and are greedy candy bros. it aint any worse than any other monitor or cab, the 2930 is rock solid and so are the latter revisions. sure the 2931 has quirks but if its maintained, it going to be good as any other. think of the import cab and how long its been thriving in arcades before we get em. maintenance needs done period, regardless of the monitor or cab all caps are out of spec and things will start shitting.
 
Pop out the fuse F701 near the flyback, and this'll let it run without HV (the flyback). If it's "running" (that is, the relays click, and you can faintly hear the deflection on the yoke) then it's happy other than the HV. If that's the case then you know to work on the HV side which is isolated from the rest. Start by seeing if the MOSFET (Q701) that drives the flyback is toast.

Otherwise, move on to the horizontal section. Try Q511, D511, and Q952.
 
the blast city is boss. the reason why they recommend not getting one is they want them for themselves and are greedy candy bros. it aint any worse than any other monitor or cab, the 2930 is rock solid and so are the latter revisions. sure the 2931 has quirks but if its maintained, it going to be good as any other. think of the import cab and how long its been thriving in arcades before we get em. maintenance needs done period, regardless of the monitor or cab all caps are out of spec and things will start shitting.
The 2930 is extremely not rock solid. The HV circuit on the 2930 and 2931 is infamous for having explicit and unique failure modes. The things that make it this way seem to have virtually nothing to do with maintenance. Never mind the tube itself having a pretty bad rate of developing poor emissions. Even here in Japan Blasts are the most difficult to service and keep working and many get gutted and discarded for good reasons.

I love the Blast when it's working and have owned and restored many of them, but the surface of what can go wrong and how difficult or expensive it is to fix it is nearly one of the worst among any mass-produced cabinet in this form factor. Capacitors are baby time stuff and are not even the surface.
 
I have two 2931 chasis with the same problem: they protect as soon as they are powered on. I really have no idea what else to check.
 
I have two 2931 chasis with the same problem: they protect as soon as they are powered on. I really have no idea what else to check.
Try without HV and then attacking the horizontal section if they still go into protection.
 
Man
Pop out the fuse F701 near the flyback, and this'll let it run without HV (the flyback). If it's "running" (that is, the relays click, and you can faintly hear the deflection on the yoke) then it's happy other than the HV. If that's the case then you know to work on the HV side which is isolated from the rest. Start by seeing if the MOSFET (Q701) that drives the flyback is toast.

Otherwise, move on to the horizontal section. Try Q511, D511, and Q952.
Man this is some good troubleshooting tips right here.

Also chirping can sometimes generally be assumed as a power supply issues sometimes (at least to my understanding) The power supply is trying to cycle up and cant do it fully because of something in the power supply or something later down the line causing issues that cause the PSU to shutdown and restart if you will. (at least this is some of my understanding).

The 2930 and 2931 are alot different compared to many other monitor chassis's.
Nanao didnt truly revise most of the chassis until really the 2933 (a larger revision to the 2931) where they started using a different flyback and a different HV Regulation daughter board to go with that.

If your trying to get your hands dirty then first step is check your B+ voltage and HV (if you have the meter for that) tbh but if you get no neck glow and or cant hear the deflection running its likely entering a shutdown situation (of which theres a number of different reasons that can trigger)

Take the chassis out inspect for bad solders. The MS2930 I seen alot where they get some cold solder joints in the primary power supply and a few other areas. Touch up any bad solders.
You should check the HOT for shorts, and the Mosfet by the Flyback because the HOT alone does not drive the flyback on this chassis.
(would follow the steps moffet mentioned because isolating the HV and Horizontal Output Stages is a really good way to narrow stuff down (theres alot of stuff going on).

Best of luck.
 
The 2930 is extremely not rock solid. The HV circuit on the 2930 and 2931 is infamous for having explicit and unique failure modes. The things that make it this way seem to have virtually nothing to do with maintenance. Never mind the tube itself having a pretty bad rate of developing poor emissions. Even here in Japan Blasts are the most difficult to service and keep working and many get gutted and discarded for good reasons.

I love the Blast when it's working and have owned and restored many of them, but the surface of what can go wrong and how difficult or expensive it is to fix it is nearly one of the worst among any mass-produced cabinet in this form factor. Capacitors are baby time stuff and are not even the surface.
yeah caps can be assumed baby time, but you can't expect it to be run optimally and it's the bare minimum on any monitor thats 25+ years old. i love all games when they're working, its just how it is with cabs (candy or not).
 
Thanks for all the help. This is a lot to digest so I'll probably be asking a lot more questions in here later.
 
F701 is socketed (near the flyback) so if you take it out it disables the HV circuit. You can do this and determine in which neighborhood the problem lies and go from there.
 
So I had a guy come look at it today. Here is my chassis.

IMG_20230828_161135_309.jpg


He insisted that I should just put a flat screen monitor in there, but obviously I rejected that idea every time. Should I look for another flyback or another chassis entirely?
 
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