Nanao MS9-29 "Goop of Death"?

[cgbartek]

There has been a lot of talk about the so-called "death goop" issue in Nanao MS9-29 Blast City monitors, but I'm starting to have doubts about what role it plays in the demise of the chassis, if at all. I have 5 Blast City cabinets. 3 monitors are fully-working, 1 has an occasional audible flicker, and 1 is completely dead. All 5 have the goop. In other words I have more working gooped chasses than dead ones... so then what is going on? These machines are from different operators all over the States, so I don't think it's a weird coincidence.

A few other things:

I picked up an MS9-29 tube and chassis awhile back which looked to be in mint or near mint condition. There was no dust and no burn on the tube. I previously thought it had no goop on it but upon closer inspection it does, even if only a little bit.

I have heard from others with Blast Cities that have noticed the same thing; the monitor is gooped, yet it still works fine.

I'm not sure if the goop is actually coming from the flyback, I think it's coming from the gray component labeled 750 A1 above it. I think gravity then pulls the liquid onto the top of the flyback where it hardens. This makes me think that it does not come this way at the factory, but long-term use triggers it due to heat.

I have seen this exact same phenomenon on a Wells-Gardner K7602 chassis. It was halfway covered by a brown goo that was not an epoxy, and I think it was originating from a large capacitor.


My theory is it is not much more than a melting component adhesive crawling across the chassis. Does anyone have evidence to refute any of what I have noticed? If anyone here has an MS9-29 chassis WITHOUT the goop I would be very interested to see pics of it. Let's try to get more clues together so we can solve this mystery.

[Mr-Megalo]

myself and Ordyne were discussing this last year - its not actually the flyback that "goops" it is something either besides or under the flyback

i've got a dead ms29-31 chassis thrown in the backroom which died as soon as it gooped - yet others like N80G80's IIRC still worked even though his had gooped too

nice phrase that "gooped"

[SuperPang]

Great thread this.

[cgbartek]

Maybe the presence of goop itself is not the tell tale sign its dead but perhaps the goop is responsible for causing a short that eventually kills the chassis?

Yeah you definitely don't want anything conductive bleeding around your board, especially in the high voltage section. I think that the goop could very well be shorting the chassis, but I don't think it's the flyback "bleeding to death". It could also be that the component in question can't properly function without the goop and kills the board.

I have a 2 gooped chassis, both turn on and show a black screen but they are both definitely on so maybe they are repairable for a tiny bit more life?

I'm glad you mentioned that, because that doesn't sound like a flyback issue. I'm not a monitor expert but I think if the flyback was dead you would get nothing at all from the tube because you would have no HV to power it. If I were you I'd check with AtariJim in Seffner, he can fix just about any monitor.

[oxtsu]

I was curious about this awhile back as well. This is the best article I could find on the subject of flybacks/LOPTs, which sheds a little light on the MS-2931 issue:

(sections 3.8, 3.9)
http://www.repairfaq.org/REPAIR/F_flyte ... LYTEST_012

If the 'goop' that everyone is seeing is the potting epoxy it would be non-conductive. Apparently when the insulation or epoxy breaks down it will lead to overheated windings, arcing or short circuits, which kill the flyback or components nearby.

His suggestion of sealing the flyback with a silicone compound sounds like it might be worth a try. My MS-2931 chassis is goop free so I was going to try it myself. My only concern was that if the epoxy breaks down would the compound really hold it in? I thought there would likely be bubbles inside from it's slight movement which would lead to a rather swift demise regardless. I wouldn't want to slap the compound on if it was only going to prolong the chassis' life by a negligible amount of time. Anyway, something to consider.

[cgbartek]

Here's what I was talking about before:

Keep in mind the flyback side faces downward when mounted in the cabinet. Therefore it's safe to say the leak is coming TO the flyback and not FROM it. Anyone have an idea what that component is or what it does?

Oxtsu, thanks for the interesting article. You're lucky to have a virgin chassis. How long have you used it, and how many hours does it get left on? If I were you I'd double-check to see if there's goop on it now, and look for it on the component above it. And as a preventative measure, I would install some sort of makeshift pathway to reroute the goop away from the flyback and other components when it invariably starts to leak.

[oxtsu]

srarcade - Awesome, looking forward to it.

cgbartek - Wow...ok. From that angle you can really see; it does indeed look like the goop is coming from that '750 A1' component. I will have a look at the MS-2931 service manual and report back. If something had to be a problem part, anything is better than the flyback, so I consider this good news if it all pans out.

About my Blast City, I've had it for a little over one year, maybe 200-300 hours on it since then, 5-10 hours a week. I bought from a guy in Florida who had it in his home (still Bass Fishing dedicated) for a few years prior to that. I don't think he used it much at all. Was in excellent condition, but there is some burn-in. Checked for goop back last summer..will definitely check again.

[grantspain]

yes it looks for sure that the crap is coming from the 750 a1 component,whatever that is

[oxtsu]

Here we go..

Symbol: L512
Code: 05F16750A1
Name: H.LIN
Description: ETS75

[grantspain]

it is a coil no?
by the description it is the horizontal linearity coil,does it have 4 legs?

[oxtsu]

Cool..thanks grantspain. Yes, it has four legs.

[oxtsu]

It looks like yours is leaking from the '750 A1' component as well, not the flyback. It's pretty clear from all of your pics, particularly the first one. Remember the chassis is angled downwards towards the flyback (in horizontal orientation); the goop is flowing towards there and pooling around it. The flyback's epoxy potting looks flawless.

[grantspain]

maybe crack open the case and take a look,i have a feeling it is a coil

[oxtsu]

Pretty sure it's an adjustable horizontal linearity coil, as you alluded to, grantspain.

I have no idea what the procedure is for measuring the specs on it though, and an e-search of the part# brings up nothing.

I'll ask a shop I know of In Japan (who does Nanao MS-2931 monitor repairs) if they can source the part in question. If you guys can figure out the specs on it and source a factory replacement in the States, all the better!

[Ordyne]

The "goop" is from the component at the side of the Horizontal deflection plug, its potting compound and nothing to worry about, it has nothing to do with the dead /faulty chassis.. I don't know of that part failing on any chassis.. IIRR it's used on the MS29-30 and MS29-31, the part is NLA like all custom parts on nanao's

[Mr-Megalo]

would be interested to know if this potting compound is what is causing flyback of doom though, AFAIK mainly from my own experience it is the flyback that goes tits up (double "yay" on the NLA items list IIRC)
has anyone ever tried cleaning up a dead chassis with flyback gloop of doom to see if it it is actually the flyback ? only way to tell I guess would be by doing some component swapping after a PCB clean up I guess - but brave man be the one who toy with $1000+ chassis containing several NLA parts to satisfy curiousity

[Ordyne]

I'll say it again, the "goop" has NOTHING to do with dead chassis.. it's not conductive, doesn't cause any problems.

For srarcade,
Before you start hunting for another coil check the inductance against another and see if its actually bad... the whole means nothing, i've seen them cracked/split/leaking and they've always been fine.. and yes to answer your question another coil of the same spec will be fine, or find someone with a scrap chassis.

[Mr-Megalo]

the question I have is - is there anybody else out there as mad as me and would be willing to part with around £800+ for a one of these monitors if any were to become available ?

[Ordyne]

the question I have is - is there anybody else out there as mad as me and would be willing to part with around £800+ for a one of these monitors if any were to become available ?

Hehehhe..

[cgbartek]

srarcade, I'll donate my dead one to you if you want to experiment with it. If they don't both have the same problem, maybe you can get a good one out of it and we might move a step closer to determining the source of the issue.

The screen burn issue on Blast City tubes definitely gives you a hint as to why gooped chasses are so common. Obviously the arcade managers would leave the machines on for days at a time and things would naturally start burning up. Unfortunately these monitors, as nice as they are, just weren't built to the harsh physical conditions of the American Wal-Mart arcade.