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Sydney-based monitor/chassis repairs


OzDJ

Question

(My first thread outside the sheltered workshop which is the 'New member intros' section. Hopefully I've posted this in the right place! :) )

 

I have a Neo Geo MVS 6 slot machine which I picked up on the weekend.

 

The image on the screen is not nearly as punchy as my teenage memories had me expecting. I found a brightness adjustment, which I dialled to the maximum setting, but it's still only barely visible when there's any overhead or strong ambient lighting. Some games are basically unplayable.

 

I looked at the chassis and noticed the largest capacitor is bulging like a roid-filled gym junkie. Some of the other caps appear to have seen better days, too (eg sunken tops). I have no idea what the 25" tube itself is like and the capacitors could simply be the proverbial red herring.

 

I've spent hours looking through other's efforts to do DIY fixes for the display here on the forums and then on YouTube. While I'm OK with a soldering iron, I'm utterly terrified of zapping myself and recognised that this part of the machine is probably something I should leave to someone who knows what they're doing. I've read numerous posts by the venerable JOMAC, got excited by his expertise and professionalism, only to discover he's on the other side of the country. Bugger!

 

Is there a Sydney-based forum member or sponsor that I can/should connect with to get my display sorted out? Do any of them do on-site repairs? The idea of having to hire a van again and move that monsterous cabinet is already making my back ache.

 

Thanks for any suggestions.

 

DJ

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The cap that appears to be bulging will not be your issue. This is pretty normal.

 

There really is only one chassis "expert" in Australia - Jomac. All the others have moved on from the industry as there is no money to be made repairing these things.

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The cap that appears to be bulging will not be your issue. This is pretty normal.

 

Thank you. And *that* proves JOMAC's point about avoiding capacitor replacement work unless you know what the hell you're doing. ;)

 

 

There really is only one chassis "expert" in Australia - Jomac. All the others have moved on from the industry as there is no money to be made repairing these things.

 

Is that your longhand way of telling me, "DJ, you're screwed unless you DIY!" ? :o

 

Cheers

 

DJ

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Removing a chassis isn't really that terrifying.. Just follow the defined steps and take your time. Sending a chassis to WA for repair / replacement it just a matter of going to the post office and waiting a week or so. All in good time. By the time you procrastinate, the chassis could be in an express bag and on its way.! Alternatively, check Joey's site, get the impedance readings from the yoke and get Joey to send you a compatible replacement chassis..

 

You say your ok with a soldering iron, so your half way there. If you can set a multimeter to ohms and follow the instructions, you almost done.

 

Grab a decent screwdriver, a length of insulated wire, an alligator clip and some electrical tape and go discharge your tube.!

 

Sent from my LG-H815 using Tapatalk

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Removing a chassis isn't really that terrifying.

 

For me, unfortunately, it is. I'm not really comfortable going into details here, but there are reasons why both high voltages and loud cracks/bangs/explosions are a problem for me.

 

Sending a chassis to WA for repair / replacement it just a matter of going to the post office and waiting a week or so. All in good time. By the time you procrastinate, the chassis could be in an express bag and on its way!

 

I know, I know. And it's not about the money, either (otherwise I would order a replacement chassis from JOMAC in a heartbeat).

 

Any Sydney-based AA members interested in helping by doing a tube discharge? I know it sounds rather pathetic for you hardcore DIYers, but I need some hands-on help in the absence of an onsite visit from a tradie. Happy to show appreciation with cash, beer money or similar.

 

Thanks

 

DJ

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State your location to narrow it down. You should get a better response to your request for help.

Thanks for the nudge, WOKA. Somewhere in the back of my mind I thought I'd already done it, but it was actually in the member intro thread and not here.[emoji15]

 

 

I'm in Zetland/Alexandria - about 4km from Sydney CBD.

 

Cheers

 

DJ

 

Sent from my SM-N910G using Aussie Arcade mobile app

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Just closing-out my own enquiry in case it helps someone else. :D

 

I ended-up speaking with Danny from http://www.megaamusements.com.au and he agreed to get his monitor guy to have a look at it. Left the machine with him for a couple of weeks and it came back with a rebuilt chassis and a stunning picture. Very happy with the result.

 

DJ

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Just closing-out my own enquiry in case it helps someone else. :D

 

I ended-up speaking with Danny from http://www.megaamusements.com.au and he agreed to get his monitor guy to have a look at it. Left the machine with him for a couple of weeks and it came back with a rebuilt chassis and a stunning picture. Very happy with the result.

 

DJ

 

Just for future reference, dont go adjusting pots blindly, the brightness pot adjusts black level, and the one you shouldve been looking for is contrast, which adjusts white level.

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Just for future reference, dont go adjusting pots blindly, the brightness pot adjusts black level, and the one you shouldve been looking for is contrast, which adjusts white level.

 

Yep. Sage advice.

 

DJ

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Do you have the details of the monitor guy did he do the work himself or did he just send it to jomac and charge you for it very keen to get my chasis done I'm in Sydney as well

 

 

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I gave up discharging tubes years ago after being bit by tubes that had been previously discharged. I found it safer just to assume they will bite you if you get to close. The spark will only jump about 30mm so if you aren't any closer than that from the hole in the side of the tube, you won't get bite. Tubes will build up charge after being discharged over time so never assume they won't bite you after you have discharged them anyway. Now days I just put a screwdriver under the HT silicon cap and lift one side of the cap off the tube using the screwdriver to hold the silicon cap up. Carefully grab the edge of the HT silicon cap, away from the screw driver you are using to hold the cap up as it is charged while it is close to the hole in the tube, and peal the HT cap back so it inverts. Now you should see the two metal tabs inside the silicon cap that are clipped inside the tube. Move your screwdriver out and push it back in so as to un-clip half of the clip. When it releases, continue pealing back the silicon cap and the other side of the clip will release. Once the lead and cap are released from the tube, you can handle the chassis as you wish.

Now to re-connect the HT lead onto the tube, invert the HT silicon cap so the metal tabs are sticking out and move you finger and thumb back to the very edge of the silicon cap. Move the metal tabs over to the hole in the tube and clip one side of the clip in the tube. Get your screw driver onto the side of the "un-mounted" side of the clip and slightly push the screw drive to get the clip to close and snap into the hole in the tube. Let go of the silicon cap and it will seal over the hole, done. Just be well aware that the power plug to the machine is disconnected from the wall before stuffing with the HT lead in anyway. The silicon on these leads does break down over time. The voltage is high and it feels like a sparkplug on a lawn mower if you get bite. If the machine is powered on when you get zapped, it will continue to bite you, not just once like it will if it is turned off and you are careless. If you are super worried about using a metal screw drive, use a plastic knife. That way you won't get bite holding the metal screw driver. Once you have done this a couple of times you can get the HT lead disconnected or re-connected in about 5 seconds.

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I gave up discharging tubes years ago after being bit by tubes that had been previously discharged. I found it safer just to assume they will bite you if you get to close. The spark will only jump about 30mm so if you aren't any closer than that from the hole in the side of the tube, you won't get bite. Tubes will build up charge after being discharged over time so never assume they won't bite you after you have discharged them anyway. Now days I just put a screwdriver under the HT silicon cap and lift one side of the cap off the tube using the screwdriver to hold the silicon cap up. Carefully grab the edge of the HT silicon cap, away from the screw driver you are using to hold the cap up as it is charged while it is close to the hole in the tube, and peal the HT cap back so it inverts. Now you should see the two metal tabs inside the silicon cap that are clipped inside the tube. Move your screwdriver out and push it back in so as to un-clip half of the clip. When it releases, continue pealing back the silicon cap and the other side of the clip will release. Once the lead and cap are released from the tube, you can handle the chassis as you wish.

Now to re-connect the HT lead onto the tube, invert the HT silicon cap so the metal tabs are sticking out and move you finger and thumb back to the very edge of the silicon cap. Move the metal tabs over to the hole in the tube and clip one side of the clip in the tube. Get your screw driver onto the side of the "un-mounted" side of the clip and slightly push the screw drive to get the clip to close and snap into the hole in the tube. Let go of the silicon cap and it will seal over the hole, done. Just be well aware that the power plug to the machine is disconnected from the wall before stuffing with the HT lead in anyway. The silicon on these leads does break down over time. The voltage is high and it feels like a sparkplug on a lawn mower if you get bite. If the machine is powered on when you get zapped, it will continue to bite you, not just once like it will if it is turned off and you are careless. If you are super worried about using a metal screw drive, use a plastic knife. That way you won't get bite holding the metal screw driver. Once you have done this a couple of times you can get the HT lead disconnected or re-connected in about 5 seconds.

 

You seriously go to all this trouble over simply discharging the tube? :017:

 

Regards,

 

Johns-Arcade.

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WHAT THE........ You do realise that one zap from a tube can put your heart in to fibulation.

I am 63..... I got here after a full life as an electrician.

All things electrical can kill.

Anything you work on should be DEAD and earth strapped or it may be you who ends up DEAD.

 

Sent from my SM-G900I using Aussie Arcade mobile app

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I realise that. I couldn't imagine trying to do all that when discharging a tube safely is so much easier and quicker.

 

Regards,

 

Johns-Arcade.

 

My point was don't every rely on the tube being discharged. A lot of people don't realize the tube will recharge over time. I also took the time to explain how to actually disconnect the HT lead whether you choose to discharge the tube or not. How is the guy to get his chassis over to Jomac if he can't even get it out of his machine in the first place.

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Hi ozdj , I can discharge and disconnect the chassis for you this weekend if that's suits :) mikie , I know what it feels like first time lol

 

- - - Updated - - -

 

For screen burn , unfortunately its permanent, if you keep the monitor can either tint the glass or get a perspex sheet with a slight tint , this will hide the burn , turn up the brightness to compensate

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I glossed over the post but I didn't bother to read the solid wall of text - - - - - - paragraphs are your friend!

 

Tubes are discharged (in normal use) by the circuitry built into the flyback transformer and/or the high voltage pack fitted between the transformer and the high voltage connection of the tube.

 

When the ultor cap is removed from the tube you have a very large capacitor. This capacitor certainly can "recharge" to a small degree BUT after the initial discharge (which is what I was taught to do at trade school as a Radio & TV apprentice BEFORE working on any chassis) any recharge will be small and usually not much of an issue.

 

The main point is to discharge the tube - wait a minute or so then AVOID going near the high voltage connection for any reason.

 

Also the fragility of the neck on all tubes is usually underestimated - the number of tubes that have been stuffed and thrown out by mishandling and breaking the neck, mostly due to lack of knowledge rather than actual intentional mishandling, is criminal IMO.

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My point was don't every rely on the tube being discharged. A lot of people don't realize the tube will recharge over time. I also took the time to explain how to actually disconnect the HT lead whether you choose to discharge the tube or not. How is the guy to get his chassis over to Jomac if he can't even get it out of his machine in the first place.

 

Yes, that's why it's important for the person removing the chassis to safely discharge the tube first and make no assumptions. As for residual, this is why I simply use a double ended alligator test lead connected to the dag wire of the tube and the other end hooked to the Anode connection on the tube after the Anode lead has been removed.

 

Regards,

 

Johns-Arcade.

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Agreed, I have several tubes that do not equalise themselves well with their own circuitry, and will bleed charge from the glass for days. I prefer to discharge before handling every two minutes or less, and usually just leave the lead sitting against the anode button. I've been bitten by spark plugs before, and those things hurt! No way would I want to do that again, or get hit by a tube.
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I'm sorry I bothered to tell you all the truth.

 

Seriously?

 

What truth is that exactly? That you prefer to remove the Anode lead from a tube without discharging it first?

 

I'm sorry, but I don't agree with this method, and would never advise anyone to attempt to do this as it's just asking for trouble.

 

If you're offended by people disagreeing with you, well hey, that's life!

 

Regards,

 

Johns-Arcade.

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I'm sorry I bothered to tell you all the truth.

 

You can, of course, do anything you like. I was merely telling all who wished to read how I was taught at trade school during a 4 year apprenticeship to do EXACTLY this!!!

 

If you want to invent your own way of doing things all I can say is good luck with that.

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I'm sorry I bothered to tell you all the truth.

 

Don't take it the wrong way :) The stories you've shared are amazing, and it's always nice having another expert around to help noobs like me. You clearly know your stuff. But most of us would prefer to discharge a tube before handling it, especially people doing it for the first time. It's safest all round. The shock is short and sharp, I've heard, but none of us are getting any younger, and the risk of said shock interrupting the timing of your heart muscles only increases with age. We'd prefer nothing happen to you either.

 

I've given myself enough juice at 240VAC to know when enough is enough, and twice is enough ;)

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