Connections on a Hantarex MTC9000. Which to use?

[MaximumFish]

Hi all,

I inherited an old JAMMA cab minus any game boards some time ago, and have finally gotten round to trying to get my PC hooked up to it using an ArcadeVGA card and a J-PAC.

From comparing pictures of monitors on the net with mine it looks very much like I have a Hantarex MTC9000, but I've become a bit unstuck by two connectors hanging from the main monitor chassis. One is a two pin connector, coming from around the main tube, with two black wires and the other is a six pin connector coming from the back of the tube, but not the detachable part.

All well and good so far, but the main circuit board has two of each connector type and I'm not sure which to connect to!

The two 2-pin connectors seem to be labelled "Push Button Degaussing" and "Degaussing Coil", while the 6 pin connectors have no obvious labels but are immediately next to eachother.

Can anybody help me match them up?

I'd also be very grateful of some assistance regarding my isolating transformer (or possible lack thereof). I have a bit of a fear of electric shocks, especially 120/240 volt ones, so I really don't want to make my whole chassis live! But that can wait for another post...

Much thanks for any help.

Max

[grantspain]

can you post a pic.
i think you are talking about the degauss coil and the yoke connector plugs
the yoke connector will be a 6 pin plug/the 2 centre pins will be linked together
the degauss coil will go to degauss(not push button) and it does not matter which connector the yoke goes to out of the two 6 pin headers (one is an inverted screen so if your picture is upside then swap to the other connector))

[MaximumFish]

Perfect, thanks! Funnily enough I do have a pic from when I first posted here:



It's not the best shot, but you can see the two 6 pin connectors just underneath the massive capacitor. If you have any idea as to which is normal and which is inverted, that would be awesome - I'd really rather not have to poke around by that capacitor once it's been on! As it is the machine has been sitting unplugged for about a year so it's nice and safe right now.

You can also see one of the 2 pin connectors in the top right of the pic.

Could I ask you to take a quick gander at my original thread regarding the power supplies? I got a few replies to my worries but nothing concrete: http://forum.arcadecontrols.com/index.php?topic=78756.msg821508

Basically I'd just like to know whether simply disconnecting the Jamma PSU would be a safe thing to do in terms of keeping everything properly earthed and not frying the isolating transformer by changing its power draw.

Thanks again, especially for your very quick reply!

Max

[grantspain]

normally its the connector nearest the cap for normal image,don't be concerned about electric shocks when the power is disconnected unless you stick your hand right across both pins of a cap

the charge held by crt vary anyway,most modern chassis discharge within a few minutes or hold very little charge-unless thats microvitec of course which holds a charge not to disimilar to a nuclear explosion

will answer the other questions in post

[MaximumFish]

You are a legend, thank you!

I've also replied to your other post.

[MaximumFish]

It works! But the header closest to the cap is the inverted one. Doh!

My Dad, who was a TV repair guy back in the 70s reckons I should leave it to discharge for 24 hours before trying to swap it over, in case I touch the cap, but that was just going on my description of it over the phone. My friend/lodger thinks he might risk it soon anyway as he's eager to play Snow Bros! Are you sure these things should be safe after a few minutes?

[MaximumFish]

Never mind, he touched it and he's still here. These things are surprisingly scary to prod around in. 

[MonMotha]

Generally you should be fine if you let it sit for a few minutes unless you go messing around with the anode ("suction cup" attached to the tube itself).  Avoid touching both sides of capacitors, of course.  In general, if you're not messing around on the underside of the PCB, this shouldn't be a problem.  Most modern designs include bleed-off resistors on any caps that would store high-ish voltage, but some older designs may omit them (or, of course, they could have failed).  Even if you do get nailed by one of them, it's probably just going to hurt (possibly a lot) and not cause long-term damage unless it flows across your heart:  Thou shalt always work with thy non-dominant hand in thy back pocket.

[grantspain]

perhaps when your Father was working on tv's they were like the old phillips tx10 which could destroy aircraft carriers with the amount of charge they help

so is it all working with your jpac and mame setup?

[MaximumFish]

Mostly, yes!

The 'up' on the player one 1 is broken, 2P start gets stuck sometimes and needs to be pryed out, and for some reason the fire buttons for both players seem to be mapped to the same keyboard keys. Hopefully this can all be fixed by buying some new sticks and buttons, and thanks to me wanting to keep that classic look it's reasonably cheap to do so.

The biggest problem I'm having is that the display seems too wide for the monitor. The H-Size knob is set as low as it'll go and there's still a significant portion of the display off-screen. For example, it's enough to hide an entire player in Snow Bros.

I need to research that but it may just be that I need to tweak the game specific configs?

All stuff to think about tomorrow as it's midnight here and I've got work at stupid-o-clock in the morning. It's all so close to being perfect!

[grantspain]

classic fault on mtc9000,need to cast my mind back about 15 years but i am sure its either tr17 and/or c42-d12 and d13 could also be at fault
btw why buy new sticks and buttons when you can clean the buttons and replace microswitches that are sticking or faulty

[MaximumFish]

Damn, really? The last owner says it was fine last time he used it with a normal Jamma board. So those are capacitors that need replacing then? Time to polish up my soldering skills (or lack thereof) it seems.

I suppose I could clean buttons and replace switches. In fact, while I didn't notice it before, it turns out that one of the sticks has already been replaced. Very similar design to the original but slightly fatter and a bit stiffer. I'll certainly consider the idea, but it is very cheap to just buy straight out replacements!

Thanks again... Again!

[MaximumFish]

classic fault on mtc9000,need to cast my mind back about 15 years but i am sure its either tr17 and/or c42-d12 and d13 could also be at fault
btw why buy new sticks and buttons when you can clean the buttons and replace microswitches that are sticking or faulty

Ah yes, this place reckons it's C42. Still wondering if I can fix it with some resolution tweaking though... (it's running through an ArcadeVGA card)

Edit: Forgot to post a link: http://www.coin.demon.co.uk/monitor.htm

[MaximumFish]

Just thought I'd post to say thanks for all of your help. I ordered the cap kit from the above link and got my old man round to solder them all up for me (I have essential tremor so didn't trust myself to do a good job, and besides, he's been an electronics engineer for 30 odd years!). It all went well, fixed the H-Size issue, and I've had the machine up and running since the weekend. It's awesome! That said, the slight wobble remains but I'm hoping I can fix it by tweaking the knobs a bit more... One of them is missing so maybe that's the key.

Oh, and after replacing all the buttons and sticks, I discovered that the control issue I was having was due to one of the JAMMA harness pins not contacting the J-PAC. One blob of solder later and it was fixed! Ah well, it's kind of nice to have all new controls there anyway. It means no-one can blame them for losing a game.

I did want to ask though... Now that we've started having the monitor on for extended periods, it puts out quite an interesting smell. I can't quite tell if it's just old dust burning off or what. I'm sure I read somewhere about something on these monitors glowing white hot and putting out a smell but I can't find it any more so I'm wondering if I dreamt it! Does that sound like something you've heard of before? And is it normal/anything to be worried about?

[grantspain]

another classic problem on mtc9000 was down to the bu508a transistor would go leaky and the large load resistor would then look like an electric fire bar-sometimes this would happen with flyback failure and the power transistor failure

[MaximumFish]

Ah thanks, so I need to look around the back when it's on and see if anything is actually glowing! I do remember seeing a glow from inside the glass tube attached to the back of the main body, but I'm thinking that's the display gun and normal.