MV-1F board trouble...

O

Opel

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Hi all,

I'm having trouble with a MV-1F board. Of five cartridges I've tried in it, only one of them even comes up, and even then the graphics on that one are weird/dark and only the brightest four colors show during game play (but when it's showing its "THE 100MEGA SHOCK!" screen it looks fine, so the monitor itself seems fine), and it also shows a dim/ghostly version of the image it's supposed to be displaying when it shows the copyright/whatever splash screen. When I plug in the other four cartridges I get a light gray, low-contrast, "ghost" grid (isn't the "no cartridge grid" just black and white?), and I can plug the one cartridge that does come up back in and it will come up just the same as it did before, so I'm sure that it's not just that I'm not getting them plugged in correctly.

What should I be looking at next?? Where can I send this board for repair, if I need to?

Thanks,
-Justin-
 
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ttooddddyy

ttooddddyy

PNG FTW,
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The cross hatch is probably appearing because the cart contacts and/or slots are dirty. Clean them thoroughly before doing anything else.
http://www.hardmvs.com/html/projects.htm

Yes the grid/ cross hatch should be high contrast black and white lines.
It is not only there to indicate no carts present or dirty contacts, but a usefull pattern for checking monitor picture geometery and convergence.

It also sounds as if the monitor may require some adjustment, the screen volts could be low (that would not explain a "low contrast" x-hatch though)

A piccy would help

Edit: forgot to ask, do other boardsets plugged into that cab work OK ?
 
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O

Opel

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I don't understand why I'm getting the contrast issue in such an odd manner. It does show me a proper white with black (and red?) when it does the "THE 100MEGA SHOCK!" screen (for the one game that even plays), but when it shows the grid for the non-working carts, it's just gray with barely a shadow of the grid. I did adjust the "screen" on the flyback transformer, and adjusted the black-level [brightness] and contrast on the monitor remote adjuster board, but none of that affected the way it grays itself out for a couple of different screens and then just doesn't look right (except for the "THE 100MEGA SHOCK!" screen) the rest of the time. I'm not sure what volts to check for on the monitor boards...

I haven't tried any cartridges other than the ones they had there, but they said those cartridges had all worked at one point. It just seems REALLY weird to me that all five of the cartridges that were sitting outside of the game fail in the exact same way, and then the one in the game has its own problem as well (seemingly). It makes me think there's something weird about the main board... I'll have to take a cartridge or two of my own over and see how/if they work.... And I'll see if I can manage to get some pics...
 
O

Opel

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I worked on this unit again this last weekend, and didn't get anywhere with it really. The couple tells me that it looked like that on the monitor that was in the cabinet before, and so someone changed the entire monitor but that didn't change the picture problem.

I did get another cartridge to work in the system, and the video looked exactly the same on it. In the test-mode's color screen (with the red, blue, green, and white blocks) I could just barely make out the text (as on any other test-mode text) and the color blocks were all the same gray as the rest of the screen, but with a ghost of an edge, so I could tell where the blocks were supposed to be, but they weren't any kind of color whatsoever.

Does anyone know where I can get an MVS 1-slot board? I would send this one for repair, but I'm doubting it would get back in time for their daughter's birthday party, like they are wanting it for... I found boards on www.coinopexpress.com but they're in Hong Kong and I doubt they would get here in time. Anyone have any suggestions?
 
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Hewitson

Hewitson

Metal Slug Mechanic
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Xian Xi said:
You do know that is Segafan4life's ebay account in that link, do you?
Click to expand...
Sorry, wasn't aware of that :emb:

Nearly all the multi slot boards on ebay seem to be from this seller. I hope I never have to resort to buying one from him.

Look at his conditions:

If Paying by paypal I will only ship your item when you reconfirm payment by email and confirm you will leave positive feedback when the item arrives in good working condition.

Failure to contact me confirming payment and intention of leaving positive feedback after successful transaction will cancel the current transaction , And you will be refunded and reported to ebay for failing to to adhere to auction policy.
Click to expand...
 
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channelmaniac

channelmaniac

Mr Neo Fix-it
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I listed my multi-slot boards on my website.

I have a couple of boards that aren't listed up there as well. PM me and we can talk price on those.

RJ
 
O

Opel

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I've just realized that I didn't even test the isolation transformer for the monitor! And actually, I have no idea how to test that... :oh_no: Can anyone tell me what to test/look for, coming out of that isolation transformer?

Channelmaniac, I've just won a board on ebay, only because I'm trying to get this all finished before someone's birthday party, but I do appreciate what you're doing by keeping these boards in repair! I'll be keeping track of you for future reference though! :D
 
channelmaniac

channelmaniac

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Thanks,

As for the isolation transformer you can verify it by hooking up a voltmeter (set to read AC) and see if you have 110-120 volts coming out of it. It's a 1:1 transformer, not a step-up or step-down transformer.

RJ
 
Hewitson

Hewitson

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I've always wondered what exactly does it transform since it doesnt alter the voltage?
 
IcBlUsCrN

IcBlUsCrN

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Hewitson said:
I've always wondered what exactly does it transform since it doesnt alter the voltage?
Click to expand...


i am pretty sure thats its used as a filter on the power line
 
channelmaniac

channelmaniac

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It isolates the power so you don't have one side of the mains connected directly to the monitor chassis.

It's a safety thing.
 
ttooddddyy

ttooddddyy

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As cm said.
It is for electrical safety reasons.

Quite often with 240 volts mains there is a step down transformer fitted in the cab for use with 110 v monitors (as is the case with my L&A 6 slots) which doubles as isolation.

With older monitors the chassis was sometimes live (half mains after rectification)
in that case the iso transformer is essential to avoid a shocking experience.

My advice would be, if the cab was originally fitted with an isolating transformer leave it in, or replace it if noisey/faulty. It was installed for a reason.
 
Hewitson

Hewitson

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Would someone mind explaining this in a bit more detail? I don't quite get it.

Thanks
 
channelmaniac

channelmaniac

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From a US standpoint...

110v nominal coming from the wall. One wire is hot and the other is neutral. Neutral and ground can be bonded together in a 2-wire socket.

On the monitor... you have 2 connections: hot and neutral. A ground may be connected to the chassis. Hot carries the current. Neutral may be connected to the chassis on some monitors.

Now, if you have a miswired outlet... you'll put the hot on the chassis of the monitor. Very bad shock hazard.

The isolation transformer puts a gap between the monitor and the power to keep that hot wire from ever possibly connecting to the chassis.
 
O

Opel

n00b
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Posts
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ttooddddyy said:
As cm said.
It is for electrical safety reasons.

Quite often with 240 volts mains there is a step down transformer fitted in the cab for use with 110 v monitors (as is the case with my L&A 6 slots) which doubles as isolation.

With older monitors the chassis was sometimes live (half mains after rectification)
in that case the iso transformer is essential to avoid a shocking experience.

My advice would be, if the cab was originally fitted with an isolating transformer leave it in, or replace it if noisey/faulty. It was installed for a reason.
Click to expand...

The older monitors I see usually have a label on them that say they require an isolation transformer, or that they don't. Recent monitors don't seem to have a label and I think they probably all just run stright to the 110AC.
 
channelmaniac

channelmaniac

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Opel said:
The older monitors I see usually have a label on them that say they require an isolation transformer, or that they don't. Recent monitors don't seem to have a label and I think they probably all just run stright to the 110AC.
Click to expand...

Recent monitors typically have switching power supplies on them and don't hook up the line to one side of the chassis.

RJ
 
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