Argh - I killed my 1-slot MVS! :( Help please?

Hi - well, I've not had it long and already managed to kill my 1-slot MVS. I think (hope) it'll be an easy fix, was wondering if I could prey on the knowledge of y'all. Thanks!

Essentially what happenned was I was trying to adjust the volume. When I originally bought the MVS the guy showed me a little white potentiometer with a cross hole in the top, and told me he "thought" that it was the volume control, and that to adjust it I should use a phillips head screw driver.

So : Wanting to play late at night and not disturb the kids, I decided to attempt to turn it down slightly. I tried to adjust the volume whilst the machine was on and running ( a stupid mistake perhaps, but I figured it was the best way to tell how loud/quiet I had adjusted it to. ) I used the first screwdriver that came to hand ( again perhaps a stupid mistake - it didn't occur to me until afterwards to check if it had a magnetic tip or not... )

Anyway, long story short when I touched teh potentiometer, the arcade cabinet started talking to me (which scared the crap outta me till I realised it was somehow picking up radio transmission!) so I instntly took the screw driver off it. I tried turning the pot with my fingers instead, and even though I was trying to be insanely gentle, rather tahn turning, it bent ever so slightly, then fell right off, reveling a crappy soldering job by whoever owned it last!

Now whenerv I turn on my cabinet it works perfectly, except I get no music/sound effects and instead get a VERY loud and VERY annoying 2 tone alarm noise through the speaker. Other than simply disconnecting the speaker - is this something I can easily fix?

Any input appreciated - good job I was on the lookout for a 4 or 6 slot to replace this one anyways, otherwise i'd be even madder than I currently am!

Solder it back on.

I do not know what potentiometer goes on that board exactly.

I own one that I can de-solder (the board has been dead for years and I only keep it to salvage parts) and mail to you if you'd like.

I will need a photo of the pot and the underside of the PCB so I can make sure the pins are identical.

From what I know of electric circuits, the busted leads are probably just sending a square wave form through the speakers.

thanks for the repies I still have the potentiometer, I didn't loose it - is it really just as simple as soldering it back onto the three points?

Please excuse my huge ammount of ignorance, but why would a missing potentiometer for the volume cause teh machine to make such a noise? I would have thought it would have just run silently?

Thiessen said:

thanks for the repies I still have the potentiometer, I didn't loose it - is it really just as simple as soldering it back onto the three points?

Please excuse my huge ammount of ignorance, but why would a missing potentiometer for the volume cause teh machine to make such a noise? I would have thought it would have just run silently?

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Part of the circuit runs through the potentiometer. I'm barely passing my electric engineering classes so I'm not much help.

I do know that in complex circuits, a small subtraction like this can have very large consequences. Perhaps something akin to having a small marble dropped into a large engine.

Ok, cool thanks I think I'll get brave and try and fix it this weekend when I get time off work I am really not confident when it comes to electricals!

I thought that the volume was a slider on the side of the board.

I thought that the volume was a slider on the side of the board.

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He must be talking about an MV-1F or something...cause the MV-1 doesn't have any pots....

BTW, you could also just look at the numbers on your pot for the rating and buy a new one. There should be three digits: place 1 is the first number, place holder 2 also stays the same and place holder 3 is the x10 multiplier. Example:

501= 500ohms
500= 50 ohms
503= 1000ohms

etc.


-Segasonicfan

Also, shouldn't this be in the tech forum? You'd get more help over there

Thanks for the info Sorry I didn't see the tech forums lol

The volume pot on MVS boards is always 1k (whose code will be 102 not 503). It's a dual-gang slider only on stereo boards (multi-slots, MV-1, MV-1F). If it's "a little white potentiometer with a cross hole in the top" as he said, then it's one of the smaller mono boards.

Magnaflux said:

Part of the circuit runs through the potentiometer.

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Not part, all of it. It's a single mono trace that goes through the pot and then off to the power amp so if the pot is removed there is just no input to the amp and consequently also no output. If he's getting some noise from the speakers it's because the amp is powered and connected to the speakers.

That all makes sense, thank you all so much I just hope my "l33t" soldering "skillz" are up to the job! And yeah its a mono board. Once I take it out to fix on the weekend I'll find out what model [edit] Aha! Fixed it I now have a 4slot too, so the 1-slot is for sale/swap in the neo market section