WrestleFest horizontal bars

Apocalypse

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I grabbed a PCB of WrestleFest, US version (Technos).
When the volume is set to more than say 10%, horizontal bars start to appear on screen. The loudest the sound, the more the bars are visible.
There isn't any problem with the sounds (no distortion of whatever) however the amp gets very hot if I turn the pot too much.
If I set the sound to a very low volume the game just plays fine (tested for one hour or so).
I've checked the documentation and the board only needs +12V and +5V (-5V pins on the edge connector lead nowhere).
 

mikejmoffitt

Mickey's Coach
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That sounds like one of the speaker output pins is shorted to something. I wouldn't turn it up any further for a risk of damaging both the power amp and the logic on the board.
 

Apocalypse

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This is a JAMMA board (with 2 extra connectors for players 3 & 4) so it's mono only.
I tried it on a supergun and although + and - pins for the speaker are wired correctly to the JAMMA connector, once connected to the TV the - pin gets connected to GND... I checked and on the supergun side + and - pins are just connected to the corresponding pins on the JAMMA connector and nothing else (no common grounding for the - pin of speaker). So the issue is on the TV side. I made the test with 3 different TVs and the result was the same.
I've played many other JAMMA boards with that supergun without any issue so I guess WrestleFest has something slightly different on the audio amp (which isn't a problem on a real JAMMA cab since + and - pins are connected directly to the speaker, no grounding).
What if I add say a 1k resistor between the - pin and the scart connector to the TV?
 

mikejmoffitt

Mickey's Coach
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That supergun isn't wired correctly, then. No mono amplifier is going to be happy with the negative terminal connected to ground. Other boards are just handling it correctly, but it's bad for all of them.
 

Apocalypse

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That supergun isn't wired correctly, then. No mono amplifier is going to be happy with the negative terminal connected to ground. Other boards are just handling it correctly, but it's bad for all of them.
Yes I know, and the SuperGun doesn't connect the - speaker to the ground directly. It's inside the TV.
So I rewired the SuperGun by leaving pin L unconnected and wiring the TV audio ground to the SuperGun ground and everything is fine now.
Problem solved.
 

Xian Xi

JammaNationX,
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Add an attenuation circuit so you can flip between mono(dual) and stereo output from the supergun. I have a tutorial on my site for it.
 

Apocalypse

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Add an attenuation circuit so you can flip between mono(dual) and stereo output from the supergun. I have a tutorial on my site for it.
I'll have a look but I'm a bit confused as JAMMA is mono only. Is it a mod to plug MVS stereo boards?
I this case I use a MVS to JAMMA converter.
 

Xian Xi

JammaNationX,
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I'll have a look but I'm a bit confused as JAMMA is mono only. Is it a mod to plug MVS stereo boards?
I this case I use a MVS to JAMMA converter.

It makes jamma either mono or dual mono and stereo just left channel or full stereo.
 

Apocalypse

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Yeah I had a look and I understand it better now. Will definitely add it to my supergun.
Also I will probably build a new one and although RGB with scart connection is the standard for me, I was wondering what you guys in the US do? Composite out built from the RGB signals?
 

Xian Xi

JammaNationX,
15 Year Member
Joined
Dec 1, 2005
Posts
27,748
Yeah I had a look and I understand it better now. Will definitely add it to my supergun.
Also I will probably build a new one and although RGB with scart connection is the standard for me, I was wondering what you guys in the US do? Composite out built from the RGB signals?

There's a lot of people that use RGB that have the proper monitors for them, others usually get component, VGA or HDMI(analog to digital).
 
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