Auto Switching MS9 / J-pac issue

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Andypc
Posts: 46
Joined: Sat Apr 11, 2009 4:53 pm

Auto Switching MS9 / J-pac issue

Post by Andypc »

I have a strange issue with my J-pac and Auto Switching MS9 when trying to switch between 15Khz and 24Khz. I have all my emulator up and running perfectly in 15Khz (Groovymame, GroovyUME etc and CRT_Emu drivers). However the only emulator I am having an issue with is the Model 2 Emu as it looks poor running interlaced and the sound is skipping. So I thought I would run VMmaker and add 24Khz modelines. Changed the jumpers on the J-pac to 15Khz and 25Khz started the PC and the 15Khz picture was all scrambled. Changed the jumper back to just 15Khz and started the PC again and the picture displayed perfectly again. Tried a 24Khz resolution and the picture is scrambled? Tried with the jumper on just 25Khz started the PC again and the 15Khz picture is scrambled again. 

To cut a long story short the J-pac doesn't seem to auto switch between 15Khz and 24Khz no matter what jumper setting I try. If I start the PC in 15Khz with the 15Khz jumper selected on the J-pac and then start a 24Khz game the picture is scrambled. If I then unplug the keyboard lead to power down the J-pac change the jumper to 25Khz and plug the lead back in it syncs and the picture displays perfectly. The only way to switch between 15Khz and 24Khz is to power down the J-pac and change the jumper manually. This defeats the point of having an auto switching chassis. I thought the J-pac would auto switch with the right jumper settings. 

I would just give up, but running the model 2 emu at 24Khz looks great and fixes the sound issue.
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antron
Posts: 2861
Joined: Wed Feb 22, 2006 7:53 pm
Location: Egret 29, USA

Re: Auto Switching MS9 / J-pac issue

Post by antron »

Removing all jumpers allows all signals through. You just loose the 31kHz screen doubling/protection.
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