No video on Mega32

[msamiullah]

I recently bought a Mega32 mobo and Idol Janshi Suchie-Pai II cart, when I connect this to my Astro city I see no picture, I rekon Idol Janshi Suchie-Pai II requires a special expansion adapter which I do not have, would I see any picture if expansion adapter is not connected ? Asking if this is normal behavior or my mobo is defective ?

 

[twistedsymphony]

The Mahjong games do indeed require a mahjong adapter and will not run without it. This is a set of two small boards one connects under the mobo and plugs into the large white connector on the underside of the right front of the board. and then there is a second board that connects to the JAMMA edge and there is a small harness that connects these two boards.
they look like this:

technically you can get the game to boot with just the lower board but you wont be able to play it as the controls will be incomplete/missing

I could be wrong but I seem to recall getting garbage on screen (like TV static) when trying to boot a mahjong game without this adapter.
I'm not sure what behavior your game is exhibiting.

 

[msamiullah]

Thanks, that seems right then as sometimes I am getting static screen and sometimes this blue screen:

Are VR1 and VR2 for audio?

 

[twistedsymphony]

yup, that screen is normal behavior for a mahjong game without the mahjong adapter.

Are VR1 and VR2 for audio?

I don't have a board in front of me to know what is labeled VR1 and VR2 but if this is the large pots near the audio heat syncs then yes they're for left and right channel volume.

only 1 channel is attached to the JAMMA edge and the 2nd channel outputs on the 2 pin header next to the JAMMA edge. (it works this way on Mega System 1 boards a well)

 

[msamiullah]

only 1 channel is attached to the JAMMA edge and the 2nd channel outputs on the 2 pin header next to the JAMMA edge. (it works this way on Mega System 1 boards a well)

From what I have gathered from reading manuals and internet search is both of these audio channels are Mono as M32 cannot output stereo audio so the 2nd channel is just a replica of the 1st channel, is that consistent with your understanding?

 

[twistedsymphony]

I honestly haven't looked at the circuit to determine if it's stereo or just 2 channel mono.