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Main => Monitor/Video Forum => Topic started by: chapas on October 27, 2015, 01:15:15 pm

Title: Connecting a ZX Spectrum +2B to J-Pac
Post by: chapas on October 27, 2015, 01:15:15 pm

Hi,
I have a  J-PAC and a Hantarex Polo2 in my MAME cabinet.
I have made an adapter from Amiga 1200 (from Amiga RGB to VGA) and it worked great.
Now i have tried to do the same with my ZX Spectrum +2B, but it did not worked so great.

I have build the schematic i have found in this link, but for a VGA15 plug instead of a 9Pin VGA

http://www.worldofspectrum.org/forums/discussion/25849/redirect/p1 (http://www.worldofspectrum.org/forums/discussion/25849/redirect/p1)

I plugged into the VGA of the J-PAC but could't 'hold' the image steady.


I'm i missing something here?

What's your opinion?

Thanks in advance,
chapas

Title: Re: Connecting a ZX Spectrum +2B to J-Pac
Post by: opt2not on October 27, 2015, 03:38:56 pm

Check this doc out: http://mts.speccy.cz/doc/128_rgb.pdf (http://mts.speccy.cz/doc/128_rgb.pdf)
(read the Spectrum +2A/+3 RGB Differences section)

Correct me if I'm wrong, but it looks like the +2B doesn't put out separate H&V, from what I see here it only outputs CSYNC on pin 4 of it's RGB socket.
Doesn't the JPAC expect to have separate H&V sync from the VGA cable?