Amstrad Mega PC / Amstrad Mega PC Plus

Allow me to clarify: I disabled the FM output on my CT-1350 solely because I didn't want the CT-1350 outputting Ad Lib. I knew full well it wouldn't have any effect on the Mega PC's Ad Lib support.

CT-1350 is indeed a good card esp. if you have the C/MS chips installed. Gives you 3x the audio support which is very valuable with only one slot free. Use jumper J12 ("FM") on the CT-1350 to silence Ad Lib on the card.

Really though, I'd have preferred having enough space in the Mega PC case to install an 8-bit Pro Audio Spectrum. It would have been very handy as I do not have another machine in which it would be convenient to install this particular card.

 

Well it could be that JP12 either really disables the onboard opl2 or it could only mean that the sb part just ignores it while it is still active on the bus? Needs investigation.
There is a 3rd ISA slot on the back that is unpopulated and can be used for some custom made card that only has the SB-compatible part. I will look into it in the following weeks. Projects like this I suppose can be trimmed in the way we want: https://www.vogons.org/viewtopic.php?p=751057#p751057

 

I tried it in a computer other than the Mega PC and can say for sure that the jumper doesn't make the YM3812 "invisible" : programs and games still detect it. The result is only that the sound card itself does not output Ad Lib sound.

 

...

 

You are correct, on VOGONS I found that those "FM" and "VOICE" pins are connectors for the "SB2.0 CD-ROM interface card (CT-1800)" which I assume it has it's own mixer and mixes SB2 sounds with CD-ROM Audio.
I will search for another solution

 

yes, I can finally re-create the photo on the ad when the monitor gets set up as well
Anyone knows what apps/games Counterpoint came with already setup'ed (if it even came with any) ?
At least the "Amstrad Desk Top" shell seems complete...

 

Anyone here know of a Motorola 68000 Memory Ram mapper-decoder with 74LS612? Looking for schematic for something like that. If anyone can help me in my thread here https://assemblergames.com/threads/chance-of-a-ram-cart-for-homebrew.54468/#post-988072 let me know! Thanks.

 

did some upgrades today....
First of all I restored the megadrive card to the original 60hz (pretty sure amstrad realized too late that since their target was EU they needed to make the card compatible with PAL cartridges so they made the extra modification for 50hz at a later point). I just removed the patch wire and fitted the missing 1kΩ resistor - now it looks factory-made



Second upgrade was the clip-on TI486SXLC2/50 cpu - it has 8kb of L1 cache and that gives it a nice speed boost - way better than the Cyrix 486slc2 upgrade with 1kb L1



This upgrade gave the pc-side a much needed boost for those 386 games.
The 486sxlc cache-enabling program needs the " h+ " switch for the megapc, else it will be a little unstable on soft reboots once cache is activated. H+ switch controls cache flushing.
Overall today was a success

edit:
is there any newer Quadtel 7600 bios? I see references to 3.07.01 but nothing to download...