ZXM General Sound - not working

[Shockwav3]

Hi,
I recently assembled a ZXM General Sound. It's using a 18MHz crystal and a Z80 rated at 20MHz, ROM is 1.05, firmware upload worked nicely, using the 18MHz variant version 1.01 and later 1.02. External power is being connected and produces nice +5V and -5V voltages for the analog part.
However when I try to use it on my Scorpion 256 Turbo+ the system hangs when attempting to upload a tune (Alienate Demo by Hooy-Program or the GS patches version of Zynaps, when no soundcard is connected it loads everything into a void and then starts the demo/game). Test 4.3 hangs for a brief moment when trying to detect a soundcard. Sympthoms are the same with a real floppy or when using a .trd image from the HDD on my SMUC2

Removing the CPU and/or ROM doesn't change things.

Any ideas what to check?

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[Shockwav3]

Turns out the Z84C0020VEC I'm using is dead :/

[Shockwav3]

Just got a replacement CPU which is confirmed working. Sadly the ZXM GS still doesn't work
Quarz is 12MHz, Firmware 1.02 12MHz, gs105a.rom, CPU is a Z84C0010VEC (I know it's overclocked, but the CPU stays absolutely cold)
Whenever I try to load a programm which uses the GS the whole computer hangs.
EPM7128STC100 is the -15 variant, for the ROM I'm using an SST 39SF010A-70, Power is provided via the molex connector on the card.

Host computer is a ZS Scorpion 256 Turbo+ with ProfROM using a real floppy (same issues when using a SMUC). I'm using the outmost ZX Bus slot at the edge of the computer.

Any ideas or other things to check?

[JV-Soft]

Shockwav3 , зашить тест пзу - https://zx-pk.ru/threads/17696-gener...l=1#post910400

[Shockwav3]

Do you have the mentioned Test ROMs available for download? The links in the thread are broken.

[JV-Soft]

The links in the thread are broken.

Ссылка в самом конце темы , рабочая.

[Shockwav3]

Found the ROM ... sadly absolutely nothing is output from the card.

[JV-Soft]

Shockwav3 , если карта не вставлена в компьютер , надо подтянуть reset через резистор ,и поставит на него кнопку на землю ,что бы самому делать сброс процессора , или вставить в компьютер и нажать reset /
если ничего не происходит , смотреть осциллографом стартует ли процессор ,что на шинах.

[Shockwav3]

Well ... some progress has been made. Using a scope I could confirm the clocks for the CPLD & CPU, also I can see some activity on the Data/Adress buses.
One of my cards appears to be dead with the reset line only going as high as 3.7V

Using my other card with a 18MHz crystal and the 18MHz firmware for the CPLD + the 1.05a ROM I can get my test demo and zynap_gs to load. However only the first sample plays briefly (but long enough to recognize) and then the card goes silent.
With a 12MHz crystal and 12MHz firmware it still hangs whenever I try to load anything onto the GS.

I guess the 20MHz Z80s I got are fake? They have a suspiciously new datecode with 1326 (26th week of 2013 I guess). However any ideas why the 12MHz firmware gets me nowhere?

[Shockwav3]

Seems like the CPU was the culprit ... loading and playback now works reliable.
Output still is a bit unclean, but I guess that's an issue I can resolve on my own