images I found the web show that there is no ram installed on this, just the 1mb rom bank
this card was probably made for windows environment - you would have a 1mb wavatable midi device, pcm playback/record and joystick interface
ram is needed to upload better banks (under windows) or gus classic compatibility
I believe I have seen someone adding ram to this board - it would certainly make it useful under DOS for gus classic stuff

Thanks, so basically it's just a wavetable sound card with the ability to sound like a low quality GUS PnP would when playing GM music (provided the GUS didn't load high quality samples despite being able to)?
I mean it's still kinda cool, but I had hoped to be able to get GUS compatibility here, so would be really cool if there was a way to upgrade the board.
The PCB definitely looks like there are intended spaces for 2 ICs, maybe a RAM and some kind of controller?

I am almost certain that adding a SOJ40 dram chip on the empty space at U8 will add some ram to the card
if you find a 512kb x16 chip then you will get 1mb of ram and it will be enough for DOS gus classic stuff
but I do not have such a card so there is always the chance it won't work - maybe someone else already did this and can chime in

The manual shows a socket where that empty space at U8 is, and the initializing program offers to load either a 4MB or 1MB sound set, so maybe even a bigger capacity might work? Or maybe they just didn't bother to make the initializer different from this card's bigger brother, the Pro version with a SIMM socket.

It's probably the same initialisation program on both 😀

Here's how you can put 1MB of RAM on a similar interwave: Upgrading Philips PCA761AW / AMD Interwave 'GuS Clone' to 1MB RAM
You'd need to install a socket, stack up 2x 256k x 16 soj-40 chips on all pins except for the CAS (UCAS/LCAS) lines on the top chip. Then run the chip select lines from the top to the two un-used bank select pins on the chip, probably 97 & 98 but you should check on your card to be sure.

That looks janky as hell..

appiah4 wrote on 2024-05-24, 14:53:

That looks janky as hell..

Yeah I re-did the wiring later with thinner enamel wire and cleaned the flux up, it looks better now.

Sadly going over 512KB of RAM on Interwave cards without a SIMM slot does require some janky mods 😜
It'd need a new PCB though to have more than 1MB with designs that only have a footprint for an SOJ-40 chip