MiSTer FPGA Forum

Hi,

I picked up a QMTech mister SOC and I wanted to flatten it out using ribbon cables.

I had some 40 pin IDE cables (6 inch), some 40 pin GPIO cables (9 inch I think) so I tried those and it doesn't seem to be working. I have it set to boot directly into an Amiga core and it boots up and tries to display the AmigaVision menu, but the video cut out and it acts like it isn't getting enough voltage. Just to be clear when stacked it seem to work flawlessly.

I've tried the PSU that comes with it and an after market one (https://www.amazon.com/dp/B078RT3ZPS). I've checked to make sure the ribbon cables are in the correct orientation by checking the continuity on my multi meter.

1. Has any one flattened out their QMTech Mister? If so, what ribbon cables did you use?
2. I'm still seaching to see if there is a spec sheet, so if anyone has a link that''d be appreciated. I was wondering what the input voltage range is for the QMTech. I have a bench power supply with adjustable voltage, so I could try to up it a bit and see if that makes it stable too, I just didn't want to fry it.

Thanks!

EDIT: Meant to post in the Hardware Clone forum, so feel free to move this if you like.

The power source for the QMTECH Mister board is 5V. You may refer to the materials they provided in Github.

Schematic, User Manual, Test Program are provided via below Github:

https://github.com/ChinaQMTECH/QMTECH_C ... Dual_SDRAM

probably your IDE cables are too long, ether getting too much interference, or the impedance is wrong
Also double check to see if you got your ribbon cables going the right way

Thanks for teh link. I see manuals for assembly and such, but nothing with any detail. Maybe I missed it, but I was hoping for something with some deatails of the switches on the pcb too.

andrezheng wrote: ↑Tue Jan 07, 2025 4:35 am

The power source for the QMTECH Mister board is 5V. You may refer to the materials they provided in Github.

Schematic, User Manual, Test Program are provided via below Github:

https://github.com/ChinaQMTECH/QMTECH_C ... Dual_SDRAM

I don't think they make cables much shiorter than 6 inches. <insert joke here>

As for the impedance, that is very possible. I didn't check it as it's just wire. Interferance is a possibility too. I'm not sure if it would help, but I could try wrapping some aluminium foil around the cables and see if that changes anything.

Cheers!

darksakul wrote: ↑Tue Jan 07, 2025 5:32 am

probably your IDE cables are too long, ether getting too much interference, or the impedance is wrong
Also double check to see if you got your ribbon cables going the right way

On page 6, it shows the switches' location.

Thanks, yeah I saw that.

I'm still looking for more info on them. If I compare that picture to what I have, it looks like my switches are setup for daul-sdram. Which I only have the soldered sdram. It'd be nice to know what each switch does incase my configuration in incorrect.

andrezheng wrote: ↑Tue Jan 07, 2025 6:38 am

On page 6, it shows the switches' location.

Fur DIP switches settings, refer to this thread.
viewtopic.php?t=8558

lamprey wrote: ↑Tue Jan 07, 2025 6:44 am

Thanks, yeah I saw that.

I'm still looking for more info on them. If I compare that picture to what I have, it looks like my switches are setup for daul-sdram. Which I only have the soldered sdram. It'd be nice to know what each switch does incase my configuration in incorrect.

andrezheng wrote: ↑Tue Jan 07, 2025 6:38 am

On page 6, it shows the switches' location.

Perfect. Thanks!

andrezheng wrote: ↑Tue Jan 07, 2025 8:11 am

Fur DIP switches settings, refer to this thread.
viewtopic.php?t=8558

lamprey wrote: ↑Tue Jan 07, 2025 6:44 am

Thanks, yeah I saw that.

I'm still looking for more info on them. If I compare that picture to what I have, it looks like my switches are setup for daul-sdram. Which I only have the soldered sdram. It'd be nice to know what each switch does incase my configuration in incorrect.

andrezheng wrote: ↑Tue Jan 07, 2025 6:38 am

On page 6, it shows the switches' location.

Just wanted to follow-up on this incase it might help anyone else.

I was able to get this working, but the regular 40pin ribbon cables did not work. I was successful with 40 pin (80 wire) ribbon cables.

Here is an example of what I wsa able to use successfully:
https://www.ebay.com/itm/304377555971