Recent content by charlysan

Yes, I know. The goal here was not to get best DAC accuracy, but rather re-create an old R-2R design.

Hello! Although numerous LPT DAC designs exist, I was inspired to create a new one similar to a model I owned 30 years ago. By taking ideas from various projects, I have shaped this design to closely resemble the format of the original, which I regrettably lost. KiCad and gerber files can be...

It would be great to have this feature, maybe for Mod Master 2.x. Are there any plans for this? Alternatively, could the source code be released? This is Modplay Pro with 2 LPT DACs: Unfortunately, Modplay Pro only supports .MOD and it is limited to 4 channels. And below, your Mod Master XT...

@FreddyV, is it possible to get stereo output (LPT1+LPT2) using lpt DAC in MOD Master XT?

Have you tried different BIOS? Like GlaBIOs?

Little experiment sending modded CGA card output to GBS (RGB + CSYNC):

There is an error in my previous schematic, the diodes are oriented in the opposite direction: And scope on CS:

I might be able to answer that question if I ever manage to recover the data from the ST-238R HDD that this PC had.

@Eudimorphodon, your assumptions were correct. After following the traces using a multimeter, I got these schematics: Some conclusions can be taken from the above diagram: 1 - HSYNC and VSYNC are combined into CSYNC, which then goes to 74LS374 latch. 2 - The card is sending R, G, B and...

That's correct, some traces have been cut: I will trace them out, and upload a schematic soon. Another thing I haven't mentioned: they were using a DB9-Y cable, so I guess they were driving two monitors in parallel from one of the cards. I have already tested out the splitter with two...

If I have the time, I will create a schematic and try to read/decode the PLD.

Exactly. I will do additional tests in the following days. This PC had a ST-238R HDD + ST 11R controller. Once I can read the data in the hard drive I might be able to find the software used for this thing. And BTW, I might need some help with the ST-238R, as this is the first time I have one of...

I recently received a Juko XT clone PC that has two CGA cards connected to the board. One of those CGA cards has the following mod: ICs: #1 -> PAL16R4ACN #2 -> DS26LS31CN For the moment, I have done the following tests: 1. Connect the modded CGA card to another Juko board (A: standalone...

I've just done a quick test and modified the BIOS to search for option ROMs up to F7000, and it didn't find it. So, I think this confirms your thoughts; the ROM just sits at F8000 on this board.

I have used Y cable and two monitors with Hercules card in the past without any issues, and recently I have successfully tested this approach with three monitors. You can check an example video here.