Search results

For all those that are interested, I made a CGA to SCART/VGA 15 kHz adapter. https://github.com/profdc9/CGA2Scart It is useful with converters like the GBS-8200 because it will create the composite sync signals needed for the GBS-8200 to work. It also has some experimental support for...

I wanted to share an experience that I had. I have a 5160 PC XT and a Model F keyboard. The Model F keyboard always acted flaky, and I noticed that if I bent the circuit board backwards the keyboard would work for a while, but then produce 301 POST errors and stop working. I even made the...

Thanks for the advice. Here is what I've tried: I used a hair dryer to heat up the board to see if that would cause failure, or cause it to start working if it was not working. It did not seem to change anything, even though the board was probably heated over 40 C, and I didn't want to go any...

Ok, I found out the drive is the 3rd type specified in the documentation. Unfortunately the scanned schematic is low resolution and the letters and numbers are very difficult to make out, and I haven't been able to successfully use it. So I have left it on for an hour and the drive seems to be...

I am looking for a service manual for a IBM PC XT 5160 5.25" drive. However, it is NOT a Tandon drive. It has a part # 0384-002 and 6181147. There are pictures of it in this thread https://forum.vcfed.org/index.php?threads/ibm-360k-floppy-drive-not-tandon.70394/ The problem is that for a...

I have tried the Xinluda 82C55 and they seem to work ok. It required a slight slow down in the Arduino, but otherwise works fine.

Well I have the Apple ][ version of the hardware working. I don't have a video of that however, but I could make one I suppose. I have just started making the PC version, thinking that the principle would work basically the same for both, with a ATMEGA328P doing the heavy lifting connected by...

Hello, I have design a 8-bit card for mass storage with SD cards. The schematic is here and based on a design I did for the Apple ][. http://www.github.com/profdc9/ISACard http://www.github.com/profdc9/Apple2Card The designs for the two cards (ISA and Apple ][ bus) are so similar that this...

I was looking at lcsc.com because they tend to have parts from many Chinese suppliers, and I have found them pretty reliable in representing sources of ICs. I was encouraged to use 74LS86/74HCT86 and 74LS32/74HCT32 because they are so fundamental and there's three to four manufacturers of...

I am just worried with the semiconductor shortage many of these chips may never be made again once current stocks run out. If a Chinese company is cloning it, perhaps that means there will be other sources of it for awhile. I've been burned a few times by parts that are no longer supported...

Hello, I am working on my own ISA card for storage and peripheral interface: http://www.github.com/profdc9/ISACard I decided against using the 74LS644 because I thought a new design in 2022 should not use a chip that is already rare, so I improvised the function from XOR 74LS86 and OR 74LS32...

Hello, I designed a easy to build Apple ][ SD card mass storage device. It uses only five commonly available through-hole integrated circuits. It supports two SD card slots. It includes all of the ROM firmware and gerbers. You can find it at the github...

Hello, I have a IBM PC XT Model 5160 with original Model F keyboard with capacitive keys. I have struggled to make the keyboard work, however, the keyboard is quite unreliable. In particular, before I fixed it, the error "3B 301" would appear upon POST, which shows that the F1 key was "stuck"...

Hello, Version 1.1 of the SD card to parallel port is released. It includes the following improvements: 1. Supports 32-bit sector sizes for those versions of DOS that allow for it. 2. Small speed ups in the transfer rate. The README is included below. It is fairly simple to interface...

I was having some fun and I created a falling letters screensaver for DOS. I have attached the source and the compiled COM files. There is one for CGA and one for MGA. Take a look at the screenshot and see what you think. Dan Instructions from README are below: This is a "falling...

Hello, I have written an MS-DOS driver to connect SD cards to the parallel port which is attached. Because floppy disks and floppy disk drives are hard to come by these days, this might help transfer data to or from your old PC, especially in large quantities. I have tried it on my IBM PC...

Hello, I modified the packet drivers for the NE2000 card to work on 8-bit slots and have included the modified NE2000.ASM and the compiled NE2000.COM below. Use it at your own risk, and if you break your vintage computer, it is not my responsibility. It has been tested on my IBM 5160 PC XT...