Recent content by Olav_nordmann

Okay... One of the previous owners really did not go to town on this. After a brief inspection, it's apparent that someone tried to upgrade this from 2MB to 8MB using 256Kx4 chips.

I have this expansion, but I'm a bit puzzled when it comes to compatibility for the disk drive in this sidecar. The original disk seems to have died between since I got it and now (doesn't spin), but nevertheless here are my observations: With KS1.3, I get a blue screen at boot IF both the...

Declaring interest!

I seem to remember the newer C64c with the new SID use 12V AC instead of 9V AC of the older machines. But basically, the older C64 is the most iconic and compatible with vintage C64 games. It might also have a higher failure-rate depending on what chips it use, in particular certain chips made...

My Tapuino which I assembled some time ago! The holes are a bit rough in the edges as I didn't have a drill to make them. I used a Swiss-army pocket-knife instead, and to my surprise it worked quite a bit better than what I expected. Assembly went without a hitch. Things, including power...

If these chips are in different machines, won't they be a tiny bit detuned from each other? No two crystalls are 100% in tune. But nevertheless, slight detune is a well known way to richen the sound. It was for example a widely used technique to enhance the sound of the antique big-box disk...

If your trapdoor RAM has an enable/disable switch, you only need to cut and change one jumper (JP2) just above the Kickstart ROM socket. I've soldered a switch on mine as well to have it easily reversible. For 1M chip, set the RAM expansion to disable and the JP2 switch to the "changed"...

Found what I was after elsewhere.

Okay, did some testing and my assumption seems to be correct. if your trapdoor RAM board does have an Enable/Disable switch, then you can just set it to "Disable" and JP7A won't matter for the 1M Chip mod. This way, ONLY JP2 needs to be changed.

Received, tested, verified working! Thanks.

Package just received! Already started building it :D

I saw the demonstration video, and I thought it might be a bit slow to scroll through the whole list of TAP files one by one. What about the list scrolling with +/-10 (and maybe increasingly more) steps if you hold down the next/prev buttons for long enough?

Declaring Interest Thanks!

I will also recomend starting small, untill you got the full understanding on how a data-bus works and how these old CPUs use them. To handle anything more than 8-bits at a time over an 8-bit bus, latching will be needed. There's only 8 data lines to work with. As for pulling a line high...

With the XT-IDE project, one of the goals was to use FAT-formatted IDE harddrives inerchangeably between modern machines and the old machines, which is why it was nessecary to have the 16-bit/8-bit interface converter. If the intention is just to get data on and off the disk, then only using the...