Recent content by CommodoreZ

Progress update time. A friend of mine has designed a simple triple RC-circuit combined with Schmitt triggers to replace the power check circuitry of the original PSU. Here's my implementation of that design: It takes the presence of 5V, and uses that to provide 5V OK, MEM OK, and /POWER...

So, VCF Midwest 17 was a blast. I got the Nova all set up, and did a bit of debugging on the show floor on Saturday next to a very encouraging sight: Nevets01's DCC-116 running a fancy new power supply, made using the same Meanwell modules and card edge connector as mine. He was able to avoid...

Howdy folks, it's been awhile. Time to regale you all with the progress of the Nova 1200 power supply replacement. Forgotten Machines/firebirdta84 designed a passive interface board for the Nova's power supply for our development work. Nevets01 and I vetted his work, and each ordered a few...

Oh, very nice a Hero Jr! May I ask what options you've got the little guy specced out with?

Measuring the startup time of a VIC-20 with a 16K expansion cartridge, I get closer to 4.5 seconds from power-on to prompt. It's been suggested by the VIC-20 Denial forums that the 155 markings on the 16K prototype actually mean 15S for 15 seconds of reset. That's not too far off, I measured...

Yes, they do overlap on the board. On the connector to the resistor board, they're sandwiched top and bottom. As for heat output with a thermal camera, here's two photos from a series I took a few months back when I was studying replacing the fan. Eventually, I elected not to. This is how I...

Indeed, I am familiar with Forgotten Machines' work. He's one of the resources I've been consulting in this process. The switching supplies I've selected are a pair of Meanwells: RT-125A and LRS-150-15. The former will provide the 5V, -5V, and 12V for the 11-17V lamp voltage, as well as...

There's no really good way to put an ammeter in series between the power supply and the backplane. I'd have to find the weird pitch 26-position card edge connector, build an extension with gaps in it, and put your ammeter across that. That, or I'd have to destructively damage traces and that's...

I have replaced a significant portion of the components already. Here's a recap of everything I've done on this power supply so far: Reformed 4 of the 5 large electrolytic capacitors (C1, C3, C4, C5) Replaced C2, 1 of the 5 large electrolytic caps (it's part of the 5V regulator circuit)...

Howdy! I brought the Nova 1200 to VCF East last month as my exhibit. All was going well on Thursday during I set it up and BASIC ran fine that night. I ran a test on Friday morning, which was 5 minutes in when it halted part-way through Single User BASIC and refused to resume, or reload the...

Howdy, A few weeks ago at VCF East, I spoke with Robert "Bob" Russell, one of the VIC Commandos. I don't know what convinced him to do so, but he gave me a pair of later VIC-20 prototype boards. First, the 16K VIC-20 Prototype. This machine is an internal prototype from Commodore of a VIC-20...

That's pretty standard practice these days for VCF video streams. After the initial stream, they take the footage, clean it up, and cut it down to individual videos for each presentation. We just have to wait for them to repost the processed version, that's all.

Gladly! I've attached my source code, which started out as the PDP-8 BASIC version, and was converted for Nova Single User BASIC's limitations. If you can find optimizations which work within those limits, I would love to see what you come up with. I've found myself quite baffled by Nova...

Update time: After running BASIC a few times and having fun with it, I started having problems re-entering BASIC following a clean shutdown, as if it were an unclean shutdown. I tried simpler programs, and it was halting part way through on those too. Not good. I wasn't sure what was going on...

I'm well overdue to post updates on this thread, so here goes: The Nova 1200 is up and running now! Step one was verifying that the power supply was operational. I started by reforming the 5 large electrolytic capacitors. The smallest of which was too far gone to be reformed and was...