Recent content by labomb

So after seeing the built up prototype, I was motivated to take another look at the regulator and as suggested, I looked at my Dazzler replica that I did a couple of years ago. As it turns out, Hugo's original layout was spot on. With that, here's yet another update...

Ah... seeing the actual prototype is quite helpful. :) Here is the update. The only other thing I changed was to eliminate the two pads next to Q1 and Q2, which I assume were used to bolster the track junctions (vs. as test points or some such). I added some additional copper at those locations...

I looked at several datasheets for TO-220 regulators, all seem to specify a max of 6.35mm length for the wide portion of the pins. The holes are currently located at 6.35mm from the bottom of the package. Factoring play with the mounting hole, that should be fine. I also aligned the holes...

So at the moment, I have the holes plated through. Apologies if I missed it, but is there a specific reason as to why they shouldn't be? Re. the regulator footprint, I actually have the holes a few mils further from the body than the standard package footprint used by my software. I can put...

Angles converging on a pad like this are generally fine, but changed per your request:

Updated with labels for external connections and proper TO-220 footprint.

I intend to build a couple of these as well... very neat project. So here is a variation with pad sizes that are a bit more suitable from my perspective. All component pads are 1.8mm with the exception of the regulator and the 4 link pads, which are at 2mm. All hole sizes are per Hugo's...

They are close together, but when scaled the pad sizes seem to match the original jpg that was uploaded. I should probably reduce the pad sizes on that one (indeed, all the component pads are a bit larger than I would personally use). Hugo: the pad sizes I came up with by scaling your original...

Attached are the gerbers for the JS-1 board. I added some identification text, and filled in the junctions at C5 and Q1. No problem making revisions at any point, just let me know.

Ahh... sorry about that. The diodes were a bit difficult to discern. One more for review... I'll upload the gerbers when you give the okay.

If this works, I can upload the gerbers.

Hmmm... you've peeked my curiosity. I located a dump of the ROMS that I found online way back in 2013, and it does indeed have a 0 byte where the 'A' should be, as well as the boot code at $FF00. I also located a dump (not really a dump actually, but rather a terminal emulator capture of the...

So I've just started to rebuild an Atari 800 (original, not an XL), and one thing that I thought would be on the agenda is to replace the 'Option' switch on the power supply board. The key was sticking down and wasn't operating correctly. However, upon disassembling I discovered that the switch...

I probably have a single-board something-or-other that is slower, but my MITS Altair 680b boxes are clocked at 500 khz.

That's quite likely. And it does have a decidedly frontpanelexpress.com 'ish look to it. I dug my Obtronix variation out... here's a pic: As mentioned, the color looks different.