Recent content by dfnr2

@smbaker: At the VCF Southwest last summer, I picked up an AIM-65 with the same case as yours. Mine had an internal backplane with four slots in a 2x2 arrangement, and a buffer board to interface the expansion bus to the backplane. The backplane supports 44-pin connectors, and doesn't appear...

Thank you so much for sharing this. There's a lot there, and it will be fun to look through it all. Dave

I found some TE28F400CEB120 parts on ebay, which can handle a 5V supply. They ship from California and have the textured appearance, so I suspect they are genuine.

Thanks Vince! Also, I see that I can get the intel TE28F400 parts on ebay. Would that be better than a 29F400 from Mouser (Alliance Memory)?

Hi all, Somewhere around 2010 there was a group buy of IOB6120 PCBs and parts. I got all my parts from the gentleman who arranged the buy and built up the board without really critically reviewing the parts, and when I attached it to my (working) sbc6120, the whole system was unresponsive. I...

Hello All, It's time to start planning for the next DFW Retrocomputing meetup. The first Retrocomputing Meetup of 2024 will be on January 21, brought to you by the DFW Retrocomputing Meetup group and the Vintage Computing Collective of North Texas. Our winter meetup is generously sponsored by...

Beautiful artwork. Those machines are amazing. Too bad they are so rare. I saw your displays at the VCF Southwest, but alas, I only had a couple of hours there and I didn't have a chance to dwell there. Where are you in Texas? It would be awesome if you made it to one of our quarterly...

Very nice project. I like the pure hardware approach.

Just to clarify: By "Larger error signals" I meant larger overvoltage error. Undervoltage will generate larger feedback voltage and stretch the pulses.

Shoot, somebody posted a description already! I had this in draft since last night, and just did some edits and posted. At a glance the breakdown seems to be similar.

I will have to go through in detail, but at a glance, this is what I am seeing: - D1/F1/C1 provide fused rectified unregulated DC (voltage depends on what is hooked to J1). - Q4 provides an unregulated 12V to power the rest of the regulator -E1, as you said, is an oscillator providing a pulse...

That's the difference between the "5-pin" keys and the "3-pin" keys. Cherry MX and non-Cherry brands will have both options. The 5 "pins" refer to the two contact pins, the center post, and the two alignment posts. The "3 pin" variety does not have the alignment posts. The 3-pin variety is...

I was referring to displaying the logo as a background to be traced. Kicad 7 has a button (icon of mountains and sun) along the right-hand side toolbar to import a bitmap for viewing/tracing. In general, it's better to work with vector images like DXF or SVG rather than bitmaps, because they...

Got it. You have a couple of options: 1) Find or create a DXF of the logo in a drawing program like Illustrator or Inkscape, then import the DXF to the desired layer You can convert closed shapes to polygon or pour zones. If you use pour zones, then you can place smaller "keepout" zones...

There is a way to get curved traces. It's a little indirect, but the results are nice. You need to install the mitxela curved tracks plugin, by selecting it in the plugin manager and installing. First, in the PCB routing settings, select any-angle traces. Then using a photo as a template...