Almost Manufacture-Ready
As 2021 draws to a close, Yellowstone is very nearly finished, with just a few details left to iron out. I recently tested a new v2.3 prototype with a couple of small PCB changes, and so far it’s looking good.…
Year 2021
Edge Connectors, ENIG Plating, and Galvanic Corrosion
Yellowstone is inching slowly towards the start of manufacturing. One question that’s arisen is the type of surface plating to use on the PCB. The default / cheap plating is HASL or Hot Air Solder Leveling, which is just a…
Circuit Sleuthing: Unidisk 5.25 Enable and PHI1
While chasing down some Yellowstone hardware bugs, I discovered an unexpected analog-type behavior on the enable input of the Unidisk 5.25 (A9M0104). This is an active low digital input that’s used to enable or disable the disk drive. Under the…
Apple IIgs 80 Column Mode Crash
Here’s the part of our program where I describe a problem I’m having, and somebody tells me what I’ve done wrong, because I’m not smart enough to figure it out myself. The problem is with the Yellowstone disk controller, the…
Global Chip Shortage Hits Home
Discouraging news from the BMOW manufacturing front: the global chip shortage seems to be growing worse, and is now causing major problems for some of my vintage computer products. This is a change from a year or two ago, when…
Yellowstone Beta Testing Continues
The goal of a “do everything” disk controller for Apple II is getting closer to reality, thanks to the efforts of the hard-working beta testers. If all goes well, I’m hoping to have Yellowstone cards available for sale in the…
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