SysInfo and GemBench work great on my diagnostic cart, thanks! I have not analyzed details of your 16-bit ROM cart, but if you are making a proper use of ROM3/4 lines you may use both 64kB and 128kB ROMs. Yet over-complicated jumper settings tell me that you are switching between 64/128kB cart modes...

Some time ago I was asking about possibility of preparing ROM versions of YAART and SysInfo, but with no response. I only know, that it is impossible to just put an PRG file on a ROM.

RLL drives are 100% backward compatible with RLL controllers, it is only a different encoding scheme. But better to use ST238R for repairing MegaFile 60...

With only power connected they don't spin? What drive ID is set on drive's jumpers? You need to be ID 0, while most PC disks have ID 1. Using an ST238R would be a waste, as this controller won't use RLL encoding. ST238R and ST251 are basically the same drive, but first one has a better quality surfa...

SH204 has an Adaptec ST-506/412 compatible HDD controller inside, and can be used only with such disks. It can be either 5,25" or 3,5" and MFM or RLL compatible. SCSI is something completely different. *** Sorry, I was wrong, SH204 was using a SCSI host adapter (ACSI - SCSI "converter"), and a SCSI ...

One more notice - as the internal TOS date format is intact, any software using non-standard methods of reading it will still work correctly (however if using 2-digit year format we may see year 118 for 2018). As TOS stores a year on 7 bits it will work only until 2027.

I personally dislike the whole idea of STF remake, but I guess adding an ATX connector (possibly with angular header) to use pico-PSU modules would be a very useful solution. Power output connectors on motherboard are obsolete then, as Pico-PSU has a cable to connect FDD power.

Recently I was trying to diagnose my... diagnostic cart with a Logic Analyzer (Logic-8 clone). I did it, but not in the way I'd like to. All lines were looking legit on the LA software, but I realized that, with probes connected, cart behaves differently. So I started disconnecting the probes, one b...

I find lead free solder fine for a new stuff, but not for repairing old one. I would't care about inhaling lead, as it almost doesn't vapor during soldering. What is really toxic are the vapors of flux. I'm using Sn60Pb40 with SW26 flux and lead free Sn99Cu0.7Ag0.3 with 1.1.3 flux (1.1.3 a.k.a. SW-2...

This is a TOS ROM chip layout for 520ST: