Micronics motherboard has that MIC491 chip located in perfect VLB spot, right on CPU address/data busses.

douglar wrote on 2026-07-19, 17:58:

The traces for the IDE go to the back of the board, then come up for the yellow chips

resistor networks.

douglar wrote on 2026-07-19, 17:58:

then go to the back of the board to come up under the TI PAL chips.

data from 245 goes further all the way to around U50, also perfect spot for landing on CPU Data bus where ram data connects thru another bunch of resistor networks.
3 PALs is too much for stupid PIO controller, I would asses it as probably local bus IDE controller
one thing - arent VLB controllers meant to take 32bit writes and convert on the fly? connecting 16bit IDE data path directly to RAM data bus suggest there is no byte swapping/FIFO magic happening here.

This card is pretty curious--

https://theretroweb.com/expansioncards/s/axis … ed-vga-gui-2100

It has a chip labeled "MachSpeed GTK6189" from Q1 1994 that looks like it could be an IDE controller but on every card that I've seen, the IDE header isn't populated.

The BIOS doesn't seem to do anything with int13h.

So I'm stuck with the question, what does "MachSpeed GTK6189" do?

FCC seems to show as a graphics card only, but if you look at the other grants to Axis Micro you see I/O VGA combos under other numbers.... but the couple I searched didn't bring up any cards.

Its always a good sign when you see VGA card that cheapened on crystal and uses ISA provided 14MHz, sign of quality 😀 /s
Note to self: dont post while falling asleep!
'machspped' are four 74 245s packaged together, maybe with few extra logic gates (74 32, 74 04) that are needed to make CL-GD542x pretend its 16bit VLB. That footprint is for optional Video ram expansion.

rasz_pl wrote on Today, 03:06:

Its always a good sign when you see VGA card that cheapened on crystal and uses ISA provided 14MHz, sign of quality 😀 /s
'machspped' are four 74 245s packaged together, maybe with few extra logic gates (74 32, 74 04) that are needed to make CL-GD542x pretend its 16bit VLB. That footprint is for optional Video ram expansion.

It does look like a cheap card, but isn't that a 14Mhz crystal between the MACHSPEED and the 40 pin connector? The pinout for that 40 pin connector doesn't look like a memory expansion to me. Looks like an IDE pinout, with pins 19, 22, 24, & 26 going to ground and the I/O traces going to the MACHSPEED chip, not the 5428 like I'd expect for a memory expansion.

JP1 looks like it could be jumpers for IO port, recovery time & IORDY, but it looks like it is just hard wired to disabled.

I see what you mean about being a replacement for some 74-245 chips. Does seem to fit that part of the board. The traces from the 5428 that should go to the VLB get there through the MACHSPEED chip .

Maybe the MACHSPEED chip attaches both the VGA and IDE to the VLB connector like a glue ASIC to attach two devices to VLB on the same card. It would have to be a little smarter than a couple 74-245 if it was buffering 16 bit ATA into 32bit VLB, but it's hard to know for sure if it tried to do that.

Perhaps they tried to do that and discovered late in the process that they were not able to avoid data corruption when using both the IDE and VGA at the same time, which is why the IDE connector is always disabled on all the surviving cards.

Edit These card have similar functionality, but some noticeable layout differences . They all have IDE controllers with some smarts in them, a hand full of buffer chips, and the VGA doesn't route through the IDE controller--

PDC20230 - https://theretroweb.com/expansioncards/s/octek-vl-combo-3.2
ADI2 - https://theretroweb.com/expansioncards/s/paci … -vl-bus-rev-b-3

Edit 2:

This one is curious. It is wired similarly to the MACHSPEED with the 5428 going into it, but it has 2 IDE ports--
Op VIC3 - https://theretroweb.com/expansioncards/s/octek-vl-combo-2

In my notes, I have "OPTI 82C611 = Opti VIC (VIC = Vesa Ide Controller)" but I've never seen an "Op VIC3". The "423" fab date is newer than the ones I've seen on the Opti 82C611 chips but older than the ones on the Opti 82C611a chips

The FCC ID on one card is KPM2100VIDE and the other one has Lot No: VGAIDE 21oo-1 printed, so it does seem they intended to make these as combo cards.