ET4000 is faster. But GD5429 isnt bad either, its some better then the GD5428.

Empty slot for a ISA NIC?

In DOS, most of late ISA video cards run at the same speed, as they hit the limit of ISA bus.

Already got an ISA network interface in the form of the 3Com 3C509B.

Was contemplating an Adaptec AHA-1542 with a SCSI-IDE adapter, as I've got a few to try, but I'd be back to whatever disk size restrictions the Adaptec SCSI ROM has. I would also dearly, dearly love an LAPC-I, instead of the Midiman, since the MT-32 would most often be in another room.... but the cost of anything LA-synthesis related seems to have gone through the roof in the last 5 or 6 years.

the 1542 with the updated ROM BIOS will support my 75GB external SCSI HDD. DOS can only see the first 8GB of course

Interestingly, I actually had a VLB 5428 back in the day, attached to a DX2-50. It was a decent card and I remember using it as my first graphics output for X11 on Linux in the mid-1990's; it had some built in basic, but decent acceleration for GUI interfaces such as hardware line drawing, fills, bit blits and the like. As I understand it, the 5429 was basically the same thing but with improved memory interface.

maxtherabbit wrote on 2021-01-10, 15:46:

the 1542 with the updated ROM BIOS will support my 75GB external SCSI HDD. DOS can only see the first 8GB of course

That's very interesting to know! Have you ever attempted to use Win 98SE / Dos 7 to create or access large FAT32 partitions on it?

There is the XT-IDE bios fitted to an eprom that goes in a nic boot rom socket that gets over bios hdd limitaions as well a dedicated XT-IDE interfaces cards with IDE on them or you can go the SD card route. I have one of the latter in my Redstone XT Turbo.

megatron-uk wrote on 2021-01-10, 15:51:

maxtherabbit wrote on 2021-01-10, 15:46:

the 1542 with the updated ROM BIOS will support my 75GB external SCSI HDD. DOS can only see the first 8GB of course

That's very interesting to know! Have you ever attempted to use Win 98SE / Dos 7 to create or access large FAT32 partitions on it?

Negative but AFAIK it should work. Pretty sure the ROM supports LBA, but not 100%

Ah, I know what fits in the last ISA slot... one of those new serial to PS/2 mouse adapters - I hate serial mice!

I love serial mice, they work most nicely with Win 3.1. 😀
https://www.os2museum.com/wp/jumpy-ps2-mouse- … de-windows-3-x/

Serial mice are fine for the systems they were designed to run. So good in fact IBM used the same protocol for their PS/2 mouse line up.

I am restricted in how much desk "stuff" I can use, so almost everything I have has to either go through a HDMI/USB KVM, or a VGA/PS2 KVM... Two keyboards (PS2 + usb) and two mice (PS2 + usb) and one monitor for approx 20 systems.

Hence adding a serial mouse and/or any other input tech than PS2 or USB is just not practical for me.

The replacement motherboard arrived today and I have to say that it is in absolutely perfect condition.

One problem I've got though is that it isn't exactly identical to the Peaktron PA286-SMT. This one is silk-screened as a 'MICRO SYSTEM' MICROCOMPUTER SYSTEMS PA286-SA1 Rev D3A.

At first glance the board is physically identical, but closer inspection shows a few differences to the Peaktron system:

Jumper block SW1 has 9 jumpers on the Peaktron board (1-9), on mine it is 2-9.

The FPU socket has a async/sync jumper on the Peaktron board, there isn't one (or even solder pads for one) on mine.

The Peaktron manual has jumper settings for 512KB - 16MB using combinations of the DIP and SIMM sockets using jumper block SW1 (pins 5, 6, 7, 8) as well as J7 and J8 elsewhere on the board. I don't have the same number of pins on SW1, and J7, J8 and J9 are labelled in a diferent way and the silkscreen on the board only lists up to 4MB configurations.

I'm a little concerned that the one site I found with reference to PA286-SA1 lists it as performing very fast, but only supporting 4MB (and no mention of 25MHz clock support): https://www.clous.cz/pa286-sa1/

Updated photos to follow.

Also, the Peaktron has a Bus clock 1/2, or 1/3 jumper as part of the jumper block SW1 position 1... mine is missing and has no solder pads.

This concerns me that I may not be able to run the board at 25MHz and set the bus to 1/3 of that speed. 12.5MHz (Bus clock 1/2) is going to be pushing the ISA cards very, very high...

Images of the board attached.

For comparison, the Peaktron PA286 is here: https://stason.org/TULARC/pc/motherboards/P/P … 6-20-PA286.html

There's no entry for this slight variant.

12.5MHz for the ISA bus is no big deal. Most cards will handle it just fine. Get that battery off there and send it to hell RFN

Already snipped 😀

Not having much job getting this thing set up. Just have a vga card in for now, nothing else. Trying to get it to power on with either 4x1MB or 4x4MB simms and it's not having any of it - 3 beep memory error regardless of which I use.

I've made a table of the differences between the jumpers on the PA286-SMT vs the PA286-SA1. Apart from the missing bus and fpu jumpers, it's mainly the memory config that differs.

Stason has a nice table for how memory is configured on the 'SMT board, but the only thing I have to go on with the 'SA1 is the motherboard silkscreen (in the images above). It doesn't correspond in any way to the printing on my SA1 board.

I'm unable to get this to work at all 🙁

If I use SIMM modules then I really don't know what board settings I should be using; it will memory-error-beep at me every time.

If I replace the 8x DIP chip DRAM modules that came with it, and set the board up with the same jumper settings that it had when it arrived, it will power on without a memory error beep, but I just get a black screen with a flashing green cursor in the top left.