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mdo IBM 5170 (MB)

Introduction

Today (11.09.2021) my IBM AT 5170 type 3 motherboard arrived. The first tests were successful, it works flawlessly so far. At the beginning it was unclear to me which BIOS is installed; there was no original label stuck on. How pleasing, it was the "286-BIOS (c)1989 American Megatrends Inc", very good. So I had the advantage that I didn't have to work awkwardly with GSETUP. Also the low-level formatting of the harddisk was a piece of cake, because a DIAGNOSTIC routine is implemented in the BIOS; with AUTO-INTERLEAVE and BAD SECTOR ANALYSIS.

According to Roman Ondrejka - Vintage PC Collector (IBM PC 5170 512kB System Board #4) I have a model 319/339, type 3 (green) motherboard. The keyboard controller (U126) is soldered in.

IBM 5170 type 3
IBM 5170 model 319/339, type 3, p/n 62X0670

Basically, IBM released three different motherboard types of the 5170.

In addition, there were several sub-models.

Models 68 and 99 / August 1984:

Model 239 / October 1985:

Models 319 and 339 / April 1986:

Dimensions, Sizes

I have not been able to fit the type 3 motherboard into another non IBM AT case; the holes for the spacers do not fit. See also here: minuszerodegrees, „Baby AT“ form factor.

Further details and information about the 5170 can be found in the official „IBM Announcement Letters“, see below.

My Configurations

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No. 1 - Very Close to the Original.

HDC/HDD: The default interleave is 3, but you change change to 2; it works.

Here is the Quarterdeck Manifest (MFT) file with all information.

No. 2 - With SCSI Hard Disk Drive

Since I have never worked with SCSI before, I thought, now it's about time.

Of course I removed the RAMpage AT memory expansion card first, because the AHA-1542B has its own BIOS. This is by default at DC000!

In configuration no. 1, however, UMB memory is created here. In configuration no. 3 I will then install the RAMpage AT card again.

On the AHA-1542B, I first set all jumpers to the default settings. I connected the SCSI harddisk with a normal 50 PIN cable and a terminating resistor (at the very end). Whether this is actually needed, I can not say. Never worked with SCSI before.

According to the manual I have switched off the hard disk C: in the AMI BIOS, i.e. deactivated! Both floppy drives are installed in the AMI BIOS! Booting ... and see there ...

IBM 5170 MB with AHA-1542B HDC/FDC
IBM 5170 MB with AHA-1542B HDC/FDC

After that, all you have to do is run FDISK and FORMAT, and that's it. For „Low Level Formatting“ (LLF) a SCSI hard disk drive see here.

No. 3 - With SCSI Hard Disk Drive & RAMpage AT

And now something very strange has happened. In configuration no. 1 I was able to use the RAMpage AT card without any problems (with IBM Fixed Disk and Diskette Drive Adapter). So far so good. Now with the AHA-1542B the computer crashes immediately and completely when the driver REMM.SYS is loaded. After a warm start, not even the hard disk C: is recognized, only again after a cold start.

Since I still had a last 12 MHz crystal oscillator in my tinkering box, I just changed it and what can I say: Everything is fine again! The board is now noticeably slower, but REMM.SYS is now started correctly. I tested with CHECKIT (base memory, extended memory, expanded memory); everything is fine.

Here is the Quarterdeck Manifest (MFT) file with all information.

Figures

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IBM Fixed Disk and Diskette Drive Adapter (2nd gen.)

IBM 5162
IBM 5170 (68X3948-X4) HD/FD Controller

Instead of the IBM/WD controller you can also use an original WD1003V-MM2 or WD1006V-MM2 controller. These three are fully compatible, just swap them out and good! You do not have to low level format the MFM drive!

Update: With the HFA-110W hard disk controller you can set the interleave to 1:1! Because the motherboard is just perfect for a test setup, I tested a few hard disks with my 16 bit HFA-110W controller. So LLF with the AMI BIOS (DIAGNOSTIC), then FDISK and FORMAT. I tested a Seagate ST-238R and ST-277R-1. Both are RLL hard disks, but MFM is of course always possible.

Update 19.09.2021: Since I stupidly changed the hard disk controller in between and „reformatted“ the ST-225 with an interleave of 1:1, I had to use Spinrite to set the interleave back to 2:1 while the system was running. The IBM controller can only do a maximum of 2:1.

CPU

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Intel CG 80286 8 C
Intel CG 80286 8 C (8 MHz) / 1984

BIOS

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The two ROM's (U27 & U47) are of type 27256 (32K). But you can also use 27C256 EPROM's or Winbond W27E257 EEPROM's. I use the W27E257-12 with my GALEP-5; quick and easy to burn/erase.

AMI

This AMI BIOS is a slightly newer version than the one in my IBM 5162 (XT286).


286-BIOS (c)1989 American Megatrends Inc
D286-1234-151289-K0

With this BIOS the start screen and SETUP correspond in content and view to the BIOS that you know from back that time.

I use the AMI BIOS (12/15/89), because you can access the SETUP very easily. The BIOS is Y2K capable.

In addition to the actual SETUP, there is also a DIAGNOSTICS screen. Here you can, among other things, perform a low-level format for the MFM hard disk; with AUTO INTERLEAVE DETECTION.

286-BIOS (c)1989 American Megatrends Inc
286-BIOS (c)1989 American Megatrends Inc / DIAGNOSTICS
286-BIOS (c)1989 American Megatrends Inc
286-BIOS (c)1989 American Megatrends Inc / DIAGNOSTICS

Update 16.09.2021: I found another AMI 286-BIOS in my collection, which I am currently using. This also seems to work.

286-BIOS (c)1989 American Megatrends Inc
286-BIOS (c)1989 American Megatrends Inc / 09/15/89

286-BIOS (c)1989 AMI, for G2/102
D286-1105-091589-K0

G2 = Generation 2 ?
102 = 102 key(board) layout

Supersoft - Landmark Diagnostic

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This test is a little bit tricky, but it works if you are prepared for it. Please read this detailed page from minuszerodegrees carefully. Important are the „first 20 seconds“ and the graphics card! But even if you have passed this hurdle, you may still hear a „beep concert“ during some tests, so don't be surprised!

Supersoft - Landmark Diagnostic
Supersoft - Landmark Diagnostic

I made the test with a Hercules Graphics Card (HGC) clone. You can also use the IBM Enhanced Graphics Adapter (EGA). Do NOT use the „IBM Monochrome Display and Printer Adapter“ (MDA). You will see and hear nothing!

Do not be disturbed by the RAM error messages at 080000h and 090000h, because there is no RAM in an 512 KByte computer! The last 64 KByte block (448-512) begins at 070000h and ends at 07FFFFh. Of course, the RAMpage AT card was not installed during this test!

The system BIOS check also fails, because there is no BIOS in U17 and U37!

Result: Everything is OK.

Battery

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In the IBM AT 5170 a special 6V battery of IBM part number 8286121 is built-in. Of course, nowadays you can not buy this battery. Since I only own the mainboard, I had to find a replacement. I bought an external case for four 1.5V batteries of type AAA Micro LR03 in an electronics store (Internet) and off you go.

Note: If you replace the battery you have to go thru the SETUP procedure. This is no problem with the AMI BIOS with a built-in SETUP!

Battery connection
Motherboard battery connection (J21)
(+) RED left // (-) BLACK right

RAM

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The RAM is made up of two components: 5170 mainboard & „AST Rampage AT“ expansion memory adapter.

  1. 000 KB - 512 KB (512 KB): 2x 8+1 DIP RAM
    • ... Hitachi: HM50256P-15
  2. 512 KB - 640 KB (128 KB): 1x 8+1 DIP RAM
    • ... AST RAMpage AT, NEC D41256C-12
  3. Extended memory (384 KB): 3x 8+1 DIP RAM
    • ... AST RAMpage AT, NEC D41256C-12
    • ... AST RAMpage AT, Motorola MCM6256BP12

AST RAMpage AT

More by chance, I tested my memory expansion adapter AST RAMpage AT (version 202079-301-A) with this „8 MHz“ mainboard. According to the AST technical bulletin 0191 this should not work, but it does anyway!

Important: See configuration no. 3. With the AHA-1542B the RAMpage AT card only operates with 6 MHz (12 MHz crystal oscillator on the mainboard)!
AST RAMpage AT
AST RAMpage AT (version 202079-301-A)

Documents

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Downloads

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