Ardent Tool of Capitalism

Tandy 5000 MC

5kmcref1-02-03.img Tandy 5000 MC Ref Disk ver. 1.02.03 (dd'd under Linux, also HERE)

Tandy 5000 MC Brochure (alt) (from 1000bit.it)

MCMFM.EXE (09-17-93) This file contains a Micro Channel MFM disk driver written for the IBM Model 80, Tandy 5000, and other Micro Channel machines using an MFM controller. The driver is for NetWare v3.0.

Information Files
MC5000 Planar
   Power Plug Pinout
CPU Card
Memory Card
Exploded View

Rebadged GRiD-Desk 386mc? See articles from PCMag and InfoWorld on the GRiD machine.
Tandy bought GRiD on 01 Jul 1988. See GRiD Company Backgrounder (from 1000bit.it).

Information Files

2410 Beep Codes
1727 Math Coprocessor
1723 Memory Upgrades (includes jumper settings)
1728 Parallel Port
1725 Pinouts
1722 Settings
1724 Setup
1721 Specifications
1726 Video Modes
22041 Detailed Parts List
22042 Detailed Parts List
22043 Detailed Parts List

5000MC Planar P/N 8899061

The memory jumpers can be placed across two headers, not just one. So any pair of jumpers on this outline can have more than four combinations!

J7 Power Pinout

1,2,4,5 +5V 3 +12V 6,7,8,9 Gnd 10 -5V 11 -12V 12 Pwrgood

Floppy Controller

Supports 360K, 1.2M, 720K and 1.44MB drives. Transfer rates are 250K or 500K, so it cannot support 2.88MB. Don't try it.

Parallel Port

Parallel port follows IBM conventions, IRQ7 only and swapped LPT1 and LPT2. It can be set up as Compatible (ouptut only) or Extended mode (bidirectional).

LPT   Data     Status   Control
 1    03BCh    03BDh    03BEh
 2    0378h    0379h    037Ah
 3    0278h    0279h    027Ah

S1 Memory Card Definition Switch (also P103)

Now to figure out which switch is what... Looks as if these bits have some sort of logical operation performed on them, there is no direct correlation between bits 3-2 and 1-0 that is apparent.

I did find S1, but it is not labeled, and it feeds some logic chips.

Bit 7 - 2MB/8MB Card installed. 0 = 8MB card

Bit 4-6 - Reserved = 1

Bits 3-2 Memory Card in second connector
   Bit 3    Bit 2
      0      0     Invalid
      1      0     Memory card in second connector
      1      1     No card in connector 2

Bits 1-0 Memory Card in first connector
   Bit 1    Bit 0
      0      0     Invalid
      1      0     Memory card in first connector
      1      1     Invalid (of course, mem1 is always used!)

S2 Memory Definition Switch

Not seen a real name, so I guessed.

Pin   Name           Description
 1    2/4 Banks      One card ON, Two cards OFF
 2    LIM Enable     Lotus-Intel-Microsoft extended memory LEAVE OFF
 3    Non-Page Mode  OFF use paged memory ON disable paged memory
 4    Fast Mode      What? LEAVE ON
 5    N/C            What? LEAVE OFF
 6    N/C
 7    N/C
 8    256K/1MB       256K simms ON, 1MB simms OFF

My guesses for valid configurations. It looks that the memory controller cannot handle mixed SIMMs, unlike our beloved PS/2s. As the memory is interleaved, all eight sockets on each card need to be filled.

       2MB    4MB    8MB   16MB
Card1  256K   256K   1MB    1MB
Card2   No    256K    No    1MB
Banks   2      4      2      4

CPU Board Rev A P/N 8709839

L2 Cache

L2 cache is organized as two banks (A and B) of 4K double words.
Cache hits, DRAM or bank, returned with 0 wait states.
Cache miss with page hit is returned with 2 wait states.
Cache miss with page miss is returned with 4 wait states.

Memory PCB Rev B P/N 8899065 25-6030

256K SIMMs 256K X 9 SIMM chips at 80 or 100 ns 1MB SIMMs 1 MB x 9 SIMM chips at 60, 80 or 100 ns Jumper and switch settings

Battery Replacement

MX-1560: (U11) CMS Battery Clock Chip
MX-1561: (U19) DS1287A REAL TIME

Exploded View

(Click on the picture to enlarge it)

Alan Hightower will be receiving the complete 5000MC Technical Reference that I've had on a shelf for more than ten years. Micro Channel never forgets.