70/80 - 486DX33 Upgrades

At least some of these upgrades were made by Hypertec of Australia.

7080pu.exe 486DX33 Proc. Upgrade for 70/80 16/20Mhz
pbe01066.exe HyperRace Blue 70/80
193-312 Processor Upgrades For Models 70 and 80 (16 and 20MHz)

Hypertec Software Archive (all files dead!)

486A (Model 70)
486B (Model 80)
486/P70 (8573-P70)
   P70 installation
Compatibility Plug
General Information
Switch Settings
Installing the Processor Upgrade
Known Problems


486A IBM FRU P/N 92F0436


486B IBM FRU P/N 92F0437


486/P70 (is this really from Hypertec?)

Installing 486/P70

Remove 386/387. Install compatibility plug. Remove both M3 screws.
Note: If the M3 screws use washers, make sure you don't drop the washers into the computer! Install 486/P70. Replace both screws and any washers.


Compatibility Plug (fits in 387 Socket)


General Information

The IBM PS/2 486DX33 Processor Upgrade for Models 70 and 80 is an i486 accelerator for 16 MHz and 20 MHz 80386-based computers.

You must use 8570/80 Reference Diskette Version 1.10 or later.

Important In some cases, with the Processor Upgrade installed, the diagnostic tests for some Micro Channel adapters might indicate that the adapter is failing when the adapter actually operates correctly. If you experience this problem, do the following: Set SW-1 on the Processor Upgrade to OFF (SW-1 OFF = cache disable for testing purposes!)

If you hear ONE-long and TWO-short beeps when the computer starts, then this is normal if there is an 8514/A adapter installed.

The Upgrade Option package contains:

  • Model 70 or Model 80 Processor Upgrade
  • 132-Pin Socket Extender (only needed for 8570)
  • Module-removal tool for extracting 80386 processor
  • Option Diskette
  • 70 486 or Model 80 486 Logo
  • Co-processor compatibility plug (not included in FRU P/N 92F0436)
  • Sheet of system labels

Switch Settings

1 ON    Cache on (default)
  OFF   Cache off
2 ON    Cache HIMEM enabled (default)
  OFF   Do not flush cache on INT 9
3 ON    Cache enabled C000-D000
  OFF   Cache disabled C000-D000 (default)
4 ON    Cache system BIOS enabled (default)
  OFF   Cache system BIOS disabled
5 ON    do not change (default)
  OFF   Not applicable
6 ON    XGA video adapter (slows processor speed) (default) *
  OFF   No XGA present
7 ON    cache all extended memory (default) **
  OFF   Disable cache above 14MB
8 ON    Delay write cycles
  OFF   fast write cycles (default)

* - slows processor speed when system accesses XGA video. Use if XGA software is speed sensitive. If you don't have XGA, set to OFF.
** - cache all extended memory. IF you have <14 MB AND you have boards that require space at the top of extended memory, turn OFF.


Installing the Processor Upgrade

  1. Upgrade the Refdisk (V-1.10 or higher) with the Option diskette. (use COPY AN OPTION DISKETTE function)
  2. Power-OFF the computer
  3. Remove the Power-Cable
  4. Open/lift the Machine cover
  5. Remove HD(s) / Adapters
  6. Locate the Processor on the System Board (Pin 1)
  7. Remove the Processor (80386)
  8. Remove the Co-processor ((80387) if any is installed)
  9. If the machine is a 8570 and the processor is nearby the power supply fan then insert the 132-Pin socket extender (Pin-1 to Pin-1) into the 80386 socket.
  10. Install the Co-pro compatibility plug into the Co-pro socket. (be sure PIN-1 to PIN-1)
  11. Install the Processor Upgrade Board into the Processor socket (be sure PIN-1 to Pin-1)
  12. Reinstall all previously removed Cable/Adapter
  13. Reconnect the Power cord
  14. Power-ON the system
  15. Run Setup / Test

Known Problems

Cannot load Application Program

The application program might be speed sensitive. Refer to the application program manual for information on speed (memory caching) requirements. See also in above Switch-table "Memory caching" above.

Application Program Displays Damaged Data

Is an 80387 Coprocessor installed? If yes then remove the Coprocessor and install the Coprocessor compatibility plug.

Cannot Load Windows 3.0 in Enhanced Mode

Check the CONFIG.SYS file for a line

device=C:\windows\smartdrv.sys 2048 1024

and change it to the following

device=C:\windows\smartdrv.sys 2048 1024 \b-

This problem occurs only with the version of Smartdrive supplied with Windows V-3.0 and DOS V-5.0. The Smartdrive supplied with Windows V-3.1 does not have this problem, nor does it use the same syntax (enabling/disabling double buffering).

Note: Before running diagnostic tests, check that the processor upgrade card is fully seated in the system board and that the 80486 processor is fully seated in the upgrade card.

  1. Power-off the computer.
  2. Insert the 70/80 Reference Diskette in drive A.
  3. Power-on the computer.
  4. Follow the instructions on the screen to test the processor upgrade. If the tests cannot find a problem, replace the processor upgrade with an 80386 processor from a new system board (or the original 80386 processor, if available). If the failure does not occur again, replace the processor upgrade with a new one. If the failure does occur again, replace the system board, and reinstall the original processor upgrade. If the failure occurs again after replacing the system board, replace the processor upgrade also.

Note: Use the 80386 processor only to diagnose the problem. If it came from the customer, be sure you return it to them. If the processor came from a new system board that you brought with you, and the system board is not the problem, reinstall the processor on the new system board before you return it to stock. If the system board is the problem, return the 80386 processor with the bad system board.

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Last update: 19 Nov 2021 - Changes & Credits | Legal Info & Contact