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IBM 5170  -  POST  -  Some on-screen errors


IMPORTANT:  The following is specific to the IBM 5170 (IBM AT).
  Certain portions will not be applicable to clones that were made of the IBM 5170.

NOTE:  Execution of tests is not always done in numerical order.
  For example, the hard drive tests are done in order of 1782, 1780, 1781, 1790, 1791



Error As shown on screen      Description
  161 161-System Options Not Set-(Run SETUP)
Battery problem.

Some possible causes:
* Battery is dead/low - replace it and then run the SETUP procedure.
* A dead/low battery was replaced with new but the SETUP procedure has yet to be done.
 
  162 162-System Options Not Set-(Run SETUP)
CMOS/RTC checksum problem, or other configuration issue.

Known causes:
* A hiccup of some kind has corrupted CMOS/RTC configuration (SETUP). Correct this by running the SETUP procedure.
* Battery is dead/low. Some 5170 motherboards, for unknown reason, don't produce a 161 error. Check/replace battery, and then run the SETUP procedure.
* A CGA video card is fitted, but the CMOS/RTC configuration (SETUP) is set for MDA (monochrome), or 'special' (EGA/VGA).
* An MDA ( monochrome) video card is fitted, but the CMOS/RTC configuration (SETUP) is set for CGA, or 'special' (EGA/VGA).
 
  163 163-Time & Date Not Set-(Run SETUP)
Clock (RTC) error.         [ detection of invalid time values in RTC chip, or clock not ticking over]

Some possible causes:
* The SETUP procedure was started but not finished.
* Motherboard failure (in RTC related circuitry).
 
  164 164-Memory Size Error-(Run SETUP)
164 NOT PRECEDED BY A 201 ERROR

The amount of base RAM and expansion (extended) RAM discovered by the POST is more than the two amounts recorded in CMOS/RTC configuration (SETUP).
Some possible causes:
* User has added RAM but failed to then perform the SETUP procedure.
* User ran the SETUP procedure, and during that procedure, entered incorrect amounts for the RAM (ones lower than fitted).


164 PRECEDED BY A 201 ERROR

Deal with the 201 error first. Correcting that will probably remove the 164 error as well.
 
  201 201-Memory Error
RAM related problem.

Displayed on screen in the format of "AAAAAA  BBBB  201-Memory Error",
where AAAAAA is the hexidecimal address (in bytes) of the failing word and BBBB shows which bits in the word have failed.

You can use the diagram here to calculate the failing bit/s, and the address as a KB figure.

Sometimes, you may see an address that is one word beyond the actual failing address, e.g. 080002 instead of 080000


NOTE: If the BBBB portion (failing bits) contains many "F", example: "FFFE", then it is highly likely that non-existing RAM is being tested.
For example (one of many), this would occur if the machine SETUP is configured for 640K of RAM, but only 512K is fitted.
For example (one of many), a RAM card has failed completely.
 
  301 301-Keyboard Error
Keyboard problem.

If the error is preceeded by a byte, e.g. "21 301-Keyboard Error", that indicates that a key is stuck down on the keyboard. The byte indicates which key.

If instead, the error is just "301-Keyboard Error", that indicates a general keyboard error.
Some possible causes:
* No keyboard.
* Wrong type of keyboard - AT class keyboard required - PC/XT class keyboards will not work.
* Faulty keyboard.
* Faulty motherboard (specifically the keyboard circuitry on it).
* In certain AT clones, a keyboard error can be caused by the front panel keyswitch being in the 'locked' position.
* In certain AT clones, a keyboard error can be caused by a blown keyboard fuse on the motherboard. (Note: The IBM 5170 does not have a keyboard fuse.)
 
  401 401-CRT Error
A known cause: Having only a CGA video card fitted, but motherboard switch SW1 is incorrectly set to the MDA position (rear).
 
  501 501-CRT Error
A known cause: Having only an MDA (monochrome) video card fitted, but motherboard switch SW1 is incorrectly set to the 'CGA' position (front).
 
  601 601-Diskette error
Some possible causes:
* POST can't find the floppy portion of the IBM Fixed Disk and Diskette Drive Adapter
* Wrong type of twisted cable is being used - hard drive type instead of floppy drive type. (photo of difference)
* Floppy drive A: - faulty
* Floppy drive A: - does not have power to it (either +5V or +12V, or both).
* Floppy drive A: - jumpered incorrectly for the 5170
* Floppy drive A: - a make/model that is incompatible with the 5170
  
* BIOS issue:
Are you seeing the 601 after removing the IBM Fixed Disk and Diskette Drive Adapter and substituting a third-party floppy controller ?
There is something in the second and third BIOS revisions of the 5170 that expects the IBM Fixed Disk and Diskette Drive Adapter.
The first BIOS revision does not have the issue.
 
1780 1780-Disk 0 Failure The 5170's POST, upon seeing that a hard drive is included in the CMOS/RTC configuration (SETUP), asked the hard disk controller to perform an 'internal diagnostic' (see 1782 error). That passed. The POST then asked the controller to issue a 'Recalibrate drive' command to the first hard drive (C:). The 1780 error was displayed because that command failed.

Some possible causes:
* Control cable (34 pin) is missing.
* Control cable (34 pin) is no longer seated correctly on controller or drive.
* Control cable (34 pin) is faulty.
* On the controller, control cable (34 pin) accidentally connected to J1 (for floppy drives) instead of J5 (for hard drives). See this diagram.
* On the controller, control cable (34 pin) is connected to J5 upside down. See this diagram.
* Drive Select jumper on hard drive is in wrong position for the type of control cable being used. See this diagram.
* A twisted control cable is being used but is the wrong type - floppy drive type instead of hard drive type. (photo of difference)
* Hard drive does not have power to it (either +5V or +12V, or both).
* Hard drive is faulty.
* Hard drive controller card is faulty (even though it earlier passed its 'internal diagnostic' [test 1782]).
* Hard drive controller card is in an 8-bit slot (example: 5170 slot 7) instead of a 16-bit slot.
* Hard drive controller card has 'dirty' edge connectors (ones that affect this test).
 
1781 1781-Disk 1 Failure
Per 1780 error, but for second hard drive (D:)
 
1782 1782-Disk Controller Failure The 5170's POST, upon seeing that a hard drive is included in the CMOS/RTC configuration (SETUP), asked the hard disk controller to perform an 'internal diagnostic'. The 1782 error was displayed because, either the controller responded in the negative, or the controller did not respond within a minute.

Some possible causes:
* Hard drive controller card missing.
* Hard drive controller card is not seated properly in its slot.
* Hard drive controller card has 'dirty' edge connectors (ones that affect this test).
* Wrong type of hard drive controller card is fitted (example: XT class controller is fitted).
* Faulty hard drive controller card.
* Hard drive controller card is incorrectly jumpered (example: set for secondary address range, not primary).
 
1790 1790-Disk 0 Failure The 5170's POST, upon seeing that a hard drive is included in the CMOS/RTC configuration (SETUP), asked the hard disk controller to perform an 'internal diagnostic' (see 1782 error). That passed. The POST then asked the controller to issue a 'Recalibrate drive' command to the first hard drive (see 1780 error).
That passed. The POST then asked the controller to read certain sectors on the first hard drive. The 1790 error was displayed because one of those reads failed.

Some possible causes:
* Data cable (20 pin) is missing.
* Data cable (20 pin) is no longer seated correctly on controller or drive.
* Data cable (20 pin) is faulty.
* On the controller, data cable accidentally connected to J3 (for D:) instead of J4 (for C:). See this diagram.
* On the controller, data cable is connected to J4 upside down. See this diagram.
* A new hard drive was fitted but its low-level format does not match that of the controller. Low level format the drive.      <----- Common, if new drive
* Hard drive has fewer cylinders or heads than the drive C: type in the CMOS/RTC configuration (SETUP) indicates.
* Hard drive C: is faulty.
* Faulty hard drive controller card (specifically the drive data processing area).
* Hard drive C: is getting +12 volts, but not the hard drive controller card. See note 1.
* The hard drive controller card is not getting -12 volts. See notes 2 and 3.
 
1791 1791-Disk 1 Failure
Per 1790 error, but for second hard drive (D:)
 






Note 1 Maybe the +12V connection to the motherboard is bad. Try remove/refit connector P8.
   
Note 2 Check -12 volts out of power supply.
This check should not be required if you have the genuine 5170 power supply, because the corresponding lack of a POWER GOOD signal would not have allowed the motherboard to start.
   
Note 3 Maybe the -12V connection to the motherboard is bad. Try remove/refit connector P8.