Ram Memory Tests; Top Ram Test; Ram Pattern Test; Ram Addressing - HP 200 Series Hardware Support Document

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Troubleshooting and Diagnostics
RAM Memory Tests
Random-Access Read/Write Memory (RAM) is contained on optional RAM cards which are instal-
led in the accessory slots. The assemblies involved are:
09826-69524
98257-69524
These are exchange items.
Top RAM Test
256K byte RAM card
1M byte RAM card
The self test needs 16K bytes of RAM to operate properly. The top RAM test checks to see that
there are 16K bytes of good RAM available at the top of memory. While it is running, the LEOs
display 0000 0100.
If the top RAM test fails, the following LED displays and CRT messages are presented:
LED Display CRT Message Probable Cause . What to Do
10000100
NEED GOOD RAM
ABOVE FFCOOO
Defective RAM in top 16K Check addressing of RAM
bytes
1000 1010
Insufficient RAM for self- Replace RAM card for self-
~~ ~~
RAM Pattern Test
The RAM pattern test checks all system RAM in the computer; that is, all RAM not dedicated to a
specific purpose. such as the display. It exercises the RAM with an up/down march test. While it is
running, the LEOs display 0000 1001, and the CRT displays the message
TESTING MEMORY
If the RAM pattern test fails, the following LED display and CRT message is presented:
LED Display CRT Message Probable Cause What to Do
1000 1001
Memory Failed at XXXXXX RAM incorrectly addressed Check RAM addressing
W:ZZZZZZZZ,
R:YYVYYYYY
Defective RAM Replace RAM card
RAM Addressing
The size of the HP 9817 memory map is 16M bytes. Since 16M is 1000000 in hexadecimal, the
memory map covers addresses from 000000 to FFFFFF (1000000-1). The top 7.5M bytes are
reserved for RAM. Thus, RAM may occupy addresses from 880000 to FFFFFF.
The following addressing rules apply to add-on RAM:
1. It must start at the top of memory (that is, FFFFFF).
2. It must be contiguous.
3. It must not overlap.
4. It is limited to 7.5M bytes.