[sebhc] RAM testing, was: H8-IDE

[Dwight K. Elvey]

>From: "Jack Rubin" <jack.rubin at ameritech.net>
---snip---
> The only
>reason my 56K system is working is because it has a
>32K x 8 RAM board - now that it's up and running I can
>at least attempt to troubleshoot my stack of 8, 12,
>and 16K boards. 
>
Hi Jack
 When you place these in the machine, leave a memory
gap between the end of the 32K board and the board under
test ( assuming you'll use the H17 memory test at
030.003 ). Just reset the HL and DE registers before
continuing with the test to match the board addressing.
( HL= start and DE = end )
Switch back to the BC register before hitting the GO
key. The test needs to run the BC from 0 to 377 to
make a complete bit pass. If the board is socketed,
move suspect RAMs to the LSB position to save time.
The LSB's are tested most often and will fail early
in the test if bad. If you place the addressing
as continuous memory, the monitor may fail because
it likes to put the stack at the end of contiguous
memory. Placing the memory gap allows the monitor to run
in clean memory as well as saving you about 5+ mins
to test 32K plus your board under test.
 I found that Anchor Electronics has AM6044 chips as
well as 2147 and 61C47 chips ( I think these will also
work ). These are all 4Kx1 chips, similar to the TMS4044
chips used by Heathkit. They all cost about
$3.00 ea from Anchor.
Dwight


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