[Techtoolslist] Fluke 9100/6800pod and bally mpu help needed.

[John Robertson]

mail at nessandsteve.plus.com wrote:

> Hello all,

> I am hoping someone can help me out. Let me start by describing what has

> lead me to this:

> I receive a Bally MPU board P# r2518-35 (Star Trek) that needs

> repairing.

> I hook up the fluke and boot it up and get a bad clock error.

> I notice someone has replaced the 74s37 with a 74LS00, so replcing it

> restores the clock.

> I "Run UUT" and the status LED stays on.

> I check the jumpers and find that 2 are wired incorrectly so I set

> them right and and I still get nothing.

> After much head scratching and checking various things with a scope I

> couldn't see a problem.

> I replace the cpu and its socket with a spare and it starts the self

> test process.

> I continue on and it gets snagged on each step so replacing the

> sockets on the RAM and PIA at U8 and U11 gets me to the second to last

> test which failed due to a broken lead on c16. Replacing restored it

> to fully working.

>

> So the MPU board is now completetly working on the bench but if I use

> my fluke it will not start the self test process.

> I have tried starting the "Run UUT" from address $1000 and $5000 as I

> believe this to be the address for each ROM but still nothing.

>

> Just to be sure it was not a pod failure I tried a NOS one from the

> shelf and got the same effect. (Both pods pass self test)

>

> Can someone point out something really obvious?

>

> Cheers

> Steve

>

>   

"Run UUT" requires you to either accept the default boot location 
(recommended!) or enter it by hand.

Your choices (1000h or 5000h) are not the boot location the CPU is 
looking for in the ROM code, if I remember correctly the boot location 
for a 6800 is something like FFFEh or FFFCh - its in the manufacturers 
guide to the CPU in question.

Best to simply power down the UUT, then power down the 9010, then power 
the 9010 back up and then the UUT and then do the "Run UUT" and press 
"Enter" twice without adding anything else. Should work if it works for 
the original CPU.

John :-#)#

-- 
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