[Techtoolslist] Slowing down a Fluke Z80 pod?

[John Robertson]

On 2017/09/17 9:38 AM, David Gersic wrote:
> This is going to seem like a strange thing to want, but is it possible to slow
> down a Z80 pod?
>
> I have a 9010 and the Z80 pod for it. As far as I know, both are working fine.
> I don't have anything with a Z80 in it to test to prove that.
>
> What I picked these up for is to use with a Signetics 2650 adapter
> (http://www.arcades.plus.com/s2650_fluke_adapter.htm) on Zaccaria boards. It
> seems like this should work, but in practice it's very unreliable.
>
> Test reading data from ROM on a known working board, sometimes I get correct
> data, most of the time I get random garbage. If I read a byte from the same
> address 10 times, maybe one time will be correct.
>
> Test RAM, it'll go a few bytes in to the test, then "fail". If I loop on that,
> it'll eventually pass, then fail a byte or two later. This seems to be
> essentially the same symptom as displayed by the ROM reading test.
>
> The adapter board is based on the old Fluke "Troubleshooter" article from
> 1983. As far as I can see, the board is doing what it's supposed to do, moving
> signals from the Z80 to where the 2650 expects them to be.
>
> So what I'm thinking is that the Z80, running at a faster clock speed than the
> 2650, is just over-running what a board designed for a slower processor can
> deliver. Is it possible to slow down the clock speed on the Z80 pod?
>
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Silly question, but have you tried this adapter on a known-to-be-good 
2650 board? Your UUT may be defective such that you get those results 
(ducking).

John :-#)#

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