TRS-80 Model IV PALs

rescue rescue at
Thu Dec 5 12:24:00 CST 2019

On 2019-12-04 21:55, rescue wrote:
> I have a TRS-80 Model III with a IV upgrade in it (non gate array).
> I have a hunch that one or two of the HALs are bad (the primary one
> being 8075208).
> Anyone have the JED files to program any of these HALs into PALs or 
> GALs ?
> Anyone know a source for these ?
> Anyone know if these can be read, or if they are protected (for
> example, if I were able to borrow some working ones, could they be
> duplicated ?) ?
> Thanks,
> -- Curt

It has come to my attention these HALs may be readable as PALs...

I'll have to check my programmers and see if any support reading those 
on mine.... though that still doesn't give me any basis for comparison 

Anyone have a spare TRS-80 Model IV PCB that I could read the HALs 
from.... or someone who can has and can read them.

Looks like I do have the HAL that supports the memory upgrade beyond 
64k.  Mine is not the initial Model IV Rev....
When mounted in the Model III/IV chassis, the RAM is in the bottom 
right (not top left).

My PCB says 8709296 Rev C on it.

-- Curt

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