DataFlyer 500 schematic..

[Gene Buckle]

On Sat, 5 Jun 2010, Keith wrote:

> Gene Buckle wrote:
>> On Sun, 30 May 2010, Tony Duell wrote:
>> 
> Gene,
>
> Please let us know how you made out with this.  There might be some common 
> failure pattern that would be nice to know if mine ever gives up the ghost. 
> :)
>
I've shelved it until I have the time & patience to remove the caps. 
Those are the last things to check.

> There's a ROM on there(DF autoboot ver 2.1 chip), and at least one PAL chip 
> (DFS PAL), and maybe another one DTACK?
>
> Is it worth trying to read the ROM?
>
I've actually got a dump of a newer ROM rev around here somewhere.  I 
burned one for a guy that wanted to upgrade his.  Been a year or so.

> Is it possible to reverse engineer the PALs by hooking up a logic analyzer? 
> Are PALs normally just combinational logic?  No timers, counters, storage, 
> and so on?  Just formulas for combining inputs and producing outputs?
>

The board still has the +5 to ground short with all the chips pulled.  The 
only thing left on the board are two electrolytics, two ceramic or 
tantalums and a few resistors.  The resistors checked out.

When I get a chance to work on it again, I'll let you know what I find.

g.


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