7 Nov
2016
7 Nov
'16
6:32 p.m.
Hi folks,
Still working on this STC Executel and it looks like the CPU isn't too good
given how hot it gets within a minute or so. The display is the same whether
there's a CPU physically present or not. I built this circuit to test it:
http://saundby.com/electronics/8085/freerun.shtml
Using a 4mhz crystal the address lines are all over the place - I'm using a
logic analyser rather than LEDs.
Has anyone got a spare they'd like to sell me? I'm struggling to think of
something I've got that may have a socketed 8085...
--
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
collection?
7 Nov
7 Nov
8:57 p.m.
If you were on this side of the pond it would be easy.
The 8085A is a really common part with many vendors and all work.
Also if a different one gets hot (they nominally run warm not hot to the
touch)
check to see if there is a bus or address driver shorted or stuck in the
wrong direction.
Make sure the 8085A is the only warm part.
Allison
On 11/07/2016 06:32 PM, Adrian Graham wrote:
Hi folks,
Still working on this STC Executel and it looks like the CPU isn't too good
given how hot it gets within a minute or so. The display is the same whether
there's a CPU physically present or not. I built this circuit to test it:
http://saundby.com/electronics/8085/freerun.shtml
Using a 4mhz crystal the address lines are all over the place - I'm using a
logic analyser rather than LEDs.
Has anyone got a spare they'd like to sell me? I'm struggling to think of
something I've got that may have a socketed 8085...
10:52 p.m.
On 11/07/2016 03:32 PM, Adrian Graham wrote:
Hi folks,
Still working on this STC Executel and it looks like the CPU isn't
too good given how hot it gets within a minute or so. The display is
the same whether there's a CPU physically present or not. I built
this circuit to test it:
http://saundby.com/electronics/8085/freerun.shtml
Using a 4mhz crystal the address lines are all over the place - I'm
using a logic analyser rather than LEDs.
Has anyone got a spare they'd like to sell me? I'm struggling to
think of something I've got that may have a socketed 8085...
Got any old Adaptec SCSI controllers for PC? How about an old XT MFM
controller? Wangtek QIC36 tape controller?
The 8085s are all over the place. If you're buying NOS, I'd probably
go for the 80C85. Tundra made a pretty good one.
--Chuck
22 Nov
22 Nov
8:37 p.m.
Hi Adrian ,
I'm certain I have a couple 8085s you can have for the shipping . Let me go
through my storage unit this week end and find them . I'm in San Diego , CA
USA , there has to be some slick way to ship to the UK to avoid all the
unpleasantness .... Do you have PayPal or .... ? We can figure something
out . You do know the 8085 has a MINIMUM frequency of 500 KHz due to
internal dynamic logic ? It gets real pissy if you go below that . CDP1802s
you can clock down to 0 Hz . Let me know if this will work for you . Happy
Turkey Day !
Best regards, Steven C KJ6STF
On Mon, Nov 7, 2016 at 3:32 PM, Adrian Graham <witchy at binarydinosaurs.co.uk>
wrote:
Hi folks,
Still working on this STC Executel and it looks like the CPU isn't too good
given how hot it gets within a minute or so. The display is the same
whether
there's a CPU physically present or not. I built this circuit to test it:
http://saundby.com/electronics/8085/freerun.shtml
Using a 4mhz crystal the address lines are all over the place - I'm using a
logic analyser rather than LEDs.
Has anyone got a spare they'd like to sell me? I'm struggling to think of
something I've got that may have a socketed 8085...
--
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
collection?
2779
days inactive
2795
days old
3 comments
4 participants
participants (4)
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