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Trs-80 parts?

P

Poly-poly man

Jan 1, 1970
0
At my local library book sale, I found a book "Troubleshooting
Microprocessors and Digital Logic". It looked good, so I bought it. For
25 cents, how could I lose? Anyway, I read through it, and some guy has
chapter 9 bookmarked - "Radio Shack's TRS-80 Microcomputer". The first
page shows a nice little example of a radio shack store and the guy
paying for some part and the nice man ringing it up on the TRS-80. On
the 5th page, there's some schematics. I wonder what these are, so I
flip back and I find "Also included in this chapter are the complete
schematic diagrams for the TRS-80..." :) :) :)

Enough with the back story, I want to build this thing!!
The problem is, that most of the parts aren't in production anymore (as
far as I can tell). Does anyone know where I can find some of these parts?

First one : Zilog Z80 Microprocessor ;)

poly-p man

I'll be posting back here often; I really want to do this!
 
P

Poly-poly man

Jan 1, 1970
0
Poly-poly man said:
At my local library book sale, I found a book "Troubleshooting
Microprocessors and Digital Logic". It looked good, so I bought it. For
25 cents, how could I lose? Anyway, I read through it, and some guy has
chapter 9 bookmarked - "Radio Shack's TRS-80 Microcomputer". The first
page shows a nice little example of a radio shack store and the guy
paying for some part and the nice man ringing it up on the TRS-80. On
the 5th page, there's some schematics. I wonder what these are, so I
flip back and I find "Also included in this chapter are the complete
schematic diagrams for the TRS-80..." :) :) :)

Enough with the back story, I want to build this thing!!
The problem is, that most of the parts aren't in production anymore (as
far as I can tell). Does anyone know where I can find some of these parts?

First one : Zilog Z80 Microprocessor ;)

poly-p man

I'll be posting back here often; I really want to do this!

Okay, sci.electronics pointed me to jameco.com. I found many parts, read
full story there.

Anyway, I found an exact copy of my schematics at
http://incolor.inebraska.com/bill_r/trs80_schematics.htm

On sheet 1 part 4, what is "X71" (split into multiple parts) and "X3"?

help appreciated,
poly-p man
 
D

DaveM

Jan 1, 1970
0
Poly-poly man said:
Okay, sci.electronics pointed me to jameco.com. I found many parts, read full
story there.

Anyway, I found an exact copy of my schematics at
http://incolor.inebraska.com/bill_r/trs80_schematics.htm

On sheet 1 part 4, what is "X71" (split into multiple parts) and "X3"?

help appreciated,
poly-p man


X3 and X71 appear to be programming jumper strips. They are 16-pin IC sockets
with a plug-in strip of jumper wires that are either open or short, depending on
the specific configuration needed in the computer. Ferinstance, X71 appears to
be the configuration for setting the computer to see either 4K or 16K of RAM.
BTW, see Z33 and Z34?? Those are the BASIC operating system for the TRS80. You
will probably have loads of trouble finding a copy of those.

Good luck on building it (and even more luck on making it work).

Cheers!!!!
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Some days you're the dog, some days the hydrant.
 
P

Poly-poly man

Jan 1, 1970
0
rue_mohr said:
I have 2 rails of Z80's you just want one?

dan
I'm going to be nice and not ask why.

sci.electronics pointed me to www.jameco.com which sells Z80's by ones -
for less than a buck! These are the new model pin-for-pin
faster-than-the-original z*0's from Zilog! I found most of the parts
there, too.

poly-p man

Why do you have so many, though ;)
 
Poly-poly man said:
Why do you have so many, though ;)

I suspect his reason for having so many is similar to mine, although I
threw away most of my tubes of Z80s years ago.

The Z80 was a very popular microprocessor for use on embedded
controllers, ultimately being replaced by the Intel 8086 and later more
current processors.

When production of these products ceased once they became obsolet, many
tubes of them and other obsolete semiconductor devices ended up in the
trash can, or going home with employees.

In my mind the question would be: Why would you want to duplicate a
TRS-80 today, since for about the same amount of time and effort you
could produce a contemporary computer using, say, an Intel Pentium 4?

Since as a hobby I restore some older computers to operation, mainly
Atari 400s and 800s, but I start off with a complete abeit not working
machine. If I owned a TRS-80, I would likely try to respore it to
operating condition as well. Still, other than a historic collectible,
I really don't see any reason to recreated at TRS-80 from scratch.
Then too, I may be missing something. Realize that even at the time
they were being still sold by Radio Shack, most people, including their
owners, referred to the as "Trash-80s", a major reason why most of them
ended up in the trash can. It is an understatement that none of them
were very reliable and provided such poor performance that virtually
none were actaully employed in commercial use.

That said, an original Radio Shack TRS-80 (not a reproduction) is
likely a very desirable item for some specialty collectors even today.
(Check on eBay to test the market.)

Harry C.
 
M

Michael Black

Jan 1, 1970
0
Shawn said:
You do realized that you will need the ROM chips from a TRS-80 computer,
a TRS-80 keyboard, and a TRS-80 or equiv. TTL monitor... Wouldn't it
be easier just to buy a TRS-80, they practically give them away on Ebay...
I have 4 of them myself.
The only thing that will be a problem is the ROM ICs. It might take
some looking to find a keyboard with just mechanical keyswitches
that could be rewired to match the matrix of the TRS-80 computer, but
there was nothing really special about its keyboard. Same with the monitor,
the original was a tv set with the tuner missing, and if I recall,
optocouplers to get the video signal into it. Any North American TV
set would work, even better one with an actual video input jack. Any NTSC
monitor, and there are lots of them for older computers, CCTV cameras,
and whatever, would work.

Keep in mind that someone did convert their existing Z80 computer
to a Z80, and wrote about it in "Kilobaud". He did have to get
the ROMs, but at that time they could be ordered from Radio Shack.
And he had to rearrange some things so his hardware would fit that
which the ROMs expected.

It likely isn't legal, but I'd not be surprised if one could find
a dump of the ROMs online somewhere.

Michael
 
H

Homer J Simpson

Jan 1, 1970
0
Poly-poly man said:
At my local library book sale, I found a book "Troubleshooting
Microprocessors and Digital Logic". It looked good, so I bought it. For 25
cents, how could I lose? Anyway, I read through it, and some guy has
chapter 9 bookmarked - "Radio Shack's TRS-80 Microcomputer". The first
page shows a nice little example of a radio shack store and the guy paying
for some part and the nice man ringing it up on the TRS-80. On the 5th
page, there's some schematics. I wonder what these are, so I flip back and
I find "Also included in this chapter are the complete schematic diagrams
for the TRS-80..." :) :) :)

Enough with the back story, I want to build this thing!!
The problem is, that most of the parts aren't in production anymore (as
far as I can tell). Does anyone know where I can find some of these parts?

First one : Zilog Z80 Microprocessor ;)

poly-p man

I'll be posting back here often; I really want to do this!

Start at http://www.trs-80.com/ and try an emulator first.

Also try http://groups.yahoo.com/group/TRS-80

I saw a complete one of these (with floppies) go on eBay a day ago for about
$80 + S&H
 
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