<also wave their hands. And finally, I'm looking for a PC based 8080A
<disassembler. My plan is to pull the chips and airmail them to a kind
<volunteer. Actually - although I don't have a lot to spend - I will be m
<happy to pay for the preservation (restoration?) of these data. I think
<important.
Well I don't know of a dos based 8080 disassembler but... There are
several dos based programs that can emulate a 8080/z80 and run a any of
the existing 8080 disassemblers. I prefer MYZ80 and resource. 1k of
8080 code is not bad. What's tough is not knowing what a given port may
do. Though guessing is possible.
<restoring properly. I would note that the cosmetics are near flawless;
<this bodes well for the electronics inside, no?
Generally yes.
Allison
>Silly question of mine: what is the machine supposed to boot
>from?
Oh, my terminology is wrong, I guess. I've not used a front-panel machine.
I guess you'd call these roms the machine's OS? Of sorts. Well... what ARE
they, then?
>In the first stages of bit rot, single bits go "flaky" and will not
>read reliably. So the first thing to do is read the 1702A's multiple
>times and see if any are going bad in this way. Of course, be sure
>to save the results of each read pass...
Thanks for that suggestion. Wilco.
Cheers
A
>Are there any markings on the stickers covering the 1702A windows?
Only numbers identifying their position.
>What do you know of the history of the machine? Was it used for data
>acquisition? Was it used for industrial control? Who was the previous
>owner? What might they have used it for?
This from the gent I bought it from.. this is ALL i know.
"Hmmm.... The DL8a came in a job lot at an auction... It came with a CRDS
PDP11/23 clone, A gutted Universe, a 19" monitor, several hundred kilos of
RT-11
and Unix manuals, several hundred 8" disks, and some other bits and
pieces.."
>The EPROM's might hold bootstrap code, they might hold software that
>drive some sort of device that you don't have, they might contain
>a monitor, it's hard to tell.
A disassembly will make that easy(ish) to determine, surely!
>Have you checked out the power supply yet? This is definitely the
>first priority.
No, I've not checked it - having no equipment. I don't intend to supply
power to it at all until I get those EPROMS copied. So I'm thinking it's
actually a lower priority. I'll check the power while the eproms are away
being saved.
A
yes, i've seen one of those funky pcjr models too. i wish i had bought it just
for the curiosity factor. i dont remember what brand the expansion unit was
though. my particular pcjr has another drive in an external case with its own
power supply and a cable going to the unit like an apple ][
In a message dated 98-03-05 18:37:23 EST, you write:
<< I was in a thrift store during lunch and saw a PCjr which had a
second box attached to the top which contained a second floppy drive.
This almost doubled the height of the system and there was a larger
side car type box on the side as well. Any ideas as to what this may
have been? Was it just for adding a second floppy maybe? I'm
thinking about going back by and picking it up. They also had a
VIC-20 with the VIC version of the floppy drive which I think I grab
as I don't have one of those.
>>
Last I heard, Evergreen was still selling 386-486 upgrade chips, which are
really quick. US$20 each, IIRC
manney(a)lrbcg.com
"Chicken Little was right!"
Have been on vacation since Friday and still have a couple days to
go... From the thrift store outlook in the area things are improving
again (I guess people are starting their pre-spring cleaning)
Stuff I got:
- Timex/Sinclair 16k RAM unit with a few cassette programs for it.
- Given to me, a COMPLETE IBM PC (read model 5150, the first IBM PC I
think... (he had run this one until very recently when he got a new
multi-media system...) The computer has dual floppy drives, a cassette
port and everything! Computer, Monitor, Printer, (all IBM) IBM DOS and
other disks and all manuals! (Wordstar, Microplan, BASIC, etc. etc.)
Haven't powered this one up but the previous owner says drive A has
problems, but once running he could work off of B. (if anyone is
interested in it an willing to pick it up, I will pass it along,
otherwise it will go with me to VFC 2.0 (Hey, Sam, wanna raffle off a
COMPLETE GENUINE IBM PC?)
What I passed up on...
Mac Plus
Some Atari Stuff (800, 520ST, ST floppy drive)
Commodore 64 stuff (never a shortage there...)
PET 8032, 4040 dual drive.
I'm just waiting for the weather to improve one weekend, then the Flea
Market I like will be going again...
Larry Anderson
--
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
Visit our web page at: http://www.goldrush.com/~foxnhare/
Call our Commodore 64 BBS (Silicon Realms 300-2400 baud) at: (209)
754-1363
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
<> > Hey, does anyone have a list of classic systems that people have conn
<> > to the internet? I know I've heard you guys several times talking abo
<> > doing it. Well?
<
<RCS/RI has a VAX-11/750 on the net from time to time.
I'm trying to figure out how to do that with a MV-II or vs2000.
Allison
< Thanks Jim. Have you replaced the video ram in the Sol-20 before?
< Also, do you know if parts are still available or will I have to
< cannibalize from a similar vintage pieces part?
<
< Marty
If it's a bad video ram swap it with the one next to it, if the pattern
changes the ram is fried (I have tons of them). If the pattern doesn't
change is likely a bad 74ls157 or 8097(74ls367). the test for a bad
'157 or 8097 is to swap it with another on the board and see if the
symptom changes.
The fact that you've seen different patterns says the video rom is ok.
Try popping out and reinstalling all the socketed parts and boards. You
may have a crusty connection.
Allison
Thanks to all for the hints, help and tips on the problem of getting
this Sol-20 running. I fired this up last night but the screen didn't
appear as I remember it last time> I must be losing my memory.
All testing was done with the Sol-20 barebone, no S-100 add-on cards
installed.
The screen appears as such:
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
>$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
The prompt > is at the beginning of the second line, and this pattern
is repeated in all 16 rows, save the second where the prompt appears.
The upper case light and local light are on, the shift lock light is
off. The keyboard doesn't respond except for the - key which is to the
left of * on the numeric keypad section on the right.
Next, I disconnected the keyboard cable (after powering down for a
minute or so) and get the exact same result as above, less the upper
case and local lights on of course.
Finally (after powering off) I removed the SOLOS prom board and of
course don't get the prompt > but get a new video display repeated
from top to bottom of an equal sign '=' followed by a lightning bolt,
this pattern repeats = then lightning bolt (I cannot reproduce the
symbol) endlessly from top to bottom.
I also tried a different RG62 video cable in all tests and get the
same results.
Thanks again for your help-
Marty Mintzell
email:marty@itgonline.com
>> Eproms or PROMS? They're marked C1702A
>
>The first commercial EPROM's. 256 * 8. Very likely suffering
>from some form of bit rot... If
>they don't have opaque stickers over the quartz windows. put stickers on
*right
>now*!
OK, they already had stickers on them. I guess I should get these copied.
>Looking at the picture, there are 8 EPROM sockets with only 4 of them
>filled. Right? And what's the part number on the 40-pin DIP near
>where the power harness is attached? It looks a bit incongruous compared
>to the other ceramic packages on the board. Are those 10-turn
>trimpots to the left of that 40-pin DIP?
Yes, 8 sockets... 4 filled.
The 40 pin DIP at the front is AY-5-1013 / 7502
What's a trimpot?!! I can guess.
They're marked Helitrim Cw12 and have a tiny screw at the top.
>Where do the three ribbon cables from the CPU board going to? I assume at
>least one goes to the front panel - I'd guess the middle one.
The cables go to, from left to right...
1) a male 25 pin connector on the back of the chassis
2) to a board mounted behind the control panel - full of interesting small
white chips labeled Beckman
3) This is a bit tricky; a bit of this one goes to the control panel, and
another bit of it to a connector on the back (25 pin) with a sticker "TTY"
beneath it.
4) a female 25 pin connector just above the male one
Datanumerics DL8A can be seen at
http://www.comcen.com.au/~adavie/weird/datanumerics.html
Cheers
A
