weird old ROM chips...

D

DJ Delorie

Guest
I started working on restoring an ancient computer (Wang 2200E). Having
dealt with this computer before, I decided it would be prudent to read
out the ROM chips in case they need to be replaced again. However,
these chips don't match anything I've ever heard of. Most annoyingly,
there is no ground pin! There are 23 of these on the board, with no
inked numbers the same.

The pinout is as follows:


+5V 1 24 OE1
A0 2 23 D0
A1 3 22 D1
A2 4 21 D2
A3 5 20 D3
A4 6 19 D4
A5 7 18 D5
A9 8 17 D6
-12V 9 16 D7
A8 10 15 A10
A7 11 14 OE2
A6 12 13 nAR


Look familiar to anyone?
 
DJ Delorie wrote:
I started working on restoring an ancient computer (Wang 2200E). Having
dealt with this computer before, I decided it would be prudent to read
out the ROM chips in case they need to be replaced again. However,
these chips don't match anything I've ever heard of. Most annoyingly,
there is no ground pin! There are 23 of these on the board, with no
inked numbers the same.

The pinout is as follows:


+5V 1 24 OE1
A0 2 23 D0
A1 3 22 D1
A2 4 21 D2
A3 5 20 D3
A4 6 19 D4
A5 7 18 D5
A9 8 17 D6
-12V 9 16 D7
A8 10 15 A10
A7 11 14 OE2
A6 12 13 nAR


Look familiar to anyone?
Click to expand...
Interesting! "Fascinating"

Well, the 17VDC indicates the devices are MOS - I'd look into old
Rockwell parts from the mid-70s.

Any date codes on any ICs on the motherboard? If you can identify the
year then you can use the IC Master catalog from that year to find who
made ROM that were 1K X 8. I checked the 1978 guide and couldn't find
any likely suspects, but perhaps you will have more luck searching a bit
more through.

John :-#)#

--
(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
 
DJ Delorie wrote:
I started working on restoring an ancient computer (Wang 2200E). Having
dealt with this computer before, I decided it would be prudent to read
out the ROM chips in case they need to be replaced again. However,
these chips don't match anything I've ever heard of. Most annoyingly,
there is no ground pin! There are 23 of these on the board, with no
inked numbers the same.

The pinout is as follows:


+5V 1 24 OE1
A0 2 23 D0
A1 3 22 D1
A2 4 21 D2
A3 5 20 D3
A4 6 19 D4
A5 7 18 D5
A9 8 17 D6
-12V 9 16 D7
A8 10 15 A10
A7 11 14 OE2
A6 12 13 nAR


Look familiar to anyone?
Click to expand...
OK, I see the Wang 2000E/F was produced in January 1976, so check out
the IC Master for 1975 (assuming you can find one) or earlier for the ROM.

What do you mean by pin 13 "nAR"? No Connection visible? Did you do a
resistance check to common in case they used an early multi-layer PCB
and the ground plane is invisible by being in the middle plane?

John :-#)#

--
(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
 
John Robertson <spam@flippers.com> writes:
Any date codes on any ICs on the motherboard?
Click to expand...
Looks like 1978-1979 time period.

http://www.delorie.com/tmp/wang2200E-roms.html (280 KB)

(yes, the pins are *rusty*)

If you can identify the year then you can use the IC Master catalog
from that year to find who made ROM that were 1K X 8. I checked the
1978 guide and couldn't find any likely suspects, but perhaps you will
have more luck searching a bit more through.
Click to expand...
That doesn't sound like something that would have ended up online...
 
John Robertson <spam@flippers.com> writes:
What do you mean by pin 13 "nAR"? No Connection visible? Did you do a
resistance check to common in case they used an early multi-layer PCB
and the ground plane is invisible by being in the middle plane?
Click to expand...
The schematics labelled that pin AR with a bar over it. I suspect it's
"address ready".
 
John Robertson <spam@flippers.com> writes:
OK, I see the Wang 2000E/F was produced in January 1976, so check out
the IC Master for 1975 (assuming you can find one) or earlier for the
ROM.
Click to expand...
As for the year discrepancy, note the "in case they need to be replaced
AGAIN" in my original post ;-)

If the power supply loses a rail, the ROMs are the first chips to die
from it :p
 
In article <xnmxepfqpi.fsf@delorie.com>, DJ Delorie <dj@delorie.com> wrote:
I started working on restoring an ancient computer (Wang 2200E). Having
dealt with this computer before, I decided it would be prudent to read
out the ROM chips in case they need to be replaced again. However,
these chips don't match anything I've ever heard of. Most annoyingly,
there is no ground pin! There are 23 of these on the board, with no
inked numbers the same.

The pinout is as follows:


+5V 1 24 OE1
A0 2 23 D0
A1 3 22 D1
A2 4 21 D2
A3 5 20 D3
A4 6 19 D4
A5 7 18 D5
A9 8 17 D6
-12V 9 16 D7
A8 10 15 A10
A7 11 14 OE2
A6 12 13 nAR


Look familiar to anyone?
Click to expand...
If you take pin 1 as ground and pin 9 as Vcc it's the same as the
Signetics 2600 masked ROM, but that's an NMOS part (circa 1978) that runs
on +5 volts. A couple GI ROMs from 1977 also use pin 1 and 9 as gnd/vcc.
And other GI parts use +5/-[some voltage] as "ttl compatible" PMOS.

So this is a PMOS part from several years earlier. The Signetics sheet
cross references EA4600 and EA4900. Electronic Arrays, as I remember.

Mark Zenier mzenier@eskimo.com
Googleproofaddress(account:mzenier provider:eskimo domain:com)
 
DJ Delorie wrote:
John Robertson <spam@flippers.com> writes:
Any date codes on any ICs on the motherboard?

Looks like 1978-1979 time period.

http://www.delorie.com/tmp/wang2200E-roms.html (280 KB)

(yes, the pins are *rusty*)

If you can identify the year then you can use the IC Master catalog
from that year to find who made ROM that were 1K X 8. I checked the
1978 guide and couldn't find any likely suspects, but perhaps you will
have more luck searching a bit more through.

That doesn't sound like something that would have ended up online...
Click to expand...
Ah, thanks, the picture helps. Certainly the date codes are from 77
through 79. The manufacturers logo "E/A" looks familiar. I'll have to
check that tomorrow in my IC Masters if I have time...figuring out the
manufacturer should enable us to find the part number.

These are masked ROMs of course.

John :-#)#

--
(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
 
John Robertson <spam@flippers.com> writes:
These are masked ROMs of course.
Click to expand...
Of course. I was hoping I could read them out and save the data at
least. If they get toasted I'll have to figure out how to create
replacements from today's technology.
 
John Robertson schrieb:

Ah, thanks, the picture helps. Certainly the date codes are from 77
through 79. The manufacturers logo "E/A" looks familiar.
Click to expand...
Looks like "Electronic Arrays Inc.":
<http://www.elnec.com/support/ic-logos/manufacturer-description/?manuf=Electronic+Arrays>
<http://www.antiquetech.com/companies/EA.htm>

Tilmann
 
"DJ Delorie" <dj@delorie.com> wrote in message
news:xnmxepfqpi.fsf@delorie.com...
I started working on restoring an ancient computer (Wang 2200E). Having
dealt with this computer before, I decided it would be prudent to read
out the ROM chips in case they need to be replaced again. However,
these chips don't match anything I've ever heard of. Most annoyingly,
there is no ground pin! There are 23 of these on the board, with no
inked numbers the same.

The pinout is as follows:


+5V 1 24 OE1
A0 2 23 D0
A1 3 22 D1
A2 4 21 D2
A3 5 20 D3
A4 6 19 D4
A5 7 18 D5
A9 8 17 D6
-12V 9 16 D7
A8 10 15 A10
A7 11 14 OE2
A6 12 13 nAR


Look familiar to anyone?
Click to expand...
Maybe this page can add some information

http://oldcalculatormuseum.com/t-wangic.html

Cant find your part#'s there but still...
 
Also found this
http://home.wxs.nl/~janvdv/wang/wangmuseum.htm
Maybe you can dig deeper from there for more info.

Pages like these makes me num.. :)
 
Yeah, I've been though the museums some. I figured this place was an
easy first choice for finding the base part *if* it was a common part
back then, I'll try to hunt down someone who's fiddled with these parts
before, next.
 
mzenier@eskimo.com (Mark Zenier) writes:
If you take pin 1 as ground and pin 9 as Vcc it's the same as the
Signetics 2600 masked ROM, but that's an NMOS part (circa 1978) that runs
on +5 volts. A couple GI ROMs from 1977 also use pin 1 and 9 as gnd/vcc.
And other GI parts use +5/-[some voltage] as "ttl compatible" PMOS.

So this is a PMOS part from several years earlier. The Signetics sheet
cross references EA4600 and EA4900. Electronic Arrays, as I remember.
Click to expand...
Thanks for the info. /me wishes stuff back then was on the Internet
already :p
 
DJ Delorie wrote:
John Robertson <spam@flippers.com> writes:
These are masked ROMs of course.

Of course. I was hoping I could read them out and save the data at
least. If they get toasted I'll have to figure out how to create
replacements from today's technology.
Click to expand...
If you can access the data and address bus directly you could always
read the entire bank of ROM using something like a Fluke 9010 or 9100
(if the CPU is common) or even wire up an adapter so you could connect
to an Eprom reader. Schematics would help for this project!

John:-#)#

--
(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
 
Tilmann Reh wrote:
John Robertson schrieb:

Ah, thanks, the picture helps. Certainly the date codes are from 77
through 79. The manufacturers logo "E/A" looks familiar.

Looks like "Electronic Arrays Inc.":
http://www.elnec.com/support/ic-logos/manufacturer-description/?manuf=Electronic+Arrays
http://www.antiquetech.com/companies/EA.htm

Tilmann
Click to expand...
That's a help - it certainly matches the age and logo. Now DJ can post a
note here - something like: Subject: Electronic Arrays ROM data book
needed...

John :-#)#

--
(Please post followups or tech enquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
 
John Robertson <spam@flippers.com> writes:
If you can access the data and address bus directly you could always
read the entire bank of ROM using something like a Fluke 9010 or 9100
(if the CPU is common) or even wire up an adapter so you could
connect to an Eprom reader. Schematics would help for this project!
Click to expand...
Thought of that already. I have plenty of embedded MCU boards with
enough I/O to watch the whole address/data bus, if I dared power it up.
I'd rather read them *before* risking them. The other trick would be
getting the computer to cycle through all the addresses.
 
"DJ Delorie" <dj@delorie.com> wrote in message
news:xnbov1emf7.fsf@delorie.com...
John Robertson <spam@flippers.com> writes:
If you can access the data and address bus directly you could always
read the entire bank of ROM using something like a Fluke 9010 or 9100
(if the CPU is common) or even wire up an adapter so you could
connect to an Eprom reader. Schematics would help for this project!

Thought of that already. I have plenty of embedded MCU boards with
enough I/O to watch the whole address/data bus, if I dared power it up.
I'd rather read them *before* risking them. The other trick would be
getting the computer to cycle through all the addresses.
Click to expand...
Dead easy (peek/loop etc) in basic - just literally a few lines.

Just a few more lines to open/copy/close a disk file.
 
"Ian Field" <gangprobing.alien@ntlworld.com> writes:
Dead easy (peek/loop etc) in basic - just literally a few lines.
Click to expand...
You're assuming this computer's basic has instructions for reading the
40-bit-wide ROM space, which may not share a data path with the
8-bit-wide RAM space. This machine has no MCU chip - it's all
implemented in SSI and MSI logic gates.

Just a few more lines to open/copy/close a disk file.
Click to expand...
The disk format is also not compatible with anything else.

Heck, if this were easy, I wouldn't need help, would I ;-)
 
"Ian Field" <gangprobing.alien@ntlworld.com> schreef in bericht
news:OZw8q.4866$4X4.3867@newsfe27.ams2...
"DJ Delorie" <dj@delorie.com> wrote in message
news:xnbov1emf7.fsf@delorie.com...

John Robertson <spam@flippers.com> writes:
If you can access the data and address bus directly you could always
read the entire bank of ROM using something like a Fluke 9010 or 9100
(if the CPU is common) or even wire up an adapter so you could
connect to an Eprom reader. Schematics would help for this project!

Thought of that already. I have plenty of embedded MCU boards with
enough I/O to watch the whole address/data bus, if I dared power it up.
I'd rather read them *before* risking them. The other trick would be
getting the computer to cycle through all the addresses.


Dead easy (peek/loop etc) in basic - just literally a few lines.

Just a few more lines to open/copy/close a disk file.
Click to expand...
Don't think so. The number of ROMs make me think they do not contain a
monitor program but the microcode of the processor. I've seen more old
machines functioning this way. Most pre PC minicomputers did so. I like to
see the schematics if possible. They *may* give enough information to find
out how the chips have to be operated. For instance do you need to provide
12V before +5V or the other way around? Doesn't it matter? Should they be
there at the same time? As they have no external 0V reference, do some other
connected chips provide it? As there apparently is no spare available, these
questions need to be answered before a reliable interface can be build to
read these old boxes.

petrus bitbyter
 
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