19 May
2006
19 May
'06
5:43 a.m.
Hello everyone,
I recently got a DEC PRO 350. It suffering from a lack of RAM since two
of its three memory boards are defective (one of the small ones that
plug into the mainboard and one that goes into the extension cage and
seems to carry its own DRAM controller in logic).
I first wanted to take a look at the small one but I can't even find any
info on the ICs used:
JAPAN 8304U
21-18470-01
There is a small logo that seems to indicate Hitachi as manufacturer
[1]. Google refused to find anything on these chips. Does anyone know a
few things about them? Pinout and timing would be a fair start...
Thanks
Sebastian
[1] http://www.linksiden.dk/sub/ic_logo.htm
18 May
18 May
6:17 p.m.
Hello everyone,
I recently got a DEC PRO 350. It suffering from a lack of RAM since two
of its three memory boards are defective (one of the small ones that
plug into the mainboard and one that goes into the extension cage and
seems to carry its own DRAM controller in logic).
I first wanted to take a look at the small one but I can't even find any
info on the ICs used:
JAPAN 8304U
21-18470-01
That's a DEC house number...
Hoe many pins do these chips have? If 16, I'll bet they're a common DRAM.
Do you know the capacity of the board? If so, you should be able to work
out what chips would have been used (e.g. if it's a 64K word board, and
there are 16 chips, I'd guess they were 4164s).
-tony
19 May
19 May
7:51 p.m.
On 5/19/06, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
The standard chips are 4164s. It's possible to remove them, replace
them with 41256s and insert two wire jumpers on the board to upgrade
it. I know there were instructions on the 'net somewhere, in an
aggregate list of PRO-350 messages from a pre-web archive, but I was
unable to find them just now. The upgrade is straightforward - remove
the chips (easiest to clip the leads at the chip body and remove the
pins one by one), add sockets if you are so inclined, install 16 x
41256 (don't recall the speed requirement, but 120ns parts should be
fast enough - I don't think there are any 41256s slower than 150ns
anyway), and look at one end of the board for jumpers labelled, IIRC
W1 and W2 - install the jumpers for 256Kbit DRAMs, remove the jumpers
for 64Kbit DRAMs. Don't mix parts - all one type or another.
I have done this on one of my PRO-350s. No issues.
-ethan
I recently got
a DEC PRO 350....
I first wanted to take a look at the small one but I can't even find any
info on the ICs used:
JAPAN 8304U
21-18470-01
That's a DEC house number...
How many pins do these chips have? If 16, I'll bet they're a common DRAM.
Do you know the capacity of the board? If so, you should be able to work
out what chips would have been used (e.g. if it's a 64K word board, and
there are 16 chips, I'd guess they were 4164s). 
10:59 a.m.
On 5/19/06, Sebastian Br?ckner <sb at thebackend.de> wrote:
Hello everyone,
I recently got a DEC PRO 350. It suffering from a lack of RAM since two
of its three memory boards are defective (one of the small ones that
plug into the mainboard and one that goes into the extension cage and
seems to carry its own DRAM controller in logic).
I first wanted to take a look at the small one but I can't even find any
info on the ICs used:
The docs say they can either be 64Kx1 or optionally 256Kx1 chips.
http://www.bitsavers.org/pdf/dec/pdp11/pro3xx/
I'll take a look at the chips on the boards I have and see what
markings they have.
BTW, how do you get the cards out of the card cage? Pull the lever?
Twist the lever? Both? I haven't figured out how the ZIF sockets are
supposed to work and don't want to break anything trying.
18 May
18 May
6:21 p.m.
BTW, how do you get the cards out of the card cage?
Pull the lever?
Twist the lever? Both? I haven't figured out how the ZIF sockets are
supposed to work and don't want to break anything trying.
Pull the tab out as far as it will go, then twist if (IIRC, clockwise,
but I might well have mis-remembered that). Then slide the board out.
-tony
19 May
19 May
2:55 p.m.
I seem to rember twist 90 degrees to release the clamping on the
interface... but it's been 5 years or so.
Bill
On 5/19/06, Glen Slick <glen.slick at gmail.com> wrote:
On 5/19/06, Sebastian Br?ckner <sb at thebackend.de> wrote:
Hello everyone,
I recently got a DEC PRO 350. It suffering from a lack of RAM since two
of its three memory boards are defective (one of the small ones that
plug into the mainboard and one that goes into the extension cage and
seems to carry its own DRAM controller in logic).
I first wanted to take a look at the small one but I can't even find any
info on the ICs used:
The docs say they can either be 64Kx1 or optionally 256Kx1 chips.
http://www.bitsavers.org/pdf/dec/pdp11/pro3xx/
I'll take a look at the chips on the boards I have and see what
markings they have.
BTW, how do you get the cards out of the card cage? Pull the lever?
Twist the lever? Both? I haven't figured out how the ZIF sockets are
supposed to work and don't want to break anything trying.
6744
days inactive
6745
days old
5 comments
5 participants
participants (5)
-
ard＠p850ug1.demon.co.uk -
ethan.dicks＠gmail.com -
glen.slick＠gmail.com -
pechter＠gmail.com -
sb＠thebackend.de