C64 RAM - 4464 instead of 4164

[Hiryu]

I have some chips 4464 and I have some MB that use 4164. Some of this
chip is broken and i don't have new ones to replace. Can I use 4464
insted of 4164 chips ?? Someon know how??

thanx

[Vagabond420]

I belive I tried that and ended up with one very hot and very dead
4464.

[Scott McDonnell]

You should be able to do this, though it will not be a "drop in"
replacement:

4164
64kx1 DRAM.
+---+--+---+
|1 +--+ 16| GND
D |2 15| /CAS
/WE |3 14| Q
/RAS |4 4164 13| A6
A0 |5 12| A3
A2 |6 11| A4
A1 |7 10| A5
VCC |8 9| A7
+----------+

4464
64kx4 DRAM.
+---+--+---+
/OE |1 +--+ 18| GND
D0 |2 17| D3
D1 |3 16| /CAS
/WE |4 15| D2
/RAS |5 4464 14| A0
A6 |6 13| A1
A5 |7 12| A2
A4 |8 11| A3
VCC |9 10| A7
+----------+

(pinouts from http://www.kingswood-consulting.co.uk/giicm/)

The big difference (besides the pinouts) are that the 4464 has 4 data lines
and an Output Enable (/OE) while the 4164 has 1 data line (D) for input and
1 for output (Q.) The D0-D3 lines on the 4464 are both input and output
lines. Thier state is controlled by the /WE and /OE lines.

You could replace 4*4164s with one 4464, or you could just use one of D0-D3
lines on the 4464 as the D line for a single 4164 replacement.

/OE can just be connected to ground through a 2.2K resistor, IIRC (if not,
then /WE can be inverted and fed to /OE.) The data lines should be also
connected to the Q pins of the corresponding chips. All other lines should
be routed to match up. D0-D3 would go to the 4 D lines of the 4 replaced
chips. Order should not be siginificant, since however it is written will be
how it is read, so the nybbles should be accurate however you wire them. To
make troubleshooting easier later, you might want to trace the lines down to
the CPU and wire them in order, though. You can disable the replaced chips
by cutting the VCC and GND pins. Depending on how long your wiring becomes,
you may need to place some small ceramic caps between the data lines and
ground on the chips to filter out noise.

Scott

"Hiryu" <hi...@email.it> wrote in message
news:4715a130.04051...@posting.google.com...

[Peter van Merkerk]

"Hiryu" <hi...@email.it> wrote in message
news:4715a130.04051...@posting.google.com...

> I have some chips 4464 and I have some MB that use 4164. Some of this
> chip is broken and i don't have new ones to replace. Can I use 4464
> insted of 4164 chips ?? Someon know how??

It is also possible to replace the 4164 with the 41256. Those are pin
compatible, but you have to make sure that pin 1 is grounded.

--
Peter van Merkerk
peter.van.merkerk(at)dse.nl