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mjnurney
9th November 2012, 12:53
wanted 4116 Dram chips for an Apple II .

C64 has the same ram (no it doesnt )as do some other 8 bit machines...

mike.

thecellartroll
9th November 2012, 13:54
C64 has 4164s. If you need those, how many?

mjnurney
9th November 2012, 14:21
does it? no the Apple has 4116... wonder what the difference is?

it seems they do work , just the extra capacity isnt used. i need 8

or maybe not , maybe different voltage

---------- Post added at 14:21 ---------- Previous post was at 14:05 ----------

just found this...

I saw some posts recently about replacing 4116 RAM with 4164,
which is more reliable (it uses only one voltage, not three!) and
is cheaper (if you know where to look!). I wanted to come up
with a solution that works for all boards (no board hacking or
harness tricks involved). So here it is:

Take your 4164 chip and bend pin 8 up and over the top of
the chip. Solder a small wire from that pin to pin 9 (which
is directly across from it, and has +5V on it). Pin 1 of the
4164 is not used... just snip it off so you don't have to worry
about the -5V on the board. That's it. The chip is ready
to plug into the socket of the 4116.

You can do almost the same thing with a 41256 (also known
as TMS4256, MCM6256, HM51256, MB81256, etc., 256k*1).
In addition to flipping up pin 8 and connecting it to pin 9,
bend up pin 1 and connect it to pin 16 (that'll tie the high
address line to ground... you can't leave it floating).

I used TMS4256 to replace some blown out 4116 in my
Juno First, and it works great. Runs much cooler!!!
Soldering the wires is a little bit of work, but worth the effort.

Bryce
9th November 2012, 14:25
There's a huge difference. The 4116 is a 16K x 1Bit DRAM. It needs a 5V, -5V and 12V supply. It was used in the Spectrum 48K too (for the lower 16K only).

The 4164 is a 64K x 1Bit and only needs a 5V supply.

For obvious reasons, the pinout is different too.

4116 are quite often on offer on the other bay.

Bryce.

mjnurney
10th November 2012, 10:21
Ordered a bulk batch 4116 from the states - thanks all.