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View Full Version : 64 kB of video RAM in C128 wedge by default and an achievement



protek
24th February 2015, 19:44
I had recently purchased a desoldering gun so I thought I'd give it a try on my spares C128 mainboard. I was surprised to find two 4264 chips soldered directly on to the mainboard in the video RAM compartment. I was under the impression that only the 128DCR models had 64 kB by default. Have also the wedge models been supplied with 64 kB or is this just a refit?

Well, I had to salvage these chips but unfortunately the mains adapter plug didn't fit into an earthed socket. Therefore I had to do it old skool with iron and desoldering pump. To my surprise, I managed to get the vias almost completely clean and chips off in one piece. Well, I may have taken a couple of vias with the other chip but the other came out very nicely.

SaviorX
24th February 2015, 21:37
4264s should be 16k (64,000 x 2bits) each should they not? 464s are 32k each...

(a quick check on the net suggests 4164s and 4264s are compatible with each other..)

protek
24th February 2015, 21:59
Ok, then it makes sense. The replacements I got are 4464s. One reference picture of a C128 motherboard showed 1416 chips, which I then presume to be 8 k each, totalling 16k. But if a 4264 is 16 k, then the motherboard had 32 k video RAM, right? That's not standard for C128, is it?

roy_bates
24th February 2015, 22:06
sorry lads,but 4264's are 8k

SaviorX
24th February 2015, 22:21
i cant recall ever coming across 4264s before...99% of the early machines i worked on had 164, 464s, 1256s and 4256s, which were all very common in the PC world (and a lot of the 8 bit machines)

the handy thing being that they were easily identifiable....and easily replacable...

roy_bates
24th February 2015, 22:29
i actually have seen 4264's and still have some for the occasional repair.

they are the same as 4164's

TheCorfiot
24th February 2015, 23:03
@Protek

4416 and 4464 chips are only 4bit wide you need 2 for the full 8 bit data bus :)

protek
25th February 2015, 04:55
Ok, thanks guys! Well, at least I got some good practice with my spares C128 motherboard. I also removed the reset switch from it.