Will these RAM chips work for DIY upgrade?

[Astral]

To all you hackery expert people out there...

I've got an A500+. I'd like to do a DIY piggyback upgrade from 1mb to 2mb chip ram on the motherboard.

The onboard chips are 41c425680. I have 8 x spare 51425680 chips. Are these useable?

[Astral]

You can take the 500+ from 1mb chip to 2mb chip on the motherboard.

Yeah, I thought of the trapdoor option...which is still an option...but I also love a bit of hackery! So thought I'd give it a go

[Astral]

@Vince_6

I intend to add fastram to the CPU socket. I've got a Kipper2k ram expansion on order

[Astral]

@zetro...

You're right...without going back and reading it all now...it is something along those lines.

But my original question remains unanswered I have a feeling based on net searching that they are the same but I'm not 100% sure. Any idea?

[Astral]

Thanks Zetro.

Based on your info I plugged in a good ol' A501 equivalent and it shows as CHIP RAM. And your suggestion about a solder jobbie on top of the A501 chips is fantastic. That's the way I will do it!

[Astral]

Zetro....calling yo Zetro...

I need some help please, if you don't mind.

I've found some time to start this hack. Bit of a long story as to what I've tried and what I haven't...

But can't get it to work so far. The things I can think of that are relevant at the moment are...

With BACSU 1...I am thinking that schematic is incorrect. I've found this...

http://www.1000bit.it/support/manuali/commodore/a500plus_sm/amiga500plus_sm.pdf

1) And it looks like pin 36 on the expansion connector is actually tied to pin 11 on U32...not pin 1. It visually looks to be the case on the actual motherboard I have too. I don't have my multimeter at home to check at the moment to confirm this. Regardless though...when connecting the jump wire to pin 36 the extra 512k is not recognised.

I have tried two different A501 type boards too. They are both clones.

2) I haven't actually soldered the RAM pins together yet, they are "force" fitted and appear to have plenty of tension on the pins to be making contact with the mating chips. I know, yes they should be solder, I will get around to soldering them just to be sure, but at this stage not sure how relevant this is???

3) You mention removing BACSL 1 (pin 35). Do you mean cutting the trace on the actual A501?

I've tried to link your info, the above PDF's info, various google searches and so on to work out what is wrong...but so far no success. I'll keep looking at that PDF to see what difference there are to the A501+ board compared to the standard A501 and I will also solder those chips...

HELP! Please Mr

*EDIT* All soldered now and still the same results...