A600 4MB RAM upgrade board (was 8MB)

[rampartsagain]

if you put an 4 way ide on it i buy that for a dollar
hehe excellent work guys i contacted several months ago the main author of this project he is very kind he could also provide me the cpld but the problem is to get the compatible ram for it ,and my lack of time didn´t helped me ,and that 4 way ide is killing me i can´t get one even on amigakit if i could put my hands on one of those i have an amiga 600 cdrom waiting well too actually

[Lord Aga]

Kipper is a great guy and a terrific engineer. I have full confidence in all his projects

[duga]

Originally Posted by kipper2k

I mirrored the socket, I have put one of my 68 pin sockets over the cpu and checked clearance, if i have to create a daughter board then so be it. I have mapped the pins to allow for the socket being upside down/back to front. I can post a pic of the socket sitting nice and snug

So... any news?

[kipper2k]

Work in progress

http://www.kipper2k.com/4mbboard.pdf

[SleepyMan]

Originally Posted by kipper2k

Work in progress

http://www.kipper2k.com/4mbboard.pdf

Cool...

[Stedy]

@Kipper2K

Looking good. Can I make a few PCB improvement suggestions?

Add some high frequency decoupling (100nF ceramic) capacitors by every logic device and the RAM. Ideally 1 capacitor per power pin. When the DRAM initiates a refresh, there is a current surge your board may have issues with.

At the bottom of the PCB image, the tracks in the red layer, near the socket, are too close together. You should try and keep track spacing to 2x track width as a minimum to reduce crosstalk.

I might be tempted to purchase one of these

Ian

[cpiac64]

i tempted for 10 pcb only

[kipper2k]

Originally Posted by Stedy

@Kipper2K

Looking good. Can I make a few PCB improvement suggestions?

Add some high frequency decoupling (100nF ceramic) capacitors by every logic device and the RAM. Ideally 1 capacitor per power pin. When the DRAM initiates a refresh, there is a current surge your board may have issues with.

At the bottom of the PCB image, the tracks in the red layer, near the socket, are too close together. You should try and keep track spacing to 2x track width as a minimum to reduce crosstalk.

I might be tempted to purchase one of these
Ian

Hi Ian,

Thanks for the tips, i haven't finished the design yet, there are 4 more 100nf caps to go on plus the programming header. I'll move the tracks apart a little farther apart and add some decoupling caps like you suggested. i'll send you my schem once (i think) i have it done so you can take a peek at it.

The schematic is a lot more tidier than the previous one i asked you to look at

[Kehil]

Don't know if it is not a silly question... Is possible to make internal memory expansion, simmilar to this, for A1200? I know that there are ACAs and plenty of other old cards, but with +-40€ pricing it would be a nice alternative.

[duga]

Originally Posted by Kehil

Don't know if it is not a silly question... Is possible to make internal memory expansion, simmilar to this, for A1200? I know that there are ACAs and plenty of other old cards, but with +-40€ pricing it would be a nice alternative.

I guess it will be at least $10-20 more expensive because of the trapdoor port and as it should have a RTC. But it's not a silly suggestion. It should too have 4 MB memory to be compatible with PCMCIA.

[Kehil]

I ment expansion connected directly to CPU with this clip socket. Without edge connector to keep price as low as possible.

[duga]

Originally Posted by Kehil

I ment expansion connected directly to CPU with this clip socket. Without edge connector to keep price as low as possible.

That seems unnecessary in an A1200.

[keitha1200]

I would def be interested in 'at least' one board, and would be willing to give a small deposit (if needed).

On a slightly different note! I've seen ancient 8mg ram expansion boards (A1200) selling for £60+ on ebay, simple because the end user wants to use WHDload!!

Boards for anything less than the 'going' price of 'old and brittle' A1200 ram expansions, are very good value in my opinion.

[kipper2k]

Originally Posted by keitha1200

I would def be interested in 'at least' one board, and would be willing to give a small deposit (if needed).

On a slightly different note! I've seen ancient 8mg ram expansion boards (A1200) selling for £60+ on ebay, simple because the end user wants to use WHDload!!

Boards for anything less than the 'going' price of 'old and brittle' A1200 ram expansions, are very good value in my opinion.

Hi,

I won't ask for any deposits, its too messy in the event i give up or someone else finds a more popular solution so i normally just buy enough parts for myself to build a few boards and then if its good i will sell more. I will probably buy quite a few ram chips though as the shipping and customs are a pain. All the other parts are easily sourced.

[keitha1200]

Originally Posted by kipper2k

Hi,

I won't ask for any deposits, its too messy in the event i give up or someone else finds a more popular solution so i normally just buy enough parts for myself to build a few boards and then if its good i will sell more. I will probably buy quite a few ram chips though as the shipping and customs are a pain. All the other parts are easily sourced.

No problem

Anything is better than 'auld' over priced brittle A1200 ram expansions

[kipper2k]

I have all the parts, just need a few finishing touches to the board and hopefully this project can get started

[spock-79]

Originally Posted by kipper2k

I have all the parts, just need a few finishing touches to the board and hopefully this project can get started

When the design is ready and tested, is it possible to order only empty PCBs from you?

Very interesting project!

[keitha1200]

Originally Posted by kipper2k

I have all the parts, just need a few finishing touches to the board and hopefully this project can get started

[kipper2k]

Originally Posted by spock-79

When the design is ready and tested, is it possible to order only empty PCBs from you?

.

Hi, i can sell the bits separately. Trying to buy just one part instead of a few can become costly especially if you have to order them online with no local dealer available like here. If you have all the other bits kicking around and just need the board then you are all set.