Weird A3000 memory problems

[cv643d]

Hello

I have an A3000 that came with a strange zip to 72 pin memory adapter, it didnt work, as was discussed in a previous thread here. I bought a new 72 pin adapter that worked on the sellers A3000 and it didnt work either when I tried it on mine (with his working 8 mb x 2 Simm sticks of memory)! showing 0 fast mem in Workbench. I am 100% shure I mounted booth of the adapters the right way.

I dont know where to go from now, any A3000 gurus here who can help me out on this one, can it be a jumper issue?

The only thing I did to the computer was I desoldered the battery because it started to eat on the motherboard (its running with no battery now). It was jumpered as an NTSC machine when I got it, which is strange since Im in Sweden where we use the PAL format. The previous user I think didnt have a lot of Amiga knowledge judging from the harddrive contents and layout, maybe he switched jumpers? (I have no possibility to get in contact with him).

Another strange thing is the chip memory only shows up as 1,5 mb even though I the memory sockets are full on the zorro side of the motherboard. But I dont think the kickstart is copied to the ram...  Shouldnt I be getting 2 mb of chipram?

/Thanks for watching.

[redrumloa]

I don't remember specifics but there are jumpers that deal with RAM, that switch types of zip ram usage. Try looking HERE for some jumper info. Hopefully someone with more time and a better memory than me can elaborate:-)

[cv643d]

Yeah...  I really need help with this.

[Castellen]

If you power up the A3000 into just a command prompt and type "avail" then you should have pretty close to 2Mb chip mem if the 2nd Mb of chip mem is fitted.  Try reseating all the ICs from U267 to U274 (the 2nd 1Mb).

If you have a "softboot" ROM where the kickstart is loaded from disk/HD, then the kickstart will permanently eat up 512k of memory, which might explain your problem.

Hold down both mouse buttons on power up, if you see an OS 1.3 - 2.0 selection menu, then you have one of these.


Not sure about the ZIP to SIMM adapator, never seen one before.
There is a single jumper to select which size ZIPs you are using, so try that one.

Obviously you need to make sure you're using the right kind of SIMMs and each pin is socketed properly.

I doubt if it'll work if you have any fast memory in the DIP sockets just to the front of the ZIP sockets, so remove that if fitted.

Also check out:
http://www.feagurth.net/Amiga/A3000Data.HTML

Lots of useful info on A3000s.

[cv643d]

Hello, thanks for the input.

Avail gives me maximum 2 mb, and 1.5 used memory. It must be the softboot  rom you described. I wonder since I have Escom 3.1 roms, if it is built in the roms that it will softboot the rom?

I cant get any 1.3 - 2.0 boot screen but thats maybe normal when you are running with 3.1 roms.

I tried every possible setting on the jumpers from the A3000 page on the Amiga Hardware site above but no go.

I think I need to track down a turboboard to see if it will work. And I'm gonna check out that A3000 site.

[Darrin]

I don't suppose you know of anyone selling a Zorro based RAM expansion for the A3000 do you?  I've expanded the RAM on my motherboard almost to the limit, but I fondly remember using a GVP HD Card with extra RAM on it on my A2000 and even robbing ½ meg of RAM from my A2000 which was fitted on a Zorro card (early A2000) and sticking that in my A1500.

Any ideas (without resorting to a CPU upgrade card)?

Thanks.

[Castellen]

@cv643d
If you have OS 3.1 (ver 40.68) in ROM, then you should have a full 2Mb of chip mem after booting with no startup sequence.
If this is not the case, then you might have some kind of software problem with something using the memory when it shouldn't?

Are you running OS 3.5/3.9?  They do the softboot thing as well, so you'll also loose 512k of memory after that happens.

[Castellen]

@ Darrin
There were quite a few Zorro cards which allowed you to expand the fast memory.  A lot of SCSI controllers like the DKB rapidfire and Oktagon would let you add extra memory.
The problem with most of these is that they were only Zorro II, I.E. 16 bit.  The A3000 accesses fast mem at 32 bits wide, so in order to address the 16 bit memory, it has to do two (16 bit) writes instead of one 32 bit write, therefore memory access time is decreased.

I'm pretty sure the Fastlane card was Zorro III, so accessed memory at 32 bits wide.  This card also allowed you to add a LOT of extra memory, providing you can find the now hard to get 32 pin SIMMs.

I'd recommend getting a nice CPU card such as a Cyberstorm mkII.  You can add up to 128Mb fast mem, which of course is full speed 32 bit access.
Note that most CPU boards require a minor A3000 motherboard modification to run (just a wire jumper) which you can probably do yourself if you have some electronics experience and good soldering skills.

I saw a Cyberstorm mk1 on Amibench the other day at a reasonable price, might be worth a look?

Anthony.

[Madgun68]

If you have OS 3.1 (ver 40.68) in ROM, then you should have a full 2Mb of chip mem after booting with no startup sequence.
If this is not the case, then you might have some kind of software problem with something using the memory when it shouldn't?

I think I remember trying this with my A1200 and running in to one small quirk.. That is that the buffers allocated to the various partitions (if a harddrive is present) will still eat whatever amount of memory they require. (And since there's no fast mem, it's going to go for chip.)

[MrZammler]

I have one of those (AmiFast) and used it before my Cyberstorm.

First of all, make sure that you only put 8 meg simms on it. Nothing else will work.

Check that there are no bend pins on the board (they're small and easy to break). Check that it is installed properly, i.e. sitting on the specific zip slots it should.

When these are ok, install your ram simms, and start playing with jumpers J851, J852 and J853. It will eventually work.