Replacing ChipRAM in a 4000D

[+OLD CS1]

I have not been inside my 4000 in a couple of years.  Over time it has become less stable with frequent inconsistent crashes.  I noticed some icons were becoming corrupt and some strange graphics glitches in AGA screen modes, so I assumed the 2MB ChipRAM SIMM was failing.  After replacement today with an 8MB SIMM, it has run beautifully with no crashes under fairly heavy use, including moving a couple of gigabytes of data across the USB to network and flash drive endpoints.

 

Deneb USB, Picasso IV, CyberStorm MKIII, Kingston 120GB SSD via ACard SCSI-to-SATA, LiteOn DVD-RW via SCSI-to-IDE.

[Daedalus2097]

Nice catch (and nice spec!). Are you sure it's the SIMM itself and not the SIMM clips that were causing the issue? They're notorious for not giving enough pressure on the contacts.

[+OLD CS1]

5 hours ago, Daedalus2097 said:

Nice catch (and nice spec!). Are you sure it's the SIMM itself and not the SIMM clips that were causing the issue? They're notorious for not giving enough pressure on the contacts.

I had re-seated the SIMM several times.  I suppose it is still possible it was not making good contact, nevertheless the 8MB SIMM is working swimmingly so I am at the very least content that I successfully diagnosed that part of my problems.  The other part appeared to be related to my Picasso IV (which was quite frightening,) but it might just be the DPMS program I was using (covered in another thread.)

 

All said and done, I am very happy to have a stable 4000, again.  Now I just need to spend the time to replace Miami Deluxe with Roadshow.  I read somewhere else a few years back that Miami Deluxe tends to just stop network communications and has to be restarted.  I have that problem and since Miami is so old an Holger Kruse has long since left it behind, it is time to replace it.  The GUI is not important, so Roadshow is just fine and currently developed.

[Daedalus2097]

Yeah, once it's stable, then you're better off not looking for more issues

 

I used Miami DX for many years in rather elaborate network setups (e.g. as a dialup gateway for my PC and Mac, and as a WINS server and gateway on a bizarre LAN setup in uni) that no other TCP stack (or Windows) could handle. I never had it stop like that, but it was also the slowest stack on the Amiga, and DHCP wasn't reliable so it needed to use static IPs. Once I got back to using more conventional LANs, I switched to AmiTCP, which was faster, and then Roadshow, which is faster again, *and* supports DHCP properly. Definitely the pick of the bunch!

[amiman99]

Nice catch, and good to know that you can use 8MB simm.

I'm planning to replace the simm sockets om my A4000. The chip RAM simm is held by a putty.

I just got a professional solder sucker. finally I can fix it. It was bothering me for many years.

[+OLD CS1]

6 hours ago, Daedalus2097 said:

I never had it stop like that, but it was also the slowest stack on the Amiga, and DHCP wasn't reliable so it needed to use static IPs.

This has been very disappointing.  Miami worked great for dial-up, but once I put it on a LAN I found it was just terrible.  Of course, I chalked that up to the Amiga being a slower machine, but then I found running AmiTCP (Genesis) on another machine was faster.  Yeah, maybe that will be my project this weekend.

 

21 minutes ago, amiman99 said:

Nice catch, and good to know that you can use 8MB simm.

I'm planning to replace the simm sockets om my A4000. The chip RAM simm is held by a putty.

I just got a professional solder sucker. finally I can fix it. It was bothering me for many years.

I have read mention of using the 8MB over the years and only just recently got around to it.  AmigaKit had some 2MB SIMMs in stock for a short time, but I missed out on them, and now they are not even in the store.  With several spares on-hand, I should be good for another decade or so.  Maybe by then someone will be producing home-brew replacements.

 

You are not the first person I have seen mention using putty to hold SIMMs in place.  I never would have thought that would work.  Good luck with the repair.  Are you replacing all of them or just the ChipRAM socket?

[str0m]

Can it actually use the full 8MB for Chip or does it still only reference 2?

[Daedalus2097]

You can't actually access the 8MB of RAM sadly, but 2MB SIMMs are getting rare while 8MB SIMMs are still easy enough to find. You can use any SIMMs for the chip RAM - "single-rank" SIMMs will be read as 1MB though so you need "dual-rank" SIMMs (typically double-sided, 2MB, 8MB, 32MB or 128MB), and one MB of RAM will be used from each rank.

[str0m]

Thought that was probably the case. Thanks.

[amiman99]

I will replace all Simm sockets.