Amiga 1200 DKB Cobra Accelerator - memory not recognised

[Slaanesh]

I recently bought a second hand Amiga 1200 DKB Cobra Accelerator which has the full 68030 @ 28Mhz.
Included was a doubled sided 32MB 72-pin SIMM.

Plugging it in I find that 99% of the time the RAM isn't recognised - Workbench will state there is 0MB Fast RAM.
Occasionally either running Workbench or Sysinfo the RAM appears - only to disappear the next time I reboot.
The CPU DOES work and is detected every time. Sysinfo tells me I have a 68030 and MMU, etc
Frustrating.

As a side note, I also have another accelerator which is a 68020 with 4MB and works great 100% of the time.

Things I've tried:
Carefully examined the board for damage.
Cleaned the A1200 connector and the DKB Cobra's connector.
Cleaned the 72-pin SIMM and its socket on the accelerator card.
Carefully and very slightly tried bending the little pins on the SIMM connector so they make a better contact.
Gone through each pin and successfully tested continuity from the socket to the SIMM whilst the SIMM is in place.
Tried a different sized SIMM - the 4MB SIMM from my other accelerator as well as another SIMM from an older PC and yet another 4MB SIMM that I had lying around with no joy.
Randomly selected one and desoldered it and tested it and it was bang on 33uf (which was its spec).

I'm not really sure why it's so unreliable as the CPU always works and the memory almost never.
Anyway without the FAST RAM it's pretty useless.

I'm pretty good a soldering and desoldering. Whilst it the SIMM and socket look sound, it's all plastic and was wondering how good the continuity actually is (despite testing).
There are also 5x electrolytic caps in total on board but they all look fine (one is now replaced)
I can't see any damage on the board itself.
I've attached a photo of the front and rear of the card.

Any suggestions?

[kolla]

I have had this problem with some ram boards when using 3.0 kickstarts, I presume you’re using 3.1?

[Slaanesh]

I am using the original Kickstart 3.0 with Workbench 3.1

[PlatformerZ]

I have a Cobra 030 and you've reminded me that the early Cobra cards would not work with fastram using Kickstart 3.1. Amiga resource.cx gives information on it. IIRC there is a flsh utility to update the Cobra on-board rom to run. Maybe with Kickstart 3.0 there is also an issue because 3.0 doesn't autoconfigure ram but 3.1 does.


http://amiga.resource.cx/exp/cobra

[Slaanesh]

Regarding Kickstart versions:

needs firmware update for Kickstart 3.1, otherwise it works only with memory removed

I read that the other way around. As in it WILL work with kickstart 3.0 but would need a firmware update if you are using kickstart 3.1?

Anyway where is the firmware update for the card? Presumably there would be no harm in updating it?

Answer: On the companion SCSI Ferret disk

[kolla]

So does it work after a firmware flash?

[Slaanesh]

I will be doing it tonight as I had my A1200 temporary packed away
I will certainly report back either way

[Slaanesh]

The DKB Cobra/Ferret installer determines the speed of your CPU (28Mhz) and then lets you select either 70 or 80ns RAM.
The installer then flashes the card (29C256 eeprom onboard) and prompts you to turn off the computer for 30 seconds

I chose 80ns, flashed and switched off and turned on but still no RAM (this was with my 32MB card).
I removed the SIMM and found that even after cleaning it throughly a couple days ago with ISO and deoxit, the pins were dirty again when I wiped them... Strange.
So I put in one of my 4MB SIMMs with gold contacts.
I went through the flash procedure again and selected 70ns this time (my RAM is 60ns)

I also updated the relocate kickstart utility.

This time on restart it found my RAM in workbench and confirmed again with sys info.
I played a few games, switched off and back on and it is still detected.

I'll try again tomorrow morning and see if it's still working then.

Perhaps it was just dirty contacts on my SIMM? Hard to tell now as a few things have changed.

[Slaanesh]

I tried it again this morning and found that on the first power on the RAM was not detected.
The Trapdoor had not been fitted (nor yesterday as I have the A1200 opened up to switch accelerators)

So I popped the trapdoor on and tried again and this time the RAM did appear.
This leads me to believe it may be something to do with the connection from the card to the A1200.

My other accelerator doesn't seem to have this problem.

I read in a few other posts about bending the pins slightly (and carefully) on the card to make the fit tighter on the A1200 connector.
Giving it another clean probably won't hurt either; though i've done this already when I first got it - perhaps a bit too cursory.
What's a good way to clean this connector?

Other points of read are power supply - I'm using an A500 power supply - I have several - the one I am using is the high output version - but I may try the others as well.
Might be worth measuring the 5V line to the board.

[Slaanesh]

Okay so after switching off overnight and leaving it and turning it back on it seems to be recognising the RAM each time now.

Over time Ill see how reliable it is but for now it looks okay.