strange ram card problem

Secret Vampire · 07 February 2010, 19:29

In my A1200 I've got an 8MB RAM card, but alas it doesn't work properly. It appears to be a Magnum RAM8 bought as non-working off ebay, which I thought was worth a punt since the seller had only tested it without RAM.

The card can be made to work, it just seems to need warming up a bit, from cold the machine doesn't even get past the grey screen, if I'm lucky I'll get a yellow one occasionally, but if I leave the machine on for about 10 minutes and then reboot it'll guru, and after reset work flawlessly with 8MB as if nothing was ever wrong.
Frankly I'm at a loss, I've recapped the A1200, performed 1d4 timing fixes, cleaned edge connectors, tried a variety of different SIMMS, replaced the sockets on the card which held the PAL chips (The contacts had somehow been contaminated and were covered in green crud from corrosion, as if a battery had leaked) and cleaned the chip legs, removed the FPU and crystal, downgraded to C= 3.0 roms, and finally reflowed every single solder joint on the card since some looked a bit dodgy, but still no success.
I don't know what else to try, and without either another A1200 or another RAM/Accelerator on hand I can't even narrow the culprit down to one out of the machine or the card.
Can anyone suggest why it might not be working? currently I feel like this

alexh · 07 February 2010, 20:40

Possibly a physical connection problem which is fixed once the plastic expands with the heat?

Secret Vampire · 07 February 2010, 21:01

I considered that, but all the socketed chips on the card have been replaced, which only leaves the SIMM socket and edge connector. I'm not sure how much if any heat will reach the edge connector, and the simm socket being sprung shouldn't be an issue.
I guess I could replace the SIMM socket, but the edge connector is likely to be impossible

dabone · 08 February 2010, 04:11

I had a problem like that with an Apollo Accelerator,
Turned out to be a loose fitting jumper.

Later,
dabone

mombasajoe · 08 February 2010, 11:51

[quote=Secret Vampire;640590]I considered that, but all the socketed chips on the card have been replaced, which only leaves the SIMM socket and edge connector.

...and every line...

07 February 2010, 19:29	#1
Secret Vampire Registered User Join Date: Jul 2006 Location: Birmingham UK Age: 42 Posts: 214	strange ram card problem In my A1200 I've got an 8MB RAM card, but alas it doesn't work properly. It appears to be a Magnum RAM8 bought as non-working off ebay, which I thought was worth a punt since the seller had only tested it without RAM. The card can be made to work, it just seems to need warming up a bit, from cold the machine doesn't even get past the grey screen, if I'm lucky I'll get a yellow one occasionally, but if I leave the machine on for about 10 minutes and then reboot it'll guru, and after reset work flawlessly with 8MB as if nothing was ever wrong. Frankly I'm at a loss, I've recapped the A1200, performed 1d4 timing fixes, cleaned edge connectors, tried a variety of different SIMMS, replaced the sockets on the card which held the PAL chips (The contacts had somehow been contaminated and were covered in green crud from corrosion, as if a battery had leaked) and cleaned the chip legs, removed the FPU and crystal, downgraded to C= 3.0 roms, and finally reflowed every single solder joint on the card since some looked a bit dodgy, but still no success. I don't know what else to try, and without either another A1200 or another RAM/Accelerator on hand I can't even narrow the culprit down to one out of the machine or the card. Can anyone suggest why it might not be working? currently I feel like this

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07 February 2010, 20:40	#2
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,330	Possibly a physical connection problem which is fixed once the plastic expands with the heat?

07 February 2010, 21:01	#3
Secret Vampire Registered User Join Date: Jul 2006 Location: Birmingham UK Age: 42 Posts: 214	I considered that, but all the socketed chips on the card have been replaced, which only leaves the SIMM socket and edge connector. I'm not sure how much if any heat will reach the edge connector, and the simm socket being sprung shouldn't be an issue. I guess I could replace the SIMM socket, but the edge connector is likely to be impossible

08 February 2010, 04:11	#4
dabone Registered User Join Date: Oct 2009 Location: Chattanooga TN, USA Posts: 109	I had a problem like that with an Apollo Accelerator, Turned out to be a loose fitting jumper. Later, dabone

08 February 2010, 11:51	#5
mombasajoe Registered User Join Date: Mar 2006 Location: D Age: 49 Posts: 528	[quote=Secret Vampire;640590]I considered that, but all the socketed chips on the card have been replaced, which only leaves the SIMM socket and edge connector. ...and every line...

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