A500 1MB chip RAM problems

Nightfox · 14 July 2016, 13:53

I just performed the mod on my A500 to convert the A501 trapdoor memory into chip memory so I now have 1MB of chip memory. Workbench boots up fine and it shows the full MB of chip memory but now my system is unstable and it constantly reboots with a guru. It flashes the power LED and refuses to boot up again unless I completely power off the machine for a few seconds.

Any ideas what's wrong here?

The system was fine before I performed this mod.

Jope · 14 July 2016, 14:03

Which motherboard revision do you have? Which model of Agnus? Which instructions did you follow?

Nightfox · 14 July 2016, 14:18

Quote:

Originally Posted by Jope

Which motherboard revision do you have? Which model of Agnus? Which instructions did you follow?

I have rev 6A. I have 8372A Agnus. I followed the instructions here:

http://www.kipper2k.com/Xform-A500.pdf

Jope · 14 July 2016, 14:28

Ok, those are good instructions and your Agnus is compatible.

Do you have a multimeter to check that the direct continuity is indeed broken where you made the cuts?

Nightfox · 14 July 2016, 14:36

Unfortunately no

Quote:

Originally Posted by Jope

Ok, those are good instructions and your Agnus is compatible.

Do you have a multimeter to check that the direct continuity is indeed broken where you made the cuts?

Jope · 14 July 2016, 14:37

If you start your workbench disk and break the startup-sequence with ctrl-d, then type avail, does it only show chip ram and no fast ram?

Nightfox · 14 July 2016, 14:51

Well I can sometimes boot up workbench fully and when I use avail I get around 700k of available chip memory and no fast memory

Quote:

Originally Posted by Jope

If you start your workbench disk and break the startup-sequence with ctrl-d, then type avail, does it only show chip ram and no fast ram?

Jope · 14 July 2016, 14:52

Probably a RAM failure in this case?

Nightfox · 14 July 2016, 14:57

I dont see how it could be because the RAM was working perfectly before I did this

Quote:

Originally Posted by Jope

Probably a RAM failure in this case?

Nightfox · 14 July 2016, 15:04

I just undid the mod and now I am back to 512k chip and 512k fast. I used the tool MemCheck and it checked the chip and fast ram and found 0 errors. I'll try the mod once again...

ptyerman · 14 July 2016, 15:07

Quote:

Originally Posted by sacredbanana

I dont see how it could be because the RAM was working perfectly before I did this

The RAM was working perfectly as FAST RAM before you did this. Now it's setup as Chip RAM it could possibly make a difference. I'm not up to spec on the differences of RAM timing and Chip RAM speed vs Fast RAM etc. so more knowledgeable folk will help you out.

Nightfox · 14 July 2016, 15:18

I redid the mod and the problem returns. I even cut deeper to doubly make sure the tracks were cut

Nightfox · 14 July 2016, 18:05

Is the standard A501 RAM expansion not capable of being chip RAM?

Jope · 14 July 2016, 21:36

The article you linked to mentions that some RAM expansions have timing issues when used as chip. I've never encountered this myself, but perhaps you have bad luck. :-/

Nightfox · 15 July 2016, 19:55

I'm just going to have to live with 512kb of chip ram I guess

eXeler0 · 15 July 2016, 20:22

Quote:

Originally Posted by sacredbanana

I'm just going to have to live with 512kb of chip ram I guess

512kB expansions are easy enough to find and pretty cheap too.
Try with another board?
I did the chip mod on a rev 5b and it works fine even when combined with a Blizzard turbo Mem board. (So 1MB chip, 2MB Fast total).

Skickat från min HTC One via Tapatalk

14 July 2016, 13:53	#1
Nightfox Registered User Join Date: Apr 2016 Location: Perth, Australia Posts: 397	A500 1MB chip RAM problems I just performed the mod on my A500 to convert the A501 trapdoor memory into chip memory so I now have 1MB of chip memory. Workbench boots up fine and it shows the full MB of chip memory but now my system is unstable and it constantly reboots with a guru. It flashes the power LED and refuses to boot up again unless I completely power off the machine for a few seconds. Any ideas what's wrong here? The system was fine before I performed this mod.

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14 July 2016, 14:03	#2
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,910	Which motherboard revision do you have? Which model of Agnus? Which instructions did you follow?

14 July 2016, 14:28	#4
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,910	Ok, those are good instructions and your Agnus is compatible. Do you have a multimeter to check that the direct continuity is indeed broken where you made the cuts?

14 July 2016, 14:37	#6
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,910	If you start your workbench disk and break the startup-sequence with ctrl-d, then type avail, does it only show chip ram and no fast ram?

14 July 2016, 14:52	#8
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,910	Probably a RAM failure in this case?

14 July 2016, 15:04	#10
Nightfox Registered User Join Date: Apr 2016 Location: Perth, Australia Posts: 397	I just undid the mod and now I am back to 512k chip and 512k fast. I used the tool MemCheck and it checked the chip and fast ram and found 0 errors. I'll try the mod once again...

14 July 2016, 15:18	#12
Nightfox Registered User Join Date: Apr 2016 Location: Perth, Australia Posts: 397	I redid the mod and the problem returns. I even cut deeper to doubly make sure the tracks were cut

14 July 2016, 18:05	#13
Nightfox Registered User Join Date: Apr 2016 Location: Perth, Australia Posts: 397	Is the standard A501 RAM expansion not capable of being chip RAM?

14 July 2016, 21:36	#14
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,910	The article you linked to mentions that some RAM expansions have timing issues when used as chip. I've never encountered this myself, but perhaps you have bad luck. :-/

15 July 2016, 19:55	#15
Nightfox Registered User Join Date: Apr 2016 Location: Perth, Australia Posts: 397	I'm just going to have to live with 512kb of chip ram I guess

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