B2000-CR Rev 4, how is it possible? Identification - Page 2

psoma · 24 January 2023, 00:45

Huh. I have the exact same board that I'm current resurrecting for a mate. It's generally working now and I have a 2MB Agnus in there, ECS Denise and 8MB GottaGoFastRAM. I didn't realise it was an early example, but that could explain why I'm getting issues with the SCSI card I have in there (I'm getting frequent bad block and Gurus when reading from a drive I know is good)... did these early models have issues with the bus??

Jope · 24 January 2023, 07:12

Quote:

Originally Posted by psoma

did these early models have issues with the bus??

Not very many. The rev 4.5 fix might be relevant.
https://bigbookofamigahardware.com/b...uct.aspx?id=17

How to do the fixes:
http://eab.abime.net/showpost.php?p=1586877&postcount=7

psoma · 24 January 2023, 11:32

Thanks Jope - I've subsequently read that the Rev 4.5 fix (Rev. 4.5 (Add 3k3 Ohm resistor between pin 20 and pin 11 on U605 (74LS245)) addresses instability issues with DMA... and this SCSI card uses DMA. I'll give it a go tonight...

A10001986 · 07 February 2023, 14:56

Quote:

Originally Posted by mark_k

It might not be a direct chip swap. (Some other work needed.)

It only needs R5719 added.

ElectroBlaster · 23 April 2023, 21:42

At the moment I cannot add much other than I believe there is one of these boards in my storage!

I should go and locate it. I am confident its in pretty good condition with no battery damage.

shaf · 25 April 2023, 21:46

A caution about rev 4.5 revision boards, I have seen multiple instances where the ground plane trace lifted from the board due to what appeared to be a production problem. I never saw this happen with the rev 4.4 boards.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Indivision ECS on B2000-CR Rev 4.3 ?	prynhart	Hardware mods	3	19 April 2017 12:27
B2000 Schematics Question	Brass	support.Hardware	0	06 July 2012 16:19
Strange B2000 boot issue?	Fingerlickin_B	support.Hardware	7	19 December 2010 10:05
A2000 (not B2000) resurrection	Chain	support.Hardware	24	08 May 2009 09:33
B2000 subjected to pain	chiark	Hardware pics	21	25 September 2008 21:05

24 January 2023, 00:45	#21
psoma Registered User Join Date: Nov 2019 Location: Melbourne, Australia Posts: 193	Huh. I have the exact same board that I'm current resurrecting for a mate. It's generally working now and I have a 2MB Agnus in there, ECS Denise and 8MB GottaGoFastRAM. I didn't realise it was an early example, but that could explain why I'm getting issues with the SCSI card I have in there (I'm getting frequent bad block and Gurus when reading from a drive I know is good)... did these early models have issues with the bus??

24 January 2023, 11:32	#23
psoma Registered User Join Date: Nov 2019 Location: Melbourne, Australia Posts: 193	Thanks Jope - I've subsequently read that the Rev 4.5 fix (Rev. 4.5 (Add 3k3 Ohm resistor between pin 20 and pin 11 on U605 (74LS245)) addresses instability issues with DMA... and this SCSI card uses DMA. I'll give it a go tonight...

23 April 2023, 21:42	#25
ElectroBlaster Junior Member Join Date: Mar 2002 Location: Exeter, Devon, UK Age: 49 Posts: 1,714	At the moment I cannot add much other than I believe there is one of these boards in my storage! I should go and locate it. I am confident its in pretty good condition with no battery damage.

25 April 2023, 21:46	#26
shaf Registered User Join Date: Jun 2012 Location: Toronto / Canada Posts: 237	A caution about rev 4.5 revision boards, I have seen multiple instances where the ground plane trace lifted from the board due to what appeared to be a production problem. I never saw this happen with the rev 4.4 boards.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)