A25000 RAM card in an A2000

[richo132]

I have an A25000 RAM card that I want to use in an A2000.
Computer has a 3.1 ROM plus A2091 SCSI card with 2Mb RAM.

I'd appreciate some help with a couple of issues:
1. What is the function of jumpers J1 & J2 on the A25000 ?
2. I want to load WB 3.1 on the A2000
   HD setup functions only work correctly with base M/B RAM
   ie if I remove the A25000 and disable the A2091RAM.
   Any suggestions about the cause of this ?

Thanks.

[rkauer]

 AFAIK, the A25000 (aka A2052), it's an auto-configuring card with just 2Mb of RAM in it.

 Hardly this is a font of problems.

 The jumpers probably are there for test purposes only (or for disable half of the memory).

-----------

 For the A2091, there a lot of information (taken from The Big Book of Amiga Hardware :
Jumpers

JP1: Memory Size
0K: Set for no memory.
512K: Set for 512K of RAM.
1M: Set for 1M of RAM.
2M: Set for 2M of RAM.

JP2: Autoboot Enable
AUTO: Set to enable autobooting from the A2091.
DIS: Set to disable autobooting from the A2091.

JP3: Interrupt Select
INT6: Select interrupt 6.
INT2: Select interrupt 2.

JP5: Options
Option 1: LUN Enable. When jumpered, enables scanning for Logical
Unit Numbers numbers at each physical SCSI address.
Default value: Off.
Option 2: Time-Out Length. When jumpered, enables longer time-out
for slow-starting drives. Default: Off. (Note: When on,
this jumper disables parity during the message in phase.)
Option 3: Reserved. Factory default: Off.

JP201: Factory use only.

The version 7 ROM fixes the following bugs in the 6.6 ROM
- >1GB HD support
- DMA reselection bug fixed
- disconnect/reconnect performance improved a lot
- Sync messages are handled
- Error handling improved
- Sync problems with Seagate/Syquest fixed
- Removable media recognition fixed
- Slow boot jumper now does a 15 second wait plus 300ms scan

 More complete information can be found in TBBoAH.

[rkauer]

 BTW: a new program to patch the A2091 appears today on Aminet.

 Try it.

 The obvious link is: this

[richo132]

Thanks for taking the trouble to put together such a detailed response. I hadn't noticed J3 - well the pads for it anyway. This is definitely worth knowing about. Having read the article about VBAK2091, I'm wondering if it would make much difference to an A2000 - it seems mostly to be pitched at A4000+A2091. Do you have any experience with this ? Cheers.
(PS my A2091 has V7 ROMs)

[Ral-Clan]

richo132 wrote:
Having read the article about VBAK2091, I'm wondering if it would make much difference to an A2000 - it seems mostly to be pitched at A4000+A2091. Do you have any experience with this ? Cheers.
(PS my A2091 has V7 ROMs)

Before I got the GURU-ROM for my A2091 I used vbak2091 and it made a HUGE difference in transfer rates (on my Amiga 2000).

How much RAM is on the memory card.  You should be aware that you can only put a maximum of 6MB on there if you want to use the 2MB on the SCSI card (which is recommended).

[rkauer]

ral-clan wrote:

How much RAM is on the memory card.  You should be aware that you can only put a maximum of 6MB on there if you want to use the 2MB on the SCSI card (which is recommended).

 The A25000 ( =A2052) only have 2Mb in it. You could have more than one of those boards in the system (up to 8Mb, it is the Zorro memory limit). Or three, in the case you have an A2091.

 The A2091 itslef only can carry up to 2Mb too, so the system of Richo have 4Mb of "not-so"-fast RAM.

[motrucker]

Are you sure this is a 2052 and not a 2058? The 2058 has J1 & J2 jumpers on it, but I seem to remember that the 2058 hold up to 8Mb.