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Amiga 1200 MB Revs & Accelerators Compatibility

Mo Retro

Posts 70
28 Jan 2017 13:54


Recently i was looking for A1200 Motherboard revisions and their compatibility with hardware.
I found out that in the past there was some problems with certain motherboard revisions and accelerators.
It seems that the revision 1D1 is the best and that 1D4 and 2B have timing issues with accelerators.

Eyetech wrote:

A1200 motherboard revision levels

When the A1200 was designed there were - as is common in designs of that complexity - some 'bugs' in the chip designs. Many of these were corrected by the time the main production runs started, but some were not, and in fact several bugs still remain in the latest revisions of the AA chip sets.

The main production board issued in the UK - Rev 1.D.1 - had onboard provision for hardware workarounds to fix the main bugs, notably bus timing problems in the Gayle and Budgie chips. In general these boards work fine with most combinations of expansion hardware and are the boards which we use to test A1200 expansion products on before shipment.

The later revisions of motherboards - particularly the revision 1.D.4 and 2.B are a different story however. These boards revisions were designed to take corrected versions of the Gayle and Budgie chips - and therefore were designed without provision for the earlier hardware workarounds. However, revised versions of the custom chips were never produced and as a consequence all but a few of the last of the AT/Escom manufactured motherboards were shipped without either bug-free chips or hardware workarounds.

In general these 1.D.4 & 2.B defects only make themselves felt when the A1200 is expanded by the addition of an '040 (or above) accelerator, high performance IDE hard drive/CDROM subsystems, Zorro slots or I/O expanders (PortPlus etc). Often any one such accessory will work, but two or more will not work in combination. Typical symptoms are an accelerator exhibiting instability problems, a graphics card failing to be recognised or a CDROM failing to show disk icons.


(See Eyetech document below)

Question to the Vampire Team regarding the Upcoming A1200 V2:
- Are the Vampire team aware of this problem.?
- How do you want to circumvent/solution the problem?

See the 2 links below that talk about the problem. One of them is a technical note of eyetech:

EXTERNAL LINK 
EXTERNAL LINK 


Roger Shimada

Posts 18
29 Jan 2017 00:08


Apparently certain A1200+accelerator combinations have timing signal integrity problems. A good place that describes this is EXTERNAL LINK 
I will wait (and hope) for the standalone system. (I do not own a 1200, so was blissfully ignorant of this potential problem.)


Mo Retro

Posts 70
29 Jan 2017 01:49


Roger Shimada wrote:

Apparently certain A1200+accelerator combinations have timing signal integrity problems. A good place that describes this is EXTERNAL LINK 
  I will wait (and hope) for the standalone system. (I do not own a 1200, so was blissfully ignorant of this potential problem.)

Thanks Roger,

So Ian Stedman's page gives more information about  the changes to make certain accelerators like ACA &  Apollo.
Hope the team finds a solution to circumvent the fysical modifications  on the A1200.
Imagine a couple of thousands A1200 users on move for some modifications.
The modifications for the ACA and Apollo-core.com cards are not completely the same.  So one cannot do a pre-emptive modification of his A1200  unless the Team does tests on all existing MBA revisions and share their findings soon enough with us.



John Heritage

Posts 89
31 Jan 2017 16:04


I had the timing fixes done on my A1200 because it also had other issues.  I was under the impression the timing fixes address a lot of issues with add-on cards or accelerators in general, so maybe this isn't a bad thing to do?

posts 4