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Old 09 November 2011, 20:38   #1
source
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16 Meg bridgeboard upgrade

I was wondering if anyone out there has tried the 16 meg upgrade for the 386sx bridgeboard that is available on aminet. I would like to increase the ram available, but I am not that technically inclined to do a board from schematics. as well there is a change needed with the eprom to allow the bridgeboard to address the extra mem.

Thanks in advance
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Old 10 November 2011, 03:09   #2
Magic
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It has been done. Be aware there is an error in the Aminet version of the 16 meg bios modification. Although I have the corrected version I am not clear if I have the right to redistribute. The daughter board has been tested in a small run and it does work. Good Luck.
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Old 10 November 2011, 04:05   #3
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Do you know how to get a PCB made? do you know if anyone has more of the pcbs? was this the pcb schematics from aminet v1.3?
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Old 17 November 2011, 10:41   #4
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I successfully did the mod many years ago. I got the EPROM file from the guy who developed it, forgotten his name unfortunately. I'll have to check to see if it is the same as the Aminet version.

For the hardware portion, I used an AmiFast II ZIP to SIMM converter made by ProvTech. This was intended to convert the A3000 from ZIP to SIMM, but it works just as well on an A2386. I doubt if they are still made.

I remember that the full 16MB was not available, presumably because of a clash with the 128KB of dual port RAM the Bridgeboard shares with the Amiga.

Last edited by A4000Bear; 09 December 2011 at 23:58.
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Old 02 December 2011, 07:38   #5
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do you have a picture of the amifast II zip converter. I just got one from ebay. I hope this one will work. if not I will use it in my A3000. This mod is getting outside of my comfort zone, but would like to have 16 megs. As for the eprom how do I go about making it. Thanks
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Old 09 December 2011, 23:57   #6
A4000Bear
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I don't have a pic, but I'm going to pull apart my A4000 that has the Bridgeboard installed later this weekend, so I can take a pic of it then.

The original Amifast was a single large board, which can be seen here: http://amiga.resource.cx/exp/amifast
I really doubt if this will work on a Bridgeboard.

The Amifast II was a pair of small circuit boards each with a single 72pin SIMM socket. You only need one for the Bridgeboard, using a 16MB non-EDO SIMM. If I remember correctly, I had to add a wire from the AmifastII to the Bridgeboard, it was an extra address line for 16MB total.

You need a 27512 EPROM, and an EPROM programmer to 'burn' the 16MB Bridgeboard BIOS. If you don't have a programmer, you may be able to get someone to do it for you.
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Old 11 December 2011, 01:17   #7
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Thanks. i just purchased the amifast with 16 megs on board on ebay. I was hoping that it would work, but I was reserved. this will allow me to free up some zips I have and either attempt to get my other bridgeboard up and working. or can use the zips in a mem expansion for the A500. Do you still have 1 board left over? would you be willing to part with it if you do?
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Old 12 January 2015, 16:04   #8
superbonio
 
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Does anyone know where exactly, and where there is an error in the modification of the BIOS?
Or maybe you have someone ready to program EPROM file?
That fight with this BB A2386SX and maximally I get 8MB, after modifying the BIOS from Aminet, BB card does not start.
Please help, can somebody spreading ready, modified the ROM file.

Last edited by superbonio; 14 January 2015 at 18:00.
 
Old 13 July 2015, 04:52   #9
Magic
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I worked with Jordan Krim on the A2386 16 meg hack back in the comp.sys.amiga.hardware days He fixed the errors in the Bios image and sent it to me years ago. I just found it again going through some older stuff. I hope it works for you! I am about to finish mine.

Modified Bios is now in the Zone
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Old 13 July 2015, 07:01   #10
Calabazam
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Thanks for zoning this. You must upload it to Aminet too!
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