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AuthorTopic: Amiga 500 rev 7, why it is from 1988?  (Read 580 times)

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Offline utri007

Amiga 500 rev 7, why it is from 1988?
« on: October 06, 2021, 06:15:29 PM »
Hello,

here is rare rev7 Amiga 500 motherboard. It is manufactured 1988, when there was still rev 5 and rev 6 motherboards on sale.

Rev 6 was sole for something like 1990, so does anyone know why rev 7 is from 1988 and was it pulled back?

https://1drv.ms/u/s!AsdbQ2CKZfHPhLh5y82Gk2w3_Zp8aA
ACube Sam 440ep Flex 800mhz, 1gb ram and 240gb hd and OS4.1FE
A1200 Micronic tower, OS3.9, Apollo 060 66mhz, xPert Merlin, Delfina Lite and Micronic Scandy, 500Gb hd, 66mb ram, DVD-burner and WLAN.
A1200 desktop, OS3.9, Blizzard 060 66mhz, 66mb ram, Ide Fix Express with 160Gb HD and WLAN
A500 OS2.1, GVP+HD8 with 4mb ram, 1mb chip ram and 4gb HD
Commodore CDTV KS3.1, 1mb chip, 4mb fast ram and IDE HD
 

Offline Matt_H

Re: Amiga 500 rev 7, why it is from 1988?
« Reply #1 on: October 07, 2021, 02:36:42 AM »
I can only guess at the possible reasons why:
1. There were problems with rev 7 so they stopped making them and rolled back to an older version. I’m sure that chip tower near the trap door added costs that Commodore didn’t want to have to pay…
2. Only certain factories were producing rev 7 while most of the others stayed on older revs.
3. Given how Commodore’s various international marketing divisions had to place orders with HQ, maybe most countries didn’t want rev 7 machines. (Just like how no divisions ordered the finished A2200.) Maybe they didn’t want to have to provide post-sale support/service for another variant.

As to the strange matter of rev 7 being older than expected, another possibility that I wonder about is that rev 6 was an internal version that was never released, like the rev 5 A2000. The next version was 7, they pulled that one from distribution, then created rev 6A, a fork from rev 6 instead of fixing/iterating rev 7.

Offline psxphill

Re: Amiga 500 rev 7, why it is from 1988?
« Reply #2 on: October 07, 2021, 12:23:14 PM »
6a & 7 share the same schematics....

https://archive.org/details/system-schematics-a-500-revisions-5-6a-7/page/12/mode/2up

So I'm not sure what the difference actually is...
 

Offline Matt_H

Re: Amiga 500 rev 7, why it is from 1988?
« Reply #3 on: October 07, 2021, 05:17:14 PM »
6a & 7 share the same schematics....

https://archive.org/details/system-schematics-a-500-revisions-5-6a-7/page/12/mode/2up

So I'm not sure what the difference actually is...

Judging by the part number (314981-02), that seems to be a revised version of the schematics. I wonder if 314981-01 would more clearly delineate differences between 6A and 7. i.e., the differences were so minor they didn't even bother to describe them in the revised printing.

A tiny circuit pathway layout change? Something not significant enough to require a different schematic.

Could rev 7 have been pre-jumpered to use 1MB Chip instead of 512K Chip / 512K Slow? I could imagine Commodore trying something like that and then pulling back.

@ utri007

Are you the original owner of the machine with this board? What country did you buy it in?
 

Offline utri007

Re: Amiga 500 rev 7, why it is from 1988?
« Reply #4 on: October 07, 2021, 05:33:05 PM »
I'm not a original owner, but 1mb chip mod is made by me. Case and mobo s# doesn't match.

This is NTSC machine and I have not idee how it ended up to here Finland.

ACube Sam 440ep Flex 800mhz, 1gb ram and 240gb hd and OS4.1FE
A1200 Micronic tower, OS3.9, Apollo 060 66mhz, xPert Merlin, Delfina Lite and Micronic Scandy, 500Gb hd, 66mb ram, DVD-burner and WLAN.
A1200 desktop, OS3.9, Blizzard 060 66mhz, 66mb ram, Ide Fix Express with 160Gb HD and WLAN
A500 OS2.1, GVP+HD8 with 4mb ram, 1mb chip ram and 4gb HD
Commodore CDTV KS3.1, 1mb chip, 4mb fast ram and IDE HD
 

Offline psxphill

Re: Amiga 500 rev 7, why it is from 1988?
« Reply #5 on: October 08, 2021, 01:40:46 PM »
Could rev 7 have been pre-jumpered to use 1MB Chip instead of 512K Chip / 512K Slow? I could imagine Commodore trying something like that and then pulling back.

It kinda reminds of the time they assigned an agnus chip the wrong number for the pin out they used.

It's commodore, they might have had an argument over what to call it and sent the wrong artwork.

The other option is slightly different for some part commodore thought they could get cheaper, then didn't.
« Last Edit: October 08, 2021, 01:44:49 PM by psxphill »