Welcome, Guest. Please login or register.

Author Topic: Amiga 500 Revisions 4 & 5  (Read 3954 times)

Description:

0 Members and 1 Guest are viewing this topic.

Offline fordpTopic starter

  • Jr. Member
  • **
  • Join Date: May 2011
  • Posts: 51
    • Show only replies by fordp
Amiga 500 Revisions 4 & 5
« on: May 29, 2011, 01:44:27 AM »
So I'm doing some archaeology with my collection, and have noted a couple perhaps not surprising oddities with my hardware.

Firstly  I have a Rev 4 mainboard, and I haven't found any information about  this particular revision anywhere. It claims to be a 'W.C. Build' from  March 1987, and has what I'll refer to as 'high quality' RCA   connectors. That is they are color coded Red/White/Yellow with a plastic  insert, as opposed to the cheaper looking rust colored inserts on most  of my other machines. This is currently sitting in a standard A500 case  w/standard keyboard, but those may not be original.

Secondly I have two Rev 5 machines, based on pictures at BBOAH both appear to be the 'Type 4' mainboards.

If  my suspicion that the silk screened label reading '1298A    23--87'  refers to a manufacturing date, than the older of these machines also  has the same high quality RCA connectors as above, but also has a  keyboard with a a C= key in place of the left Amiga key, and the C= logo  is part of the case casting, as opposed to a sticker on my other  machines. This machines also has a metal cross bar running diagonally  across the Agnus socket, and the top shielding was not made with a  removable section over the CPU as in later machines. Finally this  machine has the number 24 hand written on the yellow serial number  sticker.

The newer machine, i.e. '1298A    19--88', has the lower  quality RCA jacks, No cross bar on the Agnus, and the more common  keyboard and case. The shielding in this case has a removable section  over the CPU.

I'm not particularly interested in the 'newer'  Rev5, as it meets all my expectations and memory of what a Rev5 A500  looks like, the older one is a different matter. My original plan was to  use the Rev5 machines as parts for my workhorse Rev6a, but now I'm having second thoughts, at  least for the 'older' machine.

As for the Rev4 mainboard. I can't find any information on it, perhaps some one out there has some.
 

Offline platatomi

  • Newbie
  • *
  • Join Date: Nov 2011
  • Posts: 6
    • Show only replies by platatomi
Re: Amiga 500 Revisions 4 & 5
« Reply #1 on: November 30, 2011, 04:23:27 AM »
I have the same board, the mysterious rev 4. I cannot find any info about it what so ever. Any info is welcome. If anybody needs pics, let me know.
 

Offline freqmax

  • Hero Member
  • *****
  • Join Date: Mar 2006
  • Posts: 2179
    • Show only replies by freqmax
Re: Amiga 500 Revisions 4 & 5
« Reply #2 on: November 30, 2011, 11:27:05 AM »
Could you photo document these differences in:
 * RCA jacks
 * C= / Amiga key
 * Agnus socket
 * CPU socket

 ..?
 

Offline Pentad

Re: Amiga 500 Revisions 4 & 5
« Reply #3 on: November 30, 2011, 12:35:22 PM »
I have another mystery/story for you about that motherboard.

Back in the late summer of 1987 a Commodore rep and a EA rep showed up with the new Amiga 500 computer (the ones with the Commodore and Amiga keys instead of the later Amiga - Amiga keys)  at our local computer store that sold Amiga computers.  The store was fairly large and did much business so I could see why Commodore and EA would demo the new Amiga 500 here.  

Users Groups from around the area and regular customers were all here to see the new Amiga 500.

They showed it off and it was quite different from the Amiga 1000.  I was 17 at the time but my first thought was of Kickstart.  Since it was in ROM how would older software run under Kickstart 1.2 and what about future revisions of Kickstart?  

I posed my questions and mentioned that I did not think EA's Archon would run under Kickstart 1.2.  (It might have been another EA game, it has been a long time...)

Here is where is gets weird, ready?

Without missing a beat the Commodore guy and the EA guy mention you can hold down the Control - Commodore - Amiga keys to have the computer prompt for a Kickstart disk.  The EA guy even mentions that they were worried about older software under Kickstart 1.2 so this option gives the customer backwards compatibility.

All eyes watch the monitor for the Kickstart hand.  At that moment, I thought it was a great option that Commodore came up with.

Well, nothing happened.  

The Commodore guy didn't really say much but the EA seemed genuinely shocked that it didn't work.  He eventually calls EA from the store to ask about this feature.  He talks with some folks and then tells us he will get back with us when the machine ships.

Of course this feature never materilizes.

I believe this feature must have been talked about at some point during the Amiga 500 development since both of these guys were so quick to talk about Control Commodore Amiga.

Further, EA (as well as others) would have something to gain with this feature.  Any compatibility issues with new revs of Kickstart could be easily fixed by having the customer boot into an older Kickstart.

We all know now there is not way that could work given the design of the motherboard.  However, I would have liked to talk with either Haynie or Herd about this story.  I do not think the EA and Commodore reps would just lie about this feature since we could obviously test it on the computer in front of us and they genuinely seemed sincere with their answer.

Cheers!
-P
Linux User (Arch & OpenSUSE TW) - WinUAE via WINE
 

Offline freqmax

  • Hero Member
  • *****
  • Join Date: Mar 2006
  • Posts: 2179
    • Show only replies by freqmax
Re: Amiga 500 Revisions 4 & 5
« Reply #4 on: November 30, 2011, 01:44:37 PM »
It's all about RAM. No RAM no floppy-kickstart. More RAM => more price.

Thus function not implemented since A500 is a budget solution.

The only catch is if the function was prepared in ROM.. IF the adequate RAM was installed?
 

Offline Ral-Clan

  • Hero Member
  • *****
  • Join Date: Feb 2006
  • Posts: 1974
  • Country: ca
    • Show only replies by Ral-Clan
    • http://www3.sympatico.ca/clarke-santin/
Re: Amiga 500 Revisions 4 & 5
« Reply #5 on: November 30, 2011, 02:23:44 PM »
There are instructions for upgrading a revision 4 Amiga 500 motherboard here:

http://www.fortunecity.com/skyscraper/capacity/457/jsptech3.html

Just do a text search for the phrase "FOR AMIGA 500 MOTHERBOARD REVISION 4 & 5" in the website.

Oh, and in case anyone hasn't mentioned it, I would guess that "W.C. build" refers to "West Chester build" (the location of Commodore's USA branch).
« Last Edit: November 30, 2011, 02:26:06 PM by ral-clan »
Music I've made using Amigas and other retro-instruments: http://theovoids.bandcamp.com
 

Offline platatomi

  • Newbie
  • *
  • Join Date: Nov 2011
  • Posts: 6
    • Show only replies by platatomi
Re: Amiga 500 Revisions 4 & 5
« Reply #6 on: December 01, 2011, 04:48:27 PM »
For some photos of my board, check out my thread on EAB: http://eab.abime.net/showthread.php?t=62063

These pics above are severely limited in resolution so I will zip up the hires originals and give a link to download in a minute.


As for the other stickers on my board, one of which says "Pass Wrap 2", is this referring to a wire wrap?

This board is soldered and not wrapped so this doesn't make much sense. Perhaps this means this board is a working copy of wrap #2? Any ideas?
 

Offline platatomi

  • Newbie
  • *
  • Join Date: Nov 2011
  • Posts: 6
    • Show only replies by platatomi
Re: Amiga 500 Revisions 4 & 5
« Reply #7 on: December 01, 2011, 05:13:09 PM »
Here are the hi-res pics if anyone wants them:

http://overhackit.com/A500%20rev%204%20pics.zip