User avatar
JYakapucci

Posted Mon Dec 13, 2021 1:35 pm

I managed to pick up a nice Amiga 500 package for what I think is a very good price. However, being a total newb to the Amiga scene (my only other Commodore was a 64 back around 1990) I have some questions.

The package that I got was the 500, a 1080 monitor, 570 CD drive and an external floppy (can't remember the model).

Upon getting it home, I noticed that the warranty stickers had been removed so I opened it to see what had been done already. It is a Rev 6A board and has the A501 module (which I am going to open and check the caps on) as well as some type of ROM switch. The guy I bought it from mentioned something about pressing keys on start up to change the ROM, but it was his father's computer and this is about the limit of the knowledge. Is anyone familiar with this version of board and can point me to any documentation so I know how to use it and what all the jumpers are for?

Thanks in advance for any help that anyone can provide.
ROM-Switch-scaled.jpg

User avatar
rpiguy9907

Posted Mon Dec 13, 2021 1:52 pm

JYakapucci wrote:
Mon Dec 13, 2021 1:35 pm
I managed to pick up a nice Amiga 500 package for what I think is a very good price. However, being a total newb to the Amiga scene (my only other Commodore was a 64 back around 1990) I have some questions.

The package that I got was the 500, a 1080 monitor, 570 CD drive and an external floppy (can't remember the model).

Upon getting it home, I noticed that the warranty stickers had been removed so I opened it to see what had been done already. It is a Rev 6A board and has the A501 module (which I am going to open and check the caps on) as well as some type of ROM switch. The guy I bought it from mentioned something about pressing keys on start up to change the ROM, but it was his father's computer and this is about the limit of the knowledge. Is anyone familiar with this version of board and can point me to any documentation so I know how to use it and what all the jumpers are for?

Thanks in advance for any help that anyone can provide.
Looks like a Switch-It, or clone. The key combination and more information is located here:

https://bigbookofamigahardware.com/bboa ... spx?id=687

User avatar
JYakapucci

Posted Mon Dec 13, 2021 1:54 pm

rpiguy9907 wrote:
Mon Dec 13, 2021 1:52 pm


Looks like a Switch-It, or clone. The key combination and more information is located here:

https://bigbookofamigahardware.com/bboa ... spx?id=687
Super. Thanks much.

User avatar
Zippy Zapp
CA, USA

Posted Mon Dec 13, 2021 7:16 pm

Really cool. I have never seen a 2.04 ROM exactly like that one. Credit Card? Interesting.
It is a Rev 6A board and has the A501 module (which I am going to open and check the caps on)
It probably has the original Varta barrel clock battery which is way more dangerous than the caps. I have seen them leak and corrode the connector on the A500 and nearby vias. Those batteries are evil. ;)

User avatar
JYakapucci

Posted Tue Dec 14, 2021 7:59 am

Zippy Zapp wrote:
Mon Dec 13, 2021 7:16 pm
Really cool. I have never seen a 2.04 ROM exactly like that one. Credit Card? Interesting.
It is a Rev 6A board and has the A501 module (which I am going to open and check the caps on)
It probably has the original Varta barrel clock battery which is way more dangerous than the caps. I have seen them leak and corrode the connector on the A500 and nearby vias. Those batteries are evil. ;)
Yeah, I meant the battery. I am not sure where my heavy duty soldering iron is so that I can open the case, but by shining a flashlight in the end, I can see a small amount of leakage on one end.

User avatar
Zippy Zapp
CA, USA

Posted Tue Dec 14, 2021 12:24 pm

Hopefully it isn't too bad. If the A500 connector is green then it's bad.

User avatar
JYakapucci

Posted Tue Dec 14, 2021 5:42 pm

Looks like the damage isn't too bad.
Attachments
Battery.jpg

User avatar
intric8
Seattle, WA, USA

Posted Tue Dec 14, 2021 6:44 pm

Boy, I dunno man. But you should be able to clean a lot of the crud off of there (starting with vinegar and/or lemon juice, isopropyl to clean everything off) and squeeze more life out of that board if it's still functional.

But I bet if you go back and look at it again in a year, some of that acid will have magically returned. It's alien blood and acts almost like a virus in that they aren't alive but seem to share some of the properties of life.

The really annoying thing about that stuff is while it looks like a localized problem, I've seen cases where tiny almost invisible specs of the stuff will go airborne and drift several inches away, land on something else, and start to go to town. Had that happen to a single pin on an Agnus socket once. I had no idea until the day I removed the Agnus and saw a piece of metal fall off the socket. Put on my jeweler's glasses and couldn't believe what I saw.

User avatar
obitus1990
USA

Posted Wed Dec 15, 2021 7:18 am

Looks like a pretty simple fix. Remove battery, clean as described above, sand away the solder mask until you hit clean copper (using something like a fiberglass pencil), desolder the other affected components and replace them, then recoat the area with clear nail polish. If there are any busted traces, repair them with jumper wires.

User avatar
JYakapucci

Posted Wed Dec 15, 2021 9:43 am

I got the battery off and started the clean up. Doesn't look like it will be too bad. Then again, I haven't done any board work for years. One thing that I find curious is the damage to R913. It looks like the coating on the resistor is ripped. I believe that the board was still functional since the guy that I bought it from said that he had to go through the floppies that he had on hand to make sure that there was no personal info on them before delivery.
Attachments
Damage-scaled.jpg





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