Amiga.org
Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: spaceman88 on September 26, 2016, 09:25:05 PM
-
I bought a 3.1 ROM on EBay for my A500 (Rev. 5, 1 meg chip RAM). My 1.3 chip has 40 pins the new one has 42, I THINK the seller says to leave pins 1 and 42 disconnected in this case (I say "think" because I emailed him twice with no results). Of course it doesn't work. Is there something else I'm supposed to do? Thanks.
-
Here is a pic of the rom, if you look carefully at the picture you will see in front of the ROM that there is 2 pins empty.
-
Here is a pic of the rom, if you look carefully at the picture you will see in front of the ROM that there is 2 pins empty.
That is a picture of an a600 motherboard, they either have 40 pin or 42 pin sockets. I can't tell from that angle as there are too many optical illusions going on with the lighting and the angle. Here is a less insane picture http://www.bigbookofamigahardware.com/bboah/media/download_photos/a600mb_rev15_2.jpg
This is a rev 5 a500 http://www.bigbookofamigahardware.com/bboah/media/download_photos/a500mb_rev5_3.jpg, which only has a 40 pin socket (the a500+ has a 42 pin socket).
Normally you would only use 42 pin sockets for 1mb kickstart roms (i.e. 3.9 etc), 2 extra pins means there is up to 4 times the capacity. If he programmed each part of the rom with the same contents then you may get away with leaving the extra pins floating (1mb rom would need two copies, 2mb rom would need 4 copies). I'd personally bend the extra pins up and solder a wire to ground to avoid any doubt.
I believe the extra pins that don't go into the socket are the ones at the end with the notch, because when you go the other way and put a 40 pin rom into a 42 pin socket then these are the pins that are empty.
-
That is a picture of an a600 motherboard, they either have 40 pin or 42 pin sockets. I can't tell from that angle as there are too many optical illusions going on with the lighting and the angle.
Really? I got it from Amigakits website, here is the link. http://amigakit.leamancomputing.com/catalog/product_info.php?products_id=157
-
Really? I got it from Amigakits website, here is the link. http://amigakit.leamancomputing.com/catalog/product_info.php?products_id=157
Yes really, next to the rom is a square surface mount 68000. You won't find one of those anywhere but an a600.
I could only count 19 pins on the rom due to the lighting and angle, which makes it hard to tell what is going on. They may have stuck a sticker on a random 38 pin chip for the photograph, but it could also be that it's screwing with my eyes.
However the 2d sticker on their picture is a bit of a give away as it's obviously a 2d A600 and those have 42 pin sockets but only shipped with 40 pin roms. http://www.bigbookofamigahardware.com/bboah/media/download_photos/a600mb_rev2d_2.jpg
If you have a 42 pin rom and a 40 pin socket and the two halves (or four quarters) aren't identical then you'll need to wire up the extra pins to gary or the 68000.
-
I could only count 19 pins on the rom due to the lighting and angle, which makes it hard to tell what is going on. They may have stuck a sticker on a random 38 pin chip for the photograph, but it could also be that it's screwing with my eyes.
Must be a difference of your monitor. His picture was clearly identifiable for me, on my phone and on my computer. Either way, it's still good information. :)
Edit, just re-read the question. OP, are you saying your chip has 42 pins and your socket only has 40 pins? IMHO I'd just buy the proper ROM from AmigaKit, they're available new for <$20 USD.
-
Must be a difference of your monitor. His picture was clearly identifiable for me, on my phone and on my computer. Either way, it's still good information. :)
Ok, edit the picture and number the pins & upload it somewhere :-) I dotted them in paint as the pins and spaces between them turn into an escher style puzzle, what I thought might be pins furthest away from the camera don't look as if they would fit into the socket.
-
That is a picture of an a600 motherboard, they either have 40 pin or 42 pin sockets. I can't tell from that angle as there are too many optical illusions going on with the lighting and the angle. Here is a less insane picture http://www.bigbookofamigahardware.com/bboah/media/download_photos/a600mb_rev15_2.jpg
This is a rev 5 a500 http://www.bigbookofamigahardware.com/bboah/media/download_photos/a500mb_rev5_3.jpg, which only has a 40 pin socket (the a500+ has a 42 pin socket).
Normally you would only use 42 pin sockets for 1mb kickstart roms (i.e. 3.9 etc), 2 extra pins means there is up to 4 times the capacity. If he programmed each part of the rom with the same contents then you may get away with leaving the extra pins floating (1mb rom would need two copies, 2mb rom would need 4 copies). I'd personally bend the extra pins up and solder a wire to ground to avoid any doubt.
I believe the extra pins that don't go into the socket are the ones at the end with the notch, because when you go the other way and put a 40 pin rom into a 42 pin socket then these are the pins that are empty.
That's the way I installed it, with pins 1 & 42 (by the notch) hanging over the end. It's supposed to be a regular 3.1 (licensed from Cloanto). I didn't think of AmigaKit at the time!
Mike- Yes socket 40 pins- 1.3 ROM 40 pins - 3.1 ROM 42 pins
-
That's the way I installed it, with pins 1 & 42 (by the notch) hanging over the end. It's supposed to be a regular 3.1 (licensed from Cloanto). I didn't think of AmigaKit at the time!
Mike- Yes socket 40 pins- 1.3 ROM 40 pins - 3.1 ROM 42 pins
You say Cloanto. Is it a standard 3.1 ROM or the special Cloanto "3.X" ROM? If it's a 3.X, you may have it installed properly, but have myriad completely unrelated problems because of the changes they made in it (http://www.amiga-news.de/en/news/AN-2015-10-00068-EN.html). :(
What color is your screen when you try to boot with the ROM installed? Any clicks from the floppy drive, does the power light go bright or stay dim, stuff like that?
-
This info does not address your problem but it might address the not working.
https://web.archive.org/web/19980524103433/http://www.softhut.com/31500.html
-
You say Cloanto. Is it a standard 3.1 ROM or the special Cloanto "3.X" ROM? If it's a 3.X, you may have it installed properly, but have myriad completely unrelated problems because of the changes they made in it (http://www.amiga-news.de/en/news/AN-2015-10-00068-EN.html). :(
What color is your screen when you try to boot with the ROM installed? Any clicks from the floppy drive, does the power light go bright or stay dim, stuff like that?
This is the EBay link... http://www.ebay.ca/itm/152218201029?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
I'm using a Dell monitor which takes a few seconds to show a screen then goes black, but I think I saw a pink flash before it went black. No floppy click, not sure about the light. If I put 1.3 back in the 1.3 "hand" comes back.
Amiwest- Very interesting link, would have been nice for the seller to share this info. Would be nice for him to answer my Emails!!
-
Interesting that the picture in the auction shows a standard 40-pin chip. Of course everyone uses stock photographs not photos of the actual product, so that's not really anything to go by... :(
IMHO if a seller won't respond to messages after a reasonable period of time it's some kind of scam.
-
I should given a different link which gives a lot more info for updating.
https://web.archive.org/web/19980524102616/http://www.softhut.com/faqs.html
I should also mention our SACC links page.
http://www.sacc.org/index-a.html also http://www.sacc.org/amiwest/ for the Amiwest show
-
This info does not address your problem but it might address the not working.
https://web.archive.org/web/19980524103433/http://www.softhut.com/31500.html
Yes, I forgot that a rev 5 a500 motherboard will also need the standard pin 1 to 31 3.1 strap.
A small piece of wire wrapped around the pins at each end will probably work. Although soldering would be better, but I'd still bend the extra pins up and ground them.
-
Just a quick update... After 3 emails to the seller, no response. Great customer service! I didn't want to solder the jumpers on the chip in case it didn't work and the seller claims I "damaged" it. I took apart my A2500 which has 3.1 and found an Escom 40 pin ROM chip, I removed it and put the 42 pin EBay chip in the 2500 and it worked. So I kept the Escom chip for the 500 and ordered a socket so I could do the soldering on it instead of the ROM chip in case I swap things around again :-). Thanks to everyone for the links and info about jumpers.
-
and ordered a socket so I could do the soldering on it instead of the ROM chip in case I swap things around again :-)
You can also just solder a wire on the bottom side of the a500 motherboard. You need to be careful plugging sockets into other sockets as depending on which one you order, you could damage the motherboard socket.