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Home » Products » Trade/Sell/Wanted » [WANTED] Cheap ROM 1 Chip
icon5.gif  [WANTED] Cheap ROM 1 Chip [message #85] Fri, 26 June 2015 07:12 Go to next message
nutcase84 is currently offline  nutcase84
Messages: 2
Registered: June 2015
Poster
I have a ROM 0 IIGS, and nothing runs on it since it's ROM 0. I'm looking for a cheap (about $10 USD) ROM 1 chip, or a way to make one. I contacted a online Apple II store and they said it would cost $40. A bit too high for me. Thanks!
Re: [WANTED] Cheap ROM 1 Chip [message #86 is a reply to message #85] Fri, 24 July 2015 12:17 Go to previous messageGo to next message
Dagen is currently offline  Dagen
Messages: 27
Registered: August 2014
Location: United States
Member

Great question. I asked around and some people thought the 271001 would work. Here's some info on that chip, http://www.digchip.com/datasheets/parts/datasheet/000/271001.php

Here are some various sources around $5 a piece for most. https://octopart.com/m27c1001-15f1-stmicroelectronics-55830769

Let us know if you get one and are able to use it.
Re: [WANTED] Cheap ROM 1 Chip [message #87 is a reply to message #86] Fri, 24 July 2015 14:29 Go to previous messageGo to next message
nutcase84 is currently offline  nutcase84
Messages: 2
Registered: June 2015
Poster
How would I program it?
Re: [WANTED] Cheap ROM 1 Chip [message #88 is a reply to message #87] Fri, 24 July 2015 15:50 Go to previous messageGo to next message
Dagen is currently offline  Dagen
Messages: 27
Registered: August 2014
Location: United States
Member

Ah sorry, I was thinking about it from a different angle... my own desire to burn new ROM firmware.

You are looking for pre-programmed ROMs, right? I think it's so high in cost because those would have to come from recycled systems. There's not a lot floating around like that.

Also, if you were to use the programming method above, you could use pretty much any cheapo ROM burner ($50 or less). But if you don't already have one, that means you'd end up paying a lot more than just purchasing that ROM for $40.

Also, since the IIgs uses mask ROMs (comes pre-programmed by the manufacturer), they don't have the programming pins. This means you'd need to make an adapter to put the (E)EPROM in your IIgs socket , so it's a bit more complicated than just dropping in a replacement ROM. For completeness' sake, here's the adapter layout for that chip. http://www.appleii-box.de/APPLEIIGS/iigsreplacementrom0.htm


I'm posting a copy of that image here so it doesn't get lost if that site goes down, but all credit to that site for the image.
Re: [WANTED] Cheap ROM 1 Chip [message #99 is a reply to message #85] Tue, 19 April 2016 19:59 Go to previous message
damauk is currently offline  damauk
Messages: 5
Registered: April 2016
Location: Riverton, WY
Contributor
I know this thread is old but there are now two options, both cost around $30:

https://www.ultimateapple2.com/catalogzen154/index.php?main_ page=product_info&cPath=1_17&products_id=99

http://a2heaven.com/webshop/index.php?rt=product/product& ;product_id=137
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