MAKE AMIGA 500 TO A500+

The beauty of retrocomputing is also SMANETTING, and being in possession of an A 500 REV 6A (one of the best A500 plates), I decided to take some time ...
 
If in fact it is quite easy to make the change to 1MB CHIP RAM on this card (find the article on this site), the almost total transformation towards a 500+ is a little less so.
 
In fact, the problem is not so much that of soldering or pulling wires, but that of finding compatible ICs; reason for this article ...
 
Having recovered a broken A500 + (the classic killer battery) at a low price, I decided to recover as much as possible, in order to transform my A500 REV 6A into a 500+.
First you change the OCS (DENISE) graphics chip with the latest ECS DENISE mounted on the 500+ (and also supported by AGNUS 8372A mounted in the REV6A), this turns out to be PIN to PIN compatible, so now the 500 is able to display the standard resolution 320x256 640x256 (OCS) and the SUPER HI-RES 1280x256 coming from the CHIPSET ECS of the 500+ (then we have the interlaced modes that double the vertical resolution).
 
Another thing you can change quickly (if you find it easy) is the 68010 PIN to PIN compatible with the 68000, slightly brighter and allows you to use some functions under whdload. Now comes the difficult, FAT AGNUS, Amiga chip that among other things is able to address up to 2MB of CHIP memory (it depends on the model), making it possible to use certain games or programs even on the 500!
 
 
As always asked in the various groups before changing CHIP of which you are not sure of the PIN to PIN compatibility and conflicting opinions forced me to do tests which later proved to be unsuccessful!
 
In fact 8375 (of the 500+) with P / N: 390544-01 typically mounted on Rev.8A plates, it is not compatible with the A500 REV6A board (which usually uses the 8372A P / N: 318069-XX). Decided to deepen this aspect, I then retrieved the documentation (which I am attaching) which shows what has just been described. Therefore, if you are also in the process of upgrading, please avoid using (and ruining) this CHIP that does not work on the REV 6A, but first read the attachment in this article.
 
The Shark!

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