johna@van-bc.UUCP (John Altstadt) (12/31/89)
Does anybody have any information on how to add 1 Meg chips to the
Aerco "easieST" solderless ram upgrade for a 520? The literature
that came with the board claimed that the board would hold up to
4 Meg, but neglected to state how the extra ram should be added to
the sockets provided. Since I could not afford the 1 Meg ram chips
when I bought the kit, I didn't bother finding out how it was done.
I tried the most obvious method of plugging the chips into the extra
sockets in the orientation implied by the dimple on the sockets
themselves. This resulted in the ram test program insisting that I
had 2.5 Meg, but I wound up with 3 partial images of everything on
the screen. The ram check program would crash with several bombs, the
number of bombs not repeatable. Just for the fun of it, I removed all
but one of the extra chips, and had exactly the same results. Now how
robust can the power-up memory check (not test) be if it will find ram
on the basis of one bit being set?
Any hints anybody? Do I have to toss the board (it was ~ $250 back in
1987) and buy a different one? For a little extra info, my ST has
sticker saying it was made in 7 1985.
Does Aerco still exist? They have not replied to a letter I sent
them on October 31 (I think that two months should be ample time
to reply).
John
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johna@wimsey.bc.ca || ...!ubc-cs!van-bc!johna
|| ...!uunet!van-bc!johnadclemans@mentor.com (Dave Clemans @ APD x1292) (01/04/90)
From article <131@van-bc.UUCP>, by johna@van-bc.UUCP (John Altstadt): > > Does anybody have any information on how to add 1 Meg chips to the > Aerco "easieST" solderless ram upgrade for a 520? The literature > that came with the board claimed that the board would hold up to > 4 Meg, but neglected to state how the extra ram should be added to > the sockets provided. Since I could not afford the 1 Meg ram chips > when I bought the kit, I didn't bother finding out how it was done. While the Aerco board can be upgraded to 4mb, it is NOT just a simple matter of swapping chips (at least for the early boards that this message talks about). There are a number of traces that have to be cut, jumpers that have to be added, resistors that have to be swapped, etc. The upgrade instructions were on the order of 10-20 pages. Note that the above doesn't apply for a 2.5 meg system; those were just chip swaps. To go to four megabytes, you have to cut traces/add jumpers to allow one of the memory banks to take 1mb chips (256kb chips and 1mb chips are not pin compatible; the Aerco board was shipped with one bank set up for 256kb chips, and the other bank set up for 1mb chips; to goto 4mb you have to rewire the bank that was set up for 256kb chips). dgc
johna@van-bc.UUCP (John Altstadt) (01/05/90)
In article <1990Jan3.220950.470@mentor.com> dclemans@mentor.com (Dave Clemans @ APD x1292) writes: +>From article <131@van-bc.UUCP>, by johna@van-bc.UUCP (John Altstadt): (that's me) +>> +>> Does anybody have any information on how to add 1 Meg chips to the +>> Aerco "easieST" solderless ram upgrade for a 520? The literature +>> that came with the board claimed that the board would hold up to +>> 4 Meg, but neglected to state how the extra ram should be added to +>> the sockets provided. +> +>While the Aerco board can be upgraded to 4mb, it is NOT just a simple +>matter of swapping chips (at least for the early boards that this +>message talks about). There are a number of traces that have to be +>cut, jumpers that have to be added, resistors that have to be swapped, +>etc. The upgrade instructions were on the order of 10-20 pages. +> +>Note that the above doesn't apply for a 2.5 meg system; those were +>just chip swaps. Almost that simple. > +>To go to four megabytes, you have to cut traces/add jumpers to allow +>one of the memory banks to take 1mb chips (256kb chips and 1mb chips +>are not pin compatible; the Aerco board was shipped with one bank +>set up for 256kb chips, and the other bank set up for 1mb chips; to +>goto 4mb you have to rewire the bank that was set up for 256kb chips). > +>dgc Ooops, I should have been just a little more specific... I was having problems upgrading to 2.5 meg. A little local help here let me know that upgrading to 2.5 meg requires pulling out the existing chips. I was under the impression that the 2.5 megs were all on the upgrade, not split between the upgrade and the main board. The package I bought contained the board (with 1/2 meg installed), a floppy with two ram test programs, a multi-page photocopy showing how the board was to be installed, and a 2.5 foot length of dental floss (to tie the board in place!!!). It did not contain any documentation on upgrading to 2.5 meg, any documentation on upgrading to 4 meg, or a lifetime subscription to PC Magazine. Since I now have 2.5 meg running, could anybody send me info on how to go all the way (or do I have to figure out which traces have to be cut and which jumpers have to be soldered in myself?). Last question: does Aerco still exist as a corporate presence? John -- johna@wimsey.bc.ca || ...!ubc-cs!van-bc!johna || ...!uunet!van-bc!johna