[Coco] Bad memory reported by Disto Coco III RAM Test by Tony Distefano
computerdoc at sc.rr.com
Thu Nov 17 01:52:41 EST 2016
I am so glad you figured out what the problem was. Whew! That was an easy fix.
computerdoc at sc.rr.com
> -----Original Message-----
> From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Michael R. Furman
> Sent: Thursday, November 17, 2016 1:47 AM
> To: coco at maltedmedia.com
> Subject: Re: [Coco] Bad memory reported by Disto Coco III RAM Test by Tony Distefano
> Thanks Kip, Richard, and Gene.
> I figured out what the problem was.
> I was using a brand new CocoSDC and it has a a jumper to connect the CART line to Q so you can use it to autostart ROM images in it’s
> onboard flash. Well when I opened up the CoCoSDC package the jumper fell out on the floor and I absently found a place to connect
> it to without thinking and it wound up in the AUTO position. The CoCoSDC manual clearly says not to do this to use SDC DOS. Oops.
> Michael R. Furman
> Email: n6il at ocs.net
> Phone: +1 (408) 480-5865
> > On Nov 16, 2016, at 9:37 PM, Richard Goedeken <Richard at fascinationsoftware.com> wrote:
> > I would suggest running my RAM test program:
> > http://www.fascinationsoftware.com/media/Coco3_RAM_Test_v1.2.zip
> > It will run continuously and print multiple errors, and give you the
> > values written and read back, so you may see a pattern.
> > Richard
> > On 11/16/2016 09:25 AM, Kip Koon wrote:
> >> Hi Michael,
> >> Whenever a 512KB memory upgrade is installed in the Coco 3, the original 4 memory chips are removed and C65 & C66 are
> removed by cutting one leg and lifting up on the cap slightly. That's the procedure I used when I added my 512KB memory board to
> my Coco 3. That upgraded Coco 3 is still running strong.
> >> As to the 8K address range that is bad, if an address line is truly bad, that 8K block would be bad everywhere, not just in one place I
> would think. Maybe there is a logic problem somewhere maybe?
> >> Can anyone shed more light on this situation?
> >> Kip Koon
> >> computerdoc at sc.rr.com
> >> http://www.cocopedia.com/wiki/index.php/Kip_Koon
> >>> -----Original Message-----
> >>> From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of
> >>> Michael R. Furman
> >>> Sent: Wednesday, November 16, 2016 11:37 AM
> >>> To: coco at maltedmedia.com
> >>> Subject: [Coco] Bad memory reported by Disto Coco III RAM Test by
> >>> Tony Distefano
> >>> Does anyone have a manual for the Disto Coco III RAM Test by Tony Distefano?
> >>> http://www.colorcomputerarchive.com/coco/Disks/Utilities/Disto%20Coc
> >>> o%203%20RAM%20Test%20%28Tony%20Distefano%29%2
> >>> 0%28Coco%203%29.zip
> >>> I ran it on one of my Coco 3’s and it is returning an error, says
> >>> that block 60 is bad, which I interpret to be 0x78000 to 0x79FFF
> >>> A second observation is that when loading certain programs in to
> >>> BASIC from the CocoSDC those programs get corrupted at the same place every time.
> >>> I was looking at the schematics to try to figure this out and I am a
> >>> bit confused. What I see on the schematic is each of the 256k x 1
> >>> chips on the 512 ram expansion board is attached to one data line
> >>> and there are two sets of chips selected by WE0 or WE1. The part I
> >>> am confused about is what it means that a particular range of memory is bad. If one data bit is bad across the entire 256k range I
> understand that one, that’s a bad chip. But it only seems to be bad in a particular 8k range of addresses, so maybe this is some issue
> with RAS or CAS or a flakey address line to only the WE1 set of chips?
> >>> What would happen if C65 or C66 still in place? Why do they have those RC filters on RAS and CAS anyway?
> Coco mailing list
> Coco at maltedmedia.com
More information about the Coco