[Coco] CoCo 2 problem

[Chad H]

I was kinda leaning towards "failed ram" as the most likely culprit.
Unfortunatley, with this particular board, almost all chips are soldered in
place.  While I can solder 'OK' sometimes, I wouldn't want to risk damaging
the board or making a mess by taking a crack at it myself.  I'm wondering
how expensive it would be have someone replace the RAM chips with socks,
maybe even the soldered 6809 as well.  Would like to get it back to full
operation if is not overly expensive.

A photo of the board is here... http://www.mediafire.com/?12hf7zus7ebl49x

Would anyone be interested in such a soldering task?

- Chad

-----Original Message-----
From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] On
Behalf Of Michael Graham
Sent: Thursday, August 04, 2011 7:38 PM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] CoCo 2 problem

I had a similar problem with my CoCo 3 once, and re-seating the RAM 
chips fixed it.  I can't remember whether the RAM is socketed in any of 
the CoCo 2 models - If it is, try re-seating it, if it isn't, it could 
be one or more of your RAM chips has microfractures in it, which are 
causing the chip to fail as the casing expands from the heat produced by 
operation.

Don't take me as an expert on this though, I'm only speaking from two 
experiences I've had with this kind of thing - Once with my CoCo 3, and 
once with my TI-99/4a (the latter actually had all of its RAM chips 
fail). The microfracture thing is a theory I read from someone else.

On 8/4/2011 7:30 PM, Chad H wrote:
> Ok, I just acquired a new CoCo 2 unit (26-3127B) of unknown condition.
The
> unit looks immaculate inside and out, I had good hopes.  It did operate
> great for about 5 minutes then started acting funny with disk access.  I
> turned off the computer and rebooted and would either get garbage (columns
> of funny text characters) or a good boot screen (Microware copyright
> statement with "OK") but there is no flashing cursor.  Anyone ever see
this
> behavior before or know what it probably is?
>
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco

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