[Coco] CoCo repair-upgrade

Arthur Flexser flexser at fiu.edu
Mon Sep 26 00:02:39 EDT 2011

As far as your receiver goes, I think it's a safe bet that you had a
cold solder joint that was fixed by your resoldering.


On Sun, Sep 25, 2011 at 11:46 PM, Chad H <chadbh74 at hotmail.com> wrote:
> Ok a few months ago I had a bad CoCo 2 I had to learn to de-solder the CPU
> and solder in socket for new one.  Had such success with it I went ahead and
> unsoldered the RAM and soldered in sockets, re-using the existing ram.  Went
> ahead and did this to couple more CoCo's and feel relieved at how easy it
> was and now all I would ever had to do is replace chips that are socketed if
> they go bad.  I even ended up following the notes of a CoCo user about
> upgrading the FD-502 packs' 7416 buffer chips to 7406 (Greater voltage spike
> tolerance I'm told, 30v vs 15v of 7416).  Again was easy and great
> experience.  If anyone has a flaky CoCo or FD-501/502 controller pak they
> need repair I would highly recommend taking a crack at this..it wasn't that
> bad at all, especially if you've ever soldered anything.  If not, send it to
> me, I'd be more than happy to assist.
> While I'm not confident enough to attempt soldering SMD's(?) or other modern
> miniature surface mount ICS's, I feel pretty good about the CoCo components.
> I even finally got the nerve up to open up my old Technics audio receiver
> that had been showing "overload" seemingly randomly".  Started de-soldering
> components I could figure out how to test and then resoldered them.  I
> couldn't identify a smoking gun, but oddly enough I haven't seen the
> 'overload' anymore.weird.
> I would like comments (hopefully constructive) and suggestions on my work
> from anyone that's already experienced with soldering IC's and components.
> I've already  taken photos of a FD-502 pak I upgraded and put them in the
> link here.  http://www.mediafire.com/?cde2vmcqp63jt   The 26-3127 & 26-3127B
> CoCo 2's pictured there were both upgraded as well.  I can disassemble them
> and take photos of the work if anyone's interested.
> -          Chad
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