[Coco] 2 wasted cpus?

Thu Mar 7 17:26:17 EST 2013

It's soldered. But I think it might worth paying 5 bucks more for a third
cpu than take any chance to damage my coco3 :P but i will take other
supplier than jameco.

On Thu, Mar 7, 2013 at 5:20 PM, camillus Blockx <camillus.b.58 at gmail.com>wrote:

> Good to hear you have a coco 3, now you can test your cpu's  in that coco,
> that is if the cpu is not soldered in place.
> If it is soldered in place there is still a way to test, rather awkward but
> doable.
>
> Attache an 1 kohm resistor ( brown black red ) on a piece of wire like
> this:
>
> ------------------------------|--------------------[
>     ]--------------------
> wire +- 12 inch               resistor lead      1 K Ohm R         resistor
> lead
>
> Do this 2 x
>
> Take one of the cpu's you bought and bend carefully pin40 up, so it makes
> no contact withe lower cpu.
> Place the cpu on top of the cpu in the coco 3, and press it downso it sits
> snug into the socket together with the original cpu. Now solder one of the
> earlier made wire and resistor to an ground lever, ( + side of nearby
> capacitor) and attach the resistor side to pin 40 on the BOTTOM cpu. This
>  will HALT the bottom cpu so it will not effect the test)
>
> Now the other wire you connect to a nearby - side of a capacitor and the
> resistor side to the upper cpu pin 40,
>
> - from capacitor or supply
> -----------------------------------wire-----------------------res 1k
> ------------------- pin 40 cpu on bottom
> +from capacitor or supply
> -----------------------------------wire-----------------------res 1k
> ------------------- pin 40 cpu on upper
>
> Do not connect any pin directly to any supply connection ALWAYS use
> resistor ( at least 1Kohm )
>
> Apply power and see if you get a working image, try reset if not from the
> first try. Possible you need to press a bit on the upper cpu to make shure
> it makes good contact. If you have good screen cpu is OK, else needs more
> testing.
>
> After power down do the same with the second cpu
>
> Hope this makes sence to you
>
> Good luck
>
> If you decide to trow the board away,i will take it and pay for Shipping
>
> thnx
>
>
> On Thu, Mar 7, 2013 at 12:10 PM, Luis Antoniosi (CoCoDemus) <
> retrocanada76 at gmail.com> wrote:
>
> > i applied only to one side, it's is very difficult to put solder on top,
> > you can't reach with solder tip, and the socket's round metal legs covers
> > the solder points. I use a socket like these:
> >
> >
> >
> http://image.made-in-china.com/43f34j00uBeapAfrfwqm/IC-Socket-Machined-Pin-0110-.jpg
> >
> >
> > But I tested the traces from top and bottom and all seem to have
> continuity
> > until their components or vias.
> >
> > sending the board to you probably would cost more than buying anoter
> coco2
> > on ebay. I already have a coco3, I just want to fix my coco2b. Thanxs for
> > the help.
> >
> > Felipe.
> >
> >
> >
> > On Thu, Mar 7, 2013 at 12:58 PM, camillus Blockx <
> camillus.b.58 at gmail.com
> > >wrote:
> >
> > > The best way to know if your cpu's are busted is to put them in an
> other
> > > coco and test it.
> > >
> > > Also worth to mention is when you placed the machiened socket did you
> > > solder it on both sides?
> > > Go with a thin solderwire and add a little more solder tobottom and top
> > > side on the pins of the cpusocket.
> > > This makes sure that plated thrue holes are making goodcontact. Use
> also
> > a
> > > fine solderpoint for this.
> > >
> > > good luck
> > >
> > > ( I would like to help you, but I do not know if you live close to
> > Indiana,
> > > Valparaiso area )
> > > You can buy a coco 3 128k for $75+ S/H, so don't know if you want to
> send
> > > your board to me, I test and if damaged try to repair it, and send it
> > back
> > > to you. The cost would only be Shipping and parts, if needed.
> > >
> > > Just let me know ok
> > >
> > > camillus
> > >
> > >
> > >
> > > On Thu, Mar 7, 2013 at 2:32 AM, Arthur Flexser <flexser at fiu.edu>
> wrote:
> > >
> > > > It's also conceivable that you have a cold solder joint, depending on
> > > > how exactly you tested continuity.  (Another possibility is a cracked
> > > > or damaged trace on the motherboard.)  Try testing the continuity
> > > > between each pin and someplace the trace beneath it goes to.  If you
> > > > just tested continuity between the pin and the glob of solder beneath
> > > > it, a cold solder joint might not be detected.  A close examination
> > > > under a magnifying glass might turn up a problem more quickly.  So
> > > > might reheating all the connections to see if the problem goes away.
> > > >
> > > > Art
> > > >
> > > > On Thu, Mar 7, 2013 at 1:02 AM, Retro Canada <
> retrocanada76 at gmail.com>
> > > > wrote:
> > > > > just got my 2 mc68b09e cpus from jameco. removed the defective cpu
> > from
> > > > my coco2, installed a machined socket but when i test both cpus all i
> > get
> > > > is garbled screeen. with vdg checkerboard and at signs. the same if i
> > > > remove and turn it on without the cpu.
> > > > >
> > > > > i checked the continuity on all pins seems fine. cpu is receiving
> 5v
> > > and
> > > > making some heat.
> > > > >
> > > > > so did i get 2 busted  cpus?
> > > > >
> > > > > Sent from my iPhone
> > > > >
> > > > > --
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> > > > > Coco at maltedmedia.com
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> > > >
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> > > >
> > >
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> > >
> >
> >
> >
> > --
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> >
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