[Coco] 2 wasted cpus?

Luis Antoniosi (CoCoDemus) retrocanada76 at gmail.com
Thu Mar 7 17:35:56 EST 2013


ok, I will do more tests with the traces and then I can send them for you
for testing. Send me your address in private. Or I can send just one and
then I can keep testing with the other. If one is dead is pretty sure both
are, it can't be both dead cpus and bad soldering hehe :P

Thxs,

On Thu, Mar 7, 2013 at 5:31 PM, camillus Blockx <camillus.b.58 at gmail.com>wrote:

> OK I can test those cpus for you to, ending them baack and forth would be
> not much morethen buying a new one.
> It is up to you, ofcource, just do not trow them away, before you make
> shure they are bad.
> These cpu's will become obsolete.
>
> greetz
>
> cb
>
>
>
> On Thu, Mar 7, 2013 at 4:26 PM, Luis Antoniosi (CoCoDemus) <
> retrocanada76 at gmail.com> wrote:
>
> > 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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