[Coco] 2 wasted cpus?

Thu Mar 7 17:30:10 EST 2013

do you have any working CPU you could sell me ?

On Thu, Mar 7, 2013 at 5:26 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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>> > > > > Coco at maltedmedia.com
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>> > > >
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>> > > >
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>> > >
>> >
>> >
>> >
>> > --
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>
>
>
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