[Coco] Coco1 repair parts ?? & Results of Repair!!

[mmarlett at isd.net]

Long live the CoCo!!!! 

Good job!

>mmarlett at isd.net wrote:
>
>> Robert,
>> 
>> NTE is sold by AEI in Minneapolis if that helps you. I **think** Mouser
>> also sells them. I'm sure the distrib. list or reseller should be on
their
>> site. I have used them before, and the specs are there.
>> 
>> Good luck! No CoCo should ever die! :)
>> 
>> Mark
>
>
>I found a local electronic parts retail store locally with a stock of 
>NTE parts. The NTE219 was available but the NTE128P was not there, only 
>the NTE128 Can form. Since the specs were as good or better than the P 
>(plastic), I bought it. The Coco1 is now working like new.
>
>For those with no 5v at test point6 (at least on an F board), here is 
>what is likely a common failure mode. The main power transistor (2N6594) 
>fails, then the MPSW01 trys to carry the full load (which it can do for 
>a short time), then the MPSW01 overheats and fails. This shuts down the 
>5v bus. You may see 0.0v to 0.8v at the test point.
>
>The sequence of the repair process was to replace the MPSW01 first and 
>test the Coco. 5V was then present at the bus but the NTE128 was HOT. 
>Good thing I bought the Can version. Then the NTE219 was installed the 
>the Coco tested again. No change in voltage but now the NTE128 was room 
>temp. So based of these results I postulated the above failure route.
>
>
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