[Boatanchors] CMOS Failure

[Glenn Little WB4UIV]

This is functional:
https://www.youtube.com/watch?v=66hPg_r4IOw

73
Glenn
WB4UIV

On 3/17/2019 1:24 PM, Bill Cromwell wrote:
> Well golly,
>
> I have a couple of coffee cans full of new-old-stock CMOS. I am 
> wondering if I should dump all of that or take the trouble to run some 
> functional testing. I have a big stack of vacuum tubes and all of them 
> pass minimal testing (or they are gone). Aside from designing Arduino 
> routines for the various ICs does anybody have suggestions where to 
> look? I am NOT buying a kilobucks tester for a couple of coffee cans 
> full of old chips. Buying new ones would be much more cost effective. 
> Building something like an arduino test board would have more value 
> with the mental exercise and the reusable/reprogrammable parts. Have 
> the routines already been worked out?
>
> 73,
>
> Bill  KU8H
>
> On 3/17/19 1:10 PM, Rob Atkinson wrote:
>> Possibly inferior manufacturing conditions.  Or, the case holding the
>> chip isn't perfectly sealed.  These two problems are the enemy of
>> components going back a long time and are not tied exclusively to
>> CMOS. CMOS failure is the Achilles heel for other items, especially
>> anything with a custom designed and manufactured chip.   Kenwood
>> TS-850 for example.
>>
>> It would be interesting to note if the failed chips always are from
>> one manufacturer.
>>
>> The good news for the 9100 is that the bad chips must be common
>> components that can be replaced.
>>
>> This is interesting
>> https://www.edn.com/electronics-news/4382044/What-Causes-Semiconductor-Devices-to-Fail- 
>>
>> Scroll down to the bullet point:
>> "A discharge causes “latch-up” in a CMOS device due to triggering of
>> silicon-controlled rectifiers (SCRs). "
>>
>> 73
>>
>> Rob
>> K5UJ
>>
>>
>>
>> On Sun, Mar 17, 2019 at 11:33 AM Paul Christensen <w9ac at arrl.net> wrote:
>>>
>>> While repairing items from the 1980s decade, I've found several 
>>> instances of
>>> failed CMOS logic gates.  Just recently, I repaired an Orban 9100B 
>>> audio
>>> processor that had three bad CMOS chips.
>>>
>>> Each CMOS device is in an intra-stage part of the processor, meaning 
>>> they
>>> are not exposed to the outside environment as is the case when 
>>> connected to
>>> an input or output jack where conditioning is minimal or 
>>> non-existent. The
>>> power supply tests fine.  Regulated voltages are spot-on and supply 
>>> ripple
>>> is less than 1mV RMS.  Internal temperatures are warm, but not 
>>> excessively
>>> hot.
>>>
>>> This is only the most recent occurrence.  I've seen similar failures 
>>> in the
>>> last few years.  Does anyone on the list have an understanding of the
>>> failure mechanism?
>>>
>>> Paul, W9AC
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>

-- 
-----------------------------------------------------------------------
Glenn Little                ARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIV            wb4uiv at arrl.net    AMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"