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???
11/04/10 16:01
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 		 #179484 - where would excessive ripple originate?
Responding to: ???'s previous message
Richard Erlacher said:
where would excessive ripple originate?

Ripple was just an example of the kind of thing that a simple voltmeter test won't detect.

Isn't it conceivable that there may be failure modes of the charge pump that could lead to excessive ripple on the generated supply? Or other failure modes that could lead to "instability" - that wouldn't necessarily be visible on a voltmeter test?

List of 57 messages in thread
TopicAuthorDate
counterfeit MAX232            01/01/70 00:00      
   How did you test 'em?            01/01/70 00:00      
      testing the counterfeit chips            01/01/70 00:00      
         RE: serial port issues            01/01/70 00:00      
            Only bad ISR should be able to overload the PC            01/01/70 00:00      
               PC Lockup?            01/01/70 00:00      
                  Unhandled interrupts brings almost any machine down            01/01/70 00:00      
                     Missing the point            01/01/70 00:00      
            response to Andy Neil            01/01/70 00:00      
   Ha, ha, the capacitors are too big!            01/01/70 00:00      
      maybe they're too small ...            01/01/70 00:00      
      no caps are not too big            01/01/70 00:00      
         did you verify the output voltages?            01/01/70 00:00      
   They were a good deal...            01/01/70 00:00      
      yes, I learned            01/01/70 00:00      
   here is a simple log            01/01/70 00:00      
      here's a log from a real max232            01/01/70 00:00      
         it does no matter, but            01/01/70 00:00      
      Never mind the logs...            01/01/70 00:00      
         responding to Andy Neil            01/01/70 00:00      
            logic analizer            01/01/70 00:00      
            Should Be Able To Examine Using Logic Analyzer            01/01/70 00:00      
               Logic levels            01/01/70 00:00      
               There's really no need            01/01/70 00:00      
                  Can it?            01/01/70 00:00      
                     Volt meter is good but for rough testing            01/01/70 00:00      
                        It could be a bad circuit?            01/01/70 00:00      
                           Sometimes totally untested chips            01/01/70 00:00      
                              the easiest thing to steal ...            01/01/70 00:00      
                     agreed, but ...            01/01/70 00:00      
                        Lots of things happens when packaging stolen silicon            01/01/70 00:00      
                           ripple, maybe, but proper voltages, never!            01/01/70 00:00      
                        where would excessive ripple originate?            01/01/70 00:00      
                           are we identifying counterfeits or solving other problems?            01/01/70 00:00      
                              not so            01/01/70 00:00      
                                 maybe, but not an obsolete part ...            01/01/70 00:00      
                                    Especially for obsolete parts!            01/01/70 00:00      
                                       The MAX232 was replaced by MAX232A            01/01/70 00:00      
                                          Lots have already happened            01/01/70 00:00      
                                             maybe ...            01/01/70 00:00      
                                    nope            01/01/70 00:00      
                                       Really? Why?            01/01/70 00:00      
                                          you have often advocated            01/01/70 00:00      
                                             In case you haven't noticed ...            01/01/70 00:00      
   some testing results            01/01/70 00:00      
      looks like ...            01/01/70 00:00      
         or they are from the garbage            01/01/70 00:00      
            Voltages?            01/01/70 00:00      
               yes the voltage was 7.79V            01/01/70 00:00      
                  Can't use volt meter            01/01/70 00:00      
            I doubt MAXIM would allow garbage out the door.            01/01/70 00:00      
            Counterfeit Maxim parts            01/01/70 00:00      
               How much profit could they have made?            01/01/70 00:00      
                  Profit?            01/01/70 00:00      
                     Labor isn't the critical factor here, is it?            01/01/70 00:00      
                        profit/motives            01/01/70 00:00      
   they are counterfeit!!            01/01/70 00:00      

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