Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
11/04/10 11:14
Read: times


 		 #179478 - Volt meter is good but for rough testing
Responding to: ???'s previous message
Yes, a volt meter is really good for a rough test. If the volt meter gives bad results, the chip is bad. If it gives good results, it's probably at least 95% a good chip.

But the above is only valid if assuming a valid chip from the original manufacturer.

If a bad copy, an oscilloscope would - at least - need to verify the following parameters:
- startup time for charge pump
- time until full voltages
- amount of ripple for high/low signal
- rise and fall times (remember that the chip is expected to be bandwidth-limited)
- current capability

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      

Back to Subject List