XPost: sci.electronics.design   
   From: bill.sloman@ieee.org   
      
   On 12/04/2024 3:46 pm, Trevor Wilson wrote:   
   > On 12/04/2024 3:32 pm, Bill Sloman wrote:   
   >> On 12/04/2024 5:42 am, Phil Hobbs wrote:   
   >>> On 2024-04-11 13:11, john larkin wrote:   
   >>>> On Thu, 11 Apr 2024 09:55:18 -0400, Phil Hobbs   
   >>>>  wrote:   
   >>>>> On 2024-04-10 16:30, Trevor Wilson wrote:   
   >>>>>> On 11/04/2024 3:42 am, Cursitor Doom wrote:   
   >>>>>>> On Wed, 10 Apr 2024 11:40:02 +1000, Trevor Wilson   
   >>>>>>>  wrote:   
   >>>>>>>> On 1/04/2024 4:41 am, Cursitor Doom wrote:   
   >>>>>>>>> Hi all,   
   >>>>>>>>>   
   >>>>>>>>> I'm starting to get a bit fed up with having my test equipment   
   >>>>>>>>> blow up   
   >>>>>>>>> just when it's needed. This is the drawback with vintage gear;   
   >>>>>>>>> if it's not used frequently then it can go *bang* the next time   
   >>>>>>>>> you switch it on. It makes for good practice in repairing   
   >>>>>>>>> stuff, but wastes a lot of time which could be better spent   
   >>>>>>>>> doing other things.   
   >>>>>>>>> I think it's time I modernised my test gear. I was just   
   >>>>>>>>> wondering if   
   >>>>>>>>> anyone has any recommendations they can share. Is there a   
   >>>>>>>>> particular   
   >>>>>>>>> piece of test equipment you couldn't live without? Something   
   >>>>>>>>> you're   
   >>>>>>>>> particularly impressed with? I'd be interested to know so I can   
   >>>>>>>>> perhaps acquire said item and thereby reduce the number of   
   >>>>>>>>> explosion I experience.   
   >>>>>>>>   
   >>>>>>>> **In my 55 years of servicing, I've only blown up one thing: A   
   >>>>>>>> Micronta DMM, which I connected to a laser power supply. I   
   >>>>>>>> should not have done it. Clear operator failure. Everything else   
   >>>>>>>> works just fine. Even my   
   >>>>>>>> first multimeter. A Sanwa U-50D my dad gave me on my 14th birthday.   
   >>>>>>>> Still works fine. My first DMM. A cheap 'n cheerful SOAR. Works   
   >>>>>>>> just   
   >>>>>>>> fine. My first Fluke meter. A 40 year old Fluke 85. Works fine.   
   >>>>>>>> I've had   
   >>>>>>>> to clean the switch a few times. Otherwise, no problems. Ditto   
   >>>>>>>> my other 15 or so meters. Same deal with my 'scopes.   
   >>>>>>>>   
   >>>>>>>> I don't know what your problem is. Test equipment, when treated   
   >>>>>>>> properly lasts a long time.   
   >>>>>>>   
   >>>>>>> To be fair, these "explosions" are typically capacitors: old, dried   
   >>>>>>> -out electrolytics in test gear that hasn't been used in a long time   
   >>>>>>> go bang when the power's switched on - as do old X2 safety caps.   
   >>>>>>> Those   
   >>>>>>> are the chief culprits IME.   
   >>>>>>   
   >>>>>> **Oh, I see. You ignore regular maintenance. That makes sense. I   
   >>>>>> hope no-one buys a car from you.   
   >>>>>   
   >>>>> Whereas all you Ozites are 100% rational reasonable polite beings who   
   >>>>> are always on top of everything, including predicting the exact date   
   >>>>> when an old cap will give up the ghost.   
   >>   
   >> Old electrolytic capacitors tend to give up the ghost when they have   
   >> been left unpolarised for years, and are then subject to their rated   
   >> voltage without having been re-formed first.   
   >>   
   >> Predicting that kind of failure isn't difficult.   
   >>   
   >>>>> Silly me for forgetting. ;)   
   >>   
   >> You don't have much to do with clueless newbies.   
   >>   
   >>>> You don't routinely replace caps in all your test gear? I'm shocked,   
   >>>> shocked.   
   >>   
   >> You don't replace them, you re-form them -  day or so subject to rated   
   >> voltage applied through a nice big resistor (100k comes to mind).   
   >   
   > **It would only be required if the unit has been out of service for   
   > quite some time, unless it is very old of course. In any case, if I   
   > remove a cap from equipment, it will almost always be simply replaced,   
   > unless it is a very large and expensive component.   
      
   The only time I've done it was with a "new" capacitor bought from a   
   cheap supplier for my home-brew hi-fi. It was a large - it not all that   
   expensive - component, and would have been a pest to replace.   
      
   The hi-fi worked for about thirty years. It had sat in basement for   
   quite a while - my wife eventually judged it too ugly for the living   
   room - and when it stopped working it was quicker to buy an off the   
   shelf replacement, and we then had the money to do that without thinking   
   about it. I did think about finding the fault (in the discrete input   
   transistors) but never got far enough to find the actual defective part   
   or replace it.   
      
   --   
   Bill Sloman, Sydney   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)