Re: Favourite Test Equipment

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 <pcdhSpamMeSenseless@electrooptical.net> 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 <trevor@rageaudio.com.au> 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