The truck needed some work on Friday. I did get a few pictures of some test equipment in use even though it's not comprehensive, but I figured I'd post what I have.
I was planning to use the Hantek CC 65 clamp on it for the first time so I got it set up but it wouldn't null nicely at first so that caused some pre-troubleshooting troubleshooting in the basement. The manual, if you're foolish enough to believe the manual, says to dial up a null by pushing and turning the knob, so it's like the Fluke current clamps instead of like the OTC or Agilent I have where you push a button and it does it automatically. I bought the Hantek specifically to do lower current work since all those large clamps run from 400 to 2000 amps, and low current measurements are almost in the noise at the bottom of the range on those.
The Hantek's knob wouldn't spin so I couldn't get a nice null like I can on the Fluke clamps. Take apart the Hantek and the knob doesn't spin like the manual says, the knob is actually a pushbutton and it is supposed to auto-null like the Agilent U1213A and the giant OTC clamp:
Put it back together and do a fast sanity test with a 100 ohm wirewound resistor and a bench power supply before heading outside. It still doesn't null nicely so you have to do a bit of mental math to remove whatever lingering offset it has after it auto-nulls. The slide switch also works between off and the 1 mV/100mA range. The output doesn't change between the 1mV/10mA range and the 1mV/100mA range when you'd expect it to shift by a factor of 10 so I'm going to have to take it apart again later and see if I can fix that. Between the badly written manual, the mediocre auto-null, and the balky range switch, I'm
not happy with the Hantek so I'm open to suggestions for a replacement AC/DC clamp with a similar current range for smaller applications.
The U1252B is one of the multimeters that lives in the truck full time. The plan now is to add the U1253B I got recently in the cold months when LCD displays can struggle but I'm keeping it inside until then to avoid ageing the OLED fast due to heat. Anyways, the U1252B got put into action. The remote logging and display functions aren't needed when the test leads are just long enough to let the meter sit propped between the hood (bonnet) and windshield while I sit at the controls in the driver's seat.
Mixed results. A bit over 11 volts, which I can work with since it proves the output's there, but well down from 35 volts at the other end where there's a connector that's known to be a weak spot but happens to be ok in this case, but I don't have any pictures of that. Part of that is test leads sitting on nasty looking contact surfaces by gravity only so the connection wasn't the greatest.
4.72 ohms where I'd expect 4. Again, nasty looking contact surfaces in the connector plus fairly weak one handed holding the test leads onto it. This would account for the slightly elevated resistance reading and the significantly reduced voltage on either side of that connector. Put the two halves of that connector together and I can see why it went intermittent and then open. A
lot of MG Electrosolve and a
lot of mechanical agitation got everything working properly again but it's most likely going to be a temporary fix. Chances are that connector's going to have to be replaced if it goes bad again.
I ended up not using the Hantek clamp after all. The original plan was to use it to see if current was circulating when voltage was present on this circuit without having to break the circuit. However, the results of the first voltage check pretty much had me convinced there was an open downstream which made me decided to break apart that connector so I could inspect it and do a load side continuity test at the same time. At that point, I didn't need the Hantek anymore between the voltage and resistance checks and visual inspection of that connector which turned out to be surprisingly bad inside.
That Hantek was the other thing besides that connector that was surprisingly bad. I'm really disappointed with it. I'm going to have to disassemble it and see if I can get the switch to work correctly at a minimum and give it a more thorough set of bench tests both AC and DC to see how useable or not it is, but as I said, I'm open to suggestions for a replacement. It definitely leaves a bit of a bad impression and tends towards confirming my preference for Fluke and Keysight equipment even if they can be expensive both new and on the used market.