Life’s Toolbox – The Voltmeter

Once again, I’m on the road and taking the opportunity to close out the post quota for the month. I must congratulate myself for making it through the entire month without a single bird picture. Just a little relief from the barrage last month… and a break since next month will once again be all about our feathered friends – not sure yet if it will be from our Banner Marsh outing our vacation up in Wisconsin over Easter. I can tell you are already filled with excitement. Today is actually a new topic to the blog and one I’ve been kicking around for awhile. There are tools/devices that have been around for the ages yet still play a pivotal roll in our life (well, at least mine). The ones I wanted to focus on are those that really have not changed in functionality or operation. For example, I’m ruling out the cell phone – granted it really hasn’t been around all that long – but the sexy smartphones of today are far cry from the bag phones of yesteryear. So, the guidelines are it has to have the same basic functionality that it had when I became aware of it and still providing value today.

The inaugural entry in what I am referring to as Life’s Toolbox is … drum roll….the Voltmeter. One of the reasons for this choice is due to recently having to employ it to fix my tractor. My brother originally showed me how to use this device when I was growing up and we were geeking it up modifying the Commodore 64 and testing out other circuit boards – by the way, the Radio Shack experiment set should be mandatory for ALL grade schoolers. I had a number of circuit logic classes in college and oh, there was that electronic circuit class I took just for fun one summer back – I was driving over there for some Psych classes and figured I’d just stay an extra hour and compliment my human wiring classes.

Since those days tinkering with breadboards, the voltmeter has never been far -nor has the voltmeter changed one iota. I have the same one I acquired in college and used exactly the same way I did back then. Whenever something electrical breaks around the house our need to figure out what the hell our electricians did while building our house (looooong story there), I start slapping the probes on any wires I can find. This was the case when my old John Deere decided to become stubborn. I have a 316 that was built in 1985 and a 212 built in 1975 which are used as brush and trail mowers in order to keep the wear off our X500. Nothing can stop that 212 even though its used as a trail blazer in the woods. The 316 can be a little finicky and this time it wouldn’t turn over. Alright, into the garage it went and out came the voltmeter.

Hit the jump to see how the voltmeter recently came in quite handy

Assuredly due to big government and slimy lawyers, these Deere tractors are overloaded with safety crap.  Before I could track down the engine issue, all of these extraneous circuits had to be circumvented.  The resistance setting told me exactly which wires were hooked to the seat override that prevents engagement if you are not sitting on the seat.  That was an easy fix by simply pulling the seat connector off and slamming a ‘U’ wire jumper to bypass the open circuit.  Next problem was to override the clutch since it will not start unless it is in neutral.  The clutch device had a rocker mechanism in it that opened the circuit unless the stick was disengaged.  Again, the voltmeter confirmed which wires were being connected by the bypass and those were disconnected and wired together.

Still no luck with getting anything to even respond from turning the key, so the wires to the key switch were probed and those managed by the actual key were checked to make sure they were being connected in the module – It took me awhile to figure out which was which thanks to having to manage two probes and turn the key at the same time – pretty sure Linda was hiding from me during all this. So the key circuit was fine, but still now power per the voltmeter DC setting.  Tracing the wires through a harness I found some interesting leads to the mower deck switch.  Ugh, forgot about that switch having to be off.  That device was taken off and 30 minutes later figured out how that was shorting (as intended) the power circuit.   That is the switch that is hanging at the bottom of the following picture.. right next to part number 710 (sorry, inside Cat joke).  By now, most of the wire harness was hanging like spider webs all jumped up.

Still no luck so back to the DC setting to trace back from the battery.  You better not have just thought I failed to check the battery! (that was my first check).  So for the next 2 hours I traced the power back one connection at a time until there was a complete drop in volts.  Turns out there was a broken wire to the front lights (which hadn’t worked for years) that was now shorting out.  In addition, a fuse that I had missed earlier was blown.  The wire to the lights was fixed which got my lights back (yeah) and a run to Menards provided a replacement fuse (note, I was going to get a replacement for the other fuse just, in case, but turns out it is non-standard – lucked out there… well if I still wanted the fuse there.. there’s always a straight wire option (just saying..).

A couple more probes with the voltmeter and we were soon listening to the rumble of a well designed mower (I can say that because we are not in the mower business – their construction equipment is clearly inferior but I may be biased).  So there you have it.  Thanks to relatively inexpensive device obtained 27 years ago we saved a $35 haul fee and who knows how much they would charge to find and fix the problem.

Add to that the fact the voltmeter helped wire all the Ethernet lines in my house due to drywall installers going slap happy with the rotozip and the first set of electricians failing to put tags on any outlet wires before the drywall went up means this tool was one fine investment.  I also can’t forget helping me to locate a dryer failure and modding up my original xbox.  It really is like a trusty friend that is always there when you need it and never fails to perform (for the record, that is 27 years with only one battery change).  If there isn’t one in your house , well, you are paying too much for service.  I forgot to look the last time I was there, but I’ll bet that you can walk into a Radio Shack and buy a brand new one that has two probes and a dial to select the type of test you want to do – in the same manner as my old one.

A little change of pace for the last post of the month – hope you enjoyed reading it and better yet encouraged you to get one of your own (in the rare instance you got by this long without one!)

2 thoughts on “Life’s Toolbox – The Voltmeter”

  1. Nice debugging! You’re right, voltmeters haven’t changed since the first digital ones appeared decades ago. I have a Radio Shack one from about 10 years ago that can connect through the serial port of a PC with software that will plot data over time, but I’ve never done that. Back in grad school I built my whole microcomputer by wirewrap and a small analog voltmeter, and that included testing the clocking and serial comm lines–I got very good at estimating the duty cycle of a serial line by the average voltage level, as well as estimating the speed by tiny oscillations in the needle (something I couldn’t have done with a digital meter).



  2. Admittedly, I had chuckle when I misread your sentence as “grade school” … but if I remember correctly, wasn’t that the same computer that was not exactly in FCC conformance and would have a negative impact on your neighbor’s TVs?. I completely forgot about my wire wrap tool (with the secret insulation cutter). Now that was one handy tool.


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