RTFM – even if there isn’t one!
RTFM – read the flaming (or some other word) manual, should you not be familiar – is always worth bearing in mind, AND APPLYING, even if there is no manual.
Depending on the subject, I tend to be fairly disciplined and read instruction manuals, even when obvious. The main reason for this is not a lack of understanding, but because so many designers hide things that should be intuitive, or more likely nowadays, many important functions and controls are buried in multi-level menus. If I do commit any sins in this area, it’s to read the manual from back to the front, and that’s because they are too slow to get to the important stuff.
But in this case there was no manual.
A few years ago, my energy supplier was offering free electricity monitors for the asking, so I duly asked, and was provided with a handy wireless power monitor. There was no instruction book, and setting up involved pressing a couple of buttons to link the two parts.
Everything was fine for almost 2 years, when it was time to replace the batteries in the remote head. Fitted new batteries, pressed the button to pair the units, watched the lights flash… and nothing happened. No reading or graph. Tried the pairing repeatedly, but no change, and gave up.
With nothing obvious to fiddle with, I just left it lying on the shelf.
More than a year later, I came across the box the monitor came in, and was about to parcel the bits up to get rid of them, I noticed some “Simple” instruction printed inside the lid.
A quick glance confirmed the pairing button and flashing light. BUT, I noticed that before hitting the Pair button, you also had to press a combination of buttons on the display head! Of course, to keep it tidy, they didn’t print this instruction on the head. And of course, there’s no way to know about this intuitively. You either have the instructions and know what to do, or you don’t, and you have a small doorstop.
Needless to say, the gadget I thought had expired when I changed the batteries burst into life once I followed ALL the instructions.
There’s more. Before I got the above, I had another problem to solve first.
Although not in use, the mains power supply for the display was left in use, but when I tried to use it, there was no display. Everything was dead.
After fiddling with the power supply and the display, tests showed it was the power supply that was dead, while the display was working normally.
The power supply was one of those sealed units providing 5 V from a plug with a low voltage feed.
A quick whizz with the cutting wheel split the plug case and gave access to the guts, but even a simple 5 V supply is now a complicated beast thanks to SMD (surface mount devices) and the use of SMS (switched mode supply) design. There are times when I long for a nice simple power supply – a transformer, a few diodes, transistors, resistors, capacitors, and an IC. Obvious parts, easy to guess at and replace. SMD and SMS means little chance of a repair, unless there’s something like a big black explosion mark that shouts “I FAILED!!!”. There was nothing to indicate anything that had failed, all parts looked normal, so I decided to cut my losses and just used the cable to hook the display unit to a spare 5 V supply.
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