Old habits die hard.

[G6Tanuki]

Installing a couple of new UF4007-type diodes in a piece of kit today, I found myself subconsciously forming the leads into a single-turn loop, just as I was 'encouraged' to do by an Elmer back in the 'sixties when fitting Germanium small-signal-diodes.

"So when you solder it the heat doesn't run back up the leads and affect the semiconductor junction".

I also instinctively clamp the lead between the transistor-and-the-place-I-am-cutting-the-lead with a pair of snipe-nosed-pliers, as a 'shock-sink' because I was told that the SNAP! of side-cutters used on the plated-steel leadouts of transistors could be conducted back to the junction's thin wires and cause failure.

Of course these are total nonsense with any semiconductor-device built in the last 50 years, but 'old habits die hard'.

My other 'thing' is to always test fuses and panel-lamp-bulbs before fitting them; this 'learned behaviour' came about after one of my clients took-over a small company one of whose bench-techs had the perplexing habit of putting failed fuses/panel-bulbs back into the packet from which he had just taken a new one! When we discovered what he'd been doing I had their entire stock of such parts he had ever touched consigned to the bin; it was cheap compared with the chargeable time incurred tracking-down faults where a failed fuse was replaced by an equally-failed fuse from Charlie's stash.

I wonder, what other 'learned behaviour' you may have developed?

[Charlie also had a fixation for 'recovering' cable-ties - he'd spend ages wheedling a screwdriver to release the springy tag on an old cable-tie; when I pointed-out to him that there was no customer against which to bill this activity - so he should not expect to be paid for it - he went off in a huff]

[duncanlowe]

Great post. My learned behaviour that I have tried to pass on, is to never believe what your instruments are telling you. I mean yes, believe them, but question what the 'reading' really is telling you. There are so many examples. Digital sampling systems and aliasing. Residual voltages messing with resistance measurement. Digital systems giving fault codes that are actually only clues rather tahn explanations.

So I have learned to believe what my instruments are telling me, but not to believe what they are 'telling me' if you get the subtle difference.

Then again, fuses are another, I agree. How many times have I pointed peopole to check fuses who it turns out haven't acually taken them out of circuit and done an actual test.

[Jon_G4MDC]

Those who cut high frequency quartz crystal leads using compression side cutters and not shear type would wonder why their expensive acquisitions didn't work. Sand...

[joebog1]

Funny!! I ALWAYS bend my diode leads as described. Ive done it all my life!!. Another "trick" shown me by a german engineer when I was about twelve. Some early rectifier diodes had silver leads, and they were used as heatsinks for the diode die. I have tried to explain that here many times in discussions.
A recent thread about an organ PSU comes to mind. The origional diodes ran so hot with little tiny short leads, that it had evaporated all the tin from the solder joint. If done neatly, it takes very little more room than the diode on its own. See my pic. A 1/8" or 3mm drill does a fine job.

Blown fuses!!! I think all of us have been guilty of not "really checking properly" at some stage, especially if the fault has been a real pain to find. Another check first for me is multimeter settings!!! Another multimeter with a flashed PCB.
7 colour 1/4 watt resistors!!!!! what sadist invented those?. I ALWAYS check with a meter. Some are so finely striped its nigh impossible, even with a loupe.
Things one pics up over the years huh ?.

Joe

[its ur aerial]

I also tend to hold semiconductors with long nosed pliers.
But one old habit, that has kept me safe, when working on live equipment is to keep one hand behind you.
I diagressed only once and the result was very nearly "good night Vienna" at the age of 20!
Ken G6HZG.

[Wendymott]

I remember looping the BY100 replacements for Selenium rectifiers in TV's in the 60's..and also the 15 ohm anti surge resistor..... I don't bother with my SMD Diodes though

[The Philpott]

'Take a break while it's going well. If you wait until something goes wrong before you take a break, you return with a negative frame of mind'

I acquired this one ^^ from Mark Evans, the vet/mechanic. (Doesn't mean that i always follow it though)

Also blowing on summat to cool it down or remove dust, blow away from it initially- because the second/third puffs are much drier than the first!

Dave

[lesmw0sec]

Originally Posted by duncanlowe

Great post. My learned behaviour that I have tried to pass on, is to never believe what your instruments are telling you. I mean yes, believe them, but question what the 'reading' really is telling you. There are so many examples. Digital sampling systems and aliasing. Residual voltages messing with resistance measurement. Digital systems giving fault codes that are actually only clues rather tahn explanations.

So I have learned to believe what my instruments are telling me, but not to believe what they are 'telling me' if you get the subtle difference.

Then again, fuses are another, I agree. How many times have I pointed peopole to check fuses who it turns out haven't acually taken them out of circuit and done an actual test.

I'd add to that - never trust a digital instrument when working in even modest RF fields. I recall trying to measure something on a 50W transmitter when out in the bush. Nonsense readings. I was glad I also brought an avo!

[The Philpott]

Very much so. Also phantom readings where a bunch of cables, some dead and some carrying AC, instantly confuses a DMM and reverses the 'obsolescence' of an older meter. I understand some flukes now have a low impedance setting which should avoid this particular issue..?
Dave

[John_BS]

I'm reminded of a trip many years ago to a BBC reception site on Lowther Hill in Scotland. It was picking up an FM main-station (probably Black Hill), demodulating down to L+R and sending the audio over a microwave link to be re-broadcast elsewhere. There was an issue with an adjacent CAA radar installation a few yards away which was breaking through onto the audio. When I arrrived on site, the BBC bays were screened with additional steel plates and other ad-hoc measures. No-one seemd to know the erp of the radar, other than that it could observe planes landing at Heathrow!

There was an AVO sat on the bench connected to nothing, and as the radar swept round, the needle would rise in sympathy.... I knew at this point that we had a major task on our hands.

[Lucien Nunes]

I touch everything to check its temperature, especially rotating machinery and cables. I can't walk past a large bearing without pressing the side of my hand aganst it. This comes from advice given in the 1933 Projectionist's Handbook by Pitchford and Coombs, which dad gave me at 7 or 8 years of age. I absorbed much from it but especially the advice given in capital letters to 'USE YOUR FINGERS!'

Younger techs brought up with contemporary safety practice rightly question this; my observation is that it is very important to know what you can and cannot touch. There is no harm in putting a hand round a heavy insulated and sheathed cable, but being able to gauge that it is carrying about 150 amps from the temperature rise is a useful trick they invariably don't seem to have taken the time to learn. I would not however urge them to follow my habit of touching machine brushgear while in operation. I must learn to use the IR camera for that.

One from my dad, and an early mentor (Ken), was to tighten screws symmetrically and progressively. Of course there are situations where this is essential for correct seating of components e.g. engine cylinder heads, but I often do it on unimportant things too. And I laugh heartily when the apprentice inserts and fully tightens screws only to find the last one won't go in because the components are already firmly secured in a misaligned position.

Another from Ken was always to stagger inline soldered-and-sleeved joints in multicore cables. This is good practice, because each 'lumpy' bit of the soldered joint wants to lie alongside extra layers of insulation; you don't want two or three joints crushed together with only the heatshrink separating them. But it takes slightly longer and requires slightly more free length of cable. In one of my work activities I sometimes have to joint small DC power connections in tight spaces, e.g. 2A at 12V in 0.5mm² cable, in which case I often make the tails the same length. But every time I do this, I think to myself: "Ken wouldn't like this, he'd call it lazy work." Ken is sadly no longer with us but he was one of the first to teach me finesse in restoration technique in my early teens. I was lucky.

[Vintage Engr]

I also have that edition of the Projectionist's handbook, it proved very useful over 50 years ago when I was working in both film & Television engineering.

Eerily, all the other points you raised, have been useful & used throughout my long time in the industry.

The point about cable jointing seems obvious, & I've always followed that approach, otherwise one ends up with what resembles a 'wiped-joint' on the old lead pipe!

David.

[kalee20]

Originally Posted by Lucien Nunes

One from my dad, and an early mentor (Ken), was to tighten screws symmetrically and progressively. Of course there are situations where this is essential for correct seating of components e.g. engine cylinder heads, but I often do it on unimportant things too. And I laugh heartily when the apprentice inserts and fully tightens screws only to find the last one won't go in because the components are already firmly secured in a misaligned position.

Yes I do that too!

[TonyDuell]

As do I. In fact 'diagonal tightening' (as my father called it) is so deep-seated in my brain that the other day I was fitting rubber feet to a cabinet, each held on by one central screw, and I found myself fitting them in a diagonal sequence (if you see what I mean) even though it couldn't possibly make any difference.

I also get all the screws located and 'finger tight' first (fitting them in a diagonal pattern) and then go round tightening them up in a similar pattern. Even for things like the lids on diecast boxes.

[joebog1]

Originally Posted by Lucien Nunes

This is good practice, because each 'lumpy' bit of the soldered joint wants to lie alongside extra layers of insulation; you don't want two or three joints crushed together with only the heatshrink separating them.

Your screws are too long!!!. If there is enough "screw length " to arrange the cables on top of each other, the screws are too long!!. Cables are arranged NEATLY 30 degrees or so away from the last, BUT if you do it correctly the third cable will sit in line with the first.

Fingers and temperature. PRECISLY Lucien!!. OK I will go get a thermo meter.
The bearing is now SCREAMING in mortal pain and will need replacing, forget the film, it was shredded when the take up spool failed and the film ended up in the shutter..
MODERN OH&S has its place, BUT there is nothing like humanity.

Joe