Your daftest mistakes??

[high_vacuum_house]

Good evening,
Reading the threads about biggest regrets and misses made me think about a few rather silly things I got up to many many years ago. Does anyone else have any other silly memorable moments?

The first was dismantling my grans first generation beetamax VCR when I was around 15 years old and finding the vacuum flourecent display makes a nice long tinging sound when tapped due to the filaments inside vibrating. Tapping it harder makes the effect last longer until I tapped it too hard and the thing shattered in my hands. My dad heard it go pop and gave me a good clip around the ear for making a mess on my bedroom carpet!

My first battery valve set I bought had the DK96 range of valves and I tried to get it working, believing the valves should glow like all the other valves I have come across. I wound the LT voltage up until they started to glow and at the same time they all together popped their filaments. I still have the Alba table set complete with a duff set of valves in...

I came across a halogen gas leak detector at school which had a few valves in. There was a loudspeaker which made various squeaking oscllator noises as the knobs on the front were turned. This tester had a small reciprocating air pump inside and connected to a long hose to sniff for traces of gas. After getting bored with it I put the hose in a cup of water to see what would happen which it pumped into the tester, flooded the live chassis and not suprisingly it went bang and stopped working!! It then got bunged in the bin!

Christopher Capener

[Lloyd 1985]

Ah yes... I've done the one with the battery valves too. I thought a 9V battery should be OK to power them! They all went out one by one

Other daft thing I did, I killed a Toshiba colour portable tv by trying an earthed scope on the frame stage, All the lights went out as the RCD in my workshop tripped! I was half asleep at the time, the TV didn't work afterwards, just made a quiet buzzing noise!

Probably done many more, just can't remember them right now

Regards,
Lloyd

[Mike Brett]

Many years ago I built my very first crystal set, although it worked, the reception was very weak. I remembered reading somewhere that to get the best from these sets you needed a good antenna and earth. For the earth I had the brilliant idea to solder a wire directly to the copper immersion tank in my bedroom!, well I was only 12 years old. At the time I had one of those old very heavy irons, it took ages to get hot. As soon as I touched the iron to the copper tank there was a loud bang and lots of sparks, it never did work again.
Mike

[Nickthedentist]

Mike, that sounds like you had a narrow escape there, i.e. that the tank or iron was live. Your big bang was probably the least bad outcome!

[Peter.N.]

Valve sets were very durable compared with what we have now, you could short things out with impunity without causing damage, when transistors arrived you couldn't do that and get away with it so I found, in the early days of transistors I spent more time repairing the damage I had done trying to find the fault than actually repairing it.

Peter

[HamishBoxer]

Breaking a leg of a Green/Yellow spot transistor that cost me Seven Shillings and Six old Pence!

Bought it to get more audio from my crystal set at age eleven.

[Gulliver]

Back when I was at school I was given a teacher's Ferguson receiver to try and fix. I located the fault with the top off and the mains on, and then went to turn the unit off rotating the on/off switch from inside the cabinet...big mistake...big shock...and ruined receiver

[Herald1360]

One that comes to mind was thinking that I could resolve single sideband by reversing the polarity of the detector.....

[Gulliver]

My worst mistake ever was made at the age of 5 or 6 to be honest.

My parents had given me a vanity case style record player when I was 3 (1976). I enjoyed it but one day my best friend decided it would be fun to stick butter knives through the speaker. Like a fool I followed suit (fortunately with the unit unplugged) and we even ended up throwing it out of my bedroom window. Cue one very broken record player.

I was *very* fortunate to be given another record player and learned a lesson...just because your friend says "let's do this" doesn't mean you should. Quite why he was so destructive I don't know. It was a beautiful little machine.

More recently (last week) I may have destroyed an Onkyo AV receiver by connecting it to a set of speakers which were already used by another amp...

[threeseven]

Back in the distant days when I first started messing with electronics, built a project full of 74 series logic ic's which back then represented considerable expense to me. Time came to test it and I forgot to check my bench PSU was set to 5 volts, it was on 20 volts from memory, result every single chip blown!! I've made a number of cu's since but that one REALLY sticks in my memory!

[mark_in_manc]

Originally Posted by Gulliver

Quite why he was so destructive I don't know.

Possibly because you had a record player and he didn't. I remember being on the receiving end of a bit of that, in the guise of 'let's do this for fun'.

But mistakes...using my dad's Rogers stereo as a pre-amp, to drive my cheapo guitar practice amp into heavy distortion (age 14) was a big one. I think I might now know enough to have had a go at fixing it, but at the time...no.

[Boom]

Originally Posted by Peter.N.

Valve sets were very durable compared with what we have now, you could short things out with impunity without causing damage, when transistors arrived you couldn't do that and get away with it

It was common practice to draw a spark from the PL to chassis to test the LOP. Who didn't try it (once) with their first transistor LOP set?

[threeseven]

LOL, I'd forgotten about that practice! We used to get the trade come in at CES Leeds trying it on for an exchange panel under warranty!

[ukcol]

I don't know if this qualifies as a mistake because there were no consequences, however ...........

When I was a kid my Mother bought me a Dansette Junior record player. During the time I had it I disconnected the loudspeaker and connected a long wire aerial to the anode of the output valve. With a record playing and the volume turned up it created a crude spark transmitter as it arced in sympathy with the music.

I could pick up a very distorted sound on an HMV 1507 we had downstairs. The music was all over the HMV's short wave band.

Incredibly I didn't do any damage to the Dassette and I never had a visit from the short wave police.

Colin M

[Peter.N.]

Another thing I remember, when I was about ten and well into chemistry and electrics I tried to make a water gas generator using and old 2v glass accumulator, if fitted a small diameter tube into the vent on the stopper and attempted to light the end, the result? a loud explosion and bits of glass stuck all over the shed wall, fortunately it all missed me - I think.

Peter

[Boom]

I did a similar stupid thing with a massive tractor battery. Put it down on the floor on charge, forgot about it and started welding next to it. The battery split apart with a massive BOOOOOOOOOOOOOOOM! Couldn't hear for three days afterwards.

[Valvepower]

Hi,

Getting a job in British Electronics manufacturing - sorry it’s been one of those days ...

Terry

[Paul Adams]

Working on an Avo Model 40, with Phil (G4SPZ) at my home and wondering why the meter wouldn’t read FSD, it wasn’t until Phil, pointed out that it was the batteries, so embarrassing.

Paul.

[Nickthedentist]

We've all done that kind of thing. I recently took apart my car windscreen washer system to find the fault... then only later discovered it had no fluid in it!

[Outrun_uk]

Yesterday in work fixing a MetraHit multimeter with built in insulation test. Had hold of it in both hands, forgot the orange button actually turns on the insulation test and not just selects the mode. Ouch.