Electrical eejits - a cautionary tale

[MattW]

Having just bought a second hand satnav complete with all accessories (mains adapter, car adapter and bike power lead), I thought I'd wire it in to my 1100 today.

Having sought advice on here I chose to jump it off the pilot light - handy as I always ride with lights and it's a nice dry location to house the connections. Rather than use piggyback spades (had trouble with them in the past) I soldered and heat shrunk the power leads onto the pilot light spades. All went well with 12v showing at the relevant pins of the satnav connector when I switched the side lights on, so I tucked everything away into the headlamp shell and got the satnav to test it.

Mount satnav on the bike, plug in the power connector, ignition on, lights on, satnav on - nothing...

Ars*! - what's gone wrong?

I then had a heart stopping moment.

Feck! - I hope I've not got the polarity wrong and fried the satnav (even though I'd double checked it) - rushed inside, plugged it into the mains - still working - thank God for that. Checked the pins of the satnav connector and the polarity again (comparing it to the output on the mains connector) - all fine.

Plug the satnav into the bike again - nothing.

By this time, I'm running out of ideas.

Cleaned all the contacts on the satnav and power connector with isopropyl alcohol - test again - 12v at the connector, plug the satnav in - nothing.

Diagnostic time then.

Took the headlamp out and with the bike powered up and the satnav plugged in, started working down the wiring, wiggling and twisting, from the satnav to the pilot light jumpers (all the time thinking 'but this can't be it - there's 12v at the connector' ). I reached the headlamp shell and wiggled the inline fuse holder - the satnav woke up!.... And then died again. Unplugged the satnav and put the meter on the power connector - 12v - what the feck is going on here? Took the fuse out of the inlne holder - looked fine. Wiring to the fuse holder - looked fine.

Then I looked down the inside of the fuse holder - whats that?

Had a dig with some needle nosed pliers and pulled out this:

<a href="http://picasaweb.google.co.uk/lh/photo/uj9ENJrgTqUUwx-fvEDzcQ?authkey=Gv1sRgCKLK2dPW3_bnfw&feat=embedwebsite"><img src="http://lh6.ggpht.com/_SSn2CtCOKnU/ShPnWrlwYyI/AAAAAAAAB1k/_h8wkSBve-0/s800/blob.jpg" /></a>

a little coil of scrunched up multicore solder

Then it dawned on me - It looks like the previous owner of the power cable had 'fixed' the fuse holder by shoving a ball of solder down it. Over the years this had oxidised and while it would pass enough current to read on a multimeter it wouldn't pass enough to power the satnav

I temporarily bridged the fuse holder and the satnav worked fine I've got a spare inline automotive blade type holder which I'll replace the 'fixed' one with.

Two hours fecking around because of someone else's horrible bodge job

 

[Stewart H]

Scary , you want to get a cut off bolt in there quickly
Bodger, moi

Stewart

 

[earthmover]

Reminds me (with something of a shudder) of what we used to do to keep crushing plants running in the late 80's. These things have flywheels the size of a small car, but can be rendered inoperative by a 50p fuse, and there were hundreds of the buggers! Because of the vibration and the typical English weather, all the electrics would be wet and hanging off it's rails. Just the thing for two ham fisted muppets to start poking screwdrivers into, and jamming strands of copper wire across to see which of the (solid) fuses had blown. Was lucky to only get knocked on my arse twice by this method, especially as it was 440 volt.
H & S would have had a field day.
Mark

 

[Buz]

Silver foil usually works for me...or just cut out the fuse and twist wires together, should put selotape round the join tho, jobs a good un

 

[Lord Snooty]

Reminds me (with something of a shudder) of what we used to do to keep crushing plants running in the late 80's. These things have flywheels the size of a small car, but can be rendered inoperative by a 50p fuse, and there were hundreds of the buggers! Because of the vibration and the typical English weather, all the electrics would be wet and hanging off it's rails. Just the thing for two ham fisted muppets to start poking screwdrivers into, and jamming strands of copper wire across to see which of the (solid) fuses had blown. Was lucky to only get knocked on my arse twice by this method, especially as it was 440 volt.
H & S would have had a field day.
Mark

Where's The Slow Granger when you need him most

 

[rob mac]

should put selotape round the join tho, jobs a good un

That's so gash, everybody knows you need to use Elastaplast on motorbikes cuz of the wet

 

[Buz]

That's so gash, everybody knows you need to use Elastaplast on motorbikes cuz of the wet

Thanks, that explains a lot now..... wonder if i can raid the 1st aid box at work, stationary cupboard as easy, it didnt move

 

[davegs]

Fuse

Obviously someone had put in the wrong size (length wise) fuse so needed to be packed out don't EVER use silver paper as this carries so much current it wil be like a solid cable, anyone whopse seen the results of fitting it in 30a mains fuses will now what I mean! mini nucleur blast I kid you not!
dave gs.

 

[DutchBryn]

Afternoon Matt,


Well I couldn't hear you from here, so obviously the air in Macc wasn't
all that blue..

Connecting to pilot bulb? All Dave's idea, wasn't it?

Anyway, all's well that ends well. (I'd've gone for crimp-terminals,
for my own reasons, though.)

Hope all is well, now.

B.

 

[MattW]

Afternoon Matt,


Well I couldn't hear you from here, so obviously the air in Macc wasn't
all that blue..

Connecting to pilot bulb? All Dave's idea, wasn't it?

Anyway, all's well that ends well. (I'd've gone for crimp-terminals,
for my own reasons, though.)

Hope all is well, now.

B.

Yep - all working fine now

I had a bad experience with crimps once (however I've never had a set of good quality crimping pliers which may have had something to do with it ). I can always unsolder the connections I made to the pilot bulb crimps in order to return it to standard if need be - although not as conveniently as you

 

[DutchBryn]

Well, I'm just pleased nothing went bang permanently.
Long weekend now, too...

 

[MattW]

Long weekend now, too...

Yup

 

[davegs]

Crimps

Yes, get a pair of crimping pliars, I always used to use side cuteers and always thought "one last crimp to make sure" and cut the bloody thing in half!
Not a happy bunny!.
Dave gs.

 

[MattW]

Yes, get a pair of crimping pliars, I always used to use side cuteers and always thought "one last crimp to make sure" and cut the bloody thing in half!
Not a happy bunny!.
Dave gs.

I have got some crimping pliers, but they are cheap pressed steel jobbies (rubbish).

As with all tools, you get what you pay for I guess