Its happening all again :( Fuse STILL blowing??

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Fireman Ash
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Tue May 05, 2009 8:15 am

I have an 82 Ser.80 Spanish Jet 200 which is 6V DC with indicators, battery, reg/rectifier etc. Apologies for my electrical ignorance but over the last 2 days the 8 amp fuse (on battery charging circuit) has decided to commit suicide and keep blowing. Sticky's wiring diagram for this system shows an 8 amp fuse however if you calculate the potential total wattage for all lighting and auxiliaries with relays etc. by dividing by the oltage e.g. 6v I would need around an 11 amp fuse. With an 8 amp fuse anything over 48 watts theoretcically should blow it. Or am I completely off the mark? :shock:

It may be that something is shorting but nothing is obvious. Have checked all the spaghetti under the headset too and all seems ok. It may be the rear switch (2 pin) but I haven't checked yet. I've had probs before whereby the connectors do not hold the bullet connectors in tightly and they may be loose under the rubber cover (indian pattern switrch - pants).

Any suggestions from any scooter electrical wizards would be more than welcome as their ain't much hair left to pull out and eating carrots to see at night on my scoot doesn't impress the local constabulary as an alternative lighting option!! :( :(

Cheers all

Ash, Torquay
Last edited by Fireman Ash on Mon May 25, 2009 7:52 pm, edited 2 times in total.

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coaster
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Tue May 05, 2009 9:01 am

I think you've partly answered your own question Ash. If the problem has only just come on over the last few days and the 8 Amp fuse was fine before, then something in the circuit has altered and something is causing excess current to be drawn.

Have established what is switched on when the fuse blows? If not, I would suggest turning all lights off then turn each one on individually to see if any one of them causes the fuse to blow on it's own.

Looking at the diagramme for your Jet it looks like it would be relatively easy to split the circuit by disconnecting sections at the junction box. That would be worth a go to issolate your search

Does the battery function ok, i.e. does it hold a charge? Do you have an ammeter/volt meter?

That's about all I can think of at the moment, hopefully JIMS or Firedp will be along soon ;)

Fireman Ash
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Tue May 05, 2009 1:35 pm

Thanks mate for your advice.

In terms of the blowing a fuse, where, when etc. thats what is not consistent. It can be if the lights are on/off etc so that dioesn't seem to help. I thought it was following when the back brake was a applied but why that would happen, I'm not sure. If it is shorting around that area then that may. I will check the rear brake switch this week and I guess the problem will either be a short somewhere or excessive voltage via a defective Reg/Rectifier, which I'll also need to measure with a multi-meter.

Just when I thought it was safe to enjoy my scoot!! :x

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coaster
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Tue May 05, 2009 2:59 pm

As I said before, JIMS and Firedp are way better at this sort of thing than I am but I'm reasonably sure that a defective rectifier/regulator would not cause your fuse to blow. More likely to cause lights to blow :?

Have you checked the wiring ton the front frake light switch? if they are disconnected it's possible one of them is touching earth intermittantly.

Fireman Ash
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Tue May 05, 2009 4:45 pm

Never really gave the front brake light switch any thought but maybe I should now. Thanks again bro :|

Fireman Ash
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Tue May 05, 2009 8:01 pm

Just returned from the garage and it would appear that it may be a dodgy rear brake switch (SIL tatt!) as the internal female connections are looser than a whores knickers and as I was attempting to fit after re-connecting the bullet connectors it fused....just need a decent 2 holed Italian pattern switch now. The last fake bakerlite Beedspeed SIL one (before the current replacement) just collapsed when the brake was carefully returned back into position..... :? :o :flaming:

Fireman Ash
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Wed May 06, 2009 7:52 pm

It would apear that the electrical demons have returned!! Thought that the fuse blowing was due to my rear light switch however after running without it today and on the way home from the fire station it blew again!! :x so it's back to the drawing board again or rather Stickys wiring diagram. Looks like I will need to start stripping some components to try to identify the cause of the short circuit.

Any help by you experts would be great as I'm going madder than George Mad of Madbury!! :cry:

I await any help armed with my minature multi-meter and new 8 amp fuses!!:shock:

Cheers all

Ash, Torquay

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jonny snatchsniffer
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Thu May 07, 2009 3:28 pm

your fuse hasnt got f on it by any chance has it ?

Fireman Ash
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Thu May 07, 2009 6:29 pm

As in??? :?

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jonny snatchsniffer
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Fri May 08, 2009 8:06 am

as in 12v 8f or similer as f denotes fast blow fuses and if you have a power spike when the brake light goes on for example it will blow, you can get time delayed blow fuses these will have a t on them

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