Date: 31-03-20  Time: 17:38 PM

Author Topic: Gen 1 electrical problems. Help me understand  (Read 290 times)

KeefyW

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Gen 1 electrical problems. Help me understand
« on: 16 January 2020, 02:01:27 PM »
Bought a FZS1000 with dead start circuitry. Long story so will shorten:
Found open circuit sidestand and neutral switches. Replaced but still no go. Tested all relevant loom wiring for continuity. All good. All other electrical items working perfectly - clocks, lights. rad fan, exup etc..

Turned attention to the starter cutoff relay. I had two of these as previous owner had replaced the original but didn't fix. Tested the diodes in both units. Two in each were closed circuit (0 Ohms) both polarities. Rather than buy another relay and blow that too I decided to open them up and take a look. The PCB tracks from the cathodes of both blown diodes in both units leading to the pinouts were cooked/open circuit and the common anode track to its pin had got hot too but not open circuit. Some how an over-current had occured.
Soldered in two uprated diodes and repaired the tracks. Plugged it in and all was well. Started perfectly and all the neut/clutch/stand switch interlocks worked as expected.
The only path I can see for an over current situation is for the blue/yellow - L/Y wire from the clutch switch to somehow have +12V on it then running to ground via the neutral (sky blue - Sb) and/or stand switch blue/black - L/B). As I never found the original, diode popping fault I will always worry that it will happen again. I always carry the repaired second relay in case.

I've attached a pic of the relevant bit of the circuit diagram to hopefully make it clearer what I am wittering on about.

Any ideas what caused this ? All thoughts gratefully received.
PS Love riding the bike. I can see why they have such a fan base.
« Last Edit: 18 January 2020, 02:54:40 PM by KeefyW »
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unfazed

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Re: Gen 1 electrical problems. Help me understand
« Reply #1 on: 16 January 2020, 04:05:07 PM »
The most likely cause is someone trying to steal the bike, cut and twist  all the wires of the ignition together. This shorts out the neutral sidestand and starter cut out to the battery. If the neutral and sidestand switch were not disconnected/replaced before replacing the Starter cut relay it would fry the diodes again

KeefyW

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Re: Gen 1 electrical problems. Help me understand
« Reply #2 on: 16 January 2020, 05:54:21 PM »
Hi unfazed. Thanks for reply. No one tried to steal it for sure. The loom, like the rest of the bike, is in good nick. You have given me food for thought but I really struggle to see how both the switches being buggered would cause the fault. The permanent open circuit of the NBG switches would be a condition of normal operation i.e. in gear, stand down. When the original fault occurred it was being ridden quite normally and with no warning.

I suspect that the same fault buggered the switches when it fried the diodes/pcb. The switches are designed to carry just a few hundred mA but it would take several amps to do that sort of damage to the relay unit. Where the hell did those amps come from ???
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unfazed

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Re: Gen 1 electrical problems. Help me understand
« Reply #3 on: 16 January 2020, 09:52:53 PM »
Yes, but from a theft point of damage if the initial problem had not been repaired  or repaired incorrectly it would fry the diodes again.
Saw the same thing happen on an old RI.
Since you are confident it was not stolen recovered, the only thing I could suggest is to check the loom where it rubs the frame coming out by the frame cross member under the tank and going into the plastic shroud which covers the connector blocks. Check from the connector block up to the left handle bar and the ignition switch.Check the cable from the ignition at the base of the ignition switch as there is a cable tie there which is often pulled tight enough to damage the wires.

His Dudeness

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Re: Gen 1 electrical problems. Help me understand
« Reply #4 on: 16 January 2020, 10:05:37 PM »
You did well to figure out that problem! Have you got any pics of the inside of the cut out relay? Would be interesting to see what it looks like.

KeefyW

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Re: Gen 1 electrical problems. Help me understand
« Reply #5 on: 18 January 2020, 12:17:38 PM »
Yes, but from a theft point of damage if the initial problem had not been repaired  or repaired incorrectly it would fry the diodes again.
Saw the same thing happen on an old RI.
Since you are confident it was not stolen recovered, the only thing I could suggest is to check the loom where it rubs the frame coming out by the frame cross member under the tank and going into the plastic shroud which covers the connector blocks. Check from the connector block up to the left handle bar and the ignition switch.Check the cable from the ignition at the base of the ignition switch as there is a cable tie there which is often pulled tight enough to damage the wires.
Got full history including original bill of sale and PDI document. Recent HPI (2015) so defo not nicked. Also, I took the loom out and put it through a thorough inspection. No chaffing and all metered out end to end. Didn't look at handlebar cables though, except to clutch switch. Will have a close look down there. Thanks for your comments !
There is a circuit from the clutch switch via the ignition switch to the alarm (removed years ago!) then on to the ignitor. If that is not earthed via the ignition switch the igniter might try to earth through aforementioned diodes and neut or stand switch. Ignition switch was not in a good state but lots of WD and wiggling made it better. Any idea how much current the ignitor ECU takes ?
« Last Edit: 18 January 2020, 12:47:26 PM by KeefyW »
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KeefyW

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Re: Gen 1 electrical problems. Help me understand
« Reply #6 on: 18 January 2020, 12:27:15 PM »
You did well to figure out that problem! Have you got any pics of the inside of the cut out relay? Would be interesting to see what it looks like.
Many thanks. I got so many splinters scratching my head over this one !
I have no pics and would have to undo all the gaffer tape to remove the cover and take some. If you or anyone else have a need for pics I will get some for you but if it's just idle curiosity I'd rather not.
All that's in there is two miniture relays with their flyback diodes, four more diodes for the 'safety' interlocks. There are two more, with a zenner and an 8ohm resistor. The last bit is not used on my Fazer.
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His Dudeness

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Re: Gen 1 electrical problems. Help me understand
« Reply #7 on: 18 January 2020, 01:08:25 PM »
Don't undo anything only asked out of interest on the off chance that you took some pics during the repair. Thanks for the info

KeefyW

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Re: Gen 1 electrical problems. Help me understand
« Reply #8 on: 18 January 2020, 02:50:27 PM »
Hey your Dudeness ! I thought I'd like some pics for posterity so untaped the spare one and got snapping. Sending them to you as you were decent enough to show an interest.
Glad I did. Found a dodgy bit of soldering. See attached pics. I replaced D4 and D8 with 1N1004 type diodes; a bit beefier and just fit. One buggered track on the component side can be seen running from the cathode on D4, under D8 to pin 9. It is cooked under where D8 is. Flip it over and you can see the repairs and the 2nd burnt out track runs to pin 13. The failed bit can be seen right next to the repair.
This was the prototype. The second one is a lot tidier and is fitted to the bike but I ain't untaping that ! Cheers.
« Last Edit: 18 January 2020, 02:56:33 PM by KeefyW »
No job is so urgent it can't wait until the last minute.
No problem is so great you can't run away from it.

His Dudeness

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Re: Gen 1 electrical problems. Help me understand
« Reply #9 on: 18 January 2020, 06:06:37 PM »
Nice one for taking the pics ;) Very interesting to see the components inside. Well I think so anyway :lol

KeefyW

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Re: Gen 1 electrical problems. Help me understand
« Reply #10 on: 19 January 2020, 04:09:59 PM »
You're welcome. I think I must conclude that the original fault's cause will never be known. It's sold now so I don't have to worry. I was completely straight with the bloke who bought it and he bought it anyway. Gave me asking price. Must have been too cheap.

A very brief dabble into the world of 998s ! Although I've had it for two years, I only rode it three times, last week after I finally got round to fix the foccer. I thought it might take a while to sell so I could go have some fun on it on a dry road but never got the chance.
Oh well. The Duc has half the bhp but is a lot more nimble and also great fun to ride. Just not in January  :b . I'll keep an eye on the forum but probably won't be posting much.
No job is so urgent it can't wait until the last minute.
No problem is so great you can't run away from it.