I bet those platform boots you wear are fekked at the heels now
No, but I nearly lost a flip flop
Repairing cut wires on 1200
- Thread starter darkhorse
- Start date
No, but I nearly lost a flip flop
Am I the only one wondering how the fek he managed to cut the wires
Anyhow i agree with disconecting the battery it's dead easy on a 1200 and might save hassel later, I've two good quality (well expensive-ish) soldering irons that have a voltage at the tip, one of them looks like a little arc welder when I try and solder items on the boat, 240v comes from the inverter so I can't disconnect the batteries before soldering unless i'm really quick
Shep
On most soldering irons the tip will be earthed, so you might have some sort of problem with the earthing on the inverter. Sounds like whatever you are soldering and the inverter earth have a voltage between them, which is probably not what should be happening.
Gas soldering irons do have some advantages on boats.
Myke Rocks
Registered user
Re: soldering
Shugie is absolutely correct.
Canbus systems are incredibly robust, and disconnection, or turnig off ignition is unneccessary, & disconnecting battery is pointless.
Canbus is an NPN or "Sink" system, where wires are grounded to make the circuit. Supply to each wire is 12v via an individual resistor network. Whether you touch it to 12v or ground, you can do no harm.
Myke
Shugie is absolutely correct.
Canbus systems are incredibly robust, and disconnection, or turnig off ignition is unneccessary, & disconnecting battery is pointless.
Canbus is an NPN or "Sink" system, where wires are grounded to make the circuit. Supply to each wire is 12v via an individual resistor network. Whether you touch it to 12v or ground, you can do no harm.
Myke
All sorted and back up and running
Dave
If you haven't soldered for a while get some practice in first. Pull a few wires out of your PC and see if you can rejoin those.
Get some heat-shrink tubing. The higher the ratio, the better.
Get some soldering flux (in a tin) and use fluxless solder. Dab the bare wires in the flux and then drag through a dob of molen solder on the end of your iron without trying to join the wire at this stage. When you have all the wire ends 'tinned', then start joining them (you won't need any more flux and only the smallest amount of solder on your iron (which acts as a heat-transfer medium only).
If you have three hands, so much the better.
Job done
Greg
PS Put a length of heat-shrink onto the wire before you join them. Use Mrs Darkhorse's hair dryer to shrink the tubing. Don't get flux on the hairdryer.
If you haven't soldered for a while get some practice in first. Pull a few wires out of your PC and see if you can rejoin those.
Get some heat-shrink tubing. The higher the ratio, the better.
Get some soldering flux (in a tin) and use fluxless solder. Dab the bare wires in the flux and then drag through a dob of molen solder on the end of your iron without trying to join the wire at this stage. When you have all the wire ends 'tinned', then start joining them (you won't need any more flux and only the smallest amount of solder on your iron (which acts as a heat-transfer medium only).
If you have three hands, so much the better.
Job done
Greg
PS Put a length of heat-shrink onto the wire before you join them. Use Mrs Darkhorse's hair dryer to shrink the tubing. Don't get flux on the hairdryer.
Some soldering irons do have earthed tips, some do not - I use both types all the time.
The ones that let you earth the tips by choice; normally have an extra 4mm earth terminal on the control unit for that purpose. Some unearthed irons have a surprising amount of leakage from the power supply to the tip (usually the cheap ones) - this can damage low voltage electronics.
If the the tip is earthed then you might inadvertently ground something that you don't intend to - for example a Canbus control input signal, which subsequently 'turns on' some power output that you did not intend.
I am not scaremongering - just suggesting common sense precautions that anyone 'skilled in the art' would do. The 1200s battery is a doddle to disconnect (unlike some of the earlier GSes) so a wise person would disconnect the battery before performing any work on the electrical system.
I doubt that there are many who know what a NPN open-collector, or FET open-drain circuit is let alone have a clue why it's used. An open-collecter output (as shown in the ZFE module diagram) IS a very robust way of switching high currents BUT these are still low voltage circuits that will not like high leakage voltages (from a cheap soldering iron) being applied to them.
Also, in any high current switching circuit there will NOT be any significant resistance in series with the output transistor collector, because, if there was, power would be thrown away needlessly and the circuit being powered would be not get the full 12V.
Always disconnect the battery (lift seat off and take off 2 battery screws, how hard is that, compared to risking a £1000 control unit) and use a decent soldering iron designed for use on electronic circuits and you will always be safe.
The world has moved on from magnetos and selenium rectifiers of old.
One can leads a horse to water .........
P.S. CANBUS is a control network, and really has nothing to do with the way the outputs are powered, but that's another story.
Didn't the delorean have a selenium rectifier in the back to the future film?
I wouldn't bother disconnecting the battery through a concern about the voltage on the soldering iron tip - it doesn't matter if the soldering iron tip is ground or not since the bike battery is floating (i.e. not fixed to something external). If desired, you coud happily connect any wire on the bike that takes your fancy directly to the earth of your house's ring main, or indeed to the live or neutral, and the bike would work perfectly well (just be careful getting on and off)*
However, with a bunch of exposed wires, the risk of shorting a pair of them together through the iron's metal tip is something that would make me consider disconecting the battery. It is perhaps unlikely that short-out with the iron tip would do any serious damage, but why take the risk? I can disconnect the battery in less time than it takes my iron to heat up.
* In principal some electronics can be so sensitive to electrostatics that it might upset them when they are first connected to charge-sink (such as your ring main). However, if the bike was that sensitive, it would be safer to plug it into the mains than get on it wearing polyester trousers.
judge
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screwing up your pc's is my job 
Bear
Registered user
The wiring diagram I have (from somewhere on the web rather than from BMW admittedly) shows the symbol for a PNP transistor in the middle of the ZFE module. I would have expected (although I accept that BMW do things in strange ways for reasons we mortals need not understand) that switching the supply to each electrical device, by using a PNP transistor, with the emitter to the positive supply, would be the obvious way to power devices. Using NPN devices requires a feed from the positive side of the battery to everything that uses electricity, whereas using PNP devices requires an earth connection which, being connected to the vehicle chassis, has less risk of short-circuiting the battery when the wiring loom abrades against the frame under the petrol tank (as it has on mine). Think about how the stop/tail light is wired. It has two filaments and the common connection is the sleeve on the bulb.
Nah - that was a Flux Capacitor - still trying to perfect it, but not there yet - still working on it.
Hmmm - do they do 'high side switching' with PNP transistors? They might, I will check, PNP's have always been harder to make with the same low 'on resistance' as NPNs and their gain is generally lower, but things have moved on in the last few years......
You are correct, they use PNP's and as you say this ought to reduce problems if a wire abrades and shorts to the chassis. What I dont know yet, is, are the control inputs to the ZFE 'active low' with internal pull ups or just 'normal' digital inputs? Will check the schematic again!
Either way one would not want power connected to the sytem while soldering, because the chance of activating some of the outputs or damaging inputs is real.
Bear
Registered user
It's more than 30 years since I last worked for a semiconductor manufacturer so I have no idea of what's easy to make with current (yes the pun was deliberate) technology. As far as I can remember Vce(sat) is the same for NPN and PNP devices at about 0.3 volts so there is no advantage in using one type or the other. Looking again at my wiring diagram, all the bulbs driven by the ZFE have a connection to the battery negative so I conclude that "high side switching" is how it's done.
Deleted account 220427002
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As i said use a gas soldering iron
Myke Rocks
Registered user
PNP/NPN switching
The NPN switching function I referred to earlier is an accepted industrial description of modern industrial electronic items such as PLCs or proximity switches, and I cannot overstate their robustness.
It simply describes the inputs as negative switched.
Around 20 years ago, due to a wiring error, I had a Mitsubishi PLC which had 110v ac put on approx 100 of the 24vdc inputs.
Consequence: No damage at all.
In the immoral words of Billy Connolly: I was shocked and stunned!
In more recent years, I have played heavily with Canbus switching, & found it to be very similar, with the ability to reject external electrical noise built in as standard.
Myke
The NPN switching function I referred to earlier is an accepted industrial description of modern industrial electronic items such as PLCs or proximity switches, and I cannot overstate their robustness.
It simply describes the inputs as negative switched.
Around 20 years ago, due to a wiring error, I had a Mitsubishi PLC which had 110v ac put on approx 100 of the 24vdc inputs.
Consequence: No damage at all.
In the immoral words of Billy Connolly: I was shocked and stunned!
In more recent years, I have played heavily with Canbus switching, & found it to be very similar, with the ability to reject external electrical noise built in as standard.
Myke
