ScotlandCoordinator Posted April 22 Report Share Posted April 22 (edited) Voltage Regulator ? Out for drive it day on Sunday with Forth & Borders Group touring and lunching in the glorious Scottish Borders and unfortunately one of our members cars stopped and looking for some advice here ! There appears to have been a live wire with a connector spade attached underneath the dash, which caused quite a firework display ! Car stopped and only way to get it running was a jumper wire from the solenoid to the ignition fuse. The fuse itself is ok, NO power on either side. Downloaded a circuit diagram, and found (with a multimeter) the following: E - connected to earth ok A - has 12V A1 - has 0V F & D - appear to be connected to the Dynamo although no continuity checks were done. And, with the engine running there was 12.8V across the battery, which to me meant it wasn't being charged. So, my question, if the battery isn't charging and there's no 12V output from A1, could that mean the large current from the short circuit which melted the loose spade connector, could that have damaged the Voltage Regulator. And, is there a fuse inside or any serviceable parts that could be fixed to allow 12V at terminal A1 ? Hope that makes sense. Edited April 22 by ScotlandCoordinator Wrong spelling Quote Link to post Share on other sites
Lebro Posted April 22 Report Share Posted April 22 (edited) If "A" has 12V, & "A1" has 0V, then, yes the regulator is damaged, the two should be connected inside via a coil of a few turns of quite thick wire. "D" is a thick wire going to the output of the dynamo, "F" is a thinner wire going to the field winding of the dynamo. "E" goes to earth (chassis). "A" & "A1" both are wired into the other parts of the loom (fused or otherwise) both should always have 12V (approx) on them, as they are connected to the battery via the ammeter. Bob Edited April 22 by Lebro Quote Link to post Share on other sites
ScotlandCoordinator Posted April 22 Author Report Share Posted April 22 Hey Bob, Thanks for that, do you know if there’s a fuse inside the regulator, some articles saw not and some say there is ! Quote Link to post Share on other sites
Ralph Whitaker Posted April 22 Report Share Posted April 22 On the early type control box as shown above the fuse is not "in" the control box, it is quite visible on the outside connecting 2 terminals. To my knowledge there are no changeable fuses inside later control boxes. Quote Link to post Share on other sites
Lebro Posted April 22 Report Share Posted April 22 (edited) The diagram above is not of your regulator, as said above there are no fuses inside. Ok, looking at the wiring diagram, A is connected direct to the ammeter, & the other side of the ammeter is connected to the battery. That suggests that the car should still be charging ? A1 goes to the lighting switch, & ignition switch. Neither circuit is fused, only after igniton switch is anything fused. Conclusion is that the shortout caused a large current to flow from battery, through the ammeter, through the A to A1 coil in the regulator, then to the shorted wire. result was the internal coil burning out, or somehow becoming disconnected inside the regulator. Bob Edited April 22 by Lebro Quote Link to post Share on other sites
RobH Posted April 22 Report Share Posted April 22 You seem unsure whether the battery is being charged - what does the ammeter show? As Bob says, 12v should be present on 'A' all the time If it isn't it's likely the heavy-current loop inside the ammeter has become detached. Quote Link to post Share on other sites
ScotlandCoordinator Posted April 22 Author Report Share Posted April 22 That's brilliant, we've ordered a new Voltage Regulator from Moss, and I'll update progress... Quote Link to post Share on other sites
Richardtr3a Posted April 23 Report Share Posted April 23 (edited) I did add to the Regulator problems in a recent post on here. The best end to years of worry and problems was a solid state regulator from Classic Dynamo and Regulator. I ordered a 12v, positive earth , 22 Amp version and this has ended the problems with the RB106 which needed regular tuning. Some of the new Regulators are made in the Far East and use second hand copper to reduce the cost. This makes problems requiring servicing. My Solid State unit is reliable just like a modern car. Good luck Richard & B Edited April 23 by Richardtr3a correct amps Quote Link to post Share on other sites
ScotlandCoordinator Posted April 24 Author Report Share Posted April 24 Took old unit out this morning and found one of the connecting “wires” had burnt out, I guess the 12v short had drawn so much current that it melted ! Please wait while image is uploading... Quote Link to post Share on other sites
Lebro Posted April 24 Report Share Posted April 24 If you can bridge the gap with a suitably heavy gauge wire (soldered) then the reg may well be ok to re-use Bob Quote Link to post Share on other sites
RobH Posted April 24 Report Share Posted April 24 To be honest that looks more of a crack than anything. The ends don't look melted. There is blackening at the LH end of that link though. Quote Link to post Share on other sites
RogerH Posted April 24 Report Share Posted April 24 I do not think it is a crack (unless the corners have broken away) the crack face is not complete. Almost as if the outer edges have been chamfered. There appears to be no burning but I do not think it is a crack. Roger Quote Link to post Share on other sites
Lebro Posted April 24 Report Share Posted April 24 Strange shape, but either way it's broken & won't work till its repaired. Bob Quote Link to post Share on other sites
ScotlandCoordinator Posted Wednesday at 06:58 AM Author Report Share Posted Wednesday at 06:58 AM Good morning, Just catching up, up close it definitely looks melted and bearing in mind the fireworks show inside the cockpit just before the car stopped running I'm fairly sure that it melted due to too much current flowing, maybe it was already cracked and was a weak point, I guess we'll never know. We did bridge the gap with a heavy duty wire, but we also installed a new one as we already had purchased it. And, the repaired one was wrapped and placed in the boot as a spare. Thanks for all of your help guys, really appreciate it, what a brilliant resource, hopefully see some of you at Malvern. Stephen Quote Link to post Share on other sites
Z320 Posted Wednesday at 07:54 AM Report Share Posted Wednesday at 07:54 AM (edited) The question is, why did it melt? To fit a new one maybe is not the solution but the next problem. I would not drive this way! Ciao, Marco Edited Wednesday at 07:55 AM by Z320 Quote Link to post Share on other sites
RobH Posted Wednesday at 08:33 AM Report Share Posted Wednesday at 08:33 AM Presumably the loose wire under the dash shorted to earth and did this in the regulator. If the current was high enoughto burn out that metal strip, what damage did it do inside the wiring loom? There has been another recent thread about a short circuit and the photos there of melted insulation show what may have also happened on this car. If there is significant insulation damage in the loom of this car too, there is a high likelihood of further fireworks some time in the future. Quote Link to post Share on other sites
Richardtr3a Posted Wednesday at 09:41 AM Report Share Posted Wednesday at 09:41 AM Go for a solid state and end the present problems. There will be other problems but not with the regulator. My new one is Trouble free for now ?? Richard & B Quote Link to post Share on other sites
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