Alternator short circuit has left issue

[bertavfc]

Hi, having converted from a Dynamo to alternator recently whilst undertaking other numerous jobs, I encountered a issue (mostly due to my negligence!), In my haste I left one of the hot wires from the alternator to the solenoid against the exhaust minifold, after 20 mins of running well (at idle to check for leaks), the insulation melted and the ignition system shorted, sending the ammeter off the scale and killing ignition, whilst investigating the issue the problem was intermittant (as the wire was vibrating aginst the manifold), once I'd realised the cause and rectified it the issue is now permanent?. As soon as you turn the key the ammeter drops off the scale and everything is dead, I've isolated the battery to be on the safe side and was wondering as to if anyone could give me some pointers as to what to test, many thanks in advance, Rob.

[PeterK]

Hard to diagnose electrical faults from behind a keyboard, but I suspect that the damage is likely to be
- shorting of the wire has fried the alternator (easiest to fix)
- over-heating (shorted) alternator wire has melted the insulation of one or more neighbouring wires
- something else fried

So where I'd start is.....
Simplest first test is to disconnect the alternator (pull the plug out of the back of it). If you can turn on the ignition without the ammeter going off the scale, then a new alternator is required.
If a short is still present, then with the alternator wire disconnected from both the alternator and from the solenoid, check for continuity between the thick alternator wire and earth. If continuity is there, then you'll need to strip the outer loom wrap to find the fault and effect a repair.
With the battery disconnected, check for continuity to earth from the solenoid at all three ignition switch positions. Various items will give continuity to earth, so rather than just using the 'bell' option, you'll have to look for a low impedance reading. If you find a short here, then I'd pull the dash, remove the loom wrap and check individual circuits for damage.

Peter

[bertavfc]

Hi, thanks for the reply, the good news is I pulled the 10 amp fuse and all was well, started the engine with alternator connected and all readings including ammeter were sound, I suspect perhaps my solid state voltage reg could have been damaged, will dig a little deeper, regards, Rob.