1989 n13 sunny - keeps blowing 10amp meter fuse

Hi Guys
Had this issue start yesterday, car started fine then all of a sudden the meter fuse blew, this intern stops the instrument lights (apart from the battery light) the fuel and temp gauge, the indicators and I think the reverse lights (but I need to make sure).

I changed the fuse and it was fine but as soon as I started driving off it blew again. I repeated and the same thing occurred.

the engine now runs a little s**t, at lowish constant speeds like 20mph it starts to splutter and occasionally jerks a bit. I've checked all other fuses, relays which I think are okay but I don't know how to check these.
Does anyone have any ideas as to what the problem could be? I fitted a rev gauge the other week (to the stereo loom) and could have trapped a wire? I've looked at all the wires I can see without stripping anything down and cant find anything obvious. When the fuse goes the battery light comes on quite dim and flickers from time to time too!

its a 1.6 carb manual, 78k miles, any help would be much appreciated as I've got to do a 200 mile round trip and need the indicators to be working !

cheers
Rob

I would be inclined think it could be linked to rpm gauge installed, is that running signal off ignition coil.
If it don't blow fuse stationary with engine off but ignition on and only blowing if rev it that would help point towards rpm gauge/wiring issue .
Probably easiest place start looking .

yeah I suppose that makes sense, ni assumed because its wired up to the stereo positive and negative then it wouldn't be that but yeah that does make sense that it could be the rev gauge, yeah its wired to the ignition coil's negative terminal as instructed when wiring. it now blows on startup and runs kinda rough. could the wire have melted to the coil? its weird that the rev gauge still works though?
But yeah il have a look on my break, the wiring was a bit rushed so I wouldn't be surprised if its that, strange how it worked for at least a week trouble free though!

Cheers
Rob

disconnect trigger at coil as that would be quick initial test .
rpm gauge just seems best place to start and more so as blows as soon as engine running, normally constant blowing fuses are down to aftermarket wiring or faulty component .
could be worth checking alternator output just in case that off and again another quick test with a multimeter .
Electrics are pretty basic on those carb engine n13s, hopefully is rpm gauge or wiring related as would be easier and probably cheaper .

right I disconnected the rev gauge from the coil and the problem still persists so next thing I'm going to do is disconnect the positive and negative from the rev gauge to the wiring loom and see what happens then (although its on a different circuit)

Il also check all the bulbs, would a blown bulb be a cause of this or is it cleaver enough to bypass? tomorrow at work il check the alternator when I have access to a decent multimeter, ive started taking the dashboard apart to get to the wires and have a look.

I've done some googling and if the reverse lights aren't working too could it be a bad earth from around that area causing the issue?

Cheers

Could be but bit strange if only does it when running, if light circuit you would expect blow with just ignition on !
Good idea rule rpm gauge out and check alternator then dig deeper .

Tbh I normally put the lights on after I start the car. but regardless the fuse goes when I start the car straight away, I need to find out everything that runs of that one fuse as it must be something ignition related?