Erratic readings on Volts and Ohms. that don't make sense . Tried to use Duty Cycle to convert to Dwell and never changes . Tried new battery . same thing . I hate to spend money for new leads to find out its internal
My 88 has 2 internal fuses that were causing me erratic readings, I would try replacing those first and then recheck operation. One fuse is for the ammeter, the other is for the voltage/ohms readings.
UPDATE !! Both fuses are blown . And not by me . I don't swing that way . Fuses should be here tomorrow so I'll give them a shot first .. Its a Fluke 88 and the RPM's were screwing up along with Duty Cycle , volts and Ohms
If the meter works after you replace the fuses, solder an inline fuse holder in the positive lead and install a 10 amp fuse. It's much cheaper and faster to replace the inline fuse than taking apart the meter to replace the internal fuses. I did this probably 25 years ago with my Fluke 87. I haven't had to replace the the internal fuses since.
If the fuses don't fix it, check your leads. My MAC multimeter was doing similar things and it was my leads. Replaced them and good to go.
My leads suddenly melted with a POW!. Im surprised your fused went bad with no evidence on the leads.
It's not hard to blow the fuses on them if the leads are in the wrong ports, or if the amp draw exceeds 10 amps. Also, if the meter was set to read resistance, and the leads got hooked to B+ and ground, it may blow the other fuse. We keep a few of each on hand. Happens to the best of us. Lots of things can go awry when testing things... The fuse is there to protect the leads (and the rest of the meter). If your leads melted with a pow, you either touched the wrong thing or your meter has a massive internal short.
Haha its quite easy to melt the leads ive done a few. But thats the order of destruction. Leads , fuse.
I had a Fluke safety analyzer that kept blowing the on board pico fuse. I eventually installed a fuse holder for a glass type fuse.
Just an update . I replaced both fuses and it appears to have fixed the problem . I can't check the Duty cycle or RPM readings as I don't have one of my cars here that have points . I can try the RPM on the wifes 4.3 Blazer though . Volts , AC or DC , and Ohms check good .