Old Fluke 77 meter read way off after a bench drop, fixed it with a $4 part

Dropped my Fluke 77 on the concrete floor at the Burbank hangar last Tuesday and noticed the AC voltage readings were bouncing around 12% low. Turned out the rotary switch contacts were just dirty from the shock, not broken. Cleaned them with contact cleaner and a bit of dielectric grease, now it's spot on against the lab reference at 120.7 volts. Anyone else had a meter go weird after a drop and find it was just the switch instead of a dead chip?

2 comments

2 Comments

elliotburns4d ago

Did you see that video where some guy fixed his old Simpson 260 the same way after a drop? Seems like those rotary switches are always the weak point on vintage meters, right?

ninal914d ago

I get what you're saying about the rotary switch being the weak point, but I actually see it differently. Those Simpson switches are built like tanks compared to the cheap plastic ones in modern meters. More often than not, the real issue after a drop is a cracked solder joint on the resistor board or a bent meter movement pivot, not the switch itself. The switch might look scary, but it's usually just dirty contacts that need a good cleaning. Plenty of old meters I've worked on were fixed with a simple reflow and a bit of contact cleaner. So I wouldn't blame the switch so fast, it's usually something else hiding behind it.