Hello, the tachometer in my 1st gen 4runner suddenly died, and I pulled it open to look inside to see if it was damaged inside. Upon looking inside, I saw rust on some of the traces and what i believe is capacitor fluid on the chip and a capacitor. The chip doesn't have any visible damage except for the crusties in the picture or rust on the pins underneath. I'm wondering if the chip is likely damaged from current passing though it without the needle moving or the fluid resting on it as I don't really want to reverse engineer the board if brains are dead. There is also a resistor under one of the upper left capacitors that is quite toasty looking, but I forgot to take a picture of it.
Before this all happened, the tach was also inaccurate past 3000 RPM.
I have checked grounds, coil signal, and power to the tachometer, and all are good.
Thanks!

 

Never mind .

 

Scrub the board down and obviously if you see leaking capacitors replace them. Less a detailed schematic it's hard to make any further suggestions..

Ron

 

Would you replace all of the capacitors or just the leaky ones?

 

What I wanted to say in my previous post;
Difficult to see from the photo, but it does appear that the magic smoke did escape from the IC. At least some.

 

What I wanted to say in my previous post;
Difficult to see from the photo, but it does appear that the magic smoke did escape from the IC. At least some.

I should have taken a different angle of the chip, but the casing of the chip looks fine excluding the flaky electrolyte on top of it. I'm more worried about if the chip could have been damaged because it wasn't getting the right voltages as the capacitor died.

I'll try and get better pictures tomorrow.