Combination meter diy

The problem is that something is causing C70 to fail, the solution might be to find out what is causing the failure. Replacing the component is akin to replacing a blown fuse without determining the cause!

 

It is not obvious what is the problem:

1. Did C70 actually fail or was a solder joint the problem?
2. If the problem is with the solder joints then do you have the correct tools/skill to replace surface mount components?
3. If C70 actually failed, how did you know what component value to replace it with?
4. The cost of a new capacitor is typically very small, in the pennies, shipping will cost much more than the part itself, mouser.com is one source (assuming you know the specs of the capacitor including capacitance and voltage rating.)
5. Referring to your photo, there are two solder joints below C70 associated with a multi-pin connector which look pretty bad.

 

…as I mentioned in my earlier post, I think your problem is unlikely to be fixed by simply replacing the blown component. You might be better advised advised to seek the source of the problem! Good luck! (…and if you still don't understand what I'm trying to tell you, the very best of luck! (…because you're gonna need it!))

 

When you say the "dash is lit up", I assume you mean that the combination meter is working right now?

I agree that 6R8 = 6.8 ohms, so that is a good value regarding resistor R111. Did the replacement resistor remain at 6.8 ohms or did it also blow?

How did you determine that capacitor C70 had failed? Did the original C70 have any markings on it?

It looks like the replacement capacitor is not soldered very well to the pads. You are right that there is no way to determine its value since there are no visible markings - unless you use a capacitance meter to measure it.

 

…the only other advice I have might be that when you eventually determine the value of the blown capacitor, it might be more economical to try to get a bulk deal and buy several hundred, since until you find the cause of the problem you'll likely use a lot of them!

 

I just had my Combo meter repaired by a guy on Ebay. When I received it back, I could see which component was replaced because he did not clean off the solder flux. It was the power transistor, Part # "NEC C4552" . I have circled it on the picture. So far, it has worked flawlessly.
I just thought all of you would like to know.

 

I always wondered if these repairs last... any update on this post would be helpful