I could give the bi-polar one a go if I knew what the signal was supposed to be.
It's an AC signal, your tachometer is a frequency meter. Got a signal generator? If not, don't worry. You have a broken tachometer in-hand, seems to me that the worst that can happen is that you end up with a broken tachometer. What have you to lose? I'd start with resoldering, and checking/replacing electrolytic capacitors.
In the later 107 clusters there is a single ground, in the speedo, and it's easy to fry the trace, such as by dropping the clock power line against the back of the cluster as you take it out of the car. The whole cluster gets pretty freaky after that. -- Jim _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
