I have another tach amp going bad in my 300SD. I recall seeing some discussion here about how to maybe salvage this one, before buying a new one. It's intermittent, but it's not the contact pins, I've cleaned and reseated them several times. Any other tips? Seems like it could be a bad solder joint inside? But I can't figure out how to get the innards out of the top of the cap withour breaking it apart.
TIA!
Fooling with it is a losing proposition, IMHO. BUT I've pulled the guts from the cap and placed a bit of foam inside and snapped the amp back into the cap. It worked - for a while. Now its intermittent - again.
This is one of the few weaknesses of this otherwise fine model.
'80 300SD @ 110K miles
It's not a question of the pins not being clean, it's that they don't make enough contect. You unscrew the barrelpull up (very) hard, stick a small rock in there and put it back and that "fixes" it for some period of time ranging from 6 months to 3 years. I'm assuming the 116 tach am is the same a the 126 but I relaly don't know.
rock in there
The directions say to:
"It's really easy to fix though, you just unscrew it, then pull off the top (that can be kind of tough, just pull); once you have it off, remove the tach amp from inside the casing"
But, did they change the design of these? The problem is how do you remove the electronics from inside the top of the cap? The part with the electronics and pins is floating/turning in the top of the cap and I don't see what holds it in or how to pull it out from the top of the cap.
I dunno if they change dit or not. I don't think so but looking up bothpart numbrs would probably give you an authoritative answer.
It is, in technical terms "a bitch" to remove it. I used needle nosed pliers.
But what do you grab hold of with the needle nose pliers? Again, inside the cap is the part with the pins showing that rotates/floats inside the cap. There is nothing to release it and if you pull on it, it doesn't come out. It seems to me like it may have holding tangs/fingers that compress when it put together and then grab onto the ridge of the cap lip from behind. Meaning it looks to me like it won't come apart without breaking it. Am I missing something?
Yeah that's the impression you get alright.
I can't even remember if it has male or female ends. I think they're female and I used true needle nosed pliers and stuck both sides in a hold each and wiggled it till it came downa few millimeters when was able to pull it out with my fingers. Look on the bright side, it's not hard to get it back in :-)
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