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Post by kerry on Mar 10, 2015 20:41:48 GMT -6
Just wondering if anyone has ever opened up a tach to repair it? I have 5 tachs and I guess every one has been 'blitzed' by a blown voltage regulator.They all rattle with pieces of solder that has burned away from the contacts.I managed to pry back the rear of the bezel and pull it apart.It appears to have burned out a resistor? maybe between two points.Any ideas?If I had a clue what it was I might try to replace and resolder.Worse that can happen is it doesn't work or it burns out again.Needle is free and all is clean inside. Kerry
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Post by daren007 on Mar 10, 2015 21:07:07 GMT -6
Piece-o-cake. Just re solder the resistors. dc
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Post by kerry on Mar 11, 2015 13:28:58 GMT -6
Hey daren007, Only problem I have is that there is a resistor or something that has burned away between two of the points you can see in the pic - left side burn mark in the plastic.The only stuff that came out of the tach body was solder from what I could see. Attachment Deleted Kerry
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Post by daren007 on Mar 11, 2015 16:33:06 GMT -6
Is the burn from solder or was there actually something soldered there. Take apart another tach and see what you can find out. There are plenty good tachs with faded dials to choose from. The ones I repaired were the plastic case ones. There was usually a resistor laying loose in them.
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Post by kerry on Mar 11, 2015 19:22:21 GMT -6
Yes I have 4 more and all 4 have loose solder floating around. One I have has a metal case - older than '74? One I have the bezel inside is really bad from corrosion.That one I will cut apart.May be able to salvage a resistor from it.Have to make 2 good ones eventually anyway. Kerry
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Post by kerry on Mar 28, 2015 17:51:02 GMT -6
I found another tach in my pile of parts that works! However I took two other tachs apart to find the exact same thing.They also burned at the same point between the two solder points on the left side of my pic.There has to be a resistor or something that is going up in smoke literally that I would like to find to replace but there doesnt seem to be any pics on the net I can identify.Unfortunately I dont read schematics either and I'm not sure who makes or what type of tach these are anyway. Kerry
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Post by kerry on Apr 6, 2015 20:12:53 GMT -6
So I got another one that didnt work opened up.I shook it and didnt hear anything rattling so I kept my fingers crossed.This is what I found. There is an extra resistor/diode whatever the heck it is soldered compared to the other picture.I hit all the points with the gun and gave it a go and it works!There are two blue whatever they are under which apparently is what burned in the first pic.These ones were good but the solder joint was loose at one spot. . I ended up taking the clock face from the one and switched it to the other as well cause it was better.I have one more to open up which I hope will be fixable for a spare too. Kerry
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Post by mrmotors on Apr 6, 2015 21:27:46 GMT -6
The top pic looks like a resistor in the rt center, item with different colored bands. The colored bands tell how much resistance it has. The other 4 pieces look to be diodes. The 2 big blue items are also resistors and the color bands relate the ohm's resistance of them as well. Their physical size if I recall is an indication of how much current they are meant to operate with. If you go to any electronics store, they should be able to identify and duplicate those parts for you. Could probably fix the other ones you have.
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Post by kerry on Apr 7, 2015 16:44:25 GMT -6
Thanks that is what I plan on doing.The other tach is quite clean and the white is bright so I want to salvage it for sure. Kerry
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