ClemenTang

My TT tach is giving readings that are 1/3 higher than what it should be, i.e. when I point it to a 50Hz light it shows 4000rpm 2 blade; 2700rpm 3 blade. Is there a way to fix it?

Thanks

Clement

chashint

don't point it at the light

N1EDM

My Feedback: (2)

Is it a steady signal or does it 'hunt'? Is the optical pickup clean?

I've never seen one give an incorrect reading - it either works or it doesn't. This is very unusual

Bob

ClemenTang

it's clean and steady. But I'll try clean it again. For a moment I suspected the power company altered the supply frequency.

Clement

SwampFlier-RCU

Well, you have to point it ar a 60 mhz fluorescent light to get 3600 rpm's, they also have to be individual and the long (36" or more) type

Incandescent lights or the new energy saver fluorescent bulbs will not work

ClemenTang

The local supply frequency is 50Hz so I'm expecting to see 3000rpm. But all I have at home is energy saving bulbs so that probably screwed up the reading.

Thanks for the advice. I'll try it on the engine and see if I got an extra 4k or so. Maybe there's nothing wrong with it.

Clement

ClemenTang

16000 rpm on a 4-stroker. Wish it were true. Opened case and saw 3 capacitors (among other surface mount little bits): 1uF, 47uF, 220uF. Bought all 3 capacitors for 30 cents. Replaced the 1uF, bingo problem solved.

Clement

N1EDM

My Feedback: (2)

Neat - good thoughs... were they surface mount or thru-leads?

Glad that it was a simple fix. What made you suspect the caps?

Bob

ClemenTang

The caps are thru-leads. Caps are known to dry out so I just tried. Lucky me.[8D]

and it works on all lamps incandescent energy saving long and short tubes. Maybe they blink slower here (50Hz).

Clement

tIANci

Clement - buy a strobe to claibrate the tach ... hahahahaaa