Back to S&W tachometer problem

[427 S/O]

I thought the problem with my S&W tachometer would have been solved by now?. Called S&W and this is what I was instructed to do......

Remove the tach, put in the oven, up side down at about 200 degrees for one hour?, needless to say I didn't do it....yet...

anyone out there know a fix other than the oven......

[427 S/O]

Oh!...my tach jumps to twice the RPM and then operates normally after a few minutes.........

[trularin]

The oven thing may be what we call and MSL problem. Shouldn't need it.

BTW, are you talking about a Smith and Wesson or Stewart Warner?

May I suggest a shielded cable from the dist/box to the tach. You may be picking up noise that tach is reading as the signal. They can also mix and lower the tach reading. If it is consistant, the tach will consistantly ready wrong.

It just a suggestion.

[w-lewis]

My Stewart Warner tach occassionally jumps to twice rpm and back.

[427 S/O]

NO, but I'm about to take a smith and wesson to it..........

[Pete Munroe]

My Stewart/Warner tach, delivered to me in 1998, was fine for about 3 years, 8000 miles, then readings began to be erratic.

Not moving, double? reading, lots of unreliable nonsense.

I bought a new S/W tach a month ago...(wanted to keep the vintage look for the ERA 289 FIA car).

You can get ALL the Stewart Warner gauges from XKs Unlimited in San Luis Obispo, Ca for what is about wholesale price.

List was around $150/160, price at XK's Unlimited was ~115.

I looked through the "light bulb hole" to see inside the tach body...the "circuit board" is very different...it IS a new design for sure.

Bad news?...The GRAPHICS on the plain gauge face are pathetic...I could use a felt tip pen and it would look more accurate...but, the tach works...!

So far so good.

I suppose baking in an oven at 200+ could give an "attitude adjustment" to a few belligerent silicon chips...worth a try...!

Anyone in QC for the electronics industry could add some insight here.

Pete