[xk] Rev-Counter defect? XK150

Tudor95 · February 24, 2007, 3:23pm

Good Day Gentlemen,

On a recent run my rev-counter started to read low and then
stopped working all together.

Does anyone know how the rev-counter generator works? Can I
measure the output to check if it is that or the
indicator.What should the output be?

I took the instrument apart and there are no loose
connections inside and I sprayed contact cleaner on all
connections.

Best regards

Barry Tennant
HER-XK-15
150DHC–
www.tennant-metall.com
Herne, Germany
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

Ken_Green · February 24, 2007, 4:23pm

In reply to a message from Tudor sent Sat 24 Feb 2007:

Hello Barry,

Sorry I can’t help you here but…

I seem to remember that there are two different sorts of rev
counters for XK150s, mechanical ones and electrical ones.

Do you know which sort you have?

Regards
Ken–
The original message included these comments:

Good Day Gentlemen,
On a recent run my rev-counter started to read low and then
stopped working all together.
Does anyone know how the rev-counter generator works? Can I
measure the output to check if it is that or the
indicator.What should the output be?
I took the instrument apart and there are no loose
connections inside and I sprayed contact cleaner on all
connections.
Best regards
Barry Tennant

–
Ken XK150 FHC S824252, see her on xkdata + X300 3.2 Sport
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

Gary_Otto · February 24, 2007, 4:52pm

The check for a Mk 2 rev counter generator says one volt AC per 100
RPM…hope this helps

Gary-----Original Message-----
From: owner-xk@jag-lovers.org [mailto:owner-xk@jag-lovers.org] On Behalf Of
Tudor
Sent: Saturday, February 24, 2007 9:24 AM
To: xk@jag-lovers.org
Subject: [xk] Rev-Counter defect? XK150

Good Day Gentlemen,

On a recent run my rev-counter started to read low and then stopped working
all together.

Does anyone know how the rev-counter generator works? Can I measure the
output to check if it is that or the indicator.What should the output be?

I took the instrument apart and there are no loose connections inside and I
sprayed contact cleaner on all connections.

Best regards

Barry Tennant
HER-XK-15
150DHC

–
www.tennant-metall.com
Herne, Germany
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

Tudor95 · February 24, 2007, 5:09pm

In reply to a message from Gary Otto sent Sat 24 Feb 2007:

Thanks Garry,

I tried to measure DC Volts and got all sorts of wierd
readings. I did not realise it was an AC output.

Ken - I guess you realise now that it is an electric Tacho.

I will have to measure again and see if I can get some
reasonable Volts out of it.

I don’t know what is worse. Broken Tacho or broken generator.

Barry–
www.tennant-metall.com
Herne, Germany
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

Taborcias1 · February 25, 2007, 1:02pm

Hello Barry

Try the connector piece on the alternator (that’s what the rev counter
generator is).
There is a bakelite round part that holds the stuff with two small screws;
at the bottom also very small springs, that link the output with the flat
terminals to which the cable from the instrument fit.

More than once, in my E type and S type, the rev counter failed and I
found dirt in that zone, may be due to the tiny gasket was not in shape or
the screws were loose. Cleaned and adjusted, that was all…
Good luck.
Regards

Alberto-----Mensaje original-----
De: owner-xk@jag-lovers.org [mailto:owner-xk@jag-lovers.org]En nombre de
Tudor
Enviado el: Sï¿½bado, 24 de Febrero de 2007 02:10 p.m.
Para: xk@jag-lovers.org
Asunto: RE: [xk] Rev-Counter defect? XK150

In reply to a message from Gary Otto sent Sat 24 Feb 2007:

Thanks Garry,

I tried to measure DC Volts and got all sorts of wierd
readings. I did not realise it was an AC output.

Ken - I guess you realise now that it is an electric Tacho.

I will have to measure again and see if I can get some
reasonable Volts out of it.

I don’t know what is worse. Broken Tacho or broken generator.

Barry

–
www.tennant-metall.com
Herne, Germany
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

Tudor95 · February 27, 2007, 1:13pm

In reply to a message from Taborc�as sent Sun 25 Feb 2007:

Thank’s Alberto,

I will check that at the next oportunity

Barry–
www.tennant-metall.com
Herne, Germany
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

Tudor95 · March 4, 2007, 5:24pm

In reply to a message from Tudor sent Tue 27 Feb 2007:

Hi Alberto,

I tried to measure the output of the tacho generator
yesterday to see if that is the problem but there is sooo
muuuch RF noise under the bonnet/hood that the meter just
went haywire!!!

I think I will order some new HT cables tomorrow because
they are copper wired still (I guess they are the original).

It is no wonder that the radio crackles.

I will report on the results.

Best regards

Barry–
www.tennant-metall.com
Herne, Germany
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

Ken_Green · March 13, 2007, 3:49pm

In reply to a message from Tudor sent Tue 27 Feb 2007:

Hi Barry,

are you still having problems with your rev counter?
I’ve just noticed a rev counter generator on eBay, item
220090718020.

As usual, no association etc…–
Ken XK150 FHC S824252, see her on xkdata + X300 3.2 Sport
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

Tudor95 · March 16, 2007, 2:41pm

In reply to a message from Ken Green sent Tue 13 Mar 2007:

Thanks I will check it out.

Barry–
www.tennant-metall.com
Herne, Germany
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

Mkten · August 1, 2021, 9:34am

Sorry to reopen a very old thread but can someone confirm how free spinning a Tach generator should be. Mine spins but there is considerable resistance.

Mike_Eck · August 18, 2021, 1:34am

It doesn’t exactly spin freely, it feels more like a rotary switch with 8 positions. However, it shouldn’t scrape as you rotate it. A common failure mode is for the shaft to work its way into the case, which causes the drive pawl to disengage from the camshaft and the rotor to scrape against the metal back plate. The “E” clip on the shaft should stand proud of the boss, not down inside it.

Mkten · September 26, 2021, 10:30pm

Sorry about the late reply. Do you know if this is serviceable, as it looks like this is the case.