scratching my head

Discussion of TABC-related matters
Post Reply
User avatar
dezwartj
Posts: 25
Joined: Mon Oct 07, 2019 10:49 am

scratching my head

Post by dezwartj » Sun Apr 25, 2021 11:58 am

Hi Group,

I am in later stages of rebuilding my TC. After I put the new wiring harness in everything seems to work like it should be except..... When I turn on the ignition key, the dial from the Amp meter goes to the end of the scale discharging.
I triple checked all my connections, and did not see a wiring mistake. When I take the yellow wire of the control box (the one that goes to the "D" terminal on the generator) Everything is fine. I borrowed a TF generator from a friend and hook it up with the exact same result. Which gives me to think that there might be something wrong with the regulator/controlbox ?
Of course there is still that possibility I wired something incorrectly. Everything was working fine 1 year ago when I took it all apart. I am scratching my head. Any thoughts?

Thanks in advance,

Josh in snowy Calgary, Alberta, Canada

Tom Lange, MGT Repair
Posts: 310
Joined: Mon Jan 07, 2013 10:14 am

Re: scratching my head

Post by Tom Lange, MGT Repair » Mon Apr 26, 2021 4:54 am

Josh - would you kindly contact me at tlange@acadia.net? My e-mails to you seem to bounce back. Thank you.

User avatar
SavannahDog
Posts: 30
Joined: Wed Feb 01, 2017 5:05 pm

Re: scratching my head

Post by SavannahDog » Mon Apr 26, 2021 5:09 am

Josh, On most cars when you do a change from p- to n- you half to change the amp meter leads.
Julian Carter
1948 MG TC
1952 Chevy Pickup
1967 Triumph TR4A
1970 Triumph GT6

User avatar
Rob Reilly
Posts: 352
Joined: Sun Feb 07, 2021 2:05 pm
Location: Indiana, USA

Re: scratching my head

Post by Rob Reilly » Mon Apr 26, 2021 7:28 pm

Your voltage regulator, one of the contact points is stuck.
1937 TA 1271

User avatar
Steve Simmons
Site Admin
Posts: 2737
Joined: Wed Dec 26, 2012 10:48 am
Location: Southern California
Contact:

Re: scratching my head

Post by Steve Simmons » Tue Apr 27, 2021 6:42 am

I'm with Rob. I think that's the most likely cause of this. Take the cover off and to try working the contacts by hand and see what happens. Lightly file the points also.
1949 TC8975 / XPAG 9609
1948 TC6011 / XPEG1182 (XPAG6472)
http://www.mgnuts.com

User avatar
dezwartj
Posts: 25
Joined: Mon Oct 07, 2019 10:49 am

Re: scratching my head

Post by dezwartj » Sat May 01, 2021 8:45 am

I am one step closer but still in the wild electrical woods of the TC. I tried another regulator, same thing. then I removed the V-belt from the generator and when the contact is switched on, the generator is turning like an electrical motor??
This explains why the amp meter goes full discharge since the not yet running engine stopped the generator from turning via the V-belt. I tried another generator and it does the same thing. Question now is what did I do in my wiring to get this result?
The quest continues...

User avatar
Steve Simmons
Site Admin
Posts: 2737
Joined: Wed Dec 26, 2012 10:48 am
Location: Southern California
Contact:

Re: scratching my head

Post by Steve Simmons » Sat May 01, 2021 12:49 pm

It sounds like somehow you have 12 volts going to the generator.
1949 TC8975 / XPAG 9609
1948 TC6011 / XPEG1182 (XPAG6472)
http://www.mgnuts.com

User avatar
ferricsteed
Posts: 68
Joined: Wed Oct 15, 2014 5:46 am

Re: scratching my head

Post by ferricsteed » Sat May 01, 2021 2:58 pm

Cut out is not cutting out. The contacts may be fused together.
The cut-out is supposed to remove the generator from the circuit once the voltage drops below roughly 12v.

User avatar
dezwartj
Posts: 25
Joined: Mon Oct 07, 2019 10:49 am

Re: scratching my head

Post by dezwartj » Sat May 01, 2021 5:26 pm

an update: The yellow wire (from the control box) and the white wire from the ignition contact switch managed to touch each other at the ignition light behind the dash... Hence, 12V straight from contact switch to D contact on the control box and the generator. Thanks for all your help and suggestions.

Josh, in Calgary, Alberta

Post Reply