1973 st70 faulty lights

Hi
I have a 1973 st70 that is very original nothing has been got at......
It's been kept in a loft for 20 years.."
It's now running and all is good but the head lights and tail lights are not working. Nothing at all..
All other bits work fine .....horn .brake lights etc but the front and rear lights dont..
I have checked the lamps they are fine
There is no voltage at the lamp holders

I do have the original handbook with wiring diagrams but I wondered if there was a common fault with this before I start pulling it all to bits

I'm kind of being drawn to the switch on the side of the yokes

Any help will be appreciated

Cheers jason

Hi
the front and rear lights only work when the engine is running
the horn and brake light work off the battery
hope this helps
Tufty

Cheers for the reply tufts

I have tried with the engine running . That makes no difference???

Where does the 6v pickup come from I guess it's directly from the generator/dynamo/alternator?
Do you know where I can check this from
Thanks again Jason

Possibly a faulty regulator (selenium rectiefier, the well known orange plate)
You can meassure the resistance of this (Ohms).

Cheers for that
Don't suppose anyone knows the reading

If not I'm sure I can search it

Will try tonight

Jason

Hello Jason,

Bloody electrics

To test the selenium rectifier you will need to disconnect it.
There are two directions to this unit the first direction and the proper way round, should be tested thus................

Take the positive of the tester lead and connect to the white wire (could be green) of the rectifier...........
Take the negative of the test lead and connect to the red wire (could be red and white) of the rectifier...........
The reading, if all is well, should be less than 30 ohms

If you reverse the above sequence, the reading should be greater than 2000 ohms
When the above test is performed the tester must be so set that the internal resistance within the tester be 100 ohms.

This proves that the rectifier is in good working condition, and should pass current to the battery and not discharge it back.

Hope this helps and good luck

PS you haven't put where you are from on you profile

Cheers again that's great I will get on it in the morning

Jason

Hi
I have just checked the rectifier
The reading is 60ish ohms one way
And greater than 2000 the other
So I guess if you are correct this could well be the fault

I will see of I can get hold of one and see what the results are

I did zero the leads and did try a few times but the reading is 60

Cheers
Jason

Back again
Any ideas where to get an original rectifier
Or at least what ones to avoid
Thanks in advance
Jason

Hello mate,
You can buy an electronic version, which is a striaght one for one replacement. Maybe someone on this forum can advise, or look on the OORacing website.

Cheers Si