Control box problem

[mikesloan]

Anyone had any experience of a faulty control box causing starting problems?

[boxofbits]

Hi Mike

 

Not usually the cause of starting problems as far as I know, only if the charge current is too low. But you have got your thick brown A and A1 wires going to it, and tbh any electrical gremlins might cause problems on the ign switch side. Normally it's only charging problems,

 

Describe the symptoms you have a bit more clearly you'll probably get a more accurate answer.

 

Regards

 

Kevin

[mikesloan]

Kevin,

Thanks for the response. Symptoms were : solenoid clicked but starter did not rotate at all. After a week of checking every single element of the starting circuit, including new battery, new solenoid, new cables and an overhauled starter motor, I started thinking laterally and tried a jumper wire to the solenoid with the A and A1 wires disconnected. Result was starter turning and engaging normally. I reasoned that I was losing volts somewhere and remembered that I had fitted a new control box at the end of March. Put the old control box back on and bingo, starting is fine. But what's gone wrong with the new control box?

Mike.

[boxofbits]

It could be the A1 ( sometimes or can be crossed over with A ) terminal as this provides the feed to the ignition switch and then to the starter solenoid. It's most likely a poor 12v supply to the solenoid, not enough to energise it properly ? It could be the ignition switch but you ruled that out with a jumper wire, but if you say it worked when you changed the CB then it must be the 12v supply breaking down? Obviously can't be absolutely sure without seeing it.

 

If you take the cover off the CB you'll see that A and A1 are joined by a loop of copper wire and crimped or soldered so it could be this connection has gone high resistance or is loose. I can't think of anything else offhand especially if you say another control box rectified the problem,

 

Kevin

Edited May 19, 2017 by boxofbits

[tthomson]

Hi Mike,

 

The control box may not be properly adjusted. In particular if the cutout voltage is set too high.

Control boxes need to be adjusted to suit the specific vehicle. This can be quite tricky and you need a good multimeter to do this.

 

The two adjustments are:

 

Voltage cutout - this disconnects the battery when the charging circuit drops below a preset value (designed to prevent the battery draining over time when the engine is not running).

 

Voltage adjustment - This is to provide the right charging voltage to the battery.

 

The A terminal should connect to the Ammeter,

The A1 connection connects to all other electrical systems. This uses the additional loop of wire to make a small modification to the charging voltage to compensate for a heavy current load.

 

There are various documents available on the www that give guidance on doing this.

 

Good luck

 

TT

[RogerH]

Hi Mike,

drop Richardtr3a a PM. He knows a workshop that overhauls the box and sets it up just right.

 

 

Roger

 

http://www.tr-register.co.uk/forums/index.php?/topic/20460-knebworth/?hl=%2Brb106+%2Bcontrol

Edited May 20, 2017 by RogerH

[boxofbits]

Another good reason to repair your old control box is to preserve the dated original ( if indeed it is the original).

 

Alongside where it is marked RB106/2 you should see the date in the format for example 10 66.

 

I have serviced quite a few of these including a modification to prevent arcing and burning of the contacts so if you have difficulty getting it sorted let me know.

 

Kevin

[Lebro]

Most likely poor connections inside the new reg, not an adjustment problem - the adjustments are not relevant until the engine starts.

 

Bob.

[tim hunt]

Care is needed in setting the charging voltage as I learned from bitter experience. I adjusted my control box shortly before the 2008 Club Triumph Round Britain Reliability Run and shortly after the start both new H4 headlamp bulbs blew. Fortunately I had spares with me and since it was still dusk was able to drive to a suitably well lit forecourt where I readjusted the control box and fitted new bulbs.

 

Tim

[RobH]

As Bob says - this fault is nothing to do with the adjustment. That does not stop the solenoid pulling in......

[mikesloan]

Thanks for all the replies. Just back from a long tour of Yorkshire in the TR.

I guess I need to reiterate that when I had the problem the solenoid was operating fine but the starter did not rotate. All the other electrics, lights, etc., appeared normal. The car had also just completed a round trip of 600 miles without a problem, so I don't see how adjustment of the voltage settings would be relevant. When I replaced the control box and "cured" the fault I simply transferred the wires across carefully from one to another.

My own thoughts were that something had shorted to earth in the box but I don't know how to test for this.

Mike

[stuart]

Thanks for all the replies. Just back from a long tour of Yorkshire in the TR.

I guess I need to reiterate that when I had the problem the solenoid was operating fine but the starter did not rotate. All the other electrics, lights, etc., appeared normal. The car had also just completed a round trip of 600 miles without a problem, so I don't see how adjustment of the voltage settings would be relevant. When I replaced the control box and "cured" the fault I simply transferred the wires across carefully from one to another.

My own thoughts were that something had shorted to earth in the box but I don't know how to test for this.

Mike

Dont bother with testing the control box especially if its a repro just bin it as they arent worth messing about with.

Stuart.