1200 regulator fault

H

Hans.

New member
Location
Hampshire.UK
Whilst out riding my Mirage today the ignition warning light started to flicker then came on fully. I stopped and had a cursory look at battery connections etc but could not see anything amis, but made my way home about 10 miles. I feared that I had been running on battery power, but it restarted on the button. I then saw that the earth wire from the regulator had broken free so replaced the feeble earth eye and reconnected. On starting up again the ignition light came on stronger than ever, and did not go out when revving the engine.
Question ; Have I cooked the regulator ??
 
Possibly. You need to check what happens to battery volts (measured across the terminals) when you start the engine and rev it for 30 secs or so. There is a comprehensive troubleshooting guide in the library (Although your alternator is a single phase device, the guide can still be used)
 
Thanks, I have checked that and voltage stays within the accepted parameters.
The problem I believe lays with the warning light, why is that showing.
does anyone know exactly how the RR works ?
 
do you have the original Bosch reg/rect still fitted, I show a picture for comparison, its the box at the bottom of the pic, having the light flicker, is a clear warning that it is failing, then staying on, says its HAS failed, this is of course all other parameters being OK, broken wires, corroded/loose connections etc.
if you still have the unit as pictured, then it may well be time to get a newer pattern replacement, which requires a tiny bit of modding, Electrexworld will supply you with a new one, but not with the red light enabled, (ASAIK) they are available, but not that easy to obtain.

You should be testing the battery voltage with the engine not running, and then again with it revving at (say) 3000rpm) to see if you get a rise in voltage.
CLEM
 

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Hans. said:
I have checked that and voltage stays within the accepted parameters
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OK. Perhaps I should have been more specific. Battery voltage before engine start with ignition off should be 12.8 if fully charged and healthy. With engine running and revving, it should increase. Depending on how many revs and how long you wait, I'd expect to see ~14v from the puny Bosch alternator. What values did you measure?

Simplistically, the warning light glows when reg/rect output volts are less than battery voltage. It could be that its sensing circuit has been damaged when the earth became detached. More likely that a rectifier diode has been cooked. Checking forward and reverse resistance will confirm.
 
CLEMTOG said:
do you have the original Bosch reg/rect still fitted, I show a picture for comparison, its the box at the bottom of the pic, having the light flicker, is a clear warning that it is failing, then staying on, says its HAS failed, this is of course all other parameters being OK, broken wires, corroded/loose connections etc.
if you still have the unit as pictured, then it may well be time to get a newer pattern replacement, which requires a tiny bit of modding, Electrexworld will supply you with a new one, but not with the red light enabled, (ASAIK) they are available, but not that easy to obtain.

You should be testing the battery voltage with the engine not running, and then again with it revving at (say) 3000rpm) to see if you get a rise in voltage.
CLEM
Click to expand...
Thanks Clem, I still have the original fitted, and on checking the output it seems that there is no charge going to the battery, so its probably fooked. i will look into getting a new one.
 
Rob said:
OK. Perhaps I should have been more specific. Battery voltage before engine start with ignition off should be 12.8 if fully charged and healthy. With engine running and revving, it should increase. Depending on how many revs and how long you wait, I'd expect to see ~14v from the puny Bosch alternator. What values did you measure?

Simplistically, the warning light glows when reg/rect output volts are less than battery voltage. It could be that its sensing circuit has been damaged when the earth became detached. More likely that a rectifier diode has been cooked. Checking forward and reverse resistance will confirm.
Click to expand...
Thanks Rob, there is no extra volts going to the battery when it runs, so it looks like its cooked. If when I had stopped I should have looked more thoroughly I would have seen the broken wire. Seems like a new one is required. Cheers
 
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