voltage problems

Hi all,
I've some voltage problems in 22-years old W123 200d.
My lamps shine extra bright, now and then. I searched for a reason and connected a voltage meter inside. When the lamps
shine extra bright, the voltage is about 19 Volts. It's only for about 30 seconds. Then Voltages decreases to normal level of about 14 Volts.
What's the cause of this problem ?
Damage to dynamo or voltage controller or ... ???
Who can help me ?
Titus
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The alternator has diodes that regulate its power output. Your car's seem to be failing. Sometimes these diodes can be replaced separately, rather than replacing the alternator.
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The regulator on that car is a plastic triangular thing on the back ofthe alternator. It's like, an $18 part held on by two 10mm nuts than you can replace from under the car without jacking it up.
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The voltage regulator controls the voltage, the diodes rectify the current. The VR is retained in the back of the alternator by 2 screws and on some models can be changed in situ.
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108s did not have this, 126 does, I *believe* 123's do. Not sure about 114/115 but I *think* they do. Actually I think some 109 cars, later ones, had it too.
It's a 5 minute job to replace it.
--
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When this happens what else doesn't work?
Does absolutley every other electircal thing in the car work?
On truism in an MB is when there's an electircal problem with more than one thing, find what they have in common and you've found the problem area.
You have a schematic and a volt meter?
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As far as i know, everything electrical works.
wrote:

lamps
area.
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The change the ~$18 coltage regulator on the back of the alternator.
--
Need Mercedes parts ? - http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
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Try replacing the voltage regulator first...
DO IT NOW! This can destroy other stuff.
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