Bosch dynamo regulator - Alfa Romeo Bulletin Board & Forums
 
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post #1 of 12 (permalink) Old 01-07-2019, 08:47 AM Thread Starter
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Bosch dynamo regulator

Hi there,

I would like to know if the Bosch regulator fitted on mostly 101 and early 105 is reparable ?

Picture of the same Bosch regulator.

I think mine is not more working. I tried 3, same result => just 12 V at the battery...

Thank you for help and answer...
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post #2 of 12 (permalink) Old 01-07-2019, 01:40 PM
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Mine failed. I took the cover off for a look.
It looked pristine inside....but for worn out contact points, which seemed to be the problem.
I am sure on old-school electrics workshop with full machining facilities could probably dismantle and repair any relevant bits...but the labour component would cost.
I bought a replacement with electronic internals.
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post #3 of 12 (permalink) Old 01-08-2019, 09:26 AM
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I have two friend ones (one of which was only 2 and a bit years old, OEM Bosch), so very much interested wether it's possible and DIY.

Quote:
Originally Posted by Ranz View Post
Mine failed. I took the cover off for a look.
It looked pristine inside....but for worn out contact points, which seemed to be the problem.
I am sure on old-school electrics workshop with full machining facilities could probably dismantle and repair any relevant bits...but the labour component would cost.
I bought a replacement with electronic internals.
I thought about buying one of those and trying to see wether I can house it in the original regulator housing, any idea wether that's achievable?

Tim
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post #4 of 12 (permalink) Old 01-08-2019, 01:21 PM
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Scalino1300:
This particular replacement is bigger (squarer), so I think "no", but I know others have done it using smaller electronic units than this one. That would be fiddly and time consuming (expensive) to achieve whilst retaining the stock wiring look, I would guess.
I also don't know if generator versus alternator requirements complicates this at all.
'Fried' wiring versus worn-out points is different too. It brings diagnosis/rewinding/retiring/resoldering into the equation versus (perhaps) simple mechanical repair.
Take the lid off, have a look and discuss with an electronics shop. I'd also ask what causes these to burn out early. Maybe generator output issues?
Tried YouTube or google search?
To my eyes, tho different, this replacement looks old-fashioned enough to look the part on the car.
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post #5 of 12 (permalink) Old 01-09-2019, 10:16 AM
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Quote:
Originally Posted by Ranz View Post
Scalino1300:
This particular replacement is bigger (squarer), so I think "no", but I know others have done it using smaller electronic units than this one. That would be fiddly and time consuming (expensive) to achieve whilst retaining the stock wiring look, I would guess.
I also don't know if generator versus alternator requirements complicates this at all.
'Fried' wiring versus worn-out points is different too. It brings diagnosis/rewinding/retiring/resoldering into the equation versus (perhaps) simple mechanical repair.
Take the lid off, have a look and discuss with an electronics shop. I'd also ask what causes these to burn out early. Maybe generator output issues?
Tried YouTube or google search?
To my eyes, tho different, this replacement looks old-fashioned enough to look the part on the car.
Thanks for the extensive reply! I blamed the generator first, but the guy at the electronics shop tested it and it was fine, the regulator not (he showed me). Indeed I'll take the lid of and check.

I agree it looks good, I was simply wondering wether it would easily be possible. Clearly not, grazie!

Tim
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post #6 of 12 (permalink) Old 01-09-2019, 10:27 AM
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Quote:
Originally Posted by pescara View Post
I think mine is not more working. I tried 3, same result => just 12 V at the battery...
Your explanation isn't clear. When you wrote "I tried 3, same result", what did you mean? Same result as what?

Are you saying that your Alfa blew out three new good regulators in quick succession? OR that you pulled three crusty old regulators from your pile of parts and none worked?

My point is that if your car is destroying new regulators quickly, then the regulator is not the core problem. Those old-fashioned, mechanical regulators are generally pretty reliable.

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post #7 of 12 (permalink) Old 02-19-2019, 05:58 PM
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In response:

"I would like to know if the Bosch regulator fitted on mostly 101 and early 105 is reparable ?"
Generally, No
If the points are burned .. the mechanical voltage regulator is JUNK.

"Picture of the same Bosch regulator."
Actually .. that pic is a modern electronic Bosch F 026 T02 203 or similar.
Old mechanical Bosch regulators had a center screw to secure the tin cover.

The second post pictures a BOSCH 9190040099U electronic voltage regulator.
This is a good inexpensive substitute for the original mechanical regulator.
Be aware that the external cover is + (POSITIVE) not Earth/ - GROUND (NEGATIVE).

"I also don't know if generator versus alternator requirements complicates this at all."
Yes, it does complicate things.
Dynamo/Generators develop a DC current while Alternators develop AC current and generally use an integral rectifier and voltage regulator to convert to DC current.
If they do use an external regulator it is not compatible with Dynamo/Generator use.

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post #8 of 12 (permalink) Old 02-19-2019, 08:03 PM
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I have been working with 750/101 Veloce Marelli voltage regulators and they can be repaired if the points are not burned off and the coils still work. The same is true of the 101/105 Bosch voltage regulators. The points burn and have to be cleaned using sand paper. I test the regulator coils using 12V DC and see if the points close. I have two old Bosch regulators and two old Bosch generators and see if they work. I have been repairing regulators and generators and restoring cars for a retirement hobby. I can convert the regulators to new electronic but, always try to make original parts work. I will assemble a 507 BMW engine and see if we can eliminate head gasket oil leaks.
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post #9 of 12 (permalink) Old 02-19-2019, 08:38 PM
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Right .. have a go at fixing this one:
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post #10 of 12 (permalink) Old 02-20-2019, 01:20 AM
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"If somebody can make something, somebody out there can fix it."
No fun, tho.
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post #11 of 12 (permalink) Old 02-20-2019, 08:56 AM
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The points can be replaced on any regulator but, the cost of a Bosch voltage regulator is low and that regulator should be replaced. The cost of CAD plating old regulator is high and that is another expense.
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post #12 of 12 (permalink) Old 02-20-2019, 10:24 AM
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Quote:
Originally Posted by kuni123456 View Post
The points can be replaced on any regulator but, the cost of a Bosch voltage regulator is low and that regulator should be replaced. The cost of CAD plating old regulator is high and that is another expense.
I have seen some stupid prices for an "original regulator" fortunately any "old school" starter/generator repair shop can usually do the trick for a low cost.

The older I get.. the faster I was....
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