[TS150] Electrical nightmare

[Agronski]

_Full disclosure_
I own a 1974 MZ TS150.
I replaced the mechanical regulator with this style electronic regulator: http://666kb.com/i/b1kr05gnftjhtuog9.jpg
I have analysed the regulator circuit, know how it works, and confirmed it functions on the bench with a dummy load.
I am an electronic engineer.
....and I am losing my damn mind, because the damn bike won't charge the battery any more and I don't know why...

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Took TS out for a spin the other day - knocking new clutch-plates loose, checking the gearshifts etc. She's fine - gears are smooth, clutch isn't too heavy, power is nice and even - and the electronic charge circuit seems to be working fine. The charge light went out with revs above about 2000. Sarted out with battery voltage at 6.1V. Got back, voltage was about 6.5V - so charge circuit is definitely working.

A few days later, thinking I'll take another short ride and get her warmed up ready for an oil change (going to change the oil-seals, which I'm sure are leaking gear oil into the crankcase). Suddenly, no amount of revving on the centre-stand can get the charge light to go out. Battery voltage dropped to 5.8V, and obviously wasn't getting charged from the dynamo.

Spent the last 48 hours tearing my hair out, because I can't find a damn thing wrong. The regulator circuit is fine; the commutator is not shorted to ground; the carbon brushes are sound; the field coils are not shorted; the (slightly modified) wiring harness is connected properly; I even replaced most of the awful rusty bronze DDR terminals for shiny new crimp contacts. Nothing. Not a damn thing. No charging.

PLEASE HELP! What am I doing wrong? I just cannot figure it out. The commutator is fine - I took it off, cleaned it, scraped the gunk out of the contact-gaps. I've checked and re-checked the regulator circuit. WHAT ELSE IS THERE TO GO WRONG?!
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[DAVID THOMPSON]

shiny new crimp contacts.

the key word here is crimp
i never crimp them on i always solder them ...or just solder the wire solid and do not use them

the new kid on the block is anderson power poles they work good till you try very low voltage at very low current
and i solder them on the wire also
i built my first crystal set about 1951 by 1954
i had had my fill up of crimp connectors and banana plugs and alligator clips

also any circuit on the bike that uses the frame as the ground return can be a problem
some times a small high power magnet fastened near the generator can excite some systems in to working
old lincoln welders get happy after setting for a long time when this is used on them
Dave
and i just remembered brand new shiny batteries can just stop working on a whim

[Agronski]

So, okay - the madness abates. Sometimes, I forget what a nightmare it is being an electronics engineer - things that seem to work don't, and things that shouldn't work, do....and sometimes, things work on the bench when you test them, then fail 'in the field', but work again on the bench....

The electronic regulator is dead. Long live the mechanical regulator. Stupid and ugly though it is, at least it works well enough to charge the battery.

I will in the meantime turn myself still further crazy trying to find what is wrong with the electronic reg, but with it off the bike. <sulk>

As for my connectors - double-triple checked them all, and all crimps are sound and tight, ground contacts are clean and resistance is low. Everything else is fine, except the crank seals, which I'm doing next. Thanks for the hints, anyway.

Meantime - does anyone have a template for the generator-side paper gasket for under the crank-seal holder plate? It's just a circle with some screw-holes in it, but I could do with some dimensions so I can cut my own gasket accurately...

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[DAVID THOMPSON]

quality control stinks on electrical parts any more check all the parts and watch out for really bad solder
been getting a lot of fuses that are bad when new or soon after

do you have a drawing of that reg you showed

would love to see what they did and how

as it may bring new life to my 1953 r51/3 with out the need to do a whole new system
its about same as bmw bikes to 1969
but all the voltage regulators i have are very tired

dave

[Agronski]

Here's the 'elektronikus' style electronic regulator schematic. Actually a neat little circuit, really, despite being a bit crude. Not well designed for the 'dirty' environment of a motorbike. The principle is good, though. I replaced the 15K resistor with a 10K variable so I could tune the cutoff voltage.

I learned the hard way that these electronic regulators don't need the field-coil damping resistor - if you leave it connected, it'll either burn out or the regulator won't work properly.
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[DAVID THOMPSON]

thanks the road map always helps
that resistor in the original was some times a bulb.
the wrong bulb can really make things work funny
this thing also needs a home in a cool spot not stuck in the engine or headlamp shell
lots of air and no water

bottom left that in4001 could probably stand to be something a bit sturdier there is a whole series of those some are a bit more rugged
in some circuits 1n4007 1n4009 come to mind
and the strange way br106 is drawn
dave
i am use to seeing it drawn like this
(edit) after some head scratching i think i understand what there doing