Info needed: Morris C8 dynamo problem

[pauldavies]

Hi all and yes got the Morris going then other things happen, I have had problems with my Dynamo? But it turns out after restoring the Dynamo that it is the Control Board C.A.V Type 75BT-19X which is the problem, there are 7 distribution terminals on the board and all but one Battery + have continuity with each other. In other words the Dynamo + voltage coming into the board is dissipating into the chassis which is the reason the battery keeps going flat and the dash light stays on. I have 19 volts coming from the Dynamo so no worries there but anyone know an easy fix or maybe replacement?
The guys who started the restoration did solder the back of Battery + which may be the reason for the continuity problem as the Bakerlite doesn't like the amount of heat that has been laid on it. Any thoughts guy's.
Paul

[Mike Kelly]

Hi Paul

The 75-BT 19X were still available NOS in the UK , Richard N posted one out to me years ago , it was wrapped in the original grease paper never been opened.

I have a manual with details . Will scan a few pages . Cannot offer any specific help other than read the manuals and have a fiddle.

If you are stuck, I have a few used spares, I gave one to I. Styles years ago for his Guy quad .

[Mike Kelly]

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[Mike Kelly]

few more pages

[pauldavies]

Thanks Mike and I have had a play but it would seem it's a lost cause as the 19volts from the dynamo are just being passed into the chassis, the six terminals are as one with only the B+ out on it's own. A mob called P.A Blanchard(U/K) have n.o.s ones for sale at around $500 so not cheap, shame but looks like I will go with them. Thanks for the manual pages I have read mine so much I can read it in the dark but no joy.
Paul

[Richard Farrant]

Originally Posted by pauldavies

Thanks Mike and I have had a play but it would seem it's a lost cause as the 19volts from the dynamo are just being passed into the chassis, the six terminals are as one with only the B+ out on it's own. A mob called P.A Blanchard(U/K) have n.o.s ones for sale at around $500 so not cheap, shame but looks like I will go with them. Thanks for the manual pages I have read mine so much I can read it in the dark but no joy.
Paul

Hi Paul,
These boxes were used on a lot of different WW2 army lorries, Bedford, Austin British Fordson, Humber, etc. Even n.o.s. ones suffer through age while still in the box. The electrical engineer who used to do my starters and dynamos, used the internals from a later Lucas box, not sure if it was the RB107 or RB108, I could check next week. The mod was very successful and I had a number of these done. You may find an old-time vehicle electrician who could do this.

[Mike Kelly]

Paul

Richard's suggestion , using the later type regulator mechanism, and fitting it into the original box, is a very good and cheaper solution . After doing this mod. you will end up with a reliable charging system . My series 1 Landy uses a RB regulator and its a very reliable and simple unit, I have pulled it apart and cleaned it , its never given any trouble.

[pauldavies]

Hi Richard and Mike and thanks for the info, had another play with the control box today and I have narrowed the problem down to the Voltage Regulator which seems to have fused together all bar one terminal, I was thinking of going through the resetting but it would seem it's a lost cause. I have a couple of options and may take the thing to them in the morning, one of the options may put in a modern option in rather than the old type. Using the old external box is a good option Richard and I will let you know how I get on.
Paul

[pauldavies]

Took the Control Box to two different leco's today and one took on the task of checking it over so took my spare dynamo with it and hope he can isolate the problem on the bench. Be good to get a modern equivalent or something close but the one electrician I thought would be good wasn't, Oh well keep trying.
Will keep you posted.
Paul

[pauldavies]

Hi everyone and good news on my dynamo problem, the young guy at the local auto electrics put the dynamo and control box on his "old" test rig and after adjusting the "cut-out" all was good. I have just come back from there after he showed me the whole thing on the test rig and it is good to know a young guy knows about old stuff like this. , Will put it back on the C8 in the morning.