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 K]

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 K]

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[Mike K]

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.