DCC

The R.751 "Class 37" was fitted with two types of motor bogie.

The earlier (1967 - 1973(?)) is the "standard" Tri-ang 3 Pole "Open Frame" Motor bogie. The Later version is the "clip in" "Ringfield Motor" Bogie.

From my books, the earlier pattern looks to be a bit fiddly to convert to DCC.

As I understand it, you need to isolate the motor feed AND return from any connection to the track.

It looks like the one piece pick ups (copper?) actually touch the motor brushes. So, you would possibly need to cut a small section away, or otherwise stop the contact with the brushes.

Then, the pickups would need to be connected to the feed and return wires to a DCC Chip, The Chip motor Feed and return wires would need to be connected to "clips" (Standard Tri-ang "brush clips", as used for the feed wire on X.04 motored Steam Locos.) which fit between the brush and the brush retaining "spring" clip. The "return" side of this spring would require an insulating sleeve, the same as is fitted on the "Positive" side.

(All very "basic", but I don't have any DCC stuff. I have just read a bit! )

The "Ringfield" motor pickups are different. (But the same "Isolate the Motor from the track" would apply.)

HTH

QUOTE The Tri-ang motor date up to 1977 (Running number D6830). Ringfield motor from 1978 onwards (Running number 37 130).

The last Triang Hornby R751 Class 37 model to use the old Tri-ang 3 pole motor was 37 130 in 1977. It was then re-released in 1978 fitted with the Ringfield motor and Class 47 bogies.

DCC'ing the old R751 isn't an easy job, but not impossible.
Which version of R751 do you have, the earlier version without the extra pick ups added to the rear bogie?
or the 1972 version with the extra pick ups added to the rear bogie?
If it's the 1972 version with the extra pick ups added to the rear bogie
Remove both phosphor bronze pick ups from the power bogie ad disgard.
Insulate both legs of the power clip that hold the brushes in place against the commutator.
take the two wires from the rear bogie and solder one to the red wire and the black wire to the other.
Then solder the orange and grey wires from the decoder to each brush and test for short circuits using a multi meter.
If everything's ok, place on the track and away you go.
If the motor is running slowly, set CV5 to 255 and CV2 to 50, and you should then see a improvment in the running of the motor.

MikeM56 PM me your email address and I'll email you back a copy of the Hornby service sheet for R751

K9-70