Old Hornby Class47 with new cd motor/decoder start speed very fast

[James 1707]

Hi

Ive converted my old Hornby Class 47 from the 80s with a CD motor following a recent video I saw on you tube.  I’ve also added a lais decoder and it works. However  when I turn to the first speed step it’s off very fast, probably about 20mph to scale.  Not the slow control I was after.  I’ve messed about with all decoder speed steps, start voltage CV’s I know, slight differences but nothing major.  It’s a 6v motor so I’ve also added some reversed diode pairs in line with the +ve motor and +ve decoder but still no real joy.  Anyone any wisdom?  Oh also tried another decoder brand.  Thanks Jim

[RobinofLoxley]

What is the other decoder you have tried, just out of interest?

[James 1707]

Bachmann.  Tempted to try a a half decent one like a Zimo MX635R but then the cost of the conversion starts to ramp up.  Any thoughts on a robust but economical decoder that’s best for conversions?

[Hamburger]

As Bachmann usually uses re-branded decoders it might be helpful to read CV8 to identify the manufacturer.

[James 1707]

Tried a LokPilot basic decoder I had and the performance was much better and also improved control.  Think will need a bit more weight and maybe improve the pickups.  I guess the I just need to find an economical but effective decoder.  That might be trial and error unless anyone can advise from experience?  Thanks for the feedback.

[RobinofLoxley]

The usual advice from those with a lot of DCC operating experience (which is not me but Im going that way) is that 6v and worse still 3v conversions need good chips to control them in order to avoid the motor running away. Zimo and Lenz are commonly recommended, you mention a zimo 635R but I cant undertsnad why a standard MX600R wouldnt do the job; the power rating of these 6v motors isnt that high.