VDO Sumlog impeller

[daryl.ramage]

My 1977 Serious 21 has a mechanical VDO Sumlog and the impeller is broken. Any idea if I can just replace the impeller or do I have to replace the whole unit? If I have to replace it what type should I use?

Thanks
Daryl

[Whisper Too]

My Sirius has the same instrument including the impeller but it reads very high ie about twice as high as my GPS unit. is there a way to calibrate it?

George

[34ac0002]

My 1977 Serious 21 has a mechanical VDO Sumlog and the impeller is broken. Any idea if I can just replace the impeller or do I have to replace the whole unit? If I have to replace it what type should I use?

Thanks
Daryl
hello daryl.. you can change just the impeller. better to change it with the improved version which has skinnier blades between the fat ones where the magnets are. either should work well. regards.

[34ac0002]

My Sirius has the same instrument including the impeller but it reads very high ie about twice as high as my GPS unit. is there a way to calibrate it?

George
hello george.. the way to calibrate the unit is to look at the back of the head unit, where you will find a blue set of microswitches. if you make all of these little switches "on", the unit will show 36% more than actual. if you make all of them "off" it will show 36% less than actual.
the user manual has a table showing which switches should be "on" and which "off" for each deviation, but i guess you don't have the manual. your best bet would be to play with the switches until the reading matches your gps.
regards.