Hi forums!
 I have a 1975 DT125 which I am constantly in the process of updating and working on. Curious if anyone has any experience with an odd tripometer problem:
The odometer and tripometer roll over as required and function properly, however the reset knob only rolls back the ones column. One mile at a time. I’m not convinced it’s supposed to work this way, unlike most meters which collectively roll up the ones, tens and hundreds until they reach 999 and then zero themselves. 
Anyone know how to fix this or open up the unit without removing the chrome ring?
Cheers

It is operating properly. It does not work like some other trip meters that can quickly reset to zero.

That is very good news. Yes, it works one increment at a time. This saves me from opening up an original piece. 
Interesting that they would design it this way, I suppose a good memory and math will have to suffice to remember fuel mileage!
Thanks