Veglia Cable Speedo Clack-Clack-Clack...

[Citroënbender]

It's a pretty standard piece of early '90s kit but giving me grief, there is a mechanical clacking as the needle flicks up towards the correct speed then back again, which is different to the normal "sticky cable" flickering.

The odometer and trip meter seem to work with reasonable accuracy, and the cable is low mileage OEM. 

Has anyone experienced similar issues with a Veglia speedo? I'm thinking the gears between input and speedo needle may be compromised - else possibly it's in the take-off at the 'box. 

[Citroënbender]

First up, what a screaming bargain that trailer is, which is currently listed in the Classified here!

I've not solved the clackety-clack speedo yet, however...  Murphy and I are mates from way back.  The bugger whispered in my ear to remove the cluster and dismantle it without further testing.  Once the drive head was separated from the cluster, I tested it with my cut-down cable and cordless drill. 

Notes:

• Pinion first driven by the input worm, showed wear but nothing excessive; no nicks or gaps.
• Input to a Veglia mech speedo is anti-clockwise when viewed from the back of the unit.
• Operation was smooth, all the way to an indicated 150km/h (approx.) courtesy of the cordless drill.  No clacking, nothing out of the ordinary. Not impressed!

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The most surprising find - and I insert this comment with the tag words Veglia trip meter won't reset - is that the zeroing mechanism on these trip meters uses a sort of pushing/sliding finger on a teardrop shaped cam (per counter wheel), to force the counter to zero by virtue of least height on the cam "lobes". The highest point on the lobe coincides with a "5" on the display, and this effectively blocks the zeroing action from getting started! Until I had the unit apart and examined carefully, I had conjoined the two events - inability to zero the meter and the clacking sound with needle flicking - as being wear/damage or a foreign object in the driven head.

So now I'm looking at either the worm or pinion inside the box as suspects. But the best bit of takeaway information from all this, is if your Veglia trip meter won't reset and it's got a "5" in the reading, that's probably why.