Chauvin Arnoux CA 6456 repair log

[masterx81]

Hi!
As part of my deals on ebay, i've bought quite chap a Chauvin Arnoux CA 6456, with the hope to add it to my bench.
The unit came already opened.
One of the clips retaining the rotary switch on the pcb was broken and missing, and i suspect also a contact.
The unit had some little corrosion due to the batteries leaking, nothing hard to fix.
The main  problem was that wasn't turing on.
So i've traced the switching that do the logic voltages, and wasn't turning on due to missing vcc. On a bet i've set the psu limited to 300ma, connected the vcc pin of the smps ic to the battery output... and it came back to life! The unit by now with the rotary set to off,  isn't turning off, so i think that the smps ic was getting vcc via a missing contact on the rotary switch (and actually one of the unused traces goes to the vbatt, so i think that if i put a new contact spring, it start to work correctly).
Little question, where can be sourced this springs?
The spring uncompressed is long 8.5mm, height around 2mm, the window is around 1mm.
One thing that seem strange to me is that the unit powered on is taking around 200ma in standby, seem a quite high figure for the claimed 30h battery duration with 1800mah batteries.
I've checked with the thermocamera, and i noticed only one opamp going quite hot (after few seconds 40c), but the output isn't shorted. So i've swapped it with another same component on the board, and the hot remained in the same position, so it's not an ic fault.
The opamp is an lmc6482aim, and the other same ic's aren't getting hot as him.
Some pictures:

[coromonadalix]

the best chances are to ask Chauvin Arnoux  aka Metrix ...  they usually answer fast enough,  or  sadly  try to find an used one, for a part one ?  or some service center ?


but  seeing the one in the white dial, they seems "standard"  (big word here),  maybe  search for dial contacts  on ebay or others parts websites

something like this ?

https://www.ebay.com/itm/126433546550?

really depend on how they describe it ??

[masterx81]

Interesting!
The only problem is that i'm italian... Buh as the valueis so low, i not think that is a problem an international shipping.
I not know if it's a problem in the aution, but quotes me $0.99 shipping costs, maybe it's better to ask the seller.
Thanks for the link!!

[coromonadalix]

pls  do check before ordering,  i'm not sure they are compatible

it was mostly for reference,  they where the one who resemble the most to your needs ?

[masterx81]

When i go home from work i'll measure the original contact and ask the seller. Thanks!

[masterx81]

I've also found an aliexpress link:
I think that is the same seller. The problem is that i need the "1 mm", and is soldout 😥
Ho appena trovato questo articolo su AliExpress:
6,94€ | Parti di riparazione del foglio del giradischi dello schegge dell'ingranaggio della lamiera V dello schegge del multimetro per Uni-T UT890D UT890C+
https://a.aliexpress.com/_EGOzT6Y

Damn... the seller say that the 1mm variant is discontinued 😥

[masterx81]

I'm thinking to do the new spring by myself, as i can't find the already made contacts with the correct dimensions.
I've also searched for a complete dial  of another meter, without success.
So, what material can be used?
Bronze?

---

Ordered from aliexpress some phosphour bronze 0.10mm sheets, same thicknessof the original spring. Hope that it do the job...

[masterx81]

I think that it can do the job...

[masterx81]

So, seem that it works:

Now i'm searching for a kit of earthing cables...
The chauvin arnoux kit costs way too much.
Maybe i've found a kit on ebay....