Hi all,
I hadn't used my HP33401 on 4 wire mode in years and I suddenly needed it to measure some current shunts when I noticed an issue.
On 4 wire mode, with the leads shorted, on 6 digit mode, it wont zero. The last 3 digits fluctuate about. Its a little more stable on the rear terminals which has me thinking its the front/rear switch rather than something else.
A search of the net seems to suggest that the switch might be the issue but I thought I'd ask here first before I go disassembling anything and poking about :)
So... is this a common error for 4 wire low ohms mode ?
Is it the switch ?
Is the switch sealed or open enough to squirt some contact cleaner in there ?
If the switch needs to be replaced, are they commonly available ?
If its not the switch, is it some other common fault ?
The meter is fine on all ranges and within spec when tested against other meters and my little transfer standard.
Any help appreciated.
thanks
Tim
