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Has anyone used any of these instead of the American Zettler ones? Any recommendations on brand/where to buy? At this stage I'm wondering if it isn't simply better to get the thing back from Fluke to see what impact cleaning the relays has - Then living with 'self-calibration'.
Any thoughts?
Thanks,
TonyG
I have a 5440B and 5440B/AF, both of which I have cleaned these relays, what ever brand FLUKE used in these units at the time of manufacture. It is fairly simple to remove the plastic covers and then applying a cleaner to the contacts, exercising the armature manually, and then putting the cover back on and reinstalling the relay. I also spray the contacts that go into the sockets. I used DEOXIT G5 as the cleaner as it is specifically designed for gold plated contacts, which is what the contacts appear to be. Of course FLUKE used gold plating for reliability. I see that American Zettler offers this option when ordering. American Zettler is probably the preferred vendor for this relays at the present time, no matter what vendor FLUKE used in the past.
It does take a bit of patience to remove the plastic cover as they are held on by a "one way" retainer on each of the "long" side of the rectangle. You must insert something under the cover on each side to get the latches to release and then just slide the cover off.
I did all of this as a preventative measure before calibrating them and using them. I have never sent these into FLUKE for cal as I have the necessary standards to calibrate them (732A, 752A etc.) so I don't know what FLUKE would tell me if I had sent them in.
My guess is that FLUKE wants to put new relays into the 5440 because they simply don't know the condition of the relays that are there now or how many cycles they have been used or what kind of lab conditions they have been subjected to during their lifetime. This way FLUKE can guarantee that the calibration will be stable for the period that is required in the specs. It is more an issue of meeting the specs than if the relays are worn or not. It is easier to simply replace these than to worry about a faulty relay and having to do a warranty repair at no charge later on.
IMHO of course,
Bill