Fluke 87V displaying "Lead" and sounding beeper when nothing is plugged in

[king.oslo]

Hello there,

I've got a Fluke 87V.

Today, when I came to switch it on, it began sounding an alarm and display "lead" when I switched it on, despite nothing being plugged into the jacks.

When it turn it to mA or uA, it shuts up.

Is this a common problem? What should I check?

Thank you for your time.

Kind regards,
Marius

[NiHaoMike]

Use compressed air to blow out any dust.

[king.oslo]

That worked.

Is there optical sensing of the input jack?

Kind regards,
Marius

[NiHaoMike]

If you take a look at the teardown of the 28 II, yes, it's optical.

[king.oslo]

Thanks!

Kind regards,
Marius

[alm]

The 28-II may be optical because it's easier to seal, but many other meters (which I believe includes the 87V) measure resistance between two halves of the banana jack. I would clean the jacks with either compressed air or a Q-tip with isopropanol.

[Louis_C]

There is also one other thing to look at when you have a unit with this issue. After taking the unit apart have the board face you like normal. To the right and just above the (+) input terminal is a white ceramic resistor network. Make sure you have NO cold solder joints on the resistor pins or on the board. THAT will fix your issue. Good luck! Lou.