Fluke 87 flat batteries

[Theo Markettos]

I have an original Fluke 87 (not 87 III, 87 IV etc) that has a rather
annoying fault. If I put a new alkaline battery in, it goes flat in a month
or so. This is with the meter being switched off (dial in the off position,
not relying on auto-power-off) and unused. Otherwise as far as I can tell
it works fine - I just can't use it very much as every time I reach for it
the battery is flat. I bought it secondhand about 5 years ago, and though I
haven't been using it much for the last few years I'm sure this flattening
is a fairly new phenomenon.

Just wondered if anyone had seen this before? ISTR reading that some Flukes
have a lifetime guarantee - is that right?

Cheers,
Theo

 

[Sam Goldwasser]

I have an original Fluke 87 (not 87 III, 87 IV etc) that has a rather
annoying fault. If I put a new alkaline battery in, it goes flat in a month
or so. This is with the meter being switched off (dial in the off position,
not relying on auto-power-off) and unused. Otherwise as far as I can tell
it works fine - I just can't use it very much as every time I reach for it
the battery is flat. I bought it secondhand about 5 years ago, and though I
haven't been using it much for the last few years I'm sure this flattening
is a fairly new phenomenon.

Just wondered if anyone had seen this before? ISTR reading that some Flukes
have a lifetime guarantee - is that right?

Yes, but not sure how that would work since your not the original owner.

Easiest may be to wire in a toggle.

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[Clint Sharp]

Yes, but not sure how that would work since your not the original owner.

Probably wouldn't but definitely worth asking Fluke about IMHO, nothing
ventured etc.

 

[JANA]

There is something on the circuit board that is pulling too much current.
The power control is done through the processor IC.

We have a number of Fluke meters including the 87 series. They last about
seven months to a year between battery changes with moderate use.

To service your meter properly, you will have to send it to Fluke. They have
the proper diagnostics and calibration equipment to find out what the faults
are, and to make sure that the meter is properly calibrated after it is
serviced.

--

JANA
_____


I have an original Fluke 87 (not 87 III, 87 IV etc) that has a rather
annoying fault. If I put a new alkaline battery in, it goes flat in a month
or so. This is with the meter being switched off (dial in the off position,
not relying on auto-power-off) and unused. Otherwise as far as I can tell
it works fine - I just can't use it very much as every time I reach for it
the battery is flat. I bought it secondhand about 5 years ago, and though I
haven't been using it much for the last few years I'm sure this flattening
is a fairly new phenomenon.

Just wondered if anyone had seen this before? ISTR reading that some Flukes
have a lifetime guarantee - is that right?

Cheers,
Theo

 

[Peter Matler]

I have an original Fluke 87 (not 87 III, 87 IV etc) that has a rather
annoying fault. If I put a new alkaline battery in, it goes flat in a month
or so. This is with the meter being switched off (dial in the off position,
not relying on auto-power-off) and unused.

30 days x 24 hrs = 720 hours
If we assume 500mAh-600mAh capacity (alkaline) it draws a current of 500/720=
0.7 mA. This the nearly the same as in ON state.

...ISTR reading that some Flukes
have a lifetime guarantee - is that right?

Yes, but... AFAIK not the old 87, 3 Year Limited Warranty (but may depend on the
serial number). And AFAIK with the newer stuff, Fluke wants a proof of ownership
and You to be the first owner AND the Instrument bought from an authorized
seller only.

I measured with my old 87:
Input shorted (COM/V)
0.86mA/V~
0.73mA/V=
0.73mA/mV=
0.79mA/Ohms
1.34mA/Diode
0.73mA/mA=
0.85mA/mA~
0.73mA/µA=
0.85mA/µA~

28.6mA/V= Backlight ON

0.279mA in SLEEP State
0.0075 mA/OFF (should last 7-8 Years)

This values are measured right after power on. After a while the current changes
after leaving the switch at V=:
0.91mA toggles 0.82mA/0.91mA
No idea why...

You can DL the IM of the 87II which should be not very different, but does not
contain the schematics.
May be You should clean the PCB and switch contacts...

Check
Q8 Power on/off device (Si N-DMOS FET, SOT-23)
C32 0.1µF/25V
and may be:
CR4 1N4007
CR3 BAV99
C35 4.7µF


Peter

 

[Peter Matler]

Update Sleep State is 0.363mA