FLUKE 187 Backlight leads to battery low warning

[shockpoint]

Hi all,

I have a fluke 187 that is behaving oddly.
Other than that it seems to read measurements well.

So without the backlight on it functions well
When I turn the backlight on, within a few seconds the low battery warning shows up and the screen LCD digits start to fade as though I switched it off, followed by the backlight switchin goff
- this error shows up whether I'm connecting 4 AA batteries or a 4.8V power supply
The current draw of the backlight seems to be around 40-80mA when it is on

Has anyone heard of an issue like this before?
- there seems to be some minor corrosion on the negative battery terminal - I haven't looked inside the device yet but the only thing I can think of after reading all the posts about 187 and 189 is that the corroded terminals may resist how much current is drawn into the device and possibly results in not enough energy being supplied to run both the DMM functions AND the backlight

[shockpoint]

Update
- solved

Stupid mistake on my part. Facepalm
I assumed that 4.8V was the voltage that the 187 required because I popped 4 NiMH batteries into it and it switched on
Checked the manual and realised that it called for 1.5V AAs, which is 6V
Tried 6V on my PSU, and the backlight stayed on.

False alarm! In case anyone else has the same problem I shall leave this post here, to my shame