Leader LMV-186A channel 2 not working

[Msw]

Hi

This is my first post here. I recently got a Leader LMV-186A that seems to be in good shape.
The channel 1 meter is working correctly, but i dont get channel 2 to respond to input signals.
I did zero the needle on channel 1, but did not manage to zero the channel 2 needle. Channel 2 do not adjust down to zero.
Channel 2 is not responding to the input signal in either seperate mode or in in1/in2 to ch2 mode. But in in1/in2 to ch2 mode the range the range knob is working on channel 2. But still only channel 1 meter responding.

How would you start to find the fault on this?

[Msw]

Input signal on Channel 2.

[Andy Watson]

How would you start to find the fault on this?

I always start by trying to locate a service manual with the schematic:
https://bama.edebris.com/manuals/leader/lmv186ab/
Not sure if the "B" suffix is significant - you will have to decide that.

Then remove the covers and inspect, very closely for broken wires/connections, poor solder joints and dodgy looking components - escpecially old electrolytic capacitors. What happens next depends on what other test equipment you have available.

[coromonadalix]

hum   would the input switch need to be moved to ch2 / right position ?   mmmm not so sure ... does it put the ch2 in parallel


Anyway   check the supply lines first  as usual   you have the 18vdc  ones and they get dropped to 15 vdc  further down


abd maybe  wobble the switch  left and right a few times / oxydation ??

[Runco990]

Did you "zero" the meters with the power OFF?  Also breathe on the front to dissipate any static charge.  I had one of these and the needles would repel each other.  The front switch should have some deoxit, and don't forget the rear grounding switch. 

Also, I have noticed that the needles won't zero on the low settings, the meter is picking up some hum in the environment.

These things rarely ever break.  It's a solid meter, so eliminate that first.  But the switches DO get tarnished.