B&K Precision frequency counter 1803

[zeitguy]

This is an older model with no wall wart. Does anyone know the voltage
and polarity of the miniplug power supply? How much damage could I do
starting with 5 v dc tip positive? I have $40 in the unit, so I am not
eager to fry it. Thanks for any help.

 

[Robert Baer]

zeitguy wrote:

This is an older model with no wall wart. Does anyone know the voltage
and polarity of the miniplug power supply? How much damage could I do
starting with 5 v dc tip positive? I have $40 in the unit, so I am not
eager to fry it. Thanks for any help.

Sometimes using a DMM in the diode position will give the polarity

ingo; other times a multimeter in 1K range will be needed for the
polarity info.
Another way is to take the case off and do xome circuit chasing; at
times that bay also give a clue as to the probable input voltage.
Ane then again, some meters have the voltage on a case label.

 

[zeitguy]

Thanks for the ideas. I took the case off and found an 6- AA cell
battery holder inside, and the red lead from the battery holder and the
lead from the tip of the power socket were soldered together, so it
should be a 9 volt tip positive wall wart. In the meantime, I am using
batteries, and it works great.

 

[zeitguy]

Thanks.

I opened the case and found a 6 cell AA battery holder inside with the
red lead and the socket tip lead soldered together, so it should be a 9
volt tip positive wall wart, I suppose. I wish all my other little
mysteries were so easy to solve.