Which bench multimeter? - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Radio Wrangler · 3rd Mar 2020, 11:52 pm

Another use for a high resolution DVM is tracing shorts on boards. A multilayer PCB with a ground plane and a power plane with one shorted device or decoupler pulling the supply down is a classic puzzle.

With a current limited PSU putting a moderate current into the thing, you can plot a contour map of the relative potentials of all the accessible points for each plane. You can even measure the voltage drop along the j-lead of an SMT chip.

Cheating? yes, but it doesn't half make life easier.

Once you have some good tackle, you find new ways of using it.

David

jamesperrett · 4th Mar 2020, 12:46 am

We had both the Keithley and the few of the HP's (although branded Keysight) where I used to work which were probably bought from an end of year surplus. When I first saw them I thought what are we ever going to use these for? However, the portable multimeters kept on disappearing while these ones stayed on the shelf so I gave them a try and I certainly found them very useful - especially the high resistance range on the HP which was very useful for finding leaking connectors.

3rd Mar 2020, 11:52 pm	#21
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,867	Re: Which bench multimeter? Another use for a high resolution DVM is tracing shorts on boards. A multilayer PCB with a ground plane and a power plane with one shorted device or decoupler pulling the supply down is a classic puzzle. With a current limited PSU putting a moderate current into the thing, you can plot a contour map of the relative potentials of all the accessible points for each plane. You can even measure the voltage drop along the j-lead of an SMT chip. Cheating? yes, but it doesn't half make life easier. Once you have some good tackle, you find new ways of using it. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

4th Mar 2020, 12:46 am	#22
jamesperrett Octode Join Date: May 2007 Location: Liss, Hampshire, UK. Posts: 1,873	Re: Which bench multimeter? We had both the Keithley and the few of the HP's (although branded Keysight) where I used to work which were probably bought from an end of year surplus. When I first saw them I thought what are we ever going to use these for? However, the portable multimeters kept on disappearing while these ones stayed on the shelf so I gave them a try and I certainly found them very useful - especially the high resistance range on the HP which was very useful for finding leaking connectors.