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Yes, beads or capacitors, I can't tell. Most likely ferrite beads. These are next to the spring and the big diode. Edit: And yet again it should watch it 'til the end ;)

bingo, don't know why dave refered to the jumpers as beads

because thats what they were before the fix

Yeah. Those sure look like jumpers.

Unfortunately that is often the case. If you put ferrite beads that far into a circuit you might be able to isolate the track from direct connection to the rest of your circuit at high frequencies, but that track will turn into an antenna inside your nicely screened box and then couple into absolutely everything else. Swapping the ferrites for 0 ohm links also makes a good connection between the external ground connection and the entire ground plane on the PCB. Before the modifications the problem would have been common mode RF currents flowing via leakage (capacitive coupling - hence the spooky effect of waving a hand nearby) through some sensitive part of the circuit and ultimately to ground, but afterwards those currents would flow through the 0 ohm links straight to the spring and onto the shielding foil at the back of the case without getting a chance to upset anything else. Even RF likes to take the easiest route to ground.

Yep. But why make the current track thinner?

it's on the ma range

might have just done it to save copper

Noticed that too, maybe thats part of what was coupling the interference in? But seems like they did it just to save a bit of copper really.

You don't save copper that way. The boards are made as a film across the entire surface, then the gaps are etched away in acidic etching fluid so by making the tracks smaller you just use up the etching fluid quicker and have more waste product to process.

Is that the one that went from black to yellow?

Yup, but I wasn't able to find the HiRes photos to see the writing close enough to confirm if the value changed or not.

That trace doesn't matter.

You're the expert. I was thinking it looks suspiciously like it's the same width as the pair of RF beads which they eliminated.

It's not only the track, on the REV006 board there is also JP4 which can't be seen on the old one. Wondering whether there are other changes under the second board.

Brad Crowley Maybe the rev 4 to rev 6 change was before the EMI issue was spotted, way back in the Agilent days. So the entire fix was done as mods to existing stock and returned devices. Dave spotted 2 component replacement mods and one firmware mod. Maybe they also used firmware changes to firmware controlled electrical values, such as ADC clocking or the state of seemingly unrelated FET signal switches.

The solution is to buy a Fluke 289.

Sven Kolberg You want to prevent the high frequency switching noise of your digital components from getting on your analog ground. But in this case it appears they created a ground loop (which acts like an antenna) by not providing the noise a short, low impedance path to ground

I'm pretty sure that trace would not make any difference.

+eEEVblog A true engineer would ask why the change instead of dismissing it like that. It also looks like there's some others on the sub-board that's always annoyingly just out of shot.

German Alvarez definitely a firmware change since the LPF is force on in DC amps now

I was thinking the same.

No I don't. The resonant frequency is not just the bead, it's the whole system at some point(s) in the measurement chain.

The square wave is worse.

There are many SOIC chips, be more specific. If you mean the tantalums, that's likely a normal BOM change.

near comunication led on the right

My old model is like 5 years old or something. BOM's and suppliers change.

Nowhere near skilled as you, rather a rookie. I kinda made a assumption that it could have been noisy/Intermitting caps causing the problem partially

+CoRDS And must have been changed for a good reason. But Dave knows better...

I think that was the back half of the case from the newer meter.

Actually that's the backcover of the newer multimeter, because if you notice, the tested one at 21:00 is propped up on it's tiltstand, something that wouldn't be there without the backcover. Also if you look at 6:00 when we see the new and old backplates side-by-side, the old on left, new on right, if you notice the foil shielding, the older one's foil is quite knackered while the new is smooth as a baby's behind (the one we see at 21:00). I guess you must have really believed Dave and thought the old multimeter is truly spooky, because it's now tilted and floating without a backplate stand.

correct, without the back cover MM wont stand by it self

Hahaha, looks like Dave spotted the same thing at 17:40.

No its impossible to watch until the end without screaming :-D Not recognizing 0Ohm-resistors was quite a bit to much for my nerves too... I think he was so fixated on finding added beads and stuff that he didnt want to see removing them could help.. I am not sure why they are in there in the first place. Disconnecting a ground like that doesnt seem a good idea.. if you want ground isolation you would need coupled inductors. The fault here seems to be that the shield is not referenced to the input jack but the shield is connected to the (high frequency wise) floating ground of the meter. So any coupling to the shield will throw off your measurement.

I also for all those long minutes screamed "Dave can't you see those are 0 ohm resistors? Stop calling them as different type beads :) "

Yeah... saw the 0 Ohm resistors that replaced the inductors right away as well.. Dave did originally believe they were another value inductor. Just removed my comment.

craftycoder well, dave probably took down the previous video. This one is quite a bit different, for example he correctly identifies the BD4/5 parts as being resistors instead of ferrite beads.

The original didn't have the part at the end, where dave attempts to 'fix' the original.

Ferris Bueller's Day Off. A teacher calls for Ferris during roll call.

Maybe they put another ground plain in?

Shakaib Safvi removed it

yup... my bad... removed....

Standard practice to mix caps in a BOM across different builds.

I thought I read that tantalum caps can help reduce stray inductance at high frequency or something.

Jesse Motes The tan colored caps and black caps are both tantalum. Probably a vendor change.

That's what she said.