ESD wrist strap tester

[@matambale]

We had dozens of these DESCO testers in the labs, one at each bench - never had a single one fail, was waiting for that excuse to take one apart. Thanks Mr. O'Stuff.

[@Okurka.]

Did they get a yearly calibration?

[@matambale]

@@Okurka. Yes, so they were well maintained. (Edit: Actually it might have been every 2 or 3 years. Can't remember the dates etc. It was some time ago)

[@richardhalliday6469]

I worked in an electronics factory ( Satellite receivers) . ESD wrist straps were mandatory of course when handling product, PCBs, components , reworking etc.we also wore heels/ankle ESD straps that wore around your lower leg( sock level)then around the heel of your footwear.All of the floor in the production area had a grounded conductive surface.

[@markusallport1276]

These do come in handy when repairing flat screen TV's, ask me how I know. After screwing up 2 main boards in a monitor, I decided to do the same thing on a TV main board. Now I have a wrist strap and it doesn't cost as much to repair that stuff anymore.

[@gordanmilne7034]

It is a well known fact that exposure to good beer can solve many issues.

[@TheUnofficialMaker]

and create many more

[@TheEmbeddedHobbyist]

I've been using a esd strap for years, in my test lab you had to test it everyday and sign the test sheet. In Teh towers toy room, I've still got an esd mat and strap in place, which is used every time I work on any electronic equipment. No point adding to the damage while repairing it. About 80% of the static hits do not kill the device straight away, you may just change its performance or cause it to die when it gets to your customers. If esd was not problem then we wouldn't spend a fortune on preventing it. Conductive floor paint is not cheap along with antistatic footwear but it saves you having to remember to strap up.

[@ParallelLogic]

"Have you tried disassembling it and reassembling it again?" ~ IT

[@thisoldjeepcj5]

It was broke, and now it's fixed. Salute!

[@loveminis31]

My instructor for A+ insisted on everyone use a grounding strap because class room was carpeted and first class he taught he lost so so many parts. I never seen one used again. I do still use mine at home.

[@fredflintstone1]

A nice fix almost as good as "switch it off and on again" 🙂

[@douro20]

The reason they are so expensive is that they have to be certified...and the cost of certification is very high. Some combination wrist/foot testing boxes can be over US$1000.

[@delinuxspecialist]

I suspect the spring as well, maybe you could open it up again and extend the spring a bit so it makes better contact, also change out the capacitor just to be sure.

[@HazeAnderson]

I purchased a used pedal from Reverb recently and, after a few successful uses it stopped functioning, that is the LED would not light up and the momentary soft stomp switch would not activate the relay inside. I opened it up to at least make sure there was no leaking caps, and discovered that the DC jack was connected to the circuit via a JST connector which was merely loose. EZ FIX! 😆👍

[@eDoc2020]

From your drawn schematic it looks like there is a direct connection from the touchpad to the comparator. I thought the problem was going to be a fried input from ESD which would've been ironic.

[@pileofstuff]

I did say it's only a rough approximation of the circuit.

[@t1d100]

You stated that you do not think that you have much use for the device. However, if it were mine and being that I am compulsive, I would just plain have to change out the 20 year old e-cap... grin

[@Okurka.]

And replace it with an inferior one from eBay.

[@markfergerson2145]

As soon as you pulled the board out and revealed the spring, I suspected corrosion. I also suspect you suspected corrosion as soon as you saw it but didn’t say anything. I’m honestly a little surprised to see the connection made that way, it’s such an obvious potential failure point. Planned obsolescence?

[@monophonic_og]

I also looked at the springy thing with a condemning expression. Although I must admit corrosion never crossed my mind, I thought someone had bumped or dropped the device and the unattached spring had jumped off the contact hole and stuck on the plastic cover. Thus cutting the circuit between the touch plate and itself.

[@johncoops6897]

Spring is perfectly viable method to connect such a high impedance connection, especially if touch pad is not solderable (eg: stainless or aluminium). His error in troubleshooting was to not test the bare PCB, power up, and touch the spring. So he went down a rabbit hole... 😉

[@Okurka.]

Yes, it was planned to break after exactly 20 years without calibration.

[@Pyr0100]

can you make a video of all the things you use? im a comp sci major but even as a kid i used to take apart remotes and computers just to see the circuitry. i know nothing but wish to be just like this

[@pileofstuff]

I do have a playlist of all the teardown videos I've done: kzbin.info/aero/PLE9Um5NpNcs7tN07TtichJLtK0z9Z-U1D And another one with the repairs: kzbin.info/aero/PLE9Um5NpNcs7zP_wQiGKMWu2h3I8h_iWn

[@rickhunter1984]

You grabbed the in side with the clip before you tried to plug it in and may have had no connection with the terminal.

[@PakiNewsNetwork]

Any other easy way to discharge static current?

[@pileofstuff]

When I don't have a wrist strap available, I just keep one hand on the metal chassis of the equipment I'm working on.

[@pmacgowan]

Serendipity

[@frankowalker4662]

Great fix. I guess. LOL.

[@snakezdewiggle6084]

They are meant to be On Your Ankle. Consider the path, via Toes, or via Chest. *

[@johncoops6897]

Your troubleshooting was flawed, as others have said below. You first step should have been to power up the BARE PCB, connect the wrist strap, then touch the spring with your finger. I bet it would have worked, and the fault was just the spring connection to the front pad. Because you never tested the disassembled PCB, you are left to guess at the very end.

[@pileofstuff]

If my intention was to repair it, that would have been the correct order of operations. I was simply curious about the circuit. The fact that it now works is merely a bonus.

[@DeathbyKillerBong]

did you not put the ground strap on the other banana plug connector at start of video when it was not working, and the other when it was at the end of video? yes you did

[@pileofstuff]

They're soldered to the same pad on the PCB. There's no difference between them (take another look @10:22 )

[@DeathbyKillerBong]

@@pileofstuffaha, well i have a fever from flu so im gonna blame that ;)