Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

Unfortunately you can "s/cat/dog/" and it is just as true.

It it piteous to see the poor things struggling to breath, or worse, struggling to keep cool on a hot day by panting.

Totally agree, cats and dogs are beautiful as they are meant to be. My Mum had a Boxer and she used to pant badly on a real hot day.

[Cerebus]

If the coating on the membrane contact is wearing away, you can always use silver paint, I've seen and heard of that being done before to good effect.

What works surprisingly well is good Indian ink - the pigment in Indian ink is just carbon. Just test a lick of it on paper first, let it get properly dry and hit it with the multimeter on ohms just to check that you get good conduction.

[Specmaster]

In other news:

As I've already mentioned, I started a new (software) contract last month and, the end of October having passed, I got to cut an invoice. Now, given that I've been semi-retired for a while, and me and SWMBO have got into a routine and a place that we can live comfortably on what we already have coming in, the proceeds of my labours are largely bunce^*. Thus that invoice looks ridiculously big compared to what I actually have to spend it on. So, once I get into sufficient of a routine (and used to getting early up in the mornings) that I have some free time again I can feel some serious TEA brewing going on. That said, I haven't seen anything really tempting out there for weeks.

And on that note, taking regard of how stupidly early I've been getting up this week, I'm toddling off to bed.

^*I'm not sure if that flies east of Cornwall, so - Bunce: folding beer vouchers that are extra to one's actual requirements for them.

Yep, totally agree, eBay for TEA has been piss poor of late bur Christmas is coming up so maybe it might improve then? And for the record, "Bunce" has actually made across to the East Coast of the UK safe and sound so we all understand what it is. 

[Mr. Scram]

Yeah that roughly mirrors my experience.
But, when the pads are stuffed, they're stuffed and as a temp fix I've even resorted to sticking bits of tinfoil on them. 

Apparently there are replacement conductive rubber pads available. SeanB pointed me to some years ago, IIRC on eBay.

Are those generic pads or device specific ones? If it's the former, how would you attach them to the rest?

[Specmaster]

If the coating on the membrane contact is wearing away, you can always use silver paint, I've seen and heard of that being done before to good effect.

What works surprisingly well is good Indian ink - the pigment in Indian ink is just carbon. Just test a lick of it on paper first, let it get properly dry and hit it with the multimeter on ohms just to check that you get good conduction.

I've seen conductive paint on sale in small tins for that job and also for repairing PCB traces.

[Brumby]

But, when the pads are stuffed, they're stuffed and as a temp fix I've even resorted to sticking bits of tinfoil on them. 

I've done that too.   

[Cerebus]

In other news:

As I've already mentioned, I started a new (software) contract last month and, the end of October having passed, I got to cut an invoice. Now, given that I've been semi-retired for a while, and me and SWMBO have got into a routine and a place that we can live comfortably on what we already have coming in, the proceeds of my labours are largely bunce^*. Thus that invoice looks ridiculously big compared to what I actually have to spend it on. So, once I get into sufficient of a routine (and used to getting early up in the mornings) that I have some free time again I can feel some serious TEA brewing going on. That said, I haven't seen anything really tempting out there for weeks.

And on that note, taking regard of how stupidly early I've been getting up this week, I'm toddling off to bed.

^*I'm not sure if that flies east of Cornwall, so - Bunce: folding beer vouchers that are extra to one's actual requirements for them.

Yep, totally agree, eBay for TEA has been piss poor of late bur Christmas is coming up so maybe it might improve then? And for the record, "Bunce" has actually made across to the East Coast of the UK safe and sound so we all understand what it is. 

Yes, I of course, meant to write "west of Cornwall" alluding to our 'merkin cousins. Always get those two mixed up, but what would I know, I have two right feet.

[tautech]

If the coating on the membrane contact is wearing away, you can always use silver paint, I've seen and heard of that being done before to good effect.

What works surprisingly well is good Indian ink - the pigment in Indian ink is just carbon. Just test a lick of it on paper first, let it get properly dry and hit it with the multimeter on ohms just to check that you get good conduction.

Thanks a very simple and elegant solution, thanks. 

Makes mental note to never forget.
Rummaging for Indian ink..............

[xrunner]

I've had the best results in cleaning the rubber parts by simple washing in the kitchen sink with water and ordinary dish detergent. Final rinse in deionised water for good measure and then drying with a clean linen cotton union glass-cloth. The board I just clean off with a 70% isopropanol/deionised water mixture.

If the coating on the membrane contact is wearing away, you can always use silver paint, I've seen and heard of that being done before to good effect.

Yeah that roughly mirrors my experience.
But, when the pads are stuffed, they're stuffed and as a temp fix I've even resorted to sticking bits of tinfoil on them. 

Apparently there are replacement conductive rubber pads available. SeanB pointed me to some years ago, IIRC on eBay.

What works surprisingly well is good Indian ink - the pigment in Indian ink is just carbon. Just test a lick of it on paper first, let it get properly dry and hit it with the multimeter on ohms just to check that you get good conduction.

All ideas noted thanks. For tonight with the materials on hand, I tried washing in soapy water, rinsing, the membrane KBD. I cleaned each of the PCB trace areas with 90% alcohol. I reassembled (it doesn't take much time) and tested, it may have improved a little but not as much as I wanted. It's not all the keys but a few that were used a lot.

Took apart again. I inspected some of the key pads with a magnifier and noted that the troublesome ones seemed to have a slight sheen on them, perhaps because of many presses. I had some 600 grit wet sandpaper and I carefully used it to remove the sheen with a few light passes. I then put a very small amount of Deoxit on a Q-tip, and scrubbed the PCB traces where the pads pressed. The Q-tip showed some black so something came off or was polished a bit.

I re-assembled again and tested - this time the keys worked like new. Gently pressing them in as opposed to hard presses caused the appropriate key to light up and function to initiate. So for now I am pleased as punch, and for the future some of the materials suggested will be obtained for future use in these types of repairs.

 

[tautech]

Yeah I've seen that sheen on the pads too and was always too wimpish to take to it with anything abrasive.
Cool, hope it lasts for you.

Whereas Indian ink .................... 

[Cubdriver]

I don't mind that tautech brought up the Siglent because had it been available I would have ordered it. I think it has a much better display than the Rigol....which it turns out don't work anyway.

To everybody ...

I like cats but them are some ugly ass kittens. They are the new "designer" series with the pug noses and cropped ears. Some people think it's cute. It's not.   

They are kittens - they are by default cute and adorable.  There are no ugly kittens.   Looks like a litter of Scottish Folds - I wouldn't call them 'New' designer series, considering it's been a recognized breed since the mid sixties.

-Pat

[mnementh]

I don't mind that tautech brought up the Siglent because had it been available I would have ordered it. I think it has a much better display than the Rigol....which it turns out don't work anyway.

To everybody ...

I like cats but them are some ugly ass kittens. They are the new "designer" series with the pug noses and cropped ears. Some people think it's cute. It's not.   

LIES!!! This is how those cats are made... those kittens have been 'shopped I tells ya!   

Perhaps I inflamed it with the fugly kitties    Incidentally if I had to pick between the rigol or the siglent I’d choose an HP 

All I can say here is... FLUKE YOU!!! 

mnem


Just because I can.

Couldn't resist.  All in good fun. 

When these two get into a staring contest it's lethal.   

mnem
17 EFFING POSTS in the time it took me to watch Jurassic Park with my son?!?

[mnementh]

Once membrane buttons go feral they can be a right PITA. Good luck on this.

What's the general consensus on cleaning fingers and the conductive rubber ?
I found you don't want to get IPA near the membrane pads.

I've found that there seem to be exactly two types of membrane buttons: ones that work forever with no maintenance and ones that have to be dismantled and cleaned regularly. Case in point, I've a Humax set top box and an LG TV. The Humax remote is 3-4 years older than the TV one and just keeps working, the LG remote has needed dismantling and cleaning every year since it was about 2 years old.

I've had the best results in cleaning the rubber parts by simple washing in the kitchen sink with water and ordinary dish detergent. Final rinse in deionised water for good measure and then drying with a clean linen cotton union glass-cloth. The board I just clean off with a 70% isopropanol/deionised water mixture.

     I've always used 50% alcohol to clean both membrane and PCB. Usually all you wipe off, if you're careful, is carbon underlay that's already loose. Some you can fix with cleaning; others need the pad replaced. For the ones that need to be repaired, the ButtonWorx kits are the only thing I've found that works like original and keeps working; either them, or getting a cheap universal remote and shaving the conductive pads off with a razor blade and attach that with clear silicone RTV.

There are folks selling "Conductive Button Repair Disc" assortments all over fleaBay; I'd attach those with clear silicone as well. Worth a try at ~$8 a kit.

mnem
25 years after Jurassic Park, I still subconsciously evaluate every structure I enter in terms of Velociraptor survivability.

[mnementh]

The problem here is that you have previous form for this. I've seen you kick off a bit of faux moderatrixing in several threads before, with similar results and I've seen you trot out the "whole picture" line before too. I would count it an inestimable favour if you'd knock it on the head and next time you want to take issue with someone's postings in a similar vein either PM them or punt it to the moderators. I can certainly attest that Simon will take note of a "perhaps X is posting Y too often" suggestion and deal with it both effectively and quietly.

For what it's worth I personally find your attempts to impress your idea of what is and what is not acceptable a bigger generator of a worsened SNR than any of the posters I've seen it directed at. Witness this time around, that has generated upwards of 20 off-topic messages and would have generated none if you'd hit the actual moderators instead.

I guess everyone's now berating everyone else for having an opinion, with those of course being opinions themselves. If anything, the worsened SNR is caused by people tumbling over each other to add their opinion to the pile.

Nonetheless, what you call "faux moderating" is what I'd call community sense. Calling in the moderation team is like calling the police. It's a last resort and they have better things to do. Rather than calling the cops on them, I'd rather have a chat with the people who litter the community park instead. If we can't work things out, we'll go from there.

I regret the hubbub my remark has caused, as the former seems to have been entirely unnecessary.

Everyone is not berating everyone else; YOU are berating SOMEONE else, then taking offense when we ask you to drop it. Just as I've gotten spanked for going over the top with my political diatribes; we're asking you to put a filter on your little jihad. For most of us, the activity you're having fits about doesn't even make it onto our RADAR.   

mnem
*toddles off to ded*

[bitseeker]

As I've already mentioned, I started a new (software) contract last month and, the end of October having passed, I got to cut an invoice. Now, given that I've been semi-retired for a while, and me and SWMBO have got into a routine and a place that we can live comfortably on what we already have coming in, the proceeds of my labours are largely bunce^*.

That's a nice place to be.

Thus that invoice looks ridiculously big compared to what I actually have to spend it on. So, once I get into sufficient of a routine (and used to getting early up in the mornings) that I have some free time again I can feel some serious TEA brewing going on.

I like the sound of that. I feel some nice pics of TE coming in the near future.

[Mr. Scram]

Everyone is not berating everyone else; YOU are berating SOMEONE else, then taking offense when we ask you to drop it. Just as I've gotten spanked for going over the top with my political diatribes; we're asking you to put a filter on your little jihad. For most of us, the activity you're having fits about doesn't even make it onto our RADAR.   

mnem
*toddles off to ded*

How about we put this clusterfuck to rest, rather than everyone taking turns dragging it back up again?

[0culus]

Here's a great way feel REAL smart: I was working on a project this evening and I was getting some REALLY off readings on the scope for various measurements and I finally decided to throw in the towel and figure it out tomorrow. That's when I realized that the whole time my DUT was turned off. 

[bitseeker]

How about we put this c******k to rest, rather than everyone taking turns dragging it back up again?

Yes, there's been more than enough off-topic posts today about that one off topic.


Back to TEA:

I scored a Fluke 80K-40 HV probe. According to the manual, it's rated for "1 kV to 40 kV dc or peak ac, 28 kV rms ac." Oddly, it has a sticker on it that says, "Warning: Not authorized for use over 5000 volts." Since this probe is used, I suppose someone other than Fluke may have put that on there.

Anyway, to make sure it isn't borked, I tested it to 1000V DC with my insulation tester. It measured 1GΩ from probe tip to ground and my DMM showed the expected 1000:1 ratio on the probe output. Also, the resistance on the output banana plugs measured 1.1MΩ. Seems OK.

I don't have any plans to go around measuring 40kVDC, but it will be useful to discharge CRTs (rather than shorting them with a screw driver) and verify that HT circuits are de-energized before repairing.

One thing that's not clear to me is the probe's rating starting from 1kV. I was able to correctly measure 250VDC and 500VDC being output by my insulation tester. So, what do you suppose the issue is with voltages below 1kV?

[bitseeker]

Here's a great way feel REAL smart: I was working on a project this evening and I was getting some REALLY off readings on the scope for various measurements and I finally decided to throw in the towel and figure it out tomorrow. That's when I realized that the whole time my DUT was turned off. 

Hehe. Well, as mistakes go, the DUT being off is at least a safe one.

[bitseeker]

There was a 5321B that recently sold for $200. That's a bit too much moolah for a little old counter.

Yeah, that's rather rich for one of those.     They're rare and kind of cool, but neither the rarity nor the coolness comes close to two bills worth.

No kidding. One day, one will find its way to my lab. Hopefully, with all six tubes. In the meantime, I couldn't say no to this one for a Hamilton and Jackson.

[0culus]

Here's a great way feel REAL smart: I was working on a project this evening and I was getting some REALLY off readings on the scope for various measurements and I finally decided to throw in the towel and figure it out tomorrow. That's when I realized that the whole time my DUT was turned off. 

Hehe. Well, as mistakes go, the DUT being off is at least a safe one.

Indeed, good for a laugh! What power was in the circuit was coming from the attached signal generator, which definitely made for some odd performance.

[tautech]

Everyone is not berating everyone else; YOU are berating SOMEONE else, then taking offense when we ask you to drop it. Just as I've gotten spanked for going over the top with my political diatribes; we're asking you to put a filter on your little jihad. For most of us, the activity you're having fits about doesn't even make it onto our RADAR.   

mnem
*toddles off to ded*

How about we put this YOUR clusterfuck to rest, rather than everyone taking turns dragging it back up again?

So I ask Med a question and you butt in.........now he's got some info he was after and can get the unit he wanted in the first place.

OT over !

[tggzzz]

Here's a great way feel REAL smart: I was working on a project this evening and I was getting some REALLY off readings on the scope for various measurements and I finally decided to throw in the towel and figure it out tomorrow. That's when I realized that the whole time my DUT was turned off. 

If this is the first time you've experienced that, all I can say is "wow".

[Cerebus]

Here's a great way feel REAL smart: I was working on a project this evening and I was getting some REALLY off readings on the scope for various measurements and I finally decided to throw in the towel and figure it out tomorrow. That's when I realized that the whole time my DUT was turned off. 

If this is the first time you've experienced that, all I can say is "wow".

That doesn't necessarily imply unusually ordered and tidy working practices, 0culus might just be relatively young, not a target for stair-lift salesmen like so many of us on here. 

[GreyWoolfe]

That doesn't necessarily imply unusually ordered and tidy working practices, 0culus might just be relatively young, not a target for stair-lift salesmen like so many of us on here. 

Wait a minute here.  I may be getting old but there is absolutely no stair lift if my future!!!  I won't mention the fact that I have a single storey home.  That has nothing to do with it.