Test Equipment Anonymous (TEA) group therapy thread

[bitseeker]

If it's a light scratch, you can use any of the various plastic and/or clearcoat polishes from the auto parts store. Motorcycle helmet/visor polish also works.

For deeper scratches, wet sand with 800-, 1000-, then 2000-grit sandpaper until clear. Then finish off with plastic/clearcoat polish.

Protect your screen with a cellphone screen protector cut to size. Buy a tablet screen protector if you have many meters to protect.

EPA: Equipment Protectors Anonymous

[Mr. Scram]

If it's a light scratch, you can use any of the various plastic and/or clearcoat polishes from the auto parts store. Motorcycle helmet/visor polish also works.

For deeper scratches, wet sand with 800-, 1000-, then 2000-grit sandpaper until clear. Then finish off with plastic/clearcoat polish.

Protect your screen with a cellphone screen protector cut to size. Buy a tablet screen protector if you have many meters to protect.

EPA: Equipment Protectors Anonymous

I stabbed it with a probe, so there is a small nick in the grey body itself. Doing anything to that matte finish will inevitably make it more visible, unless you know what you're doing quite well. I've been there before. Some phone screen protectors ordered for this purpose just arrived, although one of them cracked and shows they might very well be actual hardened glass, instead of the plastic I was expecting. Damn those Chinese and their improving standards.

Ah, I'll be fine. I just have to remind myself it's a tool. Tools that aren't properly used are sad tools. If I wanted something to look at and not use, I should be collecting vinyl figurines or something similar.

[bd139]

You’d think they would use hardened glass for the screens on these things by now. It’s virtually impossible to scratch and can take as much if not more impact than plastics do.

I’m actually quite surprised recently as I dropped my iPhone 6s screen first onto concrete without a protector. It hit a small stone when it went down. Not so much as a scratch! I can’t say the same for my underpants.

[bitseeker]

I stabbed it with a probe, so there is a small nick in the grey body itself. Doing anything to that matte finish will inevitably make it more visible, unless you know what you're doing quite well.

Oh! I thought it was the screen. Matte plastic enclosure is a whole different story.

Some phone screen protectors ordered for this purpose just arrived, although one of them cracked and shows they might very well be actual hardened glass, instead of the plastic I was expecting. Damn those Chinese and their improving standards.

LOL! Yeah, I was quite surprised the first time I encountered those glass screen protectors, too.

I just have to remind myself it's a tool. Tools that aren't properly used are sad tools.

Also known as...bench queens.

You’d think they would use hardened glass for the screens on these things by now. It’s virtually impossible to scratch and can take as much if not more impact than plastics do.

That would be nice, indeed.

[Specmaster]

If it's a light scratch, you can use any of the various plastic and/or clearcoat polishes from the auto parts store. Motorcycle helmet/visor polish also works.

For deeper scratches, wet sand with 800-, 1000-, then 2000-grit sandpaper until clear. Then finish off with plastic/clearcoat polish.

Protect your screen with a cellphone screen protector cut to size. Buy a tablet screen protector if you have many meters to protect.

EPA: Equipment Protectors Anonymous

Good useful information, especially the tablet protector, that should do quite a few meter screens. 

[Specmaster]

You’d think they would use hardened glass for the screens on these things by now. It’s virtually impossible to scratch and can take as much if not more impact than plastics do.

I’m actually quite surprised recently as I dropped my iPhone 6s screen first onto concrete without a protector. It hit a small stone when it went down. Not so much as a scratch! I can’t say the same for my underpants.

I always get one of those toughened glass protectors for any new phone or tablet regardless what is already fitted by the manufacturer. Samsung have been using Gorilla glass for some time now. but I still fitted another Gorilla glass screen protector, kept my old phone screen like new.

[neo]

Its somewhat funny to read these comments about smart phones and tablets and then sit back and think to myself that i STILL have neither. 

[bd139]

I think you are blessed with some luck there. Unfortunately the industry I work in requires me to be tethered to the bloody phone all the time. Half the time I'm posting on here I am doing so while on some laborious conference call staring fuzzy eyed at a blurry powerpoint about business instrumentation.

I really wish it was about 1975-1980 and I worked in an electronics lab. You know before mobile phones were invented and if anyone wanted to get hold of you they'd have to come and see you or argue with the woman on the switchboard who was under strict instructions to pretend I no longer existed

[bd139]

Some VTVM porn for you.

I have finished sorting out the Heathkit V7-AU. I've done a naughty thing and put the 1M resistor usually in the probe inside the unit. I've replaced the 4mm sockets (one of the old ones disintegrated when I was soldering), filter cap, rectifier diode. You can basically now use it as a normal multimeter albeit negative is always at earth which is not a major restriction really. The original 1/4" jack is preserved so I can whack my RF probe into it. I need to adjust the resistor on that however yet. Peak internal voltage is 169.4 volts which is fine.

I am VERY surprised this electrolytic didn't explode at all. Plessey were notorious for producing crap capacitors. I think the previous owner was drunk when they installed that diode.



New cap and rectifier. Vishay/BC this time:



Modifications and new 4mm sockets. The red wire is added between the + terminal and the 1/4" socket tip. There is a 1W Vishay/Dale 1M 1% resistor between the tip and the DC input wafer.



Calibration is complete and it's spot on with DC volts, no sign of instability. AC volts is good too. Resistance is reading a tiny bit high on my test set (small pile of 0.1% RN55D's - resistance standard = £1.50!) so I'll check the divider resistors at some point. I'm not all that bothered though for now.

Now I'm bored. Back to eBay for more TEA! 

Edit: For ref yes I'm aware there is a hazard if you plug something into the DC socket and leave AC probe in on high voltage. This is not dumbass proof but it requires the least amount of modification to it

[PA0PBZ]

Those rectifier holes... what's supposed to go in there, a selenium cell?

[Rbastler]

Those rectifier holes... what's supposed to go in there, a selenium cell?

Probably yes.
My HP412A has a 6X4 full wave rectifier. Bought it because its a VTVM. Surprisingly I didnt have to repair or change anything, looked like fresh out of the factory.

[bd139]

Yep selenium rectifier. You can see an original one in this picture:



You haven't lived until you've smelled one that has blown up

[AF6LJ]

Yep selenium rectifier. You can see an original one in this picture:



You haven't lived until you've smelled one that has blown up

Nice..

[Rbastler]

Yep selenium rectifier. You can see an original one in this picture:



You haven't lived until you've smelled one that has blown up

Thats wy in German you call them Gleich-riecht-er. "Shortly it smells". I remember while I tested a selenium bridge it burned and it smelled like shit.

[bd139]

I love German word play

They smell like shit boiled in a pan with garlic. I remember my mother being seriously annoyed at me because when I fired up the vintage valve radio I got at a jumble sale for a glorious £0.10 (10p), the rectifier blew out and made the place smell for a week. Everyone was gagging for the first hour. I remember getting told to only buy old transistor radios after that 

[neo]

I think you are blessed with some luck there. Unfortunately the industry I work in requires me to be tethered to the bloody phone all the time. Half the time I'm posting on here I am doing so while on some laborious conference call staring fuzzy eyed at a blurry powerpoint about business instrumentation.

I really wish it was about 1975-1980 and I worked in an electronics lab. You know before mobile phones were invented and if anyone wanted to get hold of you they'd have to come and see you or argue with the woman on the switchboard who was under strict instructions to pretend I no longer existed

I never got to live the 70s though i most certainly envy them. The music then was great as well.....
Can someone invent the time machine and give me ticket for 1969? I won't mind if it is one way only.

[Specmaster]

Nice, I might take it a stage further and either add another banana socket or as I don't have an RF probe, remove the 1/4" jack and fit a banana socket there for the DC jack. I'm considering taking out the C cell altogether and building a 1.5v power rail to prevent the cell leaking because its not a meter that gets used regularly. I have seen so may that have leaked and almost destroyed the guts. Mine is in mint condition and I'd like to keep that way.

[bd139]

Not a bad idea actually. I really liked the idea of keeping it original in that respect though so I can convert it back to "normal operation" fairly easily. I also wasn't sure if the hole for the jack was the same size as a 4mm socket or not. Basically I'm lazy

I too would like a battery eliminator. As you can see from the pictures of mine above, the previous owner has actually done a half decent job of getting an AA in there.

Battery eliminator circuit here for reference: https://mikeyancey.com/an-improved-vtvm-battery-eliminator/

I would also consider replacing the pilot lamp with something else if this mod is done as it's dragging the current off the filament winding. Adding more may smoke the transformer which would be a disaster.

glad to hear you got a mint one. I'm still trying to work out what to do about the meter face on mine which is actually glued on with hot snot At least it actually works though

[Specmaster]

Not a bad idea actually. I really liked the idea of keeping it original in that respect though so I can convert it back to "normal operation" fairly easily. I also wasn't sure if the hole for the jack was the same size as a 4mm socket or not. Basically I'm lazy

I too would like a battery eliminator. As you can see from the pictures of mine above, the previous owner has actually done a half decent job of getting an AA in there.

Battery eliminator circuit here for reference: https://mikeyancey.com/an-improved-vtvm-battery-eliminator/

I would also consider replacing the pilot lamp with something else if this mod is done as it's dragging the current off the filament winding. Adding more may smoke the transformer which would be a disaster.

glad to hear you got a mint one. I'm still trying to work out what to do about the meter face on mine which is actually glued on with hot snot At least it actually works though

You know, come to that, why bother with the battery eliminator, just leave the circuitry as it is, remove the battery and replace the lamp with a LED via a suitable resistor dropper? Resistance measurements is not the reason we have these in our kit is it? I have 15 other ways to measure resistance with far greater accuracy.  Thus restricting it to just voltage readings, replacing the bulb with a LED would allow the struggling transformer to better drive the valves? Perhaps the resistance ranges could be repurposed for other uses? The reason why I wanted one was to aid radio alignment via the centre zero option.

[bd139]

I bought mine because I like minimalism and equipment that requires a low component count to do an adequate job. Resistance is pretty important for me. Yeah I’ve got an Hp3478 and Fluke 8050 but they’re boring

[tggzzz]

You know before mobile phones were invented and if anyone wanted to get hold of you they'd have to come and see you or argue with the woman on the switchboard who was under strict instructions to pretend I no longer existed

My phone has an "off" switch. Doesn't yours?

I use the off switch frequently, since the phone is for my convenience, not other peoples' convenience.

[djos]

You know before mobile phones were invented and if anyone wanted to get hold of you they'd have to come and see you or argue with the woman on the switchboard who was under strict instructions to pretend I no longer existed

My phone has an "off" switch. Doesn't yours?

I use the off switch frequently, since the phone is for my convenience, not other peoples' convenience.

I just put my phone in do not disturb mode, best feature ever!

[Specmaster]

You know before mobile phones were invented and if anyone wanted to get hold of you they'd have to come and see you or argue with the woman on the switchboard who was under strict instructions to pretend I no longer existed

My phone has an "off" switch. Doesn't yours?

I use the off switch frequently, since the phone is for my convenience, not other peoples' convenience.

I just put my phone in do not disturb mode, best feature ever!

Hmm, what happens when a friend or family need to contact you urgently, I just look at who's calling and answer or ignore as appropriate depending on who it is.

[djos]

You know before mobile phones were invented and if anyone wanted to get hold of you they'd have to come and see you or argue with the woman on the switchboard who was under strict instructions to pretend I no longer existed

My phone has an "off" switch. Doesn't yours?

I use the off switch frequently, since the phone is for my convenience, not other peoples' convenience.

I just put my phone in do not disturb mode, best feature ever!

Hmm, what happens when a friend or family need to contact you urgently, I just look at who's calling and answer or ignore as appropriate depending on who it is.

On iPhone if they call twice in 3 minutes it'll ring the second time. You don't get all the noisy notifications which is nice.

[bd139]

You know before mobile phones were invented and if anyone wanted to get hold of you they'd have to come and see you or argue with the woman on the switchboard who was under strict instructions to pretend I no longer existed

My phone has an "off" switch. Doesn't yours?

I use the off switch frequently, since the phone is for my convenience, not other peoples' convenience.

I’m paid a quite frankly silly amount of money to be inconvenienced so it’s a trade off I’m willing to make in the short term. Once that mortgage is gone in three years, middle finger to everyone and I’m going to be a hermit surrounded by oscilloscopes and radios

I’m really lamenting the past where it was white difficult to be inconvenienced due to the technology of the era.