Test Equipment Anonymous (TEA) group therapy thread

[Brumby]

Yes sure beware of little springs inside, so be careful and anticipate them trying to escape...

... and if you establish a search perimeter at 3 metres, there will be at least one such escapee that will make it past 5 metres.

[med6753]

Saskia, according to USPS tracking the connectors have already been processed through Customs in Frankfurt so hopefully you'll have them in a few days.

I'm surprised it moved through US and German Customs that quick. 

[tggzzz]

On the mini Voltcraft Scope these buttons don't latch anymore. Is it worth taking them apart to fix, or would I just end up spending the afternoon looking for springs and other small parts on the floor? Or should I just look for replacements?

You might get some inspiration from the switches in https://www.eevblog.com/forum/repair/renovating-an-early-tektronix-475-oscilloscope-a-few-random-hints-and-tips/msg1438311/#msg1438311

[Vince]

Yes sure beware of little springs inside, so be careful and anticipate them trying to escape...

... and if you establish a search perimeter at 3 metres, there will be at least one such escapee that will make it past 5 metres.

There is a solution though !

Work on the switches inside one of these cabinets  !! 

[McBryce]

Yes sure beware of little springs inside, so be careful and anticipate them trying to escape...

... and if you establish a search perimeter at 3 metres, there will be at least one such escapee that will make it past 5 metres.

Yes, but I'll do it in the same area where I've lost many other small parts, so I might end up with a net profit?

McBryce.

[mnementh]

   On the mini Voltcraft Scope these buttons don't latch anymore.

Is it worth taking them apart to fix, or would I just end up spending the afternoon looking for springs and other small parts on the floor? Or should I just look for replacements?   - McBryce.

Yes sure beware of little springs inside, so be careful and anticipate them trying to escape...

... and if you establish a search perimeter at 3 metres, there will be at least one such escapee that will make it past 5 metres.

Just take the stoopit thing apart inside a gallon ziplock baggie. 

As whether it's worth it... depends on how the latch works. If individual ratchet mechanisms, might be worth the time of shopping replacements if one of the more common variants like DPDT, etc. If a weird number of contacts, or if the switch is part of an array with a canceling cam/rod between them, not really a lot of choice except to service the existing switch.

              

Some of these switches are meant to be serviced, like the ones on my 3478A. The contacts remain captive, and while it is possible to lose the ratchet link, they are made to be assembled/disassembled by removing the compression spring and lifting a retaining finger.

Good hunting!

mnem

[McBryce]

Yes sure beware of little springs inside, so be careful and anticipate them trying to escape...

... and if you establish a search perimeter at 3 metres, there will be at least one such escapee that will make it past 5 metres.

Just take the stoopit thing apart inside a gallon ziplock baggie. 

As whether it's worth it... depends on how the latch works. If individual ratchet mechanisms, might be worth the time of shopping replacements if one of the more common variants like DPDT, etc. If a weird number of contacts, or if the switch is part of an array with a canceling cam/rod between them, not really a lot of choice except to service the existing switch.

              

Some of these switches are meant to be serviced, like the ones on my 3478A. The contacts remain captive, and while it is possible to lose the ratchet link, they are made to be assembled/disassembled by removing the compression spring and lifting a retaining finger.

Good hunting!

mnem

Yes, they are part of a 3 way array, but I can't see where / how they are linked. Maybe I should open the working unit I have and compare.

McBryce.

[mnementh]

Yes, they are part of a 3 way array, but I can't see where / how they are linked. Maybe I should open the working unit I have and compare.   McBryce.

If they are supposed to be an [OR] logic array (any one of the array pressed causes the others to release), there will be a sliding bar inside the common bracket they're all attached to. It may be on the front or back side of the common bracket. These sometimes have some form of grease which eventually dries out and gums up the works.

If so, before you take everything apart you can first try to free that up by squirting alcohol or food-grade silicone (look for a brand with alcohol carrier, not naphtha or toluol or any of the other weird aggressively solvent VOCs) in there to free it up.

mnem
 

[TERRA Operative]

On the mini Voltcraft Scope these buttons don't latch anymore. Is it worth taking them apart to fix, or would I just end up spending the afternoon looking for springs and other small parts on the floor? Or should I just look for replacements?

McBryce.

They look much like the ones used by Tektronix. They aren't too hard to dismantle and clean out, usually the grease gets too sticky. I pull them apart, clean everything with isopropyl alcohol (A Q-tip fits nicely inside them) and then some deoxit and a tiny bit of lithium grease has them like new.

See the attached file. Most of the time you don't even have to remove them from the PCB.

Look closely at the metal bracket on the pushbutton end of the switch body, you'll see some tabs bent down locking it in place. After removing the spring retainer clips and springs etc, just carefully bend the tabs up a bit, then the bracket will slide sideways and come away.
To get the plungers back in with the contacts, I simply hold the contacts in place on the plunger with tweezers and slide it in from the back of the switch body.

[McBryce]

On the mini Voltcraft Scope these buttons don't latch anymore. Is it worth taking them apart to fix, or would I just end up spending the afternoon looking for springs and other small parts on the floor? Or should I just look for replacements?

McBryce.

They look much like the ones used by Tektronix. They aren't too hard to dismantle and clean out, usually the grease gets too sticky. I pull them apart, clean everything with isopropyl alcohol (A Q-tip fits nicely inside them) and then some deoxit and a tiny bit of lithium grease has them like new.

See the attached file. Most of the time you don't even have to remove them from the PCB.

Look closely at the metal bracket on the pushbutton end of the switch body, you'll see some tabs bent down locking it in place. After removing the spring retainer clips and springs etc, just carefully bend the tabs up a bit, then the bracket will slide sideways and come away.
To get the plungers back in with the contacts, I simply hold the contacts in place on the plunger with tweezers and slide it in from the back of the switch body.

Well, a serious blast of contact cleaner has fixed the centre switch (the first switch was already working). The issue with the last switch seems to be that the PCB has been pushed back over time. If I push the PCB towards the front panel all will switch properly, so it looks like I just need to "adjust" the frame that the PCB's are mounted to.

McBryce.

[mnementh]

From the Woodworking Dwagon...



Spent my "morning cuppa" time watching this guy talk about staining and finishing basics; see if I could jog loose any of the vague memories from ages ago doing this stuff in with grand-dad and mostly just making sure I just don't make any horrible mistakes from old age and forgetfulness. I quite like his down-to-earth attitude and quirky "dad-joke" sense of humor.

Welp... coffee's done and now's the moment of truth; wiping down the stain to see what lies beneath. I may have already made one egregious error; I left the stain on thick and heavy overnight, as by the time we got back from dinner with dad I was just knackered after spending all day sanding in the heat and 110% humidity...

mnem
pray for me...

[bd139]

Just take the stoopit thing apart inside a gallon ziplock baggie. 

This is such a damn good idea and one I have never used. Added to the brain bank

[mnementh]

From the Woodworking Dwagon...

Welp... coffee's done and now's the moment of truth; wiping down the stain to see what lies beneath. I may have already made one egregious error; I left the stain on thick and heavy overnight, as by the time we got back from dinner with dad I was just knackered after spending all day sanding in the heat and 110% humidity...

mnem
pray for me...

Ugggh. It's every bit as bad as I feared.
Cleaning this up will probably be as much assache as the initial stripping was.   

mnem

[Cerebus]

Got to have a poke at Cerberus here as well. A friend of mine is always poking me at how much he spends on electricity on his Tesla. My car didn’t cost £88k so I could run mine on Absolut vodka and still be better off 

Oh I think I'm winning. When the time arrived that I started looking at secondhand replacements for my car I discovered that, much to my surprise, there were quite a lot of plug-in hybrids on the market at sane prices. Last time I looked (perhaps a year ago) there was nothing on the secondhand market that I could afford (or at least wanted to pay for). What seems to have happened is that a lot of company car drivers opted for PHEVs because of the relatively mild benefit in kind taxation on PHEVs and those have now filtered onto the second hand market at sane prices.

I got lucky and found a pristine six year old BMW 330e at a local car dealers (within walking distance) at a much better price than I thought possible (<£15k) clearly previously owned by a "one man band" company director. Subsequent enquiries showed that he'd shut up shop last year (voluntary liquidation). It wasn't what I'd set out to look for, not by a long chalk, but after weighing things up I went and took a look and ended up buying it. The 20 odd miles it'll do purely on battery has turned out to be a near perfect fit with the local driving I do, no road tax, no environmental levy on my residents parking permit, surprisingly low service costs from official dealers (and my local lads I've been using for years will better that I'm sure), and 'cause I'm an old git with a good record, about as cheap insurance as it's possible to pay in London (a few hundred fully comp).

Standing costs are going to be a little less than the old car (Say £700 a year). I paid the same price for the old car 22 years ago as I just did for the 'new' one. The old car has cost me  <£700 a year in depreciation (if I consider it written off completely), a bit more in standing costs (insurance, servicing, taxation) so perhaps £1700 a year in total, plus fuel. I don't feel that's a bad price for having it available 24/7 just by walking out of the door. The overall costs for the new car will be similar to the old, perhaps less perhaps more, when depreciation is taken into account. I personally would spend significantly more to use zipcar (the ones nearest me ATM are £10/hr or £94/day) plus taxis plus public transport with significantly less convenience. I'd spend more per week just to do the weekly "big shop" by taxi or zipcar.  So for me it's a bargain worth making.

[Cerebus]

Get you friend to demonstrate how, while driving along, he deals with

• the screen starts misting up: how does he redirect ventilation
• you are about to drive through smoke from a fire; how does he switch from external air to recirculating air

I can't speak to the Tesla case but the number of bells and whistles in the new (to me) BMW surprised me in this regard. If in "auto" climate mode the answer in both cases would be "nothing", there are sensors for both misting up and external air quality and the car will automatically do the right thing. There are also physical "demist the windows with the aircon" and "fresh/recirculate/auto air circulation" buttons if I have the climate control off or in manual mode. The answer for the old car would vary between "fiddle with lots of manual controls" or "stop and put the roof up/down", but it had the two great advantages over the 'new' car of (1) having a soft top, (2) having the engine just behind the driver's seat - both qualities I shall miss.

[TERRA Operative]

Think I'm going to go buy a Peak Atlas ZEN50 Zener diode tester tomorrow. I've needed a zener diode tester on a number of occasions now and setting up a multimeter, power supply and resistor is a pain in the bum.

Anyone got any reason why I shouldn't?

[Cerebus]

Think I'm going to go buy a Peak Atlas ZEN50 Zener diode tester tomorrow. I've needed a zener diode tester on a number of occasions now and setting up a multimeter, power supply and resistor is a pain in the bum.

Anyone got any reason why I shouldn't?

It'll increase the "margin of excuse" you'll need to buy yourself a good SMU? 

Edit: The 3A current sinking capacity of my HP 6611C power supply when using it in poor-man's SMU mode came in really handy last week. I had a 5V 2A wall wart give up the ghost and the replacement eBay special could only supply 450mA @ 5V despite being rated for 2A. A photo of the HP 6611C display proving this got me a virtually instant refund.

[bd139]

Think I'm going to go buy a Peak Atlas ZEN50 Zener diode tester tomorrow. I've needed a zener diode tester on a number of occasions now and setting up a multimeter, power supply and resistor is a pain in the bum.

Anyone got any reason why I shouldn't?

I would buy another multimeter and power supply for the same money 🤣

[m k]

Get you friend to demonstrate how, while driving along, he deals with

• the screen starts misting up: how does he redirect ventilation
• you are about to drive through smoke from a fire; how does he switch from external air to recirculating air

I can't speak to the Tesla case but the number of bells and whistles in the new (to me) BMW surprised me in this regard. If in "auto" climate mode the answer in both cases would be "nothing", there are sensors for both misting up and external air quality and the car will automatically do the right thing. There are also physical "demist the windows with the aircon" and "fresh/recirculate/auto air circulation" buttons if I have the climate control off or in manual mode. The answer for the old car would vary between "fiddle with lots of manual controls" or "stop and put the roof up/down", but it had the two great advantages over the 'new' car of (1) having a soft top, (2) having the engine just behind the driver's seat - both qualities I shall miss.

Lotus Elise?

[25 CPS]

That is the problem with buses or indeed any form of public transport apart from a taxi, they either sometimes involve a reasonable amount of walking, or they go round the houses and take so long doing that. The former is no joke if you're all dressed up and the heavens open up and dump on you, even an umbrella does not afford complete protection, or if it's in the depth of winter, and you're freezing your tits off.

In the example I gave of my journey, the buses all run into the city centre on a circular route, there are no routes that go one side to the other of the city. They all radiate from the centre,  so that adds on another couple of miles, and if they get delayed, then you have to wait for your other connection to arrive. So who in their right minds would want to do that when, as you say, you have air-conditioned luxury sitting outside.

Routing difficulties is one set of problems.  Hours of service, if you do shift work, very quickly adds another layer of problems.  Public transportation to work from where I live became a lot more tedious in 2015 when the train schedule was redesigned.  Public transportation to work on Sunday mornings is not possible without arriving an hour late.  Public transportation home from work on any afternoon shift is not possible because the last express bus out of the city is scheduled to arrive 10 minutes after the last set of local buses leave the terminal at the end of the line.  That one truly takes the cake.  So it's a nice, long walk across town or a very expen$$$ive taxi ride, or Uber or Lyft if any are available.  The walk is actually quite enjoyable on a nice evening with some good music, which is fine, but if the weather's crappy, it gets old really fast.

The commuter transit agency here also jacked up fares 7% each year so those took off like a rocket.  The worst was 2017 though.  Trudeau abruptly out of nowhere ended the public transportation tax credit so that increased fares by 15% in terms of reduced tax refuund plus the commuter transit agency tacked on another 3% directly out of pocket for a total eyepopper 18% increase in one year.  Bad service/service not available when needed/extreme cost compared to when I started commuting plus the increasing need to haul tools and equipment around with me means I drive.

[med6753]

From the Woodworking Dwagon...

Welp... coffee's done and now's the moment of truth; wiping down the stain to see what lies beneath. I may have already made one egregious error; I left the stain on thick and heavy overnight, as by the time we got back from dinner with dad I was just knackered after spending all day sanding in the heat and 110% humidity...

mnem
pray for me...

Ugggh. It's every bit as bad as I feared.
Cleaning this up will probably be as much assache as the initial stripping was.   

mnem

While I have used wipe on stain before and got good results I much prefer brush on since I find it easier to control. All the benches, shelving units, scope carts, etc you see in my pictures is Minwax brush on stain followed by brush on Minwax poly.

[Specmaster]

Got to have a poke at Cerberus here as well. A friend of mine is always poking me at how much he spends on electricity on his Tesla. My car didn’t cost £88k so I could run mine on Absolut vodka and still be better off 

Oh I think I'm winning. When the time arrived that I started looking at secondhand replacements for my car I discovered that, much to my surprise, there were quite a lot of plug-in hybrids on the market at sane prices. Last time I looked (perhaps a year ago) there was nothing on the secondhand market that I could afford (or at least wanted to pay for). What seems to have happened is that a lot of company car drivers opted for PHEVs because of the relatively mild benefit in kind taxation on PHEVs and those have now filtered onto the second hand market at sane prices.

I got lucky and found a pristine six year old BMW 330e at a local car dealers (within walking distance) at a much better price than I thought possible (<£15k) clearly previously owned by a "one man band" company director. Subsequent enquiries showed that he'd shut up shop last year (voluntary liquidation). It wasn't what I'd set out to look for, not by a long chalk, but after weighing things up I went and took a look and ended up buying it. The 20 odd miles it'll do purely on battery has turned out to be a near perfect fit with the local driving I do, no road tax, no environmental levy on my residents parking permit, surprisingly low service costs from official dealers (and my local lads I've been using for years will better that I'm sure), and 'cause I'm an old git with a good record, about as cheap insurance as it's possible to pay in London (a few hundred fully comp).

Standing costs are going to be a little less than the old car (Say £700 a year). I paid the same price for the old car 22 years ago as I just did for the 'new' one. The old car has cost me  <£700 a year in depreciation (if I consider it written off completely), a bit more in standing costs (insurance, servicing, taxation) so perhaps £1700 a year in total, plus fuel. I don't feel that's a bad price for having it available 24/7 just by walking out of the door. The overall costs for the new car will be similar to the old, perhaps less perhaps more, when depreciation is taken into account. I personally would spend significantly more to use zipcar (the ones nearest me ATM are £10/hr or £94/day) plus taxis plus public transport with significantly less convenience. I'd spend more per week just to do the weekly "big shop" by taxi or zipcar.  So for me it's a bargain worth making.

Added to all of that, it is also a hell of a lot more comfortable than a bleeding old bone shaker of a bus. Our buses, although fairly new, are so uncomfortable, windows that are designed not to completely shut, the doors have huge gaps all round them, springs feel as they are steel girders and the entire bus rattles, shakes and vibrates. These new buses, are nothing at all like the ones I used to work on, they were far more comfortable, despite being many years ago. I really would have expected far more now, cars have improved massivly so why not buses?

[Cerebus]

Get you friend to demonstrate how, while driving along, he deals with

• the screen starts misting up: how does he redirect ventilation
• you are about to drive through smoke from a fire; how does he switch from external air to recirculating air

I can't speak to the Tesla case but the number of bells and whistles in the new (to me) BMW surprised me in this regard. If in "auto" climate mode the answer in both cases would be "nothing", there are sensors for both misting up and external air quality and the car will automatically do the right thing. There are also physical "demist the windows with the aircon" and "fresh/recirculate/auto air circulation" buttons if I have the climate control off or in manual mode. The answer for the old car would vary between "fiddle with lots of manual controls" or "stop and put the roof up/down", but it had the two great advantages over the 'new' car of (1) having a soft top, (2) having the engine just behind the driver's seat - both qualities I shall miss.

Lotus Elise?

1997 MGF VVC

[med6753]

What is this "public transportation" you all are talking about?  In these parts it's called a private cab/uber or put on your walking shoes. 

[Cerebus]

Added to all of that, it is also a hell of a lot more comfortable than a bleeding old bone shaker of a bus. Our buses, although fairly new, are so uncomfortable, windows that are designed not to completely shut, the doors have huge gaps all round them, springs feel as they are steel girders and the entire bus rattles, shakes and vibrates. These new buses, are nothing at all like the ones I used to work on, they were far more comfortable, despite being many years ago. I really would have expected far more now, cars have improved massivly so why not buses?

I've noted the same with London Transport's operator's stock. A bus ride used to be no penance, on the current busses it's a positively uncomfortable experience. A half hour ride on a bus and I feel like I need to visit the dentist to get my teeth reseated. Sure didn't used to be  that way. By direct comparison, in the last few years I've taken rides on busses in London and busses and trams in Dusseldorf in the same week, the latter were an order of magnitude more comfortable.