Test Equipment Anonymous (TEA) group therapy thread

[neo]

Thinking back on it, i can remember my first two experiences with electricity, when i was a baby who stuck the cord coming out of a wall wart in my mouth, that gave me awe.

And then later when i stuck my hand on a hot stove, that would be when i learned electrons are not always the friendliest bunch.

[beanflying]

Lucky for me I have spent this weeks pocket money

In Melbourne Tek/CRO Nuts 





https://www.ebay.com.au/itm/Tektronix-Type-556-Dual-Beam-Oscilloscope/253408205052?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3Deec8a039b5ad45f78a4744616720f2ea%26pid%3D100675%26rk%3D4%26rkt%3D15%26sd%3D142667848768%26itm%3D253408205052&_trksid=p2481888.c100675.m4236&_trkparms=pageci%253A94a7eec9-0999-11e8-b103-74dbd180619c%257Cparentrq%253A6072b7821610a860caa4a731fffd6bfe%257Ciid%253A1

[tggzzz]

Lucky for me I have spent this weeks pocket money

A 90ps sampler plus a 50ps source. Lucky I'm nowhere near there!

[Specmaster]

Good news and bad news, the good is that the battery less mod to the Heathkit V-7AU gives out exactly 1.5v to power the resistance range, the bad news is that it causes the transformer to run extremely hot I discover today after doing some extensive tests on it.

I tapped off the what is supposed to 6.3vac for the pilot light into a full wave bridge rectifier with a 1000uf 25v cap and straight across the output onto a cheap 5v to 1.5v converter module and while everything works OK, after a while you smell something getting warm, very warm.

That was the transformer getting too hot to touch and probing with a meter reveals that the 6.3vac supply was down to 3.2v and bear in mind that tapping feeds the heaters as well, something was clearly draining the power. Disconnected my mod, and the voltage rose to 5.3v, typical Heathkit stretching things almost to their limits.

Measuring the current draw to my battery eliminator I discover that its drawing 930ma with the function switch in the volts position. Fearing the worst, I moved into resistance mode and was pleasantly surprised to see that current draw was the same, despite the meter being deflected full scale and then some if I adjust the Ohms adjust pot.

Back to the drawing board on this, I'll do some tests on the remain 5v to 1.5v dc to dc converters I have to see if this current draw is common or a fault, otherwise I can revert back to an all insulated battery holder to maintain current enhanced functionality or disconnect the resistance completely as the prime reason for having this was the centre zero meter for radio alignment procedures. I do like having it as a fully functioning piece of kit though, despite it being highly unlikely to be used as a multimeter because of its inaccuracy compared with more modern meters.

EDIT

Tested another 5 to 1.5 converter and its maximum current draw is 0.8ma so after dinner, back in the rabbit hole I go again.

[URI]

I have already noted on the "What did you buy today? Post your latest purchase!" thread:

I worked off the next item of the check list called Recommended Test Equipment for my HP 3335A. But I allowed myself the luxury not to go for the recommended HP 436A but for the HP 437B. 

After some looking around for information on that meter I noticed that there seem to be two versions: One with an analogue meter and one without.
I haven't checked HP-catalogues extensively yet:
Is the version without the analogue meter the newer one?
I have searched data sheets on the 'net and it doesn't seem to be an option.
Strangely I only found datasheets (mostly pages of catalogues) showing the version with the analogue meter but the manuals I found and downloaded are for the version without analogue meter. 

In addition to the Power Meter I've already ordered a HP 8482A Power Sensor ("tested working..") and a matching cable also. The Power Meter was a relatively cheap entry to this field of Test Equipment.     

[Blake]

I've got another T12 Soldering Station question.  I just received the power socket w/ fuse holder in one my eBay orders from China.  My question is what size fuse is installed with the actual Quicko complete kits so I can order the correct one?  3A?  The 24v power supply from Banggood was delivered yesterday so I'm looking forward to assembling everything once the Quicko kit is here.

[mnementh]

Thinking back on it, i can remember my first two experiences with electricity, when i was a baby who stuck the cord coming out of a wall wart in my mouth, that gave me awe.

And then later when i stuck my hand on a hot stove, that would be when i learned electrons are not always the friendliest bunch.

Mine was licking 9V batteries... then plugging them into each other to get 9(n) volts... found that 2 or 3 in series would make my teeth hurt... and 9 or 10 would give me a nice bite across dry fingertips. Then I accidentally made an ac generator out of a gearbox from a rotisserie motor that ran off an oversized 60Hz clock motor... that I discovered would tingle both fingers, or illuminate a NE-2 neon bulb.

It wasn't until I was in my teens that we had our first electric stove full of angry pixies.


mnem
"Electrons may be very, very tiny, but when they gang up on you they ALWAYS win." ~ me

[bd139]

Good news and bad news, the good is that the battery less mod to the Heathkit V-7AU gives out exactly 1.5v to power the resistance range, the bad news is that it causes the transformer to run extremely hot I discover today after doing some extensive tests on it.

I tapped off the what is supposed to 6.3vac for the pilot light into a full wave bridge rectifier with a 1000uf 25v cap and straight across the output onto a cheap 5v to 1.5v converter module and while everything works OK, after a while you smell something getting warm, very warm.

That was the transformer getting too hot to touch and probing with a meter reveals that the 6.3vac supply was down to 3.2v and bear in mind that tapping feeds the heaters as well, something was clearly draining the power. Disconnected my mod, and the voltage rose to 5.3v, typical Heathkit stretching things almost to their limits.

Measuring the current draw to my battery eliminator I discover that its drawing 930ma with the function switch in the volts position. Fearing the worst, I moved into resistance mode and was pleasantly surprised to see that current draw was the same, despite the meter being deflected full scale and then some if I adjust the Ohms adjust pot.

Back to the drawing board on this, I'll do some tests on the remain 5v to 1.5v dc to dc converters I have to see if this current draw is common or a fault, otherwise I can revert back to an all insulated battery holder to maintain current enhanced functionality or disconnect the resistance completely as the prime reason for having this was the centre zero meter for radio alignment procedures. I do like having it as a fully functioning piece of kit though, despite it being highly unlikely to be used as a multimeter because of its inaccuracy compared with more modern meters.

EDIT

Tested another 5 to 1.5 converter and its maximum current draw is 0.8ma so after dinner, back in the rabbit hole I go again.

Sounds like a grounding issue. Check that the filament isn’t shorted to ground on both tubes anywhere.

[Specmaster]

I've got another T12 Soldering Station question.  I just received the power socket w/ fuse holder in one my eBay orders from China.  My question is what size fuse is installed with the actual Quicko complete kits so I can order the correct one?  3A?  The 24v power supply from Banggood was delivered yesterday so I'm looking forward to assembling everything once the Quicko kit is here.

If your talking about the fuse in the IEC connector as in the photo, then thats a 3A glass fuse and comes with that already fitted.

[neo]

4 days later and my HP 5346A STILL hasn't been marked as shipped..... at what point does it become acceptable to send a message asking  is going on? 

[Specmaster]

Good news and bad news, the good is that the battery less mod to the Heathkit V-7AU gives out exactly 1.5v to power the resistance range, the bad news is that it causes the transformer to run extremely hot I discover today after doing some extensive tests on it.

I tapped off the what is supposed to 6.3vac for the pilot light into a full wave bridge rectifier with a 1000uf 25v cap and straight across the output onto a cheap 5v to 1.5v converter module and while everything works OK, after a while you smell something getting warm, very warm.

That was the transformer getting too hot to touch and probing with a meter reveals that the 6.3vac supply was down to 3.2v and bear in mind that tapping feeds the heaters as well, something was clearly draining the power. Disconnected my mod, and the voltage rose to 5.3v, typical Heathkit stretching things almost to their limits.

Measuring the current draw to my battery eliminator I discover that its drawing 930ma with the function switch in the volts position. Fearing the worst, I moved into resistance mode and was pleasantly surprised to see that current draw was the same, despite the meter being deflected full scale and then some if I adjust the Ohms adjust pot.

Back to the drawing board on this, I'll do some tests on the remain 5v to 1.5v dc to dc converters I have to see if this current draw is common or a fault, otherwise I can revert back to an all insulated battery holder to maintain current enhanced functionality or disconnect the resistance completely as the prime reason for having this was the centre zero meter for radio alignment procedures. I do like having it as a fully functioning piece of kit though, despite it being highly unlikely to be used as a multimeter because of its inaccuracy compared with more modern meters.

EDIT

Tested another 5 to 1.5 converter and its maximum current draw is 0.8ma so after dinner, back in the rabbit hole I go again.

Sounds like a grounding issue. Check that the filament isn’t shorted to ground on both tubes anywhere.

No connection to ground on the heater circuit, what I did find however is that one of my diodes making the full wave rectification has just become a resistor with a value of .21 ohms

[mnementh]

1/2 the original delivery estimate at the time you paid; ie, if posted max delivery date is 8 days then at 4 days is reasonable to followup if you haven't seen any shipping activity.


mnem
*Veteran of a thousand psychic wars fleaBay auctions*

[Specmaster]

4 days later and my HP 5346A STILL hasn't been marked as shipped..... at what point does it become acceptable to send a message asking  is going on? 

Wheres it coming from? Remember that not everyone updates the status of your order, especially if it's a private sale?

[jjoonathan]

Sooner than your sense of propriety would lead you to believe. The few surviving ebay scams that target buyers have to work around serious buyer protection policies, and they do it by using shipping confusion to push up against the deadlines. The first stage of shipping confusion is complete radio silence. Be polite but make sure the written record is clear as to whether or not they have shipped, whether or not you have tracking information, and as to whether or not they could have "forgotten" any of the above due to a lack of polite reminders.

[Mr. Scram]

The past two days have been weekend days. If it's a trader, rather than an amateur selling some stuff, chances are he won't do anything in the weekend.

[mnementh]

Good news and bad news, the good is that the battery less mod to the Heathkit V-7AU gives out exactly 1.5v to power the resistance range, the bad news is that it causes the transformer to run extremely hot I discover today after doing some extensive tests on it.

I tapped off the what is supposed to 6.3vac for the pilot light into a full wave bridge rectifier with a 1000uf 25v cap and straight across the output onto a cheap 5v to 1.5v converter module and while everything works OK, after a while you smell something getting warm, very warm.

That was the transformer getting too hot to touch and probing with a meter reveals that the 6.3vac supply was down to 3.2v and bear in mind that tapping feeds the heaters as well, something was clearly draining the power. Disconnected my mod, and the voltage rose to 5.3v, typical Heathkit stretching things almost to their limits.

Measuring the current draw to my battery eliminator I discover that its drawing 930ma with the function switch in the volts position. Fearing the worst, I moved into resistance mode and was pleasantly surprised to see that current draw was the same, despite the meter being deflected full scale and then some if I adjust the Ohms adjust pot.

Back to the drawing board on this, I'll do some tests on the remain 5v to 1.5v dc to dc converters I have to see if this current draw is common or a fault, otherwise I can revert back to an all insulated battery holder to maintain current enhanced functionality or disconnect the resistance completely as the prime reason for having this was the centre zero meter for radio alignment procedures. I do like having it as a fully functioning piece of kit though, despite it being highly unlikely to be used as a multimeter because of its inaccuracy compared with more modern meters.

EDIT

Tested another 5 to 1.5 converter and its maximum current draw is 0.8ma so after dinner, back in the rabbit hole I go again.

Sounds like a grounding issue. Check that the filament isn’t shorted to ground on both tubes anywhere.

No connection to ground on the heater circuit, what I did find however is that one of my diodes making the full wave rectification has just become a resistor with a value of .21 ohms

These small DC-DC converters regulate by asynchronous rectification... my guess would be that at some instant, the DC-DC converter was in phase with the rectification of that element of the bridge rectifier and presented a short-circuit, or possibly an inductive reactance in mhos. They can be tricky little devils.

How much current do you need for your 1.5V? Maybe a simple voltage divider across the output of a 3.3V linear would serve better...


mnem
*Tricksy little hobbittses, tricksy they are...*

[Specmaster]

Good news and bad news, the good is that the battery less mod to the Heathkit V-7AU gives out exactly 1.5v to power the resistance range, the bad news is that it causes the transformer to run extremely hot I discover today after doing some extensive tests on it.

I tapped off the what is supposed to 6.3vac for the pilot light into a full wave bridge rectifier with a 1000uf 25v cap and straight across the output onto a cheap 5v to 1.5v converter module and while everything works OK, after a while you smell something getting warm, very warm.

That was the transformer getting too hot to touch and probing with a meter reveals that the 6.3vac supply was down to 3.2v and bear in mind that tapping feeds the heaters as well, something was clearly draining the power. Disconnected my mod, and the voltage rose to 5.3v, typical Heathkit stretching things almost to their limits.

Measuring the current draw to my battery eliminator I discover that its drawing 930ma with the function switch in the volts position. Fearing the worst, I moved into resistance mode and was pleasantly surprised to see that current draw was the same, despite the meter being deflected full scale and then some if I adjust the Ohms adjust pot.

Back to the drawing board on this, I'll do some tests on the remain 5v to 1.5v dc to dc converters I have to see if this current draw is common or a fault, otherwise I can revert back to an all insulated battery holder to maintain current enhanced functionality or disconnect the resistance completely as the prime reason for having this was the centre zero meter for radio alignment procedures. I do like having it as a fully functioning piece of kit though, despite it being highly unlikely to be used as a multimeter because of its inaccuracy compared with more modern meters.

EDIT

Tested another 5 to 1.5 converter and its maximum current draw is 0.8ma so after dinner, back in the rabbit hole I go again.

Sounds like a grounding issue. Check that the filament isn’t shorted to ground on both tubes anywhere.

No connection to ground on the heater circuit, what I did find however is that one of my diodes making the full wave rectification has just become a resistor with a value of .21 ohms

These small DC-DC converters regulate by asynchronous rectification... my guess would be that at some instant, the DC-DC converter was in phase with the rectification of that element of the bridge rectifier and presented a short-circuit, or possibly an inductive reactance in mhos. They can be tricky little devils.

How much current do you need for your 1.5V? Maybe a simple voltage divider across the output of a 3.3V linear would serve better...


mnem
*Tricksy little hobbittses, tricksy they are...*

Just a tad over 200 micro amps, that the meter sensitivity for full scale so I guess it would be around 230 micro amps to give adjustment for full scale.

I have tested the dc to dc block (the one I fitted) with a bench supply since and that one is still working perfectly ok and also has a draw of 0.8ma.

[neo]

4 days later and my HP 5346A STILL hasn't been marked as shipped..... at what point does it become acceptable to send a message asking  is going on? 

Wheres it coming from? Remember that not everyone updates the status of your order, especially if it's a private sale?

Rochester, New York, and as i said it was an ebay listing.

[Specmaster]

4 days later and my HP 5346A STILL hasn't been marked as shipped..... at what point does it become acceptable to send a message asking  is going on? 

Wheres it coming from? Remember that not everyone updates the status of your order, especially if it's a private sale?

Rochester, New York, and as i said it was an ebay listing.

Thats what I though, an ebay listing, but I have had many purchases on ebay where once you have paid, there is no more updating done on its status until you receive it and only then if you bother to leave feedback. This particularly true if the seller was a private person as opposed to a company/trader.

[Specmaster]

Good news and bad news, the good is that the battery less mod to the Heathkit V-7AU gives out exactly 1.5v to power the resistance range, the bad news is that it causes the transformer to run extremely hot I discover today after doing some extensive tests on it.

I tapped off the what is supposed to 6.3vac for the pilot light into a full wave bridge rectifier with a 1000uf 25v cap and straight across the output onto a cheap 5v to 1.5v converter module and while everything works OK, after a while you smell something getting warm, very warm.

That was the transformer getting too hot to touch and probing with a meter reveals that the 6.3vac supply was down to 3.2v and bear in mind that tapping feeds the heaters as well, something was clearly draining the power. Disconnected my mod, and the voltage rose to 5.3v, typical Heathkit stretching things almost to their limits.

Measuring the current draw to my battery eliminator I discover that its drawing 930ma with the function switch in the volts position. Fearing the worst, I moved into resistance mode and was pleasantly surprised to see that current draw was the same, despite the meter being deflected full scale and then some if I adjust the Ohms adjust pot.

Back to the drawing board on this, I'll do some tests on the remain 5v to 1.5v dc to dc converters I have to see if this current draw is common or a fault, otherwise I can revert back to an all insulated battery holder to maintain current enhanced functionality or disconnect the resistance completely as the prime reason for having this was the centre zero meter for radio alignment procedures. I do like having it as a fully functioning piece of kit though, despite it being highly unlikely to be used as a multimeter because of its inaccuracy compared with more modern meters.

EDIT

Tested another 5 to 1.5 converter and its maximum current draw is 0.8ma so after dinner, back in the rabbit hole I go again.

Sounds like a grounding issue. Check that the filament isn’t shorted to ground on both tubes anywhere.

No connection to ground on the heater circuit, what I did find however is that one of my diodes making the full wave rectification has just become a resistor with a value of .21 ohms

These small DC-DC converters regulate by asynchronous rectification... my guess would be that at some instant, the DC-DC converter was in phase with the rectification of that element of the bridge rectifier and presented a short-circuit, or possibly an inductive reactance in mhos. They can be tricky little devils.

How much current do you need for your 1.5V? Maybe a simple voltage divider across the output of a 3.3V linear would serve better...


mnem
*Tricksy little hobbittses, tricksy they are...*

I mocked it up externally with DMM's connected to the heater tapping, the output from the bridge rectifier with 1000uF cap for added smoothing and also the output from dc to dc converter but connected the dc output to the meter and everything is fine, 5.4vac to heaters, 6.1v output from rectifier and cap with 1.502v from converter. Problem comes on as soon as I connect 1.5v ground to the ground on the meter, all the voltages halve except the 1.5v. It doesn't like sharing a common ground for the AC and DC so I'll have to think about this.

I do know that someone is supposed to have done this already and put it on line, BUT did they after a while experience the same thing I did and they haven't come back on line to set the record straight if so then this highlights the differences between the web and a good magazine. If there was a problem with a published circuit, then there was a correction published in the next months edition, the web does not have that accountability that magazines have.

[beanflying]

   Light weight cardboard stuffed with peanuts only. Way to screwup a tidy bit of gear!

[Vgkid]

I'd be pissed...    

[Brumby]

Ouch.

It's going to take more than a damp rag to clean that up!

[mnementh]

Good news and bad news, the good is that the battery less mod to the Heathkit V-7AU gives out exactly 1.5v to power the resistance range, the bad news is that it causes the transformer to run extremely hot I discover today after doing some extensive tests on it.

I tapped off the what is supposed to 6.3vac for the pilot light into a full wave bridge rectifier with a 1000uf 25v cap and straight across the output onto a cheap 5v to 1.5v converter module and while everything works OK, after a while you smell something getting warm, very warm.

That was the transformer getting too hot to touch and probing with a meter reveals that the 6.3vac supply was down to 3.2v and bear in mind that tapping feeds the heaters as well, something was clearly draining the power. Disconnected my mod, and the voltage rose to 5.3v, typical Heathkit stretching things almost to their limits.

Measuring the current draw to my battery eliminator I discover that its drawing 930ma with the function switch in the volts position. Fearing the worst, I moved into resistance mode and was pleasantly surprised to see that current draw was the same, despite the meter being deflected full scale and then some if I adjust the Ohms adjust pot.

Back to the drawing board on this, I'll do some tests on the remain 5v to 1.5v dc to dc converters I have to see if this current draw is common or a fault, otherwise I can revert back to an all insulated battery holder to maintain current enhanced functionality or disconnect the resistance completely as the prime reason for having this was the centre zero meter for radio alignment procedures. I do like having it as a fully functioning piece of kit though, despite it being highly unlikely to be used as a multimeter because of its inaccuracy compared with more modern meters.

EDIT

Tested another 5 to 1.5 converter and its maximum current draw is 0.8ma so after dinner, back in the rabbit hole I go again.

Sounds like a grounding issue. Check that the filament isn’t shorted to ground on both tubes anywhere.

No connection to ground on the heater circuit, what I did find however is that one of my diodes making the full wave rectification has just become a resistor with a value of .21 ohms

These small DC-DC converters regulate by asynchronous rectification... my guess would be that at some instant, the DC-DC converter was in phase with the rectification of that element of the bridge rectifier and presented a short-circuit, or possibly an inductive reactance in mhos. They can be tricky little devils.

How much current do you need for your 1.5V? Maybe a simple voltage divider across the output of a 3.3V linear would serve better...


mnem
*Tricksy little hobbittses, tricksy they are...*

I mocked it up externally with DMM's connected to the heater tapping, the output from the bridge rectifier with 1000uF cap for added smoothing and also the output from dc to dc converter but connected the dc output to the meter and everything is fine, 5.4vac to heaters, 6.1v output from rectifier and cap with 1.502v from converter. Problem comes on as soon as I connect 1.5v ground to the ground on the meter, all the voltages halve except the 1.5v. It doesn't like sharing a common ground for the AC and DC so I'll have to think about this.

I do know that someone is supposed to have done this already and put it on line, BUT did they after a while experience the same thing I did and they haven't come back on line to set the record straight if so then this highlights the differences between the web and a good magazine. If there was a problem with a published circuit, then there was a correction published in the next months edition, the web does not have that accountability that magazines have.

Are you sure the heater isn't supposed to be left floating? You could experiment with an additional transformer to power your DC-DC converter and see if the problem goes away.

Considering how small your current requirement is, you could easily hand wind a 1:1 toroidal transformer to power from the heater transformer; or even a small AF DC-blocking transformer would probably work. If the DC-DC converter doesn't want to play nicely, a simple zener diode regulator circuit, or like I suggested earlier, a voltage divider across the output of something like an AM1117-3.3 linear which should keep your overall current draw down to a few milliamps.

  Light weight cardboard stuffed with peanuts only. Way to screwup a tidy bit of gear!

Oh, hell. That seriously sucks, man. I'd be mad enough to eat bees. 

Give yourself a little time to cool off, maybe even sleep on it before you message the seller; it's hard to keep a civil tone when your still snortin'. 

Try to operate on the assumption it was an honest, innocent mistake rather than a lack of caring or genuine mischief by the seller. You'll get a lot further quicker if you don't start out the gate by ripping their head off, even though you feel like it. 


Good luck!


mnem
Bees do not taste like honey.

[neo]

That shipping accident sucks, I've managed to avoid sellers like that so far. Let's hope the seller of my 5346A packaged it right so as to balance out the cosmic scales of TEA.
Also; It finally shipped! Or at least gave me a tracking number and a page to stare at.