Test Equipment Anonymous (TEA) group therapy thread

[tggzzz]

So, place your bets...

I'm going to a small country hamfest this weekend. Will it be

• deserted: fear of covid, crusty hams become "silent key"
• seething: pent up demand after 2 years

I'll see, but what's your guess?

Well, I'm back. There were 95 visitors. Last time, before the pandemic, there were 120. However the normal range is 90-120, and previously thy have been on a Sunday.

Overall not too bad, and I didn't even think of asking other traders what their prices were. I thinned my herd a bit and made a profit (including petrol and fees). It certainly wasn't seething - there was a pleasant amount of space.

On the way back I spotted a model railway exhibition, and went in. Only two points of interest:

• many punters looked a lot like hams. A few looked more reputable, but they tended to have bored grandkids in tow
• one of the OO guage locos was puffing out steam. Well, water vapour, but certainly an immense improvement on the burn-a drop-of-oil in 60s locos

[AVGresponding]

...but storing electronic instrumentation under a tarp in a farm field in the UK?!?!?       

WTF is the thought process there?       

-Pat

Maybe that the free-running pigs keep most pests and thieves away?

Wouldn't stop a TEA if there were anything worth having under that tarp... 

mnem
*channels bd139 for a moment* "Won't stop a Pikey either. Whatever's under the tarp."

Our biggest project at the moment is a rewire, new power and light fittings, new HVAC, new fire doors etc at a strange 1960s/1970s? designed community centre, that has several wings to it, with the central one being a sports centre, side wings including family centre, youth activity centre etc.

It's in an area with a reputation for certain types of people, and validation of this happened fairly rapidly. As soon as the harris fencing and welfare cabins were up, they were in the compound asking if we had any scrap for them.
Now, because we are considerate we left the metal piled up outside the skip, to make it easy for them. Nevertheless, overnight they had emptied the contents of the skip all over a playing field next to the compound and set fire to it all.

Now we don't have a skip on site, we bag all the small rubbish up and get one of the drivers to come round and pick it and the bigger stuff up and dump it in the skip at one of out depots.

[AVGresponding]

As Discord splutters slowly into life, I wonder to myself, "who will join the melee this week?".

[mnementh]

moi....?

mnem
moo...!

[Ice-Tea]

Nay, bookkeeping.

[Specmaster]

As Discord splutters slowly into life, I wonder to myself, "who will join the melee this week?".

If I can wrestle this cassette deck into submission in a few minutes, I'm hoping to be joining the melee myself.

[m k]

Trying to update the software in my AWG510, and can't find the button in the menu to start the update process...

Then I notice this in the readme......

If you have the AWG500 series of Program Version:1.x and hope
for the system software upgrade,please contact your local
Tektronix representative and request assistance.

I have version 1.6B.... Shit.    

I sent off a message to Tek support, but I feel like I'll get the usual 'This product is no longer supported' stonewall from them.

I read from AWG510 & AWG520 Arbitrary Waveform Generator User Manual

"This document applies to firmware version 3.0 and above"

page 3-169

"
The system software in the AWG500-Series Waveform Generator can be updated
by using the utility menu. The System software consists of both the user program
and the operating system. The upgrades can be done independent of each other.
Refer to page 3–152 for information regarding the current system software
versions.
"

"
The Select File dialog box appears.
4. Select the file for upgrade that was copied in step 1, then press the OK (side) button.
The file confirmation dialog box appears.
5. Press the OK (side) button.
The AWG500-Series Waveform Generator checks the selected file properties. The “Illegal file format” message appears if you select an invalid file.
The AWG500-Series Waveform Generator updates the system software.
6. After the updating procedure has completed, power off, then power on the instrument. The AWG500-Series Waveform Generator starts up with updated system software.
"

Is all that for newer system?

There are also 3 parts, user program, operating system and firmware.
What is that 1.x part of yours?
I understand that it's a user program.

Above is still referring to a single file.

My guess is that you can use the same procedure you do when you restore the current version.

Yeah, that's what I'm having trouble with. On Page 3-169, step 2, I don't see the 'Update System Software' option at all.
There must be some secret trick or boot disk or something that's needed to update gear with version 1.x. Once you get to V2.x, it's smooth sailing with the menu options.

Push UTILITY (front-panel) -> System (bottom) -> Update System Software... (side) -> Update Program... or Update OS... (side).

[foggy thoughts deleted, thread found]
https://www.eevblog.com/forum/repair/sonytektronix-awg520-2ch-1gss-with-no-output-repair-attempt-and-teardown/25/
As noted, reply #43 has stuff.
You need to see that setup.inf of yours, it can possibly fix your situation.

But backup first.

My guess is that the file present at install location will do the upgrade.

BTW,
it seems that I don't need to draw whole ranges of HP 34401A ohms voltages.

Something has happened to my gear, maybe these devices are finally warmed, and dried and what not.
AD584-M is labeled 2,49931 of HP 3458A at 25C.
Pictured temp is from handle bar heater temp meter of China goods, "red mercury" of ovenished(?) blue fish agrees.

[Vince]

Nixie DMM update


As always while everybody was on Discord, I was at the bench working hard.

So, progress has been made ! There is some good some bad, it's been a roller coaster working on this thing this evening.


OK so first, I tidied my PSU repair. Removed the two 470uF 63V caps in // that I bodged under the chassis to replace that failed 1000uF 50V cap.
Replaced them with a single cap, 1000uF but only 35V. It's the closest match I had in my brand new Nichicon left overs. 35V is nowhere near 50V but....  in service the cap only sees 20V. So 35V is enough headroom I think to keep this cap happy, especially since of course I hardly run my meters 24/7 all year long to begin with... 
The diameter of the cap was small enough to fit under the chassis while still clearing the cabinet. So I just used some hot glue to keep it in place. Use some heat shrink tubing to make sure it's never gonna short anything. This way the original can cap, screwed to the chassis, is still in place. That leaves me the option later to result  it if I fancy so.

Having this cap sorted was a necessity so I can now put the meter in its normal orientation,; which I could not do with the two 4760uF cap hanging in the air with long exposed leads shorting themselves all the time...
So that one good thing done.

Then I powered the thing up to work a bit on troubleshooting my "free running counter from cold" issue.
It did not disappoint : problem showed up again, and again after a few minutes warming up, it vanished and all of a sudden the meter started working just fine.

So had only a few minutes to work on it. I concentrated first, as said yesterday, on the trigger section, and the ramp generator. That's where the bad stuff starts to arrive... 

I wanted to set the meter to "Manual" Trigger, so that it does not generate a ramp at power up, so I can see if the output of the ramp was valid, as if it's not it might well play havoc with the comparators hence ripple that garbage to the Gate logic hence it would explain my free running counter.

That's when I eventually realized that the switch that selects from AUTO or MANUAL.. is dodgy ! It's a SPDT switch. In AUTO mode, the contact close and open as they should. However in NORMAL mode, it's neither clearly open nor closed. This no doubt explains why I noticed that in AUTO mode the meter displayed (once warmed up and working I mean, of course) normal/sensible results, but in MANUAL mode, the result of the measurement would be good only 10% of the time. 90% of the time it would be absolute garbage, even illegal values ( >= 5000 counts ! ).
The switch looks to be the same type/style/construction as the mains/power switch which, I remind you, is ALSO failed (open circuit). They looks like sealed plastic body stuff, so I can't open them to refurbish them.

So, for my troubleshooting purposes, I shorted the that switch so that it's hard wired to MANUAL mode. Then I realized that when I depress the push-button, I also get sometimes weird results... so this switch is probably also dodgy.  Nowhere near as bad as the MAN/AUTO one, but still a little bit.

This meter has seen too much moisture for too long, I fear it's full of gremlins and I may never get this meter working 100%, or if I do it will develop new problem every other months... I am starting to be a bit worried and depressed...

Anyway, it still was good for my troubleshooting purpose. It showed that yes I have stuff to sort out in the trigger department, but that no, it does not cause my free running counter problem... because...  I could see that the ramp was 100% valid : stuck to the negative 6V rail as it should. So I now know that both comparators are getting valid input signals when the counter is free running. So now I have narrowed it down to the comparators misbehaving, one of them at least. I mean one might give a false "Start" signal", which would get the counter started, and the other comparator, working fine maybe, would therefore of course not give any "Stop" signal, hence the counter free running.... Or, if the comparators are good, then the problem must reside in the Gate logic circuitry. So I need to probe that stuff, but its not easy because I first need to identify on the board WHERE are the relevant freaking nodes I need to measure, and it's absolutely not obvious ! I have looked at it a bit, I think I have narrowed it down to a small portion of the board, but now need to spend quite some time to pin point the precise resistors I need, and find which side of them to probe. No silk screen or board layout is A MAJOR PITA !!!! 

I got to that point, then as expected, meter was warm enough and it started to work properly. Since I now know I can count on the meter working fine after just a few minutes, I have decided to now also work on the other issues. So I wanted to adjust full scale. But that didn't go well because one of the two trim pots you need to tweak, is on the chassis, accessible from the top... so I need a long screw driver so I can get between the Nixie boards from the top, to reach the pot/chassis at the bottom. That means I also need an ISOLATED screw driver, because don't want to short things out, especially since it's not just the two nixe boards around, but also the PSU board with exposed terminals... don't wanna short the mains or secondary windings you see 
My flat screwdrivers are standard lenght, blade is 100mm long. I would need a 150mm blade at least, to do that job. So, Monday, I will go buy a log sparky screw driver.
Or at least a long non-isolated one, and isolate it with heat shrink tubing like I did the other day to one of my screw drivers to adjust the trimmers in my Tek 180A time marker generator.
Of course the goal of adjusting full scale was to determine the value of the resistor I need to put on the Vref board to achieve that. I would replace that resistor with a pot, then set the Zero adjust half-way, and adjust my pot. then substitute a fixed resistor as close as possible to the pot value. Then I would be good to fine tune full scale using the factory trim pots.

Anyway, i eventually occurred to me that, of course.. before you can adjust full scale deviation, you first need to adjust the ZERO. Isn't it...

So, I go to do that and... wow, the meter is completely out of whack : the zero  is displaying 300+ counts !!! 
I tried the Zero pot anyway, but it looks like its range is about 25 counts (which sounds sensible).

So I have big offset problem in this meter, it's NOT normal !!
As the meter warmed up, it slowly decreased/improved, down to 100 or less. But still out of adjustment range, and still not normal/acceptable to me !

As a quick test, I swapped comparator boards, and the good board.. works just fine : meter show zero not 300, and the trim pot allows you to finely tune that 10 counts above and below 0. It's absolutely.. .perfect. It's funny though, that you can display both a negative zero and a positive one... two zeros... I went for the positive one after some discussion with myself. It's absolutely irrational and all to do with some OCD I think, for some reason I don't "like" a negative zero as much as a positive one .. 

So, the problem clearly comes from that board.  Schematic attached. One can see how the zeroing is done : one input of the comparators, via a precision 2% 27k resistor, is connected to one end of a 5k trim pot whose cursor is tied to the negative 12 volt rail.
I compared the two boards and quickly noticed something weird, see pic below. On the working board, I do see those two 2% 27k resistors, no problem. But on the troublesome board, I see only ONE of them. The other one, in its place, I see... a 33k regular 5% resistor !!!
Yes, 33k not 27, and 5% not 2% !  This alone I think could cause the big offset I am seeing. Worse part is .... I am 100% certain that this completely inappropriate resistor has been fitted AT THE FACTORY !!!  For, it looks 100% like the other resistors on the board, even down to the little imperfections in the painting of the colour bands.
Leads looks like they have been bents with care, not by some cave man. But the definitive tell tale sign that this is factory is... on the solder side, the joints look factory and the conformal coating is INTACT !!!!
I can't believe it , there is no room for mistake here, this has been done at the factory for sure ! 

I don't have precision resistors, only 5% ones, but I do that 27k ones. I will lift a leg of the lone 27k resistor to measure it reliably/accurately, then I will hand pick one of my 5% 27k to get as close as possible. However the trimmer being 5k, I don't think I don't need to be ultra close to 27k anyway, so not too worried. 27k 2% is 540 ohms tolerance either side. I should not have a problem finding one of my 5% resistors in that range.  So wl do that... stay tuned ! 

[Vince]

EDIT : about the 33k resistor instead of 27k... maybe the factory did it on purpose, because that particular meter failed to zero with the specified 27k, because the in put current of the differential pair was out of spec ? So they compensated for that when they calibrated it. So maybe this trick worked back then, and the dodgy / out of spec transistor got worse and worse over the years and now even with 33k it's still impossible to calibrate. Still... assuming that is what happened, why did they mess with that precision resistor, instead of just replacing the transistors in the differential pair ? 

So... I don't know... if that is what happened, then replacing that 33k resistor by a  27k one, might make things WORSE not better.. if so then either I will need to increase the value of the resistor even more.. or replace the transistors altogether ! 

All the transistors on this board are 2N1305/1304 (PNP / NPN).. just googled them... GERMANIUM !!!!! 
OK... so yes they are probably leaky hence the offset problem, and it's now even possible that it's causing my problem with the free running counter when cold : the Gate logic is made of resistors and diodes to implement the decoding, BUT it then drives a transistor to gate the oscillator output. So... I don't know. Maybe Germanium have cold start problems ? Leaky when cold only ? Or some other cold related issue ? People ?  Anyway these transistors are now suspect to me so I will include them in my troubleshooting check list...

I hate Germanium transistors...

I see these are only 20V 300mA hFE 40 and 4MHz, so should be easy to substitute with a Silicium transistor I guess... can't be worse than leaving the rotten leaky crappy horrible Ge trannies in place anyhow.   

EDIT 2 : now wishing I had a resistor substitution box so I could quickly figure out what resistance that comparator needs to be able to zero it.... will add that to my list of stuff to get.

[TERRA Operative]

[foggy thoughts deleted, thread found]
https://www.eevblog.com/forum/repair/sonytektronix-awg520-2ch-1gss-with-no-output-repair-attempt-and-teardown/25/
As noted, reply #43 has stuff.
You need to see that setup.inf of yours, it can possibly fix your situation.

But backup first.

My guess is that the file present at install location will do the upgrade.

Ok, I got the Pocket Linux booted and working, but I am sooo lost with Linux stuff... Any chance the ftp of the disk image will work with FileZilla?
How do I run the ftp commands in pocket Linux? I am the n00biest n00b with this stuff...

[DC1MC]

[foggy thoughts deleted, thread found]
https://www.eevblog.com/forum/repair/sonytektronix-awg520-2ch-1gss-with-no-output-repair-attempt-and-teardown/25/
As noted, reply #43 has stuff.
You need to see that setup.inf of yours, it can possibly fix your situation.

But backup first.

My guess is that the file present at install location will do the upgrade.

Ok, I got the Pocket Linux booted and working, but I am sooo lost with Linux stuff... Any chance the ftp of the disk image will work with FileZilla?
How do I run the ftp commands in pocket Linux? I am the n00biest n00b with this stuff...

Hi, I'll post an answer in the specialized thread, or nobody ever will find the answer anymore, please switch the conversation there.

 Cheers,
 DC1MC

[med6753]

After running for nearly 18 hours continuously and running up my electric bill the results are in.

The "bench standard" 3456A is OK. The SDM 3055 is OK. And the AD584-M is very nicely aged. Quarterly checkout complete.

[capt bullshot]

Some short news from the Fun with TEA dept:

This 5V wallwart was supplying a banana pi based router / datalogger setup for several years. Some weeks ago this thing started to crash randomly, so I tested and replaced various components (basically the supply and the SSD).



Checking the wall wart showed quite an interesting output waveform:



Showing off the new scope



Everyone halfway familiar with this kind of stuff would guess the root cause on the electrolytics - exactly what was wrong here:





Interestingly, after testing that primary bulk cap, one lead just fell off:



R.I.P.

[Specmaster]

After running for nearly 18 hours continuously and running up my electric bill the results are in.

The "bench standard" 3456A is OK. The SDM 3055 is OK. And the AD584-M is very nicely aged. Quarterly checkout complete.

Totally agree, those Chinese AD584-M really are great little units and excellent value for money, if only they also did current and AC units like them, or could even build a unit with all three tests for a bit extra cash, it would be a great device to add into the toolkit.

[med6753]

Totally agree, those Chinese AD584-M really are great little units and excellent value for money, if only they also did current and AC units like them, or could even build a unit with all three tests for a bit extra cash, it would be a great device to add into the toolkit.

Agree, as long as it is the one's with a legitimate label on the back indicating it's actual measured voltage. Both mine are. The one's with no label or "cookie cutter" label should be considered suspect.

Edit.....like these.

[mnementh]

...R.I.P.

Heh... so I'm not the only one who has a collection of laptop battery BMS boards in the scrap PCB bin, ehhh...?

Great source of high-current FETs and Schottkeys... sometimes even useful values of shunt resistors and Polyfuses. 

Helpful hint for those playing along at home: Harvest these parts (especially Polyfuses and shunt resistors) by heating from the opposite side with a hot air rework station. If you don't have one, try carefully working a razor blade underneath the component. Trying to remove them with a soldering iron almost always damages the part by overheating due to the mass of the solder and copper they're soldered to.

mnem

[tggzzz]

Totally agree, those Chinese AD584-M really are great little units and excellent value for money, if only they also did current and AC units like them, or could even build a unit with all three tests for a bit extra cash, it would be a great device to add into the toolkit.

Agree, as long as it is the one's with a legitimate label on the back indicating it's actual measured voltage. Both mine are. The one's with no label or "cookie cutter" label should be considered suspect.

I'm not sure how trustworthy the chinese devices are w.r.t. drift over time.

I'd look at Ian Johnson's devices https://www.ianjohnston.com/index.php/onlineshop He's on this forum He's evaluating whether his stock will allow him to offer more

[TERRA Operative]

Annnndddd I just won a TDS784D with HDD option to replace my TDS784C.

I really gotta stop buying and start selling.. lol.

[mnementh]

    https://www.superdroidrobots.com/

mnem
Ehhh... I was bored.

[factory]

Nixie DMM update


As always while everybody was on Discord, I was at the bench working hard.

So, progress has been made ! There is some good some bad, it's been a roller coaster working on this thing this evening.

....snip....

I wanted to set the meter to "Manual" Trigger, so that it does not generate a ramp at power up, so I can see if the output of the ramp was valid, as if it's not it might well play havoc with the comparators hence ripple that garbage to the Gate logic hence it would explain my free running counter.

That's when I eventually realized that the switch that selects from AUTO or MANUAL.. is dodgy ! It's a SPDT switch. In AUTO mode, the contact close and open as they should. However in NORMAL mode, it's neither clearly open nor closed. This no doubt explains why I noticed that in AUTO mode the meter displayed (once warmed up and working I mean, of course) normal/sensible results, but in MANUAL mode, the result of the measurement would be good only 10% of the time. 90% of the time it would be absolute garbage, even illegal values ( >= 5000 counts ! ).
The switch looks to be the same type/style/construction as the mains/power switch which, I remind you, is ALSO failed (open circuit). They looks like sealed plastic body stuff, so I can't open them to refurbish them.

So, for my troubleshooting purposes, I shorted the that switch so that it's hard wired to MANUAL mode. Then I realized that when I depress the push-button, I also get sometimes weird results... so this switch is probably also dodgy.  Nowhere near as bad as the MAN/AUTO one, but still a little bit.

I've had a closer look at the switches in the teardown pictures and that style of switch (well the chrome push-button one) are familiar, yes we used them at work, BR used them for a reset switch on one product and they did occasionally fail, can't remember if they were just intermittent, or failed completely.
I doubt I have any, due to someone from a another company rummaging & pillaging through all the parts, before I was allowed to buy them as surplus. 

Re: the symbol tube with blue glow, this is normal for tubes with a tiny amount of Hg inside, it shouldn't be visible once the filter is back in place. If a tube fails due to a crack, they die very quickly, I think with a pinkish glow before they EOL.

David

[mnementh]

Totally agree, those Chinese AD584-M really are great little units and excellent value for money, if only they also did current and AC units like them, or could even build a unit with all three tests for a bit extra cash, it would be a great device to add into the toolkit.

Agree, as long as it is the one's with a legitimate label on the back indicating it's actual measured voltage. Both mine are. The one's with no label or "cookie cutter" label should be considered suspect.

I'm not sure how trustworthy the chinese devices are w.r.t. drift over time.

I'd look at Ian Johnson's devices https://www.ianjohnston.com/index.php/onlineshop He's on this forum He's evaluating whether his stock will allow him to offer more

We had some considerable conversation on this subject in here a year or three ago... I thought the consensus was that as long as the Vref was one of those obviously made using a reclaimed AD584x, they should be considered to be pretty well-aged and therefore pretty stable...?

mnem
 

[mnementh]

Annnndddd I just won a TDS784D with HDD option to replace my TDS784C.

I really gotta stop buying and start selling.. lol.

mnem
*kicks Amazon in the junk just on GP*

[capt bullshot]

...R.I.P.

Heh... so I'm not the only one who has a collection of laptop battery BMS boards in the scrap PCB bin, ehhh...?

Great source of high-current FETs and Schottkeys... sometimes even useful values of shunt resistors and Polyfuses. 

I harvested the cells, and threw the BMS boards away, not planning to remove any components from them. But they'll stay there until the scrap box is full and wouldn't be the first thing to be drawn out of the scrap again ...

[med6753]

Totally agree, those Chinese AD584-M really are great little units and excellent value for money, if only they also did current and AC units like them, or could even build a unit with all three tests for a bit extra cash, it would be a great device to add into the toolkit.

Agree, as long as it is the one's with a legitimate label on the back indicating it's actual measured voltage. Both mine are. The one's with no label or "cookie cutter" label should be considered suspect.

I'm not sure how trustworthy the chinese devices are w.r.t. drift over time.

I'd look at Ian Johnson's devices https://www.ianjohnston.com/index.php/onlineshop He's on this forum He's evaluating whether his stock will allow him to offer more

We had some considerable conversation on this subject in here a year or three ago... I thought the consensus was that as long as the Vref was one of those obviously made using a reclaimed AD584x, they should be considered to be pretty well-aged and therefore pretty stable...?

mnem
 

I've demonstrated on here several times that at least for the units I have the 18 - 24 hours I've had them on they were stable, at room temperature. I also demonstrated that if you put one a hot plate and crank up the temp you can watch the voltage change pretty rapidly.

Not sure if I would use one of these for long term stability such as a week, month, etc but for a quick verification they are a bargain. 

 

[mnementh]

We had some considerable conversation on this subject in here a year or three ago... I thought the consensus was that as long as the Vref was one of those obviously made using a reclaimed AD584x, they should be considered to be pretty well-aged and therefore pretty stable...?

I've demonstrated on here several times that at least for the units I have the 18 - 24 hours I've had them on they were stable, at room temperature. I also demonstrated that if you put one a hot plate and crank up the temp you can watch the voltage change pretty rapidly.

Not sure if I would use one of these for long term stability such as a week, month, etc but for a quick verification they are a bargain.

Yet that is precisely how the equipment the AD584x was harvested from was usually used.

The difference here, I think,  is we're talking more about the quality of the components used in the Chinesium VRef and how clean/stable the power source is and how stable the ambient temp is.

Obviously, these things are designed to a price not to a spec, which is why they're such good little Lego building blocks for design work. Once you have your working prototype, then you can design a AD584x reference with decent quality power source and do all the tricks to stabilize temp and eliminate noise, etc from the final product. 

mnem