Test Equipment Anonymous (TEA) group therapy thread

[Zoli]

And now, for a change from the cars, a TEA related post: HPA 34401A. The K is still missing, but I hope it will join the family soon. The multimeters agree to disagree, both in firmware and voltage readings - and I have no intention to change that. From the HP price I've successfully negotiated off 20%, based on the colour of input jacks. The A is the navy NOS, which was available in late 2020 on evilbay. The leads are original HPA, IIRC the hooks came as standard with the 34401A around year 2000.
The reference: LT1236 based, adjusted to 10.0000V past summer with a calibrated 34461A; LDO: LT1761-BYP, set for 13V. The reference is driven from two 9V batteries, in this case rechargeable Li-Ion's. The LED's are installed with RTV, not hot-melt. The foam is insulating, not dissipative.

[bd139]

And now, for a change from the cars, a TEA related post: HPA 34401A. The K is still missing, but I hope it will join the family soon. The multimeters agree to disagree, both in firmware and voltage readings - and I have no intention to change that. From the HP price I've successfully negotiated off 20%, based on the colour of input jacks. The A is the navy NOS, which was available in late 2020 on evilbay. The leads are original HPA, IIRC the hooks came as standard with the 34401A around year 2000.
The reference: LT1236 based, adjusted to 10.0000V past summer with a calibrated 34461A; LDO: LT1761-BYP, set for 13V. The reference is driven from two 9V batteries, in this case rechargeable Li-Ion's. The LED's are installed with RTV, not hot-melt. The foam is insulating, not dissipative.

Good buy that HP. Display is rev -02 which is the one that doesn’t snuff it so easily. Even if it has red jacks.

[capt bullshot]

More WT1600 fun: Cough, cough "Husten, wir haben ein Problem" Edition (German dad joke pun)

Now testing the current measurement input, using the Fluke calibrator and the Tek current clamp:



This is the lowest range (10mA), with 10mArms applied:



100mA range:



This is the largest range (5A), 1.999Arms applied:



Doesn't give too much confidence into the measured values, does it?
Basically, the current measurement using the direct (shunt) input is off all over the place, with different offset and gain errors over the ranges. The unit has an BNC input for current measurement, this input looks OK on a first glance.

The block diagram doesn't give too much info of where the range switching happens in particular, so there'll be some teardown and fault analysis activity in the next days.

[Specmaster]

Oh great, even more sensors to go wrong. The one time the 19yo Toyota Yaris failed was due to a sensor.

Well the "misting" sensor is just some LEDs and photodiodes, if those don't outlive the capacitors in rest of the electronics I'd be very surprised. The air pollution sensor is another story, it's the kind that uses a heated sensor matrix which to me dictates a certain maximum power-on hours; thankfully it's about as accessible as possible and entirely self-contained on a plug-in connector, replacing it would be a five minute job and it has a list price of €55 so not too terrifying.

The downside of all modern cars is the sheer quantity of electronics, sensors and servo motors they rely on. There most be upwards of 20 or 30 servo motors in the BMW: engine, lights, ventilation, seats, the list is endless.

Physical controls are fine.

The Tesla (and other?) touchscreen / voice activated controls are a serious problem.

I'm against touch-screen only controls on things I use on a desktop, like 'scopes, on something potentially safety critical such as in a car or plane I think they're criminal.

Likewise, my car has shitloads of servo motors and numerous mini computers or ECU's, each door has one FFS for example. The service manual shows them wedged in all over the place, under seats, in doors, loads under the dash, in the boot and engine bay, its quite scary really, just how much cars have been drive by wire devices these days.

[Cerebus]

And now, for a change from the cars, a TEA related post: HPA 34401A. The K is still missing, but I hope it will join the family soon. The multimeters agree to disagree, both in firmware and voltage readings - and I have no intention to change that. From the HP price I've successfully negotiated off 20%, based on the colour of input jacks. The A is the navy NOS, which was available in late 2020 on evilbay. The leads are original HPA, IIRC the hooks came as standard with the 34401A around year 2000.
The reference: LT1236 based, adjusted to 10.0000V past summer with a calibrated 34461A; LDO: LT1761-BYP, set for 13V. The reference is driven from two 9V batteries, in this case rechargeable Li-Ion's. The LED's are installed with RTV, not hot-melt. The foam is insulating, not dissipative.

Good buy that HP. Display is rev -02 which is the one that doesn’t snuff it so easily. Even if it has red jacks.

Yeah, I don't have quite enough information to put one together yet, but what we need is a "dichotomous key" to figuring out exactly which model of HPAK 34401A one has in front of one based on the features that can be determined from a decent set of photos.

[Specmaster]

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.

It's the same on the opposite side of the world. A typical public transport bus here has a teeth-rattling bone-jarring ride accompanied by the the constant whine of a straight-cut gear transmission.

It is my belief that many modern bus design are still based on the chassis and running gear of farm stock truck designs from the 1950s.

Gee, everyone holds the London transit system in high esteem yet poo-poo's the NYC transit system when it appears just the opposite is true. NYC buses are fully air conditioned, full automatic transmission, and ride surprisingly well over the shitty streets. The newest subway cars are fully air conditioned and insulated well enough that you can actually hold a conversation without shouting.   

Well TBH, most if not all buses over here these days are fully automatics, so have advanced a bit.

[mnementh]

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.

Yeah, your stuff tends to be a lot lighter than this table was originally, which I was trying to get as close to as possible.



This is what it looked like after the third coat yesterday, just before we went to dinner. This is actually almost exactly how it looked originally, except a better shine.

     

This what it looked like after I stripped the excess stain and gave it a 4th coat, then wiped it all down correctly. This is pretty much exactly how it looked just before the 3rd coat of stain, which indicates to me the wood has taken all the stain it's going to.

At this point, it's going to be a matter of "Gotta let SWMBO see and decide." This was her father's table and it got mangled by UHaul contract movers; big chunks knocked out of one end and bits of broken glass embedded in one edge. Those spots have been repaired to the best of my ability, so now we're getting to the final finish. I know I can make it a lot darker with a dark-tinted urethane finish; we'll see what she says when she sees it.

Restoring it is her Anniversary present this year, so it has to be the way she wants it, not how I think it looks good. I figured I'd better get it done sometime before I take the dirt nap; considering I've been promising to do it for over a decade. 

Of course, Murphy has been literally every time I turn around on this project, and the weather started being hot & 110% humid... like Houston summer humid... the very morning I started and has not let up. 

mnem
A labor of love is its own reward.

[bd139]

And now, for a change from the cars, a TEA related post: HPA 34401A. The K is still missing, but I hope it will join the family soon. The multimeters agree to disagree, both in firmware and voltage readings - and I have no intention to change that. From the HP price I've successfully negotiated off 20%, based on the colour of input jacks. The A is the navy NOS, which was available in late 2020 on evilbay. The leads are original HPA, IIRC the hooks came as standard with the 34401A around year 2000.
The reference: LT1236 based, adjusted to 10.0000V past summer with a calibrated 34461A; LDO: LT1761-BYP, set for 13V. The reference is driven from two 9V batteries, in this case rechargeable Li-Ion's. The LED's are installed with RTV, not hot-melt. The foam is insulating, not dissipative.

Good buy that HP. Display is rev -02 which is the one that doesn’t snuff it so easily. Even if it has red jacks.

Yeah, I don't have quite enough information to put one together yet, but what we need is a "dichotomous key" to figuring out exactly which model of HPAK 34401A one has in front of one based on the features that can be determined from a decent set of photos.

My rules are:

1. Does the display look fucked? run a mile.
2. Is it Agilent or Keysight branded - buy it.
3. If it isn't, ask the seller to get the firmware version from the menus and make sure it's -02 or -03 suffixed.

[Ice-Tea]

The block diagram doesn't give too much info of where the range switching happens in particular, so there'll be some teardown and fault analysis activity in the next days.

Hmmm... but if the external BNC is OK, the fault can't be too far the rabbit hole?

[capt bullshot]

The block diagram doesn't give too much info of where the range switching happens in particular, so there'll be some teardown and fault analysis activity in the next days.

Hmmm... but if the external BNC is OK, the fault can't be too far the rabbit hole?

For now, I'd guess there are independent ranging circuits for BNC and shunt that aren't drawn in the above picture. Interestingly, measured values are too small  @10mA, while too large @5A range, and there's always an offset. One can "null" the offset, but O.L. message doesn't go away and gain error stays.
Teardown of the input module will reveal the truth (hopefully).
Maybe calibration data are corrupt, but there's no error message - Cannot find any information regarding how to enter calibration / adjustment modes anyway. Holding the shift key while turning the unit on enters the firmware update mode (a 3.5" floppy disk with firmware is required), I might try all the other keys.

BTW: I'll collect all the posts and information regarding the unit here: https://www.eevblog.com/forum/testgear/yokogawa-wt1600-digital-power-meter/

[bd139]

Ooh another eBay snag. I'm on cheap and cheerful mode today. Black Star 2010 function generator for 40 quid. They are quite nice. Had the 2000 as my first function generator bought new back in the day. Unlike some of the more modern devices they have a few excellent features which are quite good:

1. 30V p-p output swing open circuit or 15V p-p into 50 ohms right up to 2MHz
2. The whole damn thing is made of standard parts, including the counter (Z80 MCU + EPROM)
3. Simultaneous TTL level output that can be used for triggering or actually you know driving TTL circuits or as a pulse gen with symmetry
4. Fully analogue control surface which makes sweeping filters less of a pain than on encoders.
5. Full service manual available.
6. LEDs. Red ones 

[Specmaster]

Ooh another eBay snag. I'm on cheap and cheerful mode today. Black Star 2010 function generator for 40 quid. They are quite nice. Had the 2000 as my first function generator bought new back in the day. Unlike some of the more modern devices they have a few excellent features which are quite good:

1. 30V p-p output swing open circuit or 15V p-p into 50 ohms right up to 2MHz
2. The whole damn thing is made of standard parts, including the counter (Z80 MCU + EPROM)
3. Simultaneous TTL level output that can be used for triggering or actually you know driving TTL circuits or as a pulse gen with symmetry
4. Fully analogue control surface which makes sweeping filters less of a pain than on encoders.
5. Full service manual available.
6. LEDs. Red ones 

Nice catch, I used to have the matching counter.

[bd139]

Ooh another eBay snag. I'm on cheap and cheerful mode today. Black Star 2010 function generator for 40 quid. They are quite nice. Had the 2000 as my first function generator bought new back in the day. Unlike some of the more modern devices they have a few excellent features which are quite good:

1. 30V p-p output swing open circuit or 15V p-p into 50 ohms right up to 2MHz
2. The whole damn thing is made of standard parts, including the counter (Z80 MCU + EPROM)
3. Simultaneous TTL level output that can be used for triggering or actually you know driving TTL circuits or as a pulse gen with symmetry
4. Fully analogue control surface which makes sweeping filters less of a pain than on encoders.
5. Full service manual available.
6. LEDs. Red ones 

Nice catch, I used to have the matching counter.

Me too.

Retro bench day... ironically designing filters with analogue toys...

[tggzzz]

Nice scope, but I'm not a fan of Black Star stuff since it always was run of the mill.

[bd139]

Nice scope, but I'm not a fan of Black Star stuff since it always was run of the mill.

Agreed. That's exactly what I'm after. I have a queue of forward engineering projects here that I have built up over 10 years and some time now so I need the kit to stay out of the way and actually do what is asked of it rather than spending hours repairing non run of the mill kit 

[tggzzz]

I have some sympathy with that, which is why I'm not going to bid on this nixie frequency counter https://www.ebay.co.uk/itm/Vintage-1977-TIMER-COUNTER-SM202M-Working-though-not-fully-tested-VGC/334441799939

[bd139]

Yes indeed. I skipped merrily past that one already 

[Cerebus]

I don't actually have anything with nixies (yes, almost heresy, I know) and I'd quitelike  something, but that doesn't hit the spot.

[mnementh]

Cerebus' standard warning about drying oils

This is folk knowledge that tends to get passed from hand to hand but for some reason is never printed as a warning on cans of drying oils used for oiling wood.

(If you already know this please ignore, but I always post this in any discussion of drying oils becuase some people don't know this, and knowing it may save a life.)

Drying oils such as Danish Oil, Tung Oil, Linseed Oil and the like can spontaneously catch fire. Rags that have been used to apply drying oils, and that still have drying oils left on them can catch fire just from being left in the open air.

The mechanism is that the increased surface area of the oil exposed to air by being soaked into a rag causes a lot of the oil to 'dry' at once. This generates heat. The heat causes the oil to 'dry' (oxidise) faster. This makes more heat, which makes the oil dry faster - you know how this one goes, it's the classic chain reaction. The heat, combined with the insulating effect of the rag's cloth can be enough to cause the rag to catch fire.

The same applies to any material such as newspaper or paper towels used to mop up spills of drying oils or used to remove excess oil from workpieces.

When using drying oils on rags and cloths always handle the rags/cloths appropriately when you have finished with them. Either thoroughly wash out rags before disposal or storage, or soak them in water and place them inside an airtight bag or container. Do not leave rags and cloths unattended for long periods (e.g. over lunch) without taking appropriate precautions to prevent them possibly catching fire, or putting them somewhere that a possible fire will not present a hazard and will be contained.

Submitted for Your Approval: PROOF That Somebody DOES Actually Listen to Cerebus!

A few minutes after I made it, I noticed that I hadn't taken a pic of the repaired end of the table for my earlier post, so I went out to take a pic. Guess what I found on the ground in the driveway?

Picking up after this afternoon's work, I had a couple handfuls of old cotton rags used to wipe the table down between coats... I almost threw them all on top of my old gas range to use later, but Cerebus' warning rang in my head, so I threw them in a pile in the middle of the driveway, far away from anything combustible. Glad I listened to the crusty ol' aardvark! 

Said smoky rags and some related stuffs are now in a bucket of water; curiously, a second nearly identical pile of rags  right next to this one not only didn't start smoking, but was absolutely cold to the touch when I handled it to throw in the water bucket too.    Only difference I can think of is I used orange oil to finish stripping the old stain when I ran out of mineral spirits; I'd guess the presence of orange oil or mineral spirits was the reason one started smoking but not t'other. 

mnem
Thanks C!

[tggzzz]

I don't actually have anything with nixies (yes, almost heresy, I know) and I'd quitelike  something, but that doesn't hit the spot.

If it is cheap, get it. That might slake your thirst for display technologies; if not you can get something else and flip that counter.

[DH7DN]

Wow!

[Cerebus]

Nice. Judging from the whisps of smoke and the charring I'd say that was a minute or two from actually catching fire. Scary isn't it.

Submitted for Your Approval: PROOF That Somebody DOES Actually Listen to Cerebus!

Normally they only listen at swordpoint.

[med6753]

Wow!

Dual beam goodness. A Type 556?

[med6753]

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.

It's the same on the opposite side of the world. A typical public transport bus here has a teeth-rattling bone-jarring ride accompanied by the the constant whine of a straight-cut gear transmission.

It is my belief that many modern bus design are still based on the chassis and running gear of farm stock truck designs from the 1950s.

Gee, everyone holds the London transit system in high esteem yet poo-poo's the NYC transit system when it appears just the opposite is true. NYC buses are fully air conditioned, full automatic transmission, and ride surprisingly well over the shitty streets. The newest subway cars are fully air conditioned and insulated well enough that you can actually hold a conversation without shouting.

No that's pretty good too.  Same level of crazy people and pools of piss as the tube 

Yep, every underground subway station has it's in resident crazy person that you avoid eye contact at your peril. 

[Specmaster]

Ooh another eBay snag. I'm on cheap and cheerful mode today. Black Star 2010 function generator for 40 quid. They are quite nice. Had the 2000 as my first function generator bought new back in the day. Unlike some of the more modern devices they have a few excellent features which are quite good:

1. 30V p-p output swing open circuit or 15V p-p into 50 ohms right up to 2MHz
2. The whole damn thing is made of standard parts, including the counter (Z80 MCU + EPROM)
3. Simultaneous TTL level output that can be used for triggering or actually you know driving TTL circuits or as a pulse gen with symmetry
4. Fully analogue control surface which makes sweeping filters less of a pain than on encoders.
5. Full service manual available.
6. LEDs. Red ones 

Nice catch, I used to have the matching counter.

Me too.

Retro bench day... ironically designing filters with analogue toys...

Hey, whats this I spy on the bench, a Casio calculator with a = key, good choice, none of that RPN rubbish here then, nothing to see here, move along