Test Equipment Anonymous (TEA) group therapy thread

[bd139]

I make an offer as a seller. I never allow offers from buyers on my auctions because quite frankly everyone wants too much of a bargain.

You couldn't possibly be hinting at any of your TEA colleagues here. No, you couldn't be. Perish the thought.

No you guys are too cheap for my sales  . I jest; if you want, make me an offer via PM on here instead of ebay.

Those versed in BD139 antics PM him. Now we know the peeling we can do on the price potato... 

There would be a decent deal for any TEA thread members on anything I'm selling. I don't need to sell for profit or as an earner; it's just a good way of disposing of something with a side effect of generating some cash

[tonyalbus]

Received an 8050A today, sold as "used". I believe a more accurate term would be "borked".

Think i have a 8050A around in my pile if you need comparison material when you decide to repair.

I'd like to take you up on this offer if I may.

I'd like your measurements of RV1, 2, and 3 to start with. They show infinite resistance here, which I'm sure is not correct...

No Problem AVG... but will be after Monday... just packing the car, i prommesed a friend to prepare his fuse/powerbox in his house from 1-fase to 3-fase..
replace the whole fusebox and main switches from his house... Monday the network will switch him over... (the part that is sealed.)..
what an idea for a weekend... me and my big mouth 
send ma a DM .. then i dont forget..
@Terra your Trio scope pictures are comming...its still on my list, i did not forget..

[bd139]

Balls’ed up the curve tracer design. To test a couple of device families and common base configuration I need an isolated collector and step supply. Back to the drawing board 

Edit: fixed it. Optoisolator to the rescue 

[dgminala]

Awesome - I don't think I've ever seen an 8 decade box before! 

It is a bit OTT, isn't it

Mind you, I think the 7-decade Kelvin-Varley Dividers are more interesting. I have one of these https://www.eevblog.com/forum/metrology/teardownjulie_reasearch_labs_vdr1067_vdr307_kelvin_varley_voltage_divider/msg1103686/#msg1103686 and there's no way I'm tearing it down! Look at the specs: resolution 0.1 ppm, accuracy 1 ppm, stability 1 ppm/year.

Makes 300ppm look anaemic

I really like my ESI DB 655 and 877 becuse they are so compact and 0.01% 6 an 8 decades.
I've got a JR106/7 too, very nice and based on their precision decades.
I anyone wants a KVD that beats BU508A's decade box for size I have a Pye "Standard Potentiometer" KVD, Bridge, and other bits in big wooden box. about 4' x 18" x 12" It has Pye "6001" instrument switches with 0.7mOhm resistance.
£10, collection only from somewere near it's "birthplace" Newmarket Rd Cambridge UK.

I have an ESI DB655 as well.  Lovely instrument and in recent cal.  Do you (or anyone) have the manual, instruction sheet or even a brochure giving the full specs for it?  I've looked everywhere I can think of for any documentation, but no luck. 
ESI instruments (now manufactured by IET) were (and still are) some of the best bench standards around. 

Thanks
DaveM

[mansaxel]

replace the whole fusebox and main switches from his house... Monday the network will switch him over... (the part that is sealed.)..
what an idea for a weekend... me and my big mouth 

Quite nice weekend, I'd say. Did it in a TEA fashion for my brother-in-law a couple weeks ago.

And, three-phase mains supply to the home is a human right.

[Specmaster]

@bd139, I never ever send out offers, makes it look like you're desperate to get shot of the item or are desperate for the money it will bring in. Also I never pack it up before it is sold as eBay recommend that you photograph the packing process in various stages showing your eBay ID on a piece of paper with the date written on it as well to avoid buyer claiming that they did not receive what they ordered or that your packing process was inadequate and the item arrived badly damaged. Also should the package get munted badly by the carrier, then your photos will serve to show just how the item was packed to protect it during transit, to prevent them from claiming it was your fault for not packing correctly in the first instance.

[tggzzz]

@bd139, I never ever send out offers, makes it look like you're desperate to get shot of the item or are desperate for the money it will bring in. Also I never pack it up before it is sold as eBay recommend that you photograph the packing process in various stages showing your eBay ID on a piece of paper with the date written on it as well to avoid buyer claiming that they did not receive what they ordered or that your packing process was inadequate and the item arrived badly damaged. Also should the package get munted badly by the carrier, then your photos will serve to show just how the item was packed to protect it during transit, to prevent them from claiming it was your fault for not packing correctly in the first instance.

I don't see any harm in sending offers. I've no evidence that it puts people off.

I haven't seen that fleabay advice, but automatically do everything except for showing the ebayid. I'll do that in the future.

So far, touch wood, I've only had one problem. I sent a couple of connectors second class and they didn't arrive. It was no problem; I just sent a couple more. Since the connectors were more-or-less free to me, I only lost the cost of the postage.

[bd139]

@bd139, I never ever send out offers, makes it look like you're desperate to get shot of the item or are desperate for the money it will bring in. Also I never pack it up before it is sold as eBay recommend that you photograph the packing process in various stages showing your eBay ID on a piece of paper with the date written on it as well to avoid buyer claiming that they did not receive what they ordered or that your packing process was inadequate and the item arrived badly damaged. Also should the package get munted badly by the carrier, then your photos will serve to show just how the item was packed to protect it during transit, to prevent them from claiming it was your fault for not packing correctly in the first instance.

Yeah I photograph the packaging when I’m packing it.

Looking desperate is good for the buyer’s perception 

[AVGresponding]

Ok, here it is, the shit-show you've all been waiting for, the Keithley 2000 unboxing and post mortem...

Fair warning, this is a pic and vid heavy post.



It's here! In a box! And it's not heavy enough to contain a brick! In fact it's very light... let's open it


Seemed a bit loose inside the outer box... only one layer of small bubble wrap? Good grief...


He's taken a left hook to the jaw, I bet that hurt


The display filter stuck back down ok, the sagging chassis will require some brute force and ignorance to bend back. Worked the front/rear input switch a few times, feels a bit spongy to me.

Strip and give me twenty, you maggot!


Hmm, so that's why the chassis sags at the front, the transformer is at that end and its mass would have done the damage when it was dropped. Transformer at the front? wth... did Ferdinand Porsche design this thing? It's at the wrong end m8...
The input selector switch is spongy because the plastic pushrod is flimsy as.

Found some evidence of the previous owner's adventures:


Nope, that's not a rolled up map of Cassiopeia, it's a 3A glass M205 in witness mode.

More evidence:


I bet that made him jump!   

Oh well, time to plug it in and turn it on. If it's dead, it's dead.

*shnnk*  *click*



Let's start with some voltage measurements (very short vid clips):


Not three bad! Let's try current:


Close enough for Hebden Bridge.
The 8840A can't follow us where we're going...


Let's check the wobbly voltage measuring:


Ok, what about ohms?


Hmm, that's not good news. Not for the meter, it's close enough to the 8840A, but that's a 100K 0.1% resistor. I trust the meters ahead of the resistor, must have drifted, it is 25 years old. About the same as the Keithley...   
I'll have to dig out the rest of them and see if they're all the same.

Low ohms:



Even in Lo ohms mode, the 289 can't compete with the 4-wire capabilities of the bench boys.


Well, that about wraps it up for now. Now I just have to rearrange my damn meter stack AGAIN   

[Robert763]

Awesome - I don't think I've ever seen an 8 decade box before! 

It is a bit OTT, isn't it

Mind you, I think the 7-decade Kelvin-Varley Dividers are more interesting. I have one of these https://www.eevblog.com/forum/metrology/teardownjulie_reasearch_labs_vdr1067_vdr307_kelvin_varley_voltage_divider/msg1103686/#msg1103686 and there's no way I'm tearing it down! Look at the specs: resolution 0.1 ppm, accuracy 1 ppm, stability 1 ppm/year.

Makes 300ppm look anaemic

I really like my ESI DB 655 and 877 becuse they are so compact and 0.01% 6 an 8 decades.
I've got a JR106/7 too, very nice and based on their precision decades.
I anyone wants a KVD that beats BU508A's decade box for size I have a Pye "Standard Potentiometer" KVD, Bridge, and other bits in big wooden box. about 4' x 18" x 12" It has Pye "6001" instrument switches with 0.7mOhm resistance.
£10, collection only from somewere near it's "birthplace" Newmarket Rd Cambridge UK.

I have an ESI DB655 as well.  Lovely instrument and in recent cal.  Do you (or anyone) have the manual, instruction sheet or even a brochure giving the full specs for it?  I've looked everywhere I can think of for any documentation, but no luck. 
ESI instruments (now manufactured by IET) were (and still are) some of the best bench standards around. 

Thanks
DaveM

See DB 877 manual below. The 655 is basically the same but only 3 decades per stack.

[McBryce]

Ok, here it is, the shit-show you've all been waiting for, the Keithley 2000 unboxing and post mortem...

It's here! In a box! And it's not heavy enough to contain a brick! In fact it's very light... let's open it

Winner, winner, chicken dinner!

McBryce.

[bd139]

That was considerably less of a shit show than I was expecting. Congratulations 

[Specmaster]

Here is a question for the team, I'm trying to repair my sons electric toothbrush which will only run if its just it's just been taken off charge. Ah ha, me thinks, duff battery, I open it up and measure the voltage across the Ni-MH battery when it is off charge, which was 1.44V but the brush will not run. Connect the brush upto a bench supply and give it 1.76V for a few seconds and the brush will switch on when the button is pressed and will continue running, even if I drop the voltage down to .7V. 

Pop the brush back onto its wireless charger base and the voltage across the battery terminals rises upto around 1.78V and the brush will start after a few seconds or so of being on the base. If I remove the battery and pop it back onto the charger base once again, the voltage across the battery terminals instantly rises upto 4.2V but the brush will not run.

I'm assuming that this is because the wireless charger is incapable of providing sufficient power to run the ultrasonic motor 

So my question is, what is the maximum theoretical voltage that Ni-MH battery could be charged upto? 

[bd139]

Something definitely wrong there. Fully charged is around 1.4V. Are there two in series? Possible one has gone short

[Specmaster]

@AVGresponding.
That is a great score after all, but it could have turned so very different, especially considering the piss poor packaging the seller provided it with for the couriers rat run that each parcel is subjected to, as witnessed by the drop and the chassis bending and display filter shifting  I really don't understand ow anyone can expect a delicate piece of equipment is fully protected by such a flimsy amount of bubble wrap.  If I only have bubble wrap to wrap something in before sticking it in its box, I always make sure that there is at least 50mm of wrap on all side of the meter with upto 100mm on the front and rear panels. I also ensure that the item is not able to move about in the box by the use of extra packing on all side to prevent movement of the item in its box to reduce any additional inertia coming into play should it suffer a serious impact on route.

Anyway, you did well in the end, but with little assistance from the wally of a seller you were dealing with   

[Specmaster]

Something definitely wrong there. Fully charged is around 1.4V. Are there two in series? Possible one has gone short

Nope, just the one cell, a AA sized with solder tabs, like this one https://www.ebay.co.uk/itm/Toothbrush-Replacement-Battery-for-Braun-Oral-B-42mm-x-17mm-Ni-MH-Rechargeable/254489273293

[Zucca]

Thanks TEA platoon for all your suggestions and input about my Ebay incident.
I sent a message to the bastard just telling him I am interested even if the probe is broken.
Let's see what happen.

Meanwhile I got the money back and I got a tastee apple in my PM, I am already moving on.

[AVGresponding]

Thanks TEA platoon for all your suggestions and input about my Ebay incident.
I sent a message to the bastard just telling him I am interested even if the probe is broken.
Let's see what happen.

Meanwhile I got the money back and I got a tastee apple in my PM, I am already moving on.

He will make another excuse.   

[AVGresponding]

Here is a question for the team, I'm trying to repair my sons electric toothbrush which will only run if its just it's just been taken off charge. Ah ha, me thinks, duff battery, I open it up and measure the voltage across the Ni-MH battery when it is off charge, which was 1.44V but the brush will not run. Connect the brush upto a bench supply and give it 1.76V for a few seconds and the brush will switch on when the button is pressed and will continue running, even if I drop the voltage down to .7V. 

Pop the brush back onto its wireless charger base and the voltage across the battery terminals rises upto around 1.78V and the brush will start after a few seconds or so of being on the base. If I remove the battery and pop it back onto the charger base once again, the voltage across the battery terminals instantly rises upto 4.2V but the brush will not run.

I'm assuming that this is because the wireless charger is incapable of providing sufficient power to run the ultrasonic motor 

So my question is, what is the maximum theoretical voltage that Ni-MH battery could be charged upto? 

My Maha Powerex can pulse about 1.7V or so at cells while it's figuring out their charge state, but as a rule 1.45-1.5V is the maximum at which the charger should be cutting off on the d_v/d_t slope.

[AVGresponding]

btw discord is available for your auditory and visual stimulation

[Specmaster]

Here is a question for the team, I'm trying to repair my sons electric toothbrush which will only run if its just it's just been taken off charge. Ah ha, me thinks, duff battery, I open it up and measure the voltage across the Ni-MH battery when it is off charge, which was 1.44V but the brush will not run. Connect the brush upto a bench supply and give it 1.76V for a few seconds and the brush will switch on when the button is pressed and will continue running, even if I drop the voltage down to .7V. 

Pop the brush back onto its wireless charger base and the voltage across the battery terminals rises upto around 1.78V and the brush will start after a few seconds or so of being on the base. If I remove the battery and pop it back onto the charger base once again, the voltage across the battery terminals instantly rises upto 4.2V but the brush will not run.

I'm assuming that this is because the wireless charger is incapable of providing sufficient power to run the ultrasonic motor 

So my question is, what is the maximum theoretical voltage that Ni-MH battery could be charged upto? 

My Maha Powerex can pulse about 1.7V or so at cells while it's figuring out their charge state, but as a rule 1.45-1.5V is the maximum at which the charger should be cutting off on the d_v/d_t slope.

Thats my understanding as well. But why when the battery voltage was at 1.44V didn't the toothbrush operate? Is it worth buying a new battery or tossing it and getting a toothbrush?

[Ice-Tea]

So I found this amplifier alike box at some other departments scrap box, free for take away:
**snip**

Dude, if you're so desperate for stuff to tinker with, I got **stuff** for you...

What kind of stuff 

Prrff.. in essence, pick your poisson. Pick a category and I have something that needs repair. But... what about a Datron 1071? I actually have a series of these that seem to work fine but all throw selftest errors. They all have depleted batteries in common but simply replacing them does not work. So, my working theory is that it needs at least halfway right correction parameters to pass selftests. And that's how far I got.

Try calibrating them more than once.  What you describe sounds familiar, I have a 1061A that lost its calibration and needed two or three calibration iterations to final success.
These things can have quite interesting and subtle faults:
http://wunderkis.de/datron1061a/index.html
https://amplifier.cd/Test_Equipment/other/Datron1061/Datron_1061.html

So if you can't get any further with them, I should be able to help you. As I've already got two 1061, you'd most probably get them back.
I've got no dedicated wish list, It's more a "I see it, repair it and I like it" process. Some stuff that I don't have yet: an SMU, a general purpose SA with 9k to maybe 2G range and narrow RBW, something like a HP53310A ...

Think I aborted at the 1000V cal stage as I have no decent source for that. Only later I figured out that I could use the photomultiplier PSU for it. Eh, maybe I'll find the time..

How about a Keithley 238? I think I have one in parts, with most parts OK except for the output bridge. I semi-repaired it but, well, time.

[mnementh]

Something definitely wrong there. Fully charged is around 1.4V. Are there two in series? Possible one has gone short

Nope, just the one cell, a AA sized with solder tabs, like this one https://www.ebay.co.uk/itm/Toothbrush-Replacement-Battery-for-Braun-Oral-B-42mm-x-17mm-Ni-MH-Rechargeable/254489273293

4.2V charge voltage no load...? Sounds like you have a 14500 LiIon cell like I use in my EDC flashlights.

mnem
 

[AVGresponding]

Something definitely wrong there. Fully charged is around 1.4V. Are there two in series? Possible one has gone short

Nope, just the one cell, a AA sized with solder tabs, like this one https://www.ebay.co.uk/itm/Toothbrush-Replacement-Battery-for-Braun-Oral-B-42mm-x-17mm-Ni-MH-Rechargeable/254489273293

4.2V charge voltage no load...? Sounds like you have a 14500 LiIon cell like I use in my EDC flashlights.

mnem
 

That's definitely a plausible explanation. Does it mention the cell chemistry on the thing?

[Robert763]

It depends on the exact model, but most of the rechargeable toothbrushes with Nimh (or NiCad in the older ones) cells used the the poor coupling (leakage inductance) between the base and brush to limit the charging current. The cell limits the voltage. Sounds like the cell has gone high impedance. Personally I'd jut go buy a new one. The motor gears and bearings are probably well worn by now.