Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

TE : I finally succumbed... decided not to buy or build a dedicated ESR meter to test the caps imy Tek 575. Not economical.
Instead I bought the dread super AVR based open source cheap component tester millions before me have already bought... thinking for 10 Euros  it can measure ESR.. and test common components on top of it, which I desperately need to sort my shit load of salvaged semiconductors over the years. Lab V2.0 is in the making and that involves turning bvoxes of shit into tested, identified, oragnized stuff in labelled boxes... so I cna actually use this stuff, not just stare at a pile of component thiking "hey maybe something in that pile could do the job ! "....

Did a few sanity checks, looks OK, readings are both plausible and repeatable. Tested a few resistors, as well as my ton of 40 years old salvage electrolytic caps, only to find out that.... 99.5% still are within spec capacitance wise, AND still have low / acceptable ESR ?!  The worse that I could find, was of course in the tiny packages, like 0.1uF 16V or something... the size of a (small/tender) pea. There, I found 2 or 3 that  read high at 25/30 ohms. but that's about it !
Gee I am glad I didn't scrap all these caps "assuming" they HAD to be all long gone ESR wise ! They are not !! 

All my big ones measure between 0,00 (resolution of the tester) and 0.100 or something, so just fine.

Then I tested the can caps in the 575, the x4   2000uF 20Vols  caps that are in parallel to smooth the low voltage supply for the Base Step Generator.
I measured them at 3000uF inseand 2000uF, and one at 2750.
Cheap tester agreed 100% with that ! Then tested ESR as that was the goal wasn't it... 3 of the 4 caps read just fine at 0,15ohm, unbelievable, but one is toast, read TWO uF not 2,000uF, and ESR is 150ohms !     So this one definitely not happy. 

Overall very happy with this cheap tester, the best 10 Euros I have spent in a long time !

Being able to do new measurements is I find even more fun and exciting than buying yet another 35th old scope... maybe there is a trend here... maybe I will wake one morning and get rid of half my scopes and concentrate on getting more test gear instead ! 

Nothing wrong with that, I have a similar tester myself and while I accept that for those who are heavily involved in RF work, these may not be accurate enough for their needs, I find them perfectly acceptable for the testing of capacitors used on power rails and will easily give you a go or no go result as far as ESR is concerned. The actual capacitance value is not a major concern in that case, especially given the wide tolerances that new electrolytics and tants have anyway.

[Neper]

I didn't think it was a problem over there as we are supposed to be waving the incoming lorries through AFAIK, is that not the case?

There were times when the traffic from France to the UK was just as badly affected and there were tailbacks from Calais all the way back to the Belgian border.

[Vince]

Notice how we go from the many gigaohms on the tester and iPad to just over 9 megaohms?  What the insulation tester is now seeing is the resistance of the extension cord’s insulation shunted by the 10 meg impedance of the DMM.  We can either observe the 1000 V test voltage independently on the second meter or the insulation strength but not both at the same time.

Time to get  HV probe, at least one Gig ohm resistance ! 

[25 CPS]

Notice how we go from the many gigaohms on the tester and iPad to just over 9 megaohms?  What the insulation tester is now seeing is the resistance of the extension cord’s insulation shunted by the 10 meg impedance of the DMM.  We can either observe the 1000 V test voltage independently on the second meter or the insulation strength but not both at the same time.

Time to get  HV probe, at least one Gig ohm resistance ! 

Oh, for sure, I definitely need a high voltage probe for other purposes but when you look at insulation resistance values like the 135 GOhm on this cord for example, even a 1 GOhm probe would load the test down and give a bad reading.

[Specmaster]

Notice how we go from the many gigaohms on the tester and iPad to just over 9 megaohms?  What the insulation tester is now seeing is the resistance of the extension cord’s insulation shunted by the 10 meg impedance of the DMM.  We can either observe the 1000 V test voltage independently on the second meter or the insulation strength but not both at the same time.

Time to get  HV probe, at least one Gig ohm resistance ! 

Oh, for sure, I definitely need a high voltage probe for other purposes but when you look at insulation resistance values like the 135 GOhm on this cord for example, even a 1 GOhm probe would load the test down and give a bad reading.

Or you could just short out the other end of the circuit and do a continuity test to ensure that both conductors are good, then remove the short and apply the 1,000V test, and then you should see something in the GOhm range?

[mnementh]

I didn't realize this was in the UK

With a name like Minchinhampton? Could it be anywhere else? When the Americans, Canadians, Aussies and Kiwis eschewed imagination and named everywhere after somewhere in Blighty, sometimes putting 'new' in front of it, they did have the good sense to leave names like Minchinhampton behind. 

Sorry. Sounded to me like a slightly less stagnant bog a few miles from the real swamps. 

mnem
In New Zealand. Or maybe Oz.

Not likely...... indigenous place names names are now the thing here were replacements for settlers towns and cities are being pushed down our throats. 

Still, they are welcome to keep some of the originals so we invaders can continue to have a good laugh:
Taumata whakatangi hangakoauau o tamatea turi pukakapiki maunga horo nuku pokai whenua kitanatahu
https://www.newzealand.com/nz/feature/the-longest-place-name-in-new-zealand/

* tries to say a few of them and winds up with his tongue tangled around his own throat*

 

mnem
};=)~~~~<

[25 CPS]

Notice how we go from the many gigaohms on the tester and iPad to just over 9 megaohms?  What the insulation tester is now seeing is the resistance of the extension cord’s insulation shunted by the 10 meg impedance of the DMM.  We can either observe the 1000 V test voltage independently on the second meter or the insulation strength but not both at the same time.

Time to get  HV probe, at least one Gig ohm resistance ! 

Oh, for sure, I definitely need a high voltage probe for other purposes but when you look at insulation resistance values like the 135 GOhm on this cord for example, even a 1 GOhm probe would load the test down and give a bad reading.

Or you could just short out the other end of the circuit and do a continuity test to ensure that both conductors are good, then remove the short and apply the 1,000V test, and then you should see something in the GOhm range?

No, you’re misunderstanding the purpose of that part of the demo - it was to show how connecting a second meter to observe the test voltage invalidates the test results.  If I wanted to continuity test the conductors in the extension cord, I’d just bring the two ends close to each ether and do that with any multimeter.  Truth be told, we know the conductors in the cord are good because it’s normally plugged in and used all the time.  I had to disconnect it for this.

[mnementh]

Actually the primary cause of the driver shortage is covid, not Brexit. There is indeed a shortage of perhaps 100k drivers, and it's also a fact that most of the drivers that have quit are British.
There is a huge backlog of HGV tests, 40k or so, due to covid absences.


I challenge anyone to prove flooding the UK with cheap labour from eastern Europe is a good thing for anyone other than the middle classes. The supermarkets and other big companies have been using this to suppress wages for decades now. That's fine for people that can send the au-pair to buy their avocados at Waitrose, but it royally fucks over every worker who can be replaced with someone from the EU for half the wage.
And it also fucks over the countries that these people come from, because it leaves them with a labour shortage, raising wages locally in an economy that can't support them. And who pays the bill for that? Taxpayers in the rest of Europe, mainly Germany and France now that we've left.

I'm sorry you feel it's a massive burden to have to get a visa to fly off to parts of mainland Europe for a holiday twice a year, but frankly I'm more concerned with being able to heat, clothe, and eat, which is the position of far too many working people in this country.

Farmers can't get workers to pick their fruit and veg? Pay a decent fucking living wage then. Supermarkets can't get drivers? The same statement applies.

Joining the EU was a Tory plan in the 1970s to increase profits for big business. It worked. The window dressing of free movement was always a canard to buy the co-operation of the middle classes, and that worked too.

It's about time we started paying the real price for food and goods, instead of having them subsidised by cheap labour from poorer countries.

1000x this for the US, particularly Tejas and SoCal; both of whose economies (and IIRC, aboot 40% of the produce farming capacity of the nation) are so fucking top-heavy in manufacturing, commerce and government they would collapse in weeks without exactly that kind of near-slave labor.

But hey, we can buy iPwns to bitch aboot it on FarceBook in the comfort of our Suburbans, so who fucking cares.

mnem
And that's all I'm going to say. 

[tautech]

I didn't realize this was in the UK

With a name like Minchinhampton? Could it be anywhere else? When the Americans, Canadians, Aussies and Kiwis eschewed imagination and named everywhere after somewhere in Blighty, sometimes putting 'new' in front of it, they did have the good sense to leave names like Minchinhampton behind. 

Sorry. Sounded to me like a slightly less stagnant bog a few miles from the real swamps. 

mnem
In New Zealand. Or maybe Oz.

Not likely...... indigenous place names names are now the thing here were replacements for settlers towns and cities are being pushed down our throats. 

Still, they are welcome to keep some of the originals so we invaders can continue to have a good laugh:
Taumata whakatangi hangakoauau o tamatea turi pukakapiki maunga horo nuku pokai whenua kitanatahu
https://www.newzealand.com/nz/feature/the-longest-place-name-in-new-zealand/

* tries to say a few of them and winds up with his tongue tangled around his own throat*

 

mnem
};=)~~~~<

You'll have less trouble with Taumata Hill which is in common usage now.

[Kosmic]

Heads-up for the folks in UK. Someone is selling bunch of gears in the FS section: https://www.eevblog.com/forum/buysellwanted/fs-electronicsrf-lab-clear-out-(keysight-tek-rs-rigol-)-reasonable-offers/msg3710440/#msg3710440

[Specmaster]

Notice how we go from the many gigaohms on the tester and iPad to just over 9 megaohms?  What the insulation tester is now seeing is the resistance of the extension cord’s insulation shunted by the 10 meg impedance of the DMM.  We can either observe the 1000 V test voltage independently on the second meter or the insulation strength but not both at the same time.

Time to get  HV probe, at least one Gig ohm resistance ! 

Oh, for sure, I definitely need a high voltage probe for other purposes but when you look at insulation resistance values like the 135 GOhm on this cord for example, even a 1 GOhm probe would load the test down and give a bad reading.

Or you could just short out the other end of the circuit and do a continuity test to ensure that both conductors are good, then remove the short and apply the 1,000V test, and then you should see something in the GOhm range?

No, you’re misunderstanding the purpose of that part of the demo - it was to show how connecting a second meter to observe the test voltage invalidates the test results.  If I wanted to continuity test the conductors in the extension cord, I’d just bring the two ends close to each ether and do that with any multimeter.  Truth be told, we know the conductors in the cord are good because it’s normally plugged in and used all the time.  I had to disconnect it for this.

Oh I see, yes TBH it is pretty obvious that another meter connected to the end will invalidate the test results as you are connecting at least a 10Megohm resistor  across the 2 conductors, plus the source impedance is in parallel so the resultant reading will be less than 10Megohm. For a moment there, I thought that the point of the voltmeter on the end was to prove that you did in fact have the full length of cable under test, hence why the continuity test I mentioned.

Edit, I went back to look again at the photos and I only see resistance values in Megohms, nothing at all in Gohms.

[25 CPS]

Notice how we go from the many gigaohms on the tester and iPad to just over 9 megaohms?  What the insulation tester is now seeing is the resistance of the extension cord’s insulation shunted by the 10 meg impedance of the DMM.  We can either observe the 1000 V test voltage independently on the second meter or the insulation strength but not both at the same time.

Time to get  HV probe, at least one Gig ohm resistance ! 

Oh, for sure, I definitely need a high voltage probe for other purposes but when you look at insulation resistance values like the 135 GOhm on this cord for example, even a 1 GOhm probe would load the test down and give a bad reading.

Or you could just short out the other end of the circuit and do a continuity test to ensure that both conductors are good, then remove the short and apply the 1,000V test, and then you should see something in the GOhm range?

No, you’re misunderstanding the purpose of that part of the demo - it was to show how connecting a second meter to observe the test voltage invalidates the test results.  If I wanted to continuity test the conductors in the extension cord, I’d just bring the two ends close to each ether and do that with any multimeter.  Truth be told, we know the conductors in the cord are good because it’s normally plugged in and used all the time.  I had to disconnect it for this.

Oh I see, yes TBH it is pretty obvious that another meter connected to the end will invalidate the test results as you are connecting at least a 10Megohm resistor  across the 2 conductors, plus the source impedance is in parallel so the resultant reading will be less than 10Megohm. For a moment there, I thought that the point of the voltmeter on the end was to prove that you did in fact have the full length of cable under test, hence why the continuity test I mentioned.

Edit, I went back to look again at the photos and I only see resistance values in Megohms, nothing at all in Gohms.

Yes - my mistake there - it was 135 MOhms in that one test with the far end open circuit, not GOhms.

Actually, I just broke out a calculator and did the RPN equivalent of 1/(1/10E6 Ohms meter Zin+ 1/135E6 Ohms for the cord measured in the previous test) and got 9.31 MOhms which is pretty close to the 9.14 MOhms the insulation tester gave with the U1272A sitting connected to the plug end of the cord watching the 1 KV, so the numbers all check out, which is reassuring.

I forgot to mention that part of the reason for demonstrating all the wireless connectivity stuff was to show what I had in mind for getting instrumentation set up on some tramcars in railway museums to get some objective measurements on controller and motor performance especially on newer ones that have automatic acceleration and dynamic braking.

[Kosmic]

Oooooh nice. Do they have any more left?

I'm afraid not, it was advertised as the last one. 

Look like there's more where it came from. The seller listed some more at 150$

https://www.ebay.com/itm/393592090990

Anybody know the lowest offer he's going to accept ?

[beanflying]

Couple of nice looking oddballs in Oz for a few $ if you are a Vintage TEA'r  eBay auction: #274960469814

Seriously not much locally worth following let alone buying at present 

[cyclin_al]

This popped up in my feed from one of my other Discords.  Just a nice lazy Illegal FPV afternoon out in the middle of nowhere, over a public road where the worst you have to worry aboot is accidentally going down in a cow plop causing a car crash and getting locked up for manslaughter. 

mnem
 

FTFY

Which you can also say aboot any one of the aircraft that has been your livelihood over the years. Or any of the gliders tggzzz flies. Or any kid with a fucking kite. Or even a spooked cow.

mnem
 

No you cannot say that.
That UAV was clearly being flown in breach of the regulations. I've never flown an aircraft low in front of an unsuspecting car driver.
I suspect tggzzz has not deliberatly flown in breach of the regulations either.
Cow's cannot be charged with a crime. (they can be euthanized  without trial if dangerous).
There is not even any TEA content so why post the link.

There are similar regulations flight standards here in the GWN.  I cringed when it flew out over the road.

There are rules for airplanes as well.  Pilots may follow the rules, or they may not to their own peril.
Minimum altitude for normal flight is 1000 ft agl, except for landing and taking off.  Therefore, aircraft would not be so close to that road, unless it was beside an airport.
There is an exception for training flights of minimum 500 ft agl.
However, my garage is not a training area, and training below minimums is not allowed; I suspect detection notices have been issued to certain aircraft owners (The owner gets the notice when it is not possible to identify the pilot).

[mnementh]

I didn't realize this was in the UK

With a name like Minchinhampton? Could it be anywhere else? When the Americans, Canadians, Aussies and Kiwis eschewed imagination and named everywhere after somewhere in Blighty, sometimes putting 'new' in front of it, they did have the good sense to leave names like Minchinhampton behind. 

Sorry. Sounded to me like a slightly less stagnant bog a few miles from the real swamps. 

mnem
In New Zealand. Or maybe Oz.

Not likely...... indigenous place names names are now the thing here were replacements for settlers towns and cities are being pushed down our throats. 

Still, they are welcome to keep some of the originals so we invaders can continue to have a good laugh:
Taumata whakatangi hangakoauau o tamatea turi pukakapiki maunga horo nuku pokai whenua kitanatahu
https://www.newzealand.com/nz/feature/the-longest-place-name-in-new-zealand/

* tries to say a few of them and winds up with his tongue tangled around his own throat*

 

mnem
};=)~~~~<

You'll have less trouble with Taumata Hill which is in common usage now.

mnem
 

[cyclin_al]

I didn't realize this was in the UK

With a name like Minchinhampton? Could it be anywhere else? When the Americans, Canadians, Aussies and Kiwis eschewed imagination and named everywhere after somewhere in Blighty, sometimes putting 'new' in front of it, they did have the good sense to leave names like Minchinhampton behind. 

Sorry. Sounded to me like a slightly less stagnant bog a few miles from the real swamps. 

mnem
In New Zealand. Or maybe Oz.

Not likely...... indigenous place names names are now the thing here were replacements for settlers towns and cities are being pushed down our throats. 

Still, they are welcome to keep some of the originals so we invaders can continue to have a good laugh:
Taumata whakatangi hangakoauau o tamatea turi pukakapiki maunga horo nuku pokai whenua kitanatahu
https://www.newzealand.com/nz/feature/the-longest-place-name-in-new-zealand/

* tries to say a few of them and winds up with his tongue tangled around his own throat*

 

mnem
};=)~~~~<

You'll have less trouble with Taumata Hill which is in common usage now.

For some reason, all I can think of is Tomatoes when I try to read that. 

Wait a minute!!!  SWMBO did ask me to go harvest the tomatoes ...   

EDIT:  Dwagon beat me to it... but I still need to go harvest the tomatoes...

[mnementh]

There are similar regulations flight standards here in the GWN.  I cringed when it flew out over the road.

There are rules for airplanes as well.  Pilots may follow the rules, or they may not to their own peril.
Minimum altitude for normal flight is 1000 ft agl, except for landing and taking off.  Therefore, aircraft would not be so close to that road, unless it was beside an airport.There is an exception for training flights of minimum 500 ft agl.

However, my garage is not a training area, and training below minimums is not allowed; I suspect detection notices have been issued to certain aircraft owners (The owner gets the notice when it is not possible to identify the pilot).

UAVs are regulated differently from manned aircraft, and it is those differences that make for much of the confusion, even among people who fly them.

In general, the regulating bodies are trying to keep UAVs below any reasonably expected flightpath of a manned aircraft. Current FAA regs state a 400 foot mandatory ceiling for recreational UAV flight, and if flying FPV, you are still supposed to have a line-of-sight spotter in direct communication with you.

As you might imagine, it can be very difficult to stay below such low ceilings while at the same time staying high enough for safety of people and property.

Most UAVs flown for recreational use will be one of two types; either waypoint-navigation types which follow a programmed flight path and fly mostly autonomously (usually used for Aerial Cinematography, aerial tourism, or as a personal action photography platform) and spend most of their time in a hover, or a directly piloted aircraft which is mostly being used in Fast Forward Flight modes and essentially respond like a plank except when sticks are centered to force a hover.

To add to the confusion, waypoint-navigation types of UAV can usually be taken over and flown manually at any time for any of the above purposes, though generally tend to be really bad at the FFF modes which are popular among acro FPV pilots.

Safe piloting of these two types of craft follows different tactics dependent on state; a hovering UAV requires that you always consider the flight path as if it were a brick and could fall straight down (allowing for it to be pushed around by the wind gods) at any time in case of power failure.

Flying an acro quadcopter like these in FFF mode one has to consider the likelihood of power failure causing it to fall, yes, but also to have sufficient forward momentum that it can carry the craft much further forward of its location at the time of failure.

mnem
*toddles off to ded*

[mansaxel]

Here are some pictures from playing with the insulation tester on Friday with one of my friends who works in the electric traction business. 

You sure have come a ways.  I did some checking of my brother-in-law's holiday cottage, which is the houses and some of the forest of a small farm out in the countryside. They've got buried cable between the barn and the cottage, and also to a small guest house. I recomissioned one of the buried lines because it was 3-phase proper buryable cable (old swedish name EKKJ 3x2.5+2.5, PE sheated 3-core with a fourth conductor for PEN wrapped around it. ) and not a barely OK 3G1.5 in a shallow cable pipe that previous owner had bodged in. Out came the "Wee" Megger and could confirm that the proper cable was OK and not leaky.

[mansaxel]

Yes - my mistake there - it was 135 MOhms in that one test with the far end open circuit, not GOhms.

That's more like sensible values, yes.    If you'd had GΩ in a bit of dirty, humid cordage, that would have been something.

My Wee Megger example yielded 250MΩ for buried cable, which is satisfactory, with margin: The Swedish (probably EU) rules establish a pass/fail insulation resistance of 1KΩ per volt of system voltage. As we're running 400VAC phase/phase voltage, I had to get above 400*1000 Ω which as noted I did, with a wide margin. If I'd been anywhere close, I'd think twice about why and perhaps would not have recommissioned the cable. Measurement voltage of course also needs to surpass the system voltage, and the Megger at 500V (verified) will satisfy that too. What it does not achieve, of course, is safety to IEC 61010-1... 

I forgot to mention that part of the reason for demonstrating all the wireless connectivity stuff was to show what I had in mind for getting instrumentation set up on some tramcars in railway museums to get some objective measurements on controller and motor performance especially on newer ones that have automatic acceleration and dynamic braking.

That is seriously cool.

[mansaxel]

Look like there's more where it came from. The seller listed some more at 150$

https://www.ebay.com/itm/393592090990

Anybody know the lowest offer he's going to accept ?

I paid $140 plus shipping. They did not respond to a $100 offer, not even by turning them down. Granted, the offer was made over a weekend, so if they're a commercial operation might not reply then anyway. And I got a Syndrome relapse and bought it anyway. It IS a good deal, even at list, because the condition as verified is essentially brand new.

Besides, who needs more than 3 ¹/₂ digits anyway?   

[med6753]

Look like there's more where it came from. The seller listed some more at 150$

https://www.ebay.com/itm/393592090990

Anybody know the lowest offer he's going to accept ?

I paid $140 plus shipping. They did not respond to a $100 offer, not even by turning them down. Granted, the offer was made over a weekend, so if they're a commercial operation might not reply then anyway. And I got a Syndrome relapse and bought it anyway. It IS a good deal, even at list, because the condition as verified is essentially brand new.

Besides, who needs more than 3 ¹/₂ digits anyway?   

You are almost convincing me to buy one. That price is damn good especially including the HV probes. And only $12 shipping for me. But I already have a HV probe and Fluke 87 is just about as tough although I don't think I should pound nails with it. 

[AVGresponding]

Look like there's more where it came from. The seller listed some more at 150$

https://www.ebay.com/itm/393592090990

Anybody know the lowest offer he's going to accept ?

I paid $140 plus shipping. They did not respond to a $100 offer, not even by turning them down. Granted, the offer was made over a weekend, so if they're a commercial operation might not reply then anyway. And I got a Syndrome relapse and bought it anyway. It IS a good deal, even at list, because the condition as verified is essentially brand new.

Besides, who needs more than 3 ¹/₂ digits anyway?   

You are almost convincing me to buy one. That price is damn good especially including the HV probes. And only $12 shipping for me. But I already have a HV probe and Fluke 87 is just about as tough although I don't think I should pound nails with it. 

As I already mentioned in Discord lest night, I blinked and bought one. Frankly, given the NIB condition and completeness of the kit (hard carry case, all the probulators one could wish for) it's a great price even with the horrific shipping and import duties I've had to pay.

[FransW]

Not to sure why it is thought that a scope is barely as good as 2.5 digit DMM, a Fluke 27 is +/-.1% +1 digit, thats a whole 2.99% better than a scope surely?

Typical scope 8 bits resolution = 0-255 = 2 1/2 digits.

Fluke 25/27 3 1/2 digits  = 0-3200 = 11.64 bits resolution

12 1/2 times more resolution than a scope.

The 3% surely refers to analogue scopes, not digital ones. At least all the analogue scope specifications I have come across all mention 3% for voltage accuracy. Also most cheap DMM's in the £20 to £30 range all boast specs far greater than 3%, typically being 0.5%+2 (DC) and 0.8% +5(AC)

All the following are DSOs -

Rigol MSO5000: 3%
HP 54621A/21D, 54622A/22D: 2%
HP 54100A/D: 3%
HP 54201A, HP54201D: 2%
Tek TDS 200 series: 3%
Tek TDS 310, TDS 320 & TDS 350: 2%

All figures taken straight from the manufacturers manuals.

Way beyond my mental capacity.
Comparison with 2 incompatible TE's.

[Robert763]

Look like there's more where it came from. The seller listed some more at 150$

https://www.ebay.com/itm/393592090990

Anybody know the lowest offer he's going to accept ?

I paid $140 plus shipping. They did not respond to a $100 offer, not even by turning them down. Granted, the offer was made over a weekend, so if they're a commercial operation might not reply then anyway. And I got a Syndrome relapse and bought it anyway. It IS a good deal, even at list, because the condition as verified is essentially brand new.

Besides, who needs more than 3 ¹/₂ digits anyway?   

You are almost convincing me to buy one. That price is damn good especially including the HV probes. And only $12 shipping for me. But I already have a HV probe and Fluke 87 is just about as tough although I don't think I should pound nails with it. 

Well the 27 is waterroof (IP67) and the 87 is only IP30. Of course a sitution where you need IP67 AND  HV probe is 

It is a good deal, even with shipping to the UK. I'm tempted but have two 25s, a 80k40 and a 80F15. Also a couple of HP HV probes.
The 80F15 is fairly rare. It's a high accuracy, 0.05%, 15kV 1000:1 probe.