Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 3998024 times)

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Offline mansaxel

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76100 on: November 25, 2020, 06:50:17 pm »

Yes, thats the one. A friend collected it and packaged and sent it to me. Voltage selection is checked every time I acquirer sth. Switched to 230V and powered it up. Seems to work although not tested yet. Pots and knobs had to be moved to get out the scratchy behaviour. It is very clean inside, the cabinet has to be washed and cleaned to remove adhesive stains.

It looks very much like mine, so am guessing 70s build, based on it being PCB and not hard wired.

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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76101 on: November 25, 2020, 07:31:02 pm »
Awww jeez... I forgot to finish the jug of iced-tea last night. It's been steeping for like 18 hours...   :palm:

mnem
*has a sip*
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Offline AVGresponding

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76102 on: November 25, 2020, 07:37:01 pm »


I don't know what the electrical regs are in Sweden, but if they permit, it may be worth investigating changing to an RCBO setup, where your main isolation switch is just that, and each circuit is protected by an individual MCB and RCD combined into one device (RCBO).

Assuming your house wiring isn't in MICC (   ::)  ) it should greatly reduce the chance of nuisance and accidental tripping...


I've tried both, and come to the conclusion that there exists a real risk of nuisance tripping when you have too small protected areas (as in single circuits) earth-fault-wise, especially if you're using grounded signal equipment like scopes and VTVMs. Or reasonably large sound systems.  Therefore the entire panel is protected by a three-phase 40A RCCB. Main fuses are 20A so rating is no problem.

No MICC in sight; I don't think it's even permitted in Sweden. All wiring from this panel (which is a new sub-panel for the garage and workshop) is what's known as EKK (or EU type A05VV-U) in Sweden, or NYM-J in Germany. Approximate UK equivalent would be twin core and earth, but cross section is circular and the PE conductor carries insulation all along, and also is same area as the phase and neutral. It's sortakinda like US Romex, but all conductors are single-strand.

At least when a single circuit goes down it doesn't take any others with it. With an overall RCCB, everything goes off, and the trip current must be fairly high also, 100mA maybe?

It tends to be earth leakage current with modern appliances that causes nuisance trips when there's no actual fault, though we've also found LED lighting to be a problem regarding inrush current; some MCBs/RCBOs have had to be uprated from 6A to 10A, though remaining type B (I have no say in this, my own preference would be to keep the current rating and go for a type C or D).
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Offline dl6lr

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76103 on: November 25, 2020, 08:21:29 pm »
No that is a standard case colour for later -hp- TE, have a look at the last three pictures from this link on the -hp- 200 series, the last picture has a very late production 200CD dating from between the late 1970's to sometime in 1980's.
https://www.kennethkuhn.com/hpmuseum/dating/vintage_dating.htm

OK, seems to be very similar.

Now for the annoying part:
The probe jaw has two core halves, each with windings, that are somehow potted into MU. The potting (I assume some kind of epoxy) has becoming soft and tacky on the surface, so the two halves of the jaw do not separate easily. Furthermore, they seem to not close enough, so the earth field has a stronger influence than specified (Spec says about 0.1mA, mine is roughly 10times that much).
This reminds me to Siemens chokes from the 80s, where the green potting becomes liquid and drops out of the cans, leaving other parts in a barely removable tacky green sea.
 

Online Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76104 on: November 25, 2020, 10:32:45 pm »
You probably should have obscured his number plate to avoid hassle. Data protection act and all that.

McBryce.
I did think about it, but then figured that if they went to the trouble of having "Teabeggers Skate Crew" written on the rear window, that they were seeking attention anyway. Apart from that, all the other photos on the net of random cars do not have the plates obscured. Those that do are generally belonging to the photographer and does not want their personal car / plate associated with them.
Who let Murphy in?

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Offline factory

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76105 on: November 25, 2020, 10:36:02 pm »
Another incorrect model number in an ePay listing, cheap at the moment for anyone nearby (collection only from Essex area), seller has other TE that maybe of interest.
eBay auction: #254789236738

David

Bah, and I'd rather like those resistance decades. Why is it so hard to post the things?   :rant:

Well, the one I've just flogged was a little larger than I expected...



McBryce rubbed salt in the wound with "Surely the 4mm Binding Posts should have given you an idea. That's how I judge the size of unknown equipment."

Well, all of this seller's stuff is collection only.

Obviously RM is impractical, but afaik the likes of Hermes are pretty cheap, and will collect from your door.


I thought there might have been someone nearer looking for something to work on.
Quite a few sellers don't want to pack stuff at the moment, not sure why.

David
 
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Offline factory

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76106 on: November 25, 2020, 11:09:27 pm »
Well some good news with the HP 5248M, the unobtainium IC on board A26 seems to be OK, the problem is with the 5MHz to 10MHz multiplier stage, now I've RTFM again  :-X & found the 10MHz output is a tenth of the level it should be (at least 5Vpp), C9 peaks OK but C14 & C18 have very little effect (supposed to be adjusted for maximum output), currently looking for some 2N708 (easy enough to find) and some 2N3640.


The 10MHz to 1MHz divider stage with the 1820-0082 IC was tested by removing Q9 and using the 3311A inputted it's place to check the output of that stage is a tenth of the input frequency (approx 100kHz with 1MHz input).  :-+



With that temporary setup I could at least see how much of the rest of the counter is working, using the 5MHz output from the back I can just about get it display a reading, I suspect more problems to be found as it's very difficult to get it to lock on to a signal, I swear this counter doesn't want to be repaired.  |O


David

P.S. Is it time to adjust the scope's clock, the picture was taken sometime before 8pm. :-DD
« Last Edit: November 25, 2020, 11:26:21 pm by factory »
 
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Offline andy3055

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76107 on: November 26, 2020, 02:55:32 am »
Med,

I pulled out those capacitor blocks and cleaned the switch contacts. Those are OK now. However, on the 10x block it seems like the pins are not making good contact. It may be the tiny sockets holding the pins are tarnished inside or the thing is lose on the back of the board where it is soldered. If I exert a little pressure on one corner, the wave form is OK. When I let go, it goes all over the screen.

I remember someone mentioning how he cleaned those sockets and I think he did say that he had to flatten the pins a bit for better contact. Was that you by any chance? I wish I save the link to that post.

Any thoughts?
Thanks.
 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76108 on: November 26, 2020, 03:36:41 am »
Med,

I pulled out those capacitor blocks and cleaned the switch contacts. Those are OK now. However, on the 10x block it seems like the pins are not making good contact. It may be the tiny sockets holding the pins are tarnished inside or the thing is lose on the back of the board where it is soldered. If I exert a little pressure on one corner, the wave form is OK. When I let go, it goes all over the screen.

I remember someone mentioning how he cleaned those sockets and I think he did say that he had to flatten the pins a bit for better contact. Was that you by any chance? I wish I save the link to that post.

Any thoughts?
Thanks.

It might have been me. I have tweaked a few of those fingers to make better contact but you have to be real careful. It's all too easy to permanently damage them.

Would it be the 0.2V or 20mV range by any chance? Those are the contacts that give the most trouble. 
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Offline andy3055

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76109 on: November 26, 2020, 04:34:23 am »
Sorry to bug you. Those finger contacts are OK. The problem is with the pins on the 10x capacitor block. It does not seem to have a good contact when installed back. the pins are nice and straight. If I push one corner, it makes contact as I see the square wave. If I let go, it goes haywire. I thought it was the fingers but the pins are the culprit.
I can't rem
 

Offline mansaxel

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76110 on: November 26, 2020, 05:03:49 am »

I've tried both, and come to the conclusion that there exists a real risk of nuisance tripping when you have too small protected areas (as in single circuits) earth-fault-wise, especially if you're using grounded signal equipment like scopes and VTVMs. Or reasonably large sound systems.  Therefore the entire panel is protected by a three-phase 40A RCCB. Main fuses are 20A so rating is no problem.
At least when a single circuit goes down it doesn't take any others with it. With an overall RCCB, everything goes off, and the trip current must be fairly high also, 100mA maybe?

Yes, it will trip everything, but since I am supposed to have an UPS on the annoying-to-trip parts, that's not an issue. Or should not be, if the UPS would do its job.  |O  :palm:

And the trip current is 30mA, which is the required value up to an upstream fuse rating of 63A -- above that you're not required to fit one; it should really come further downstream, implying another tier of sub-panels. 

It tends to be earth leakage current with modern appliances that causes nuisance trips when there's no actual fault, though we've also found LED lighting to be a problem regarding inrush current; some MCBs/RCBOs have had to be uprated from 6A to 10A, though remaining type B (I have no say in this, my own preference would be to keep the current rating and go for a type C or D).

These breakers are a mix of 10 and 16A, C type. The EV charging outlet (strictly a preparation for something that has not happened yet) is fused 16A  three-phase. Then there's a 16A single phase  MK "Commando" style outlet (But, IIRC, ABB brand) , thought for a inverter type stick welder (also a prep plan), a 10A three-phase breaker for the workshop machinery that needs it, like lathe, air compressor, and drill press.  These machines share a three-phase bus, but have individually tuned motor-protective relays. This bus also is fed through a contactor so that I have a central on/off switch and a convenient method for emergency stop.
Then, another pair of 16A Commando outlets, under the raised floor, to feed the computer rack with A / B mains buses, one being through UPS, one direct.  Finally, 10A circuits for work benches and general use.

The electronic workshop bench has a separate circuit, and is also fed through the contactor arrangement, but on a separate contactor that can be overrridden into manual on (still protected by emergency stop) if I don't feel like running the air compressor.

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76111 on: November 26, 2020, 06:34:25 am »
Sorry to bug you. Those finger contacts are OK. The problem is with the pins on the 10x capacitor block. It does not seem to have a good contact when installed back. the pins are nice and straight. If I push one corner, it makes contact as I see the square wave. If I let go, it goes haywire. I thought it was the fingers but the pins are the culprit.
I can't rem

Pull the attenuator block and try burnishing the pin with emory paper. Place a small amount of dexoit on the contact hole on the attenuator board. Reinstall and see if that helped. I have run across bad attenuator blocks. They sometimes are damaged by some Gorilla in the past applying too much voltage.

If it still doesn't work the block may be NG. I probably have one or two in my parts stash. I'll send it to you for the cost of shipping. If I don't have one Tek spare parts places like QService should have them.

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Offline andy3055

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76112 on: November 26, 2020, 07:17:38 am »
Thanks, Med. I will PM you.
Ananda
 

Online McBryce

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76113 on: November 26, 2020, 08:50:47 am »
Another incorrect model number in an ePay listing, cheap at the moment for anyone nearby (collection only from Essex area), seller has other TE that maybe of interest.
eBay auction: #254789236738

David

Bah, and I'd rather like those resistance decades. Why is it so hard to post the things?   :rant:

Well, the one I've just flogged was a little larger than I expected...



McBryce rubbed salt in the wound with "Surely the 4mm Binding Posts should have given you an idea. That's how I judge the size of unknown equipment."

You're welcome :)

Has anyone taken a look at what's inside these things? https://www.ebay.de/itm/0-9999-9-Ohm-Variable-Decade-Resistor-Resistance-Box-Physical-Teaching-TooY-tq/353276507282

If the switches were good, I'd buy one and swap out the resistors.

McBryce.
« Last Edit: November 26, 2020, 08:53:43 am by McBryce »
 

Online Zucca

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76114 on: November 26, 2020, 11:02:43 am »
Right now this is the place I come when I am bored at work.
Can't know what you don't love. St. Augustine
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Offline factory

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76115 on: November 26, 2020, 11:40:46 am »
Did someone want a -hp- 410B? There is one not too expensive on the ePay site in Europe (needs the perished probe cables replacing), seller will probably take a little bit off with an offer.
eBay auction: #174534573627


David
« Last Edit: November 26, 2020, 11:53:08 am by factory »
 
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Offline vk6zgo

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76116 on: November 26, 2020, 11:57:34 am »
Did someone want a -hp- 410B? There is one not too expensive on the ePay site in Europe (needs the perished probe cables replacing), seller will probably take a little bit off with an offer.
eBay auction: #174534573627


David

Nah! I picked up a 410C a couple of years back, at a Hamfest for quite a lot less.
I've always liked the "C" better, anyway!
« Last Edit: November 26, 2020, 12:01:13 pm by vk6zgo »
 

Offline tonyalbus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76117 on: November 26, 2020, 12:01:35 pm »
 :palm: :-DD
Electronics enthusiast, TEA and Radio Amateur (PE1ONS)
Marconi  - TTi - Thandar - Thurmbly - HP - Fluke - Philips - Siglent - Owon - TEK - Anritsu - Keitley - AVO - BG7TBL
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Offline mansaxel

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76118 on: November 26, 2020, 12:03:18 pm »
Did someone want a -hp- 410B? There is one not too expensive on the ePay site in Europe (needs the perished probe cables replacing), seller will probably take a little bit off with an offer.
eBay auction: #174534573627


David

That's me! Yes, I'll probably throw a bid that way.

Offline AVGresponding

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76119 on: November 26, 2020, 12:04:50 pm »
Has anyone taken a look at what's inside these things? https://www.ebay.de/itm/0-9999-9-Ohm-Variable-Decade-Resistor-Resistance-Box-Physical-Teaching-TooY-tq/353276507282

If the switches were good, I'd buy one and swap out the resistors.

McBryce.

I can't believe the switches will be any good at that price. I am tempted to get one to investigate though.

I suspect they will be plain brass contacts with some highly inappropriate lubrication (if any) that causes extremely inconsistent results.

Maybe brass plated aluminium lubricated with lard.
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Offline AVGresponding

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76120 on: November 26, 2020, 12:09:15 pm »
@tonyalbus

nuqDaq yuch Dapol?
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Offline Ice-Tea

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76121 on: November 26, 2020, 12:25:52 pm »
Has anyone taken a look at what's inside these things? https://www.ebay.de/itm/0-9999-9-Ohm-Variable-Decade-Resistor-Resistance-Box-Physical-Teaching-TooY-tq/353276507282

If the switches were good, I'd buy one and swap out the resistors.

McBryce.

I can't believe the switches will be any good at that price. I am tempted to get one to investigate though.

I suspect they will be plain brass contacts with some highly inappropriate lubrication (if any) that causes extremely inconsistent results.

Maybe brass plated aluminium lubricated with lard.


You know, there *are* people around here that offer quality  decade boxes (from a slightly older vintage) around here, right? :popcorn:

Offline Robert763

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76122 on: November 26, 2020, 12:30:25 pm »
Anyone near Liverpool want a bunch of PSUs, AF oscillators and meters?
www.ebay.co.uk/itm/Vintage-laboratory-Testers/284094585612
 
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Offline factory

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76123 on: November 26, 2020, 12:30:50 pm »
Has anyone taken a look at what's inside these things? https://www.ebay.de/itm/0-9999-9-Ohm-Variable-Decade-Resistor-Resistance-Box-Physical-Teaching-TooY-tq/353276507282

If the switches were good, I'd buy one and swap out the resistors.

McBryce.

I can't believe the switches will be any good at that price. I am tempted to get one to investigate though.

I suspect they will be plain brass contacts with some highly inappropriate lubrication (if any) that causes extremely inconsistent results.

Maybe brass plated aluminium lubricated with lard.


Maybe when your done with investigating one, you could forward it to photonicinduction so we can find out the voltage ratings.  >:D

David
 

Offline factory

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #76124 on: November 26, 2020, 12:36:52 pm »
Anyone near Liverpool want a bunch of PSUs, AF oscillators and meters?
www.ebay.co.uk/itm/Vintage-laboratory-Testers/284094585612

Someone with more space & time to deal with that pile maybe, also don't want to fill the storage I paid for (can't see anything I would want to keep), those Farnell LFM4 oscillators make reasonable money on their own.

David
 


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