Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

cough. lung bug. fever rising. called in sick at the job already.eff.

Take care of yerself Valkyrie. Lots of decongestant and antihistamines. I also like Lemon Ricolas for symptomatic relief. 

mnem
and of course, bedrest. Why are you up reading this...?

just woke up, 39 C fever and dry cough . I guess it's everybody's fav bug even tho the test was negative yesterday. probably picked it up during physiotherapy..
I"m letting in fresh air before I continue sleeping ...

Could be, SiL has it and also managed to give it to her friend as well..

[AVGresponding]

Update on my HP34401A with dodgy display.
Selller came right back and said OK to a refund. 

And it's relisted for £425...

[mansaxel]

HP 412A

(quick edit there to remove the wrong meter  )

Well that didn't take long. You win a picture of the glassware...

And here I was being methodical. "Not a 400H, not a 410B". I thought of the 412 but pic googling did not convince me.

[BU508A]

HP 412A

(quick edit there to remove the wrong meter  )

Well that didn't take long. You win a picture of the glassware...

And here I was being methodical. "Not a 400H, not a 410B". I thought of the 412 but pic googling did not convince me.

Picture from this auction:

[McBryce]

HP 412A

(quick edit there to remove the wrong meter  )

Well that didn't take long. You win a picture of the glassware...

And here I was being methodical. "Not a 400H, not a 410B". I thought of the 412 but pic googling did not convince me.

Picture from this auction:

Mine is in much better condition (and cost a lot less). I'll post some outer pics as soon as I've put it back together. Would anyone like to point me to the source for PH-163 power connectors so that I can power it up at some stage?

McBryce.

[med6753]

The Edison technical debt looms large over the poor continent, is all I can say on the matter. But it is my understanding that the center tap on the transformer for a 240CT system needs to be grounded to give at least a semblance of protection. Therefore, in a 4-conductor cable, two wires indeed should be commoned. It would have been much, much better to carry even the puny 208V three-phase plus PEN through that cable. The North American HV net usually is 3-phase pretty far out in the branches so "all" that's technically required is a better transformer, but that would require sparkies to forego habit. And "some" rewiring.

No, it would not be a "simple" affair to go over to a 3 phase system. Yes, 3 phase does get distributed out to many locations for businesses and for load balancing. For example.....while my road has no businesses close by 3 phase is available. But it's eventually distributed to side streets as shown. One HV line. Single phase. The cost to retrofit all those areas would be prohibitive.

[bd139]

Update on my HP34401A with dodgy display.
Selller came right back and said OK to a refund. 

And it's relisted for £425...

It will sell.

I reckon if I threw some new probes in and got a handle I could get £500 for mine

[BU508A]

HP 412A

(quick edit there to remove the wrong meter  )

Well that didn't take long. You win a picture of the glassware...

And here I was being methodical. "Not a 400H, not a 410B". I thought of the 412 but pic googling did not convince me.

Picture from this auction:

Mine is in much better condition (and cost a lot less). I'll post some outer pics as soon as I've put it back together. Would anyone like to point me to the source for PH-163 power connectors so that I can power it up at some stage?

McBryce.

You mean something like this?
https://www.ebay.com/p/19031315127


Edit:
Plan B: I could lend you one of my PH-163 cables. If you want, write me a PM.

[McBryce]

HP 412A

(quick edit there to remove the wrong meter  )

Well that didn't take long. You win a picture of the glassware...

And here I was being methodical. "Not a 400H, not a 410B". I thought of the 412 but pic googling did not convince me.

Picture from this auction:

Mine is in much better condition (and cost a lot less). I'll post some outer pics as soon as I've put it back together. Would anyone like to point me to the source for PH-163 power connectors so that I can power it up at some stage?

McBryce.

You mean something like this?
https://www.ebay.com/p/19031315127


Edit:
Plan B: I could lend you one of my PH-163 cables. If you want, write me a PM.

Considering going for the scary Plan B: 3D Printed! https://www.thingiverse.com/thing:4862134

This is the condition of the one I just bought. Handle and paintwork is original, dial is snow white.

McBryce.

[Brumby]

The North American HV net usually is 3-phase pretty far out in the branches so "all" that's technically required is a better transformer ....

Yeah, but it's that "last mile" which has just two wires .... and there are an enormous number of those "last miles".  You need at least one more for 3 phase - but the topology during any sort of changeover is something else.

In other words, it's not going to happen.

[capt bullshot]

Stupid question for the gang.
If a water electro-valve spec is 24VAC, can I use VDC to control it?

No

If yes at what voltage DC current?

Well, it depends. If the magnetic circuit gets closed by the valve operating, there will be a significant difference in current just after applying the AC voltage and when the valve is fully operated.
The valve will require the high current to start its operation, then way lower current to hold the state. Works "automatically" with AC, for DC you'd have to emulate this behaviour, by e.g. discharging a higher voltage from a capacitor, then applying the holding voltage as low as possible.
Running the valve at full operating voltage can cause overheating.

I bet it's achievable, but you'd have to do some experimenting.

[capt bullshot]

My AC voltage source is good for up to 5A/1100V, but with a maximum voltage burden of 10VA, so not really usable as a power supply.[/color][/size][/b]

What type (make/model) is this?
10VA would be a spec for kind of a calibrator or something ...

It's a 0.05% spec AC/DC V/I source, with selectable 50/60/400Hz. It's an RFL Boonton/Clarke Hess 828.

Nice one, clearly doubles as a calibrator as long as the spec is good enough for your DUTs.

[bsdphk]

Speaking if exposed metal giving people the creepies...

Running HV, be it 3, 5, 11 or 13KV on top of residental poles is traditionally defended on a cost-basis, but once you factor in all the accidents, fires and surge-protectors I seriously doubt anything has been saved.

But yeah, first mover disadvantage is getting stuck with the prototype...

Here in Denmark we get a buried 3P+N from the grid, where the N is grounded at the 10kV/400V transformers star-secondary.

We establish a PE locally, usually by driving a 2-3 meter long 10mm copper-rod into the ground. All circuits must be protected by residual current relays, so in theory all the PE will ever do is carry enough current to trip the residual current relays.

[Robert763]

Stupid question for the gang.
If a water electro-valve spec is 24VAC, can I use VDC to control it?

No

If yes at what voltage DC current?

Well, it depends. If the magnetic circuit gets closed by the valve operating, there will be a significant difference in current just after applying the AC voltage and when the valve is fully operated.
The valve will require the high current to start its operation, then way lower current to hold the state. Works "automatically" with AC, for DC you'd have to emulate this behaviour, by e.g. discharging a higher voltage from a capacitor, then applying the holding voltage as low as possible.
Running the valve at full operating voltage can cause overheating.

I bet it's achievable, but you'd have to do some experimenting.

You just have to provide the correct current through the coil. For  AC relay this can set by the coil inductance and/or resistance. For a DC rel it is set by the resistance. If you measure the RMS AC current and DC resistance of the coil and use IxR  that will give you a starting point for DC voltage. A simplification but works OK.

[TERRA Operative]

What the... hell model of car have you got, then? I thought Volvo was supposed to be a premium brand, and they can't even fit tweeters to all doors and channels  Mine even has mid range and tweeters, woofer at the bottom, mid range in the middle and tweeters right at the top by the door latch. Only 4 pop rivets hold your woofer, did you get any distortion / vibration of the speaker chassis on deep bass as a result of tahat or are your speakers slightly smaller than most, mine had 6 rivets to secure it to the door skin. I should think you certainly notice the extra top end now?

This was, as noted, the bottom rung of the quality ladder. There were several equipment levels available above this; my older cars on the same platform dodid indeed have tweeters, also as noted. Buying a used car you can't be too picky with things like this; I was happy to get the 4WD, large Diesel, semi-leather upholstery version, with hitch and OEM roof rack bars, for a very good price, with a known service record.

The top end is indeed noticeable now!

I put Alpine 3-way splits in my car, made a huge difference to the audio quality.
I spend like 2.5 hours a day in the car commuting in and out of Tokyo, so I wanted some good audio to help me endure the idiots on the road. 

[mnementh]

That's pretty horrific... shows how much standards vary between countries. You better sleeve your cpc here or you're not passing inspection, and not have any conductor showing at the phase terminations.

And those exposed bus bars?   

Not sure which big ass cables you're referring to, but if it's the cpc, if you have a cable with more conductors than is functionally necessary, you connect the unused conductors to earth here. Floating (potential) conductors are a no-no.

What do you mean by "sleeve your cpc"?

Granted, the sparky who wired this panel could have been a little neater but there's nothing that I see that would make an inspector lose his lunch. I've seen horrific on Utube with some of the absolute shit shows that some UK sparky's have to unfuck.

Those exposed bus bars are neutral (ground). To make it easy to tie in the white (neutral) and ground. What's the issue with that? None that I see.

1/ The large bare CPC "Earth" conductor appears to be tinned copper not aluminum (look at the end near the terminal)
2/ The big issue is the exposed phase teminals. Especially the input to the main (200A) isolator. Even inside a metal box, in the UK these would have to be enclosed in insulation except for cable entry and screw access. a finger should not be able to touch them accidentally.  see pic of UK one.
3/ The two large wires connected together are the CPC (earth) and Netural. A connection which according to some does not exist.

Yeeah, no. In most cases, you don't have a choice over here about what the feed-in from the utility company is going to be up to the demarc; it's almost always going to be all aluminum. What you're seeing on the end of the "CPC" wire is properly applied NOALOX, a compound used to prevent the usual hazards of "aluminum oxide poisoning" (aluminum rust contamination) of the connections.

Where the demarc is relative to a service panel will vary from locality to locality, and will be dependent upon type of service/zoning. The demarc may be at the meter, it may be a standalone breaker in a box between the meter and your service panel, it may be the main breaker in your service panel.

We do not have multi-phase power here... we have center-tapped 240V (allegedly ) single-phase split across 2 busses in the box. To make it convenient to get 240V for med-large appliances like dryers, ranges and cooktops, those busses are configured such that every other slot alternates which bus is tapped, which allows one to install a 2-pole breaker with internal common trip that taps both busses at the same time.

All GND and NEUTRAL returns ultimately connect to the same main GND/Neutral busses, which are mechanically and electrically attached to the main CB panel itself, such that once the cover is closed, everything is contained inside a "Grounded" "Fire-Resistant" enclosure and any fault is contained. We do not concern ourselves that a sparky might stick a finger in a stoopit place when the cover is removed. S/he is expected to know better. As the box itself is at GND/NEUTRAL potential, there is no need to sleeve the grounds from ROMEX, etc.

Adding GFCI complicates the picture, as a pigtail to NEUTRAL/GND is required for the breaker. But it mostly just adds another layer of spaghetti; if run tidily with correct routing, troubleshooting is pretty straightforward.

You will usually only see sleeved/insulated GND wires in commercial/industrial installations where everything is pulled through conduit. I personally prefer to see the conduit run as only a redundant GND and all connections inside with a separate "explicit" copper GND conductor, but to my knowledge, it is still "to code" to use the conduit itself as the primary GND in most applications. Even BX-shielded cable complies, IIRC. 

mnem
*tzzzt*

[bd139]

What the... hell model of car have you got, then? I thought Volvo was supposed to be a premium brand, and they can't even fit tweeters to all doors and channels  Mine even has mid range and tweeters, woofer at the bottom, mid range in the middle and tweeters right at the top by the door latch. Only 4 pop rivets hold your woofer, did you get any distortion / vibration of the speaker chassis on deep bass as a result of tahat or are your speakers slightly smaller than most, mine had 6 rivets to secure it to the door skin. I should think you certainly notice the extra top end now?

This was, as noted, the bottom rung of the quality ladder. There were several equipment levels available above this; my older cars on the same platform dodid indeed have tweeters, also as noted. Buying a used car you can't be too picky with things like this; I was happy to get the 4WD, large Diesel, semi-leather upholstery version, with hitch and OEM roof rack bars, for a very good price, with a known service record.

The top end is indeed noticeable now!

I put Alpine 3-way splits in my car, made a huge difference to the audio quality.
I spend like 2.5 hours a day in the car commuting in and out of Tokyo, so I wanted some good audio to help me endure the idiots on the road. 

AirPods pro with transparency mode on. Also works for the idiots when you get out of the car as you can turn on noise cancellation mode 

[vk6zgo]

Today, I decided to do some "ham Technicianing"!

I scratched my bum, donned my bib & braces overalls, picked a few fleas out of my beard, & headed off to the "shack".
Once there, I let off a stentorian fart, (my dog sniffed the air, & quickly vacated the scene), settled down on the long suffering "operator's chair", moaned loudly, & set to work.

The"patient" is an elderly Yaesu FT707 transceiver.

This rather nice looking device has a strange fault, with both the "carrier" control which adjusts output power in the CW (morse) mode, & a similar one in the SSB mode associated with the "mic gain" control.
In both cases, the control seems to go from "zero" to "flat out", if the control is moved, which makes the controls, & hence, the radio useless.

My main fear was that both pots were faulty, & initial tests, looking back at them, seemed to bear this out, with the resistance between the moving contact & the chassis, measured with my Fluke 77, jumping around as the pots were turned.
This was worrying, because they are pretty much "unobtainium".

After digging deeper into the manual I downloaded, I found several pages with better representation of the circuitry involved, so I resolved to try again, today.
This more thorough check still showed the resistance reading "varying all over the place", but, knowing that the "77" was a bit ancient (& digital) , I decided to call upon an even older device-------my HP 410C!

On Ohms, the 410C showed the resistance varying smoothly on both pots, ----What the hell?
Trying the Fluke again, showed the previous situation.

Slowly, my ancient solder smoke addled brain found the answer ---"Dawk!" the Fluke was auto ranging, hence the weird readings!!
Pushing the range hold button changes the readings whilst turning the pots  to something similar to that of the 410C!

Definitely, a "Trap for Old Players"!

If the pots are ok, what's your next suspect?

All the above stuff is situated on, or connected to, the "AF board", then the selected mode of signal heads off to the "IF board".
I have unplugged the connector involved to stop the Tx trying to produce excessive power & shutting down, so will be able to "key" the thing in each mode & see what the output of the AF board looks like.
The two sections on that board which are common to all modes are the 8V supply & the discrete diode balanced modulator.
(They unbalance it for CW & AM).

I was pretty "chuffed" to find out the pots were OK (I say "pots" but they are really two sections of a concentric dual pot.)

I seldom necropost, & even less often quote myself, but that seems to be the easiest way to do this:-

Update on the "ham technicianing".
Sadly, the fault is seemingly not in the AF board, as looking at the output from that board shows IF amplitude varying quite smoothly with the "carrier" control in the CW & AM positions, & the "mic gain control" varies the modulation depth of the SSB signal normally.
 
As my 7613 is still dead, I looked at the board output with my little 10MHz single channel "minion", with its tiny screen, so I'm not sure what the actual levels are.
I will probably fire up the 410C & have a look at the levels, later-------not that I know what they should be, the downloaded PDF shows dark grey rectangles where the voltages were on the original schematic!!

[mansaxel]

This is the condition of the one I just bought. Handle and paintwork is original, dial is snow white.

McBryce.

That is pretty close to mint. Providing it works, you're lucky. Schurter makes Mickey Mouse jacks (IEC 60320 C6) that almost fit in place of the PH-163 atrocities. 

[McBryce]

This is the condition of the one I just bought. Handle and paintwork is original, dial is snow white.

McBryce.

That is pretty close to mint. Providing it works, you're lucky. Schurter makes Mickey Mouse jacks (IEC 60320 C6) that almost fit in place of the PH-163 atrocities.

The seller says that the basic functionality seems fine, but he didn't check how accurate. I've been looking for a VTVM for a long time that's (A) Easily repairable (Schematics available and no unobtainium parts) and (B) Doesn't take up my entire workspace. The condition (and price) were added bonuses.

McBryce.

[mnementh]

Later today there will be a mad man working in his garage brushing up on his complete lack of metalworking skills.

Wish me luck. 

LMAO. My results may not be all that different. 

Still got my 'feng tuned into appropriate EMS frequencies... 

mnem

[med6753]

It's obvious that there is no way the bent Type 547 can be made square again unless it's completely torn down and rebuilt. Like that's going to happen. So what's the alternative other than scrapping it? Make the covers fit and give the old beast a 2nd chance. So armed with nothing more than a hacksaw and a good eye I went to work. The results are much better than I expected.

To wit. Left side upper. Compare that to yesterday. Almost perfect.

   

Right side upper. Vast improvement.



Right side lower. I had to notch the bottom corner. And you can see going up how bent the frame is.



Right side rear. You can see the hacksaw work. Also notched at the bottom corner.



Left side rear. More hacksaw work. OK.....so it isn't perfectly straight. Piss up a rope in advance. 



The covers themselves are scratched and beat to hell so for the first time in almost a year Papa Smurf's Shade Tree Painting Service will be put into full operation. But not today. It's cloudy, damp, and threatening to rain. Not good painting weather.
 
I obtained a bezel for the CRT but it's the wrong type. It's meant for older Type 535/545. The correct bezel for this scope just isn't available. So as a result the scale illumination is extremely dim. No biggie. I have a solution for the misfit of the plug-in but that won't arrive until tomorrow. Stay tuned. 

[mnementh]

mnem
How many digits did you lose in the process...?

[AVGresponding]

Update on my HP34401A with dodgy display.
Selller came right back and said OK to a refund. 

And it's relisted for £425...

It will sell.

I reckon if I threw some new probes in and got a handle I could get £500 for mine

Utter madness. It can't be even a year since I bought my minty Agilent round button 34401A, and it was around £300 iirc.

[bd139]

Update on my HP34401A with dodgy display.
Selller came right back and said OK to a refund. 

And it's relisted for £425...

It will sell.

I reckon if I threw some new probes in and got a handle I could get £500 for mine

Utter madness. It can't be even a year since I bought my minty Agilent round button 34401A, and it was around £300 iirc.

I could have got one of them the other day for about the same price if I wasn't napping like I was 80 when the auction ended