Test Equipment Anonymous (TEA) group therapy thread

[tggzzz]

Opening revealed what I was expecting, quite a mess around a GE Ni-Cd? leaktube. 

That's quite artistic, a bit like the late 60s/early 70s oil/water coloured lamps seen in cinemas and discos

[m k]

The battery?

[Vince]

Next on the bench : the last pieces from my big haul 6 months ago.
A couple HP 416B.

I rescued them because I just love the design of this era of HP products, and these two were in excellent shape, and I could not have forgiven myself for letting two beautiful pieces of HP history end in the junkyard.

However... I also jnew that I had no business owning these things, since they are two big, two of them to boot, but mostly... they look like RF related things, SWR meters or something, and it's just not my world.

So before I decide / figure out how I can best deal with these puppies.... let's at least play with them, crack them open to see how it's like inside, and try to fix them if they so require...

First problem : can't find a service manual for these things...

I guess I can just feed the input with a sine wave, but what frequency does this TE look for ?
More importantly what amplitude.. so that I don't blow them up ? That would be annoying.

No, the two aren't identical... spot the difference and win a virtual cookie.

[Vince]

EDIT : looking at the meter scale, it says  "reflection coefficient " up to 100%... so that means that amplitude-wise, I can juste feed both the input and feedback BNC wxith the same signal from my sig gen, and it should be safe and display 100% / full scale deviation ?  Sig gen has a 60dB attenuator, so I can easily start at 1mV peak, if that's not too much ?

EDIT #2 : scale says : " Use square law RF detector " .  Huuuu.... so that means I need a special probe to use this thing ? I can't just give it a sine wave ?

So it's like those RF Wattmeters... they are useless, door stops if you don't have the probe that goes with it ?

Please don't just tell me to RTFM, because as I said I can't freaking find said manual 

EDIT #3 : The thing looks like it's got a magic eye tube, so I would really like to see that working 

[m k]

Ratio Meter brochure, with price.

[Robert763]

EDIT : looking at the meter scale, it says  "reflection coefficient " up to 100%... so that means that amplitude-wise, I can juste feed both the input and feedback BNC wxith the same signal from my sig gen, and it should be safe and display 100% / full scale deviation ?  Sig gen has a 60dB attenuator, so I can easily start at 1mV peak, if that's not too much ?

EDIT #2 : scale says : " Use square law RF detector " .  Huuuu.... so that means I need a special probe to use this thing ? I can't just give it a sine wave ?

So it's like those RF Wattmeters... they are useless, door stops if you don't have the probe that goes with it ?

Please don't just tell me to RTFM, because as I said I can't freaking find said manual 

EDIT #3 : The thing looks like it's got a magic eye tube, so I would really like to see that working 

 
This meter works with external diode detectors which could be from low frequency to high microwave. The type does not matter as long as the same model is used for both inputs. Diode detectors are still made. The alternative bolometers are obsolete.  The RF used in the measurement setup most be amplitude modulated at 1000Hz. The 416B inputs are for low level 1000Hz (+_40Hz) signals i.e. audio. You can drive the meter with a 1kHz signal from an audio signal generator. Put an attenator (resistor ) between the refernce and measurement channel and it will tell you the ratio of the level s at the two inputs.
This is basically a very early scalar network analyser when used with a sweep generator, 'Scope, detectors and RF bits.
An interesting bit of history.
The 415E is a non-ratiometric (single channel) meter that uses the same detection principle. The manual may give an insight https://xdevs.com/doc/HP_Agilent_Keysight/HP%20415E%20Operation%20&%20Service.pdf

Robert.

[Vince]

Thanks a lot, will try that... tomorrow.

Time to go to bed...

I rolled a dice to pick which of the two meters I would get to work on. Bad move... missing feet/ unstable, blown fuse, missing voltage selector switch, and broken power plug....

So moved on to the other one, which doesn't have any of these problems.

Bloody thing make me uncomfortable... just like all my old Metrix gear, this HP is all metal but no earth connection...

I buzzed the power plug. High Z between both prongs and the case, and about 30+ ohms between live and neutral.

So the Y caps if there are any, are good enough I guess (though of course they might blow and kill me the second I apply power....), and the transformer must be good.

I removed the rear cover to have a peek inside. Bit dusty but otherwise looks great. No missing tubes or white ones or other obvious signs of problems.

So... I am OK powering it up via the dim bulb tester to wake him up slowly.... but... the HP plug won't fit the earthed socket on my DBT, needs a hole to clear the earth prong of course 

So need to DIY something so I can plug it. That will be for tomorrow...

[vk6zgo]

EDIT : looking at the meter scale, it says  "reflection coefficient " up to 100%... so that means that amplitude-wise, I can juste feed both the input and feedback BNC wxith the same signal from my sig gen, and it should be safe and display 100% / full scale deviation ?  Sig gen has a 60dB attenuator, so I can easily start at 1mV peak, if that's not too much ?

EDIT #2 : scale says : " Use square law RF detector " .  Huuuu.... so that means I need a special probe to use this thing ? I can't just give it a sine wave ?

So it's like those RF Wattmeters... they are useless, door stops if you don't have the probe that goes with it ?

Please don't just tell me to RTFM, because as I said I can't freaking find said manual 

EDIT #3 : The thing looks like it's got a magic eye tube, so I would really like to see that working 

#2 Nah! "Square law" just means the transfer function of the detector, like a diode, is "square law" over part of its range, so the device is compensated for that.

Bird wattmeters, ham SWR/wattmeters, & even the cheapest CB ones, are either compensated, or just go with a non-linear meter scale.

You can quite merrily test it for function with a signal generator, but the readings won't necessarily track, unless you have a variable attenuator, calculate what a diode curve would be, then adjust the levels to match.

[Neomys Sapiens]

It's not that remarkable; my bench LCR is fairly low end as these things go, and has a resolution of 0.00001pF

Huh. Interesting. My Philips PM6304 does the same resolution for L, but not for R, C, D, and Q.
I already suspected that it is not as fancy as it seems.
But a usable shop LCR meter until a better one shows up. At least a PM6306 WITH DC option. But that would have the same resolution.

What is the measurement frequency range of yours?

[factory]

Thanks a lot, will try that... tomorrow.

Time to go to bed...

I rolled a dice to pick which of the two meters I would get to work on. Bad move... missing feet/ unstable, blown fuse, missing voltage selector switch, and broken power plug....

So moved on to the other one, which doesn't have any of these problems.

Bloody thing make me uncomfortable... just like all my old Metrix gear, this HP is all metal but no earth connection...

I buzzed the power plug. High Z between both prongs and the case, and about 30+ ohms between live and neutral.

So the Y caps if there are any, are good enough I guess (though of course they might blow and kill me the second I apply power....), and the transformer must be good.

I removed the rear cover to have a peek inside. Bit dusty but otherwise looks great. No missing tubes or white ones or other obvious signs of problems.

So... I am OK powering it up via the dim bulb tester to wake him up slowly.... but... the HP plug won't fit the earthed socket on my DBT, needs a hole to clear the earth prong of course 

So need to DIY something so I can plug it. That will be for tomorrow...

A quick reply, HP TE of this age (60s) should be earthed, that mains cable should have three cores, have a look inside the chassis.

Don't know if I have a manual, but there is an application note for the 416A here.

https://www.hpmemoryproject.org/an/pdf/an_42.pdf

David

[AVGresponding]

It's not that remarkable; my bench LCR is fairly low end as these things go, and has a resolution of 0.00001pF

Huh. Interesting. My Philips PM6304 does the same resolution for L, but not for R, C, D, and Q.
I already suspected that it is not as fancy as it seems.
But a usable shop LCR meter until a better one shows up. At least a PM6306 WITH DC option. But that would have the same resolution.

What is the measurement frequency range of yours?

[m k]

For 416B cookie contest my take is that left one is older.

Good case for DIY project.
Handles wont give up first.

[Vince]

For 416B cookie contest my take is that left one is older.

It's not what I asked.. I was asking spot the difference 

But you are wrong...no cookie for you ! 

The difference is cosmetic, the HP logo at the bottom. On the left one, logo has a grey background, and the other one has a blue background.

As far as which is older... I just checked, it's the blue one on the right.
S/N = 347-000555 with can cap inside that's dated 63-52, so Xmas 1963.

The other one is S/N 410-00831 and is dated about mid 1965, so 18 months younger.

[factory]

Still can't get the desktop to cooperate with the web to view the pictures better, stuck with tiny phone screen.
I was going to say the difference might be the asset plate on the top, ex US military maybe? Then again there is something on the side of the other 416B.

David

[Vince]

[...] Bloody thing make me uncomfortable... just like all my old Metrix gear, this HP is all metal but no earth connection...

I buzzed the power plug. High Z between both prongs and the case, and about 30+ ohms between live and neutral.

So the Y caps if there are any, are good enough I guess (though of course they might blow and kill me the second I apply power....), and the transformer must be good.

I removed the rear cover to have a peek inside. Bit dusty but otherwise looks great. No missing tubes or white ones or other obvious signs of problems.

So... I am OK powering it up via the dim bulb tester to wake him up slowly.... but... the HP plug won't fit the earthed socket on my DBT, needs a hole to clear the earth prong of course 

So need to DIY something so I can plug it. That will be for tomorrow...

A quick reply, HP TE of this age (60s) should be earthed, that mains cable should have three cores, have a look inside the chassis.

Oh thanks, just had a new fresh look at it... it is earthed indeed. There is a short piece of earth wire that sticks out of the back of the power plug... but it's so dirty that last night I managed to miss that... was tired as well, didn't help.



I had a peek under the chassis and yes the earth wire is indeed connected to the inner chassis.  So why did they put a non earth plug  then ?!
Now I think of it, I think one of my old Tek scopes came with a similar plug with the bit of wire sticking out the back... so it must have been a "thing" back then...

Cool, so I can just replace that old crusty plug with an earthed one, and I will be able to use that TE easily and safely... appealing isn't it ?  Stay tuned...

Don't know if I have a manual, but there is an application note for the 416A here.
https://www.hpmemoryproject.org/an/pdf/an_42.pdf

David

Thanks ! Wow 50 pages, I am overwhelmed...and not very courageous. But right in the first few pages it's already interesting. They show this diagram of a typical application :



...which confirms everything Robert said... this instrument is meant to be used as part of a complete system, where they sweep the frequency, get the output from some "process/device" that you are testing, then the HP 416B produces an output on a BNC at the rear, which is used to plot the frequency response of the DUT on an XY recorder.
Yes... definitely makes keeping these two HP's less and less relevant... I am not into this RF magic at all, other than using a smartphone like most people.. .

[Vince]

Still can't get the desktop to cooperate with the web to view the pictures better, stuck with tiny phone screen.
I was going to say the difference might be the asset plate on the top, ex US military maybe? Then again there is something on the side of the other 416B.

David

Good try... yes but no... the other one has a similar plaque as well, but riveted somewhere else.

All the TE from my haul have the same origin : guy lives in Bordeaux and got all his palette loads of TE himself from one big haul with a semi-truck to.... Dassault Aviation (whose main HQ / plant is also near Bordeaux), who got rid of their old TE 25 years ago. So they all have a plaque marked Dassault Aviation.. sometimes "Aerospatiale " as well. I guess they shared equipment here or there.

The finest piece of his haul is still at his place... was way too big for me to take. I told him I might come back in 2 or 3 years to pick it up, once my garage is built and I can free the living room from most of my TE... he said OK keep in touch.... I fear he might be dead by then, and/or may have lost his mind and not even recognize/remember me.... 

[factory]

Computer back to normal, but wasted most the evening sorting it. 

A manual for the HP 416A, this test setup shouldn't be too difficult.
http://ftb.ko4bb.com/manuals/86.173.155.242/HP_416A_Ratio_Meter_Operation_Manual.pdf



David

[TERRA Operative]

That plug with a flylead earth looks like the 'optional earths' on Japanese appliances.
I wonder if that's something introduced by USA post-WWII?

A lot of stuff from that time has stuck around, like the outlawing of marijuana and cencoring of pornography...

[Swainster]

@vince is the difference something like that white/gold dress thing, or is it blue/grey?

[m k]

What's a search phrase for poople?
My phrases can't see it.

But I learned that DY was once a computer maker.

[Vince]

@vince is the difference something like that white/gold dress thing, or is it blue/grey?

I had to Google that one....

No I had no malicious intent...one logo is very much grey and the other very much blue, no catch there, I am not that pervert just yet ! 

[Vince]

A manual for the HP 416A, this test setup shouldn't be too difficult.
http://ftb.ko4bb.com/manuals/86.173.155.242/HP_416A_Ratio_Meter_Operation_Manual.pdf

David

Thanks for that !
Of course the A and B are bound to be very similar, so will be of great help.... <a few hours later> hell, I finally got a manual for the 416B after all !
.... No PDF online, but strangely on Ebay I found no less than 4 original paper manuals for it !
3 in the US for a fair price but obviously expensive shipping but.... the 4th and last one was in Europe, yeah !
Not in the EU though, sadly... in the UK. But only 5 quid or so ! And only 5 quid for shipping.

https://www.ebay.fr/itm/115081598875

So for 10 quid I will receive that manual.. I can afford that...
Of course I may have to pay customs and shit, but calculated on a 10 quid basis, it can't amount to much can it....

Thanks for that, nice drawing... in " 3D ", looks so artistic and cute, love it !


OK, some news... worked on the thing last evening, but was so exhausted I could not post about it, went straight to bed.
So here goes...
Got lucky, found a new plug in my electrical junk box... so I replaced the old plug. Cleaned the horribly crusty cord while I was at it... it's clean now, great, but it's still a bit sticky !  I guess the material has degraded... same that happens on some plastic trim in car interiors, cheap steering wheels etc. It's nasty.



So I could plug it at last, good, an earthed as well, great... feeling safe now.
Powered the thing up via the Dim bulb tester... which lit brightly at first, then dimmed a bit.
I could see the heater in most tubes, glow faintly, good. I let it cook this way for a few minutes, to give the old filter caps a bit of time to wake up, after decades of sleep. Thing didn't go haywire, no flickering of the DBT light, no short... looked good to me so I took my chances and plugged it straight to mains, crossing fingers.... no smoke, no explosion, good....

So I then played with the thing for a bit. There is life left in this thing for sure, but it's a bit ill, I think...
I made a video clip summarizing my findings. I fed both inputs with the same signal so that it shoudl read 100% on the scale, FSD. 1kHz sine wave, amplitude a few mV (switched on the max 60dB attenuation on my sig gen). Here is what I do, in order :

1) Instrument powered off : the needle on the meter is at Zéro, spot on.

2) I flick the power switch, come sto life : pilot light, magic eye working and open.

3) Close-up on the scale : the needle has been pushed below zero, now hitting the mechanical stop... when it ought to be full swing to the right

instead.. not good 

4) Now something else : I pan to the upper right part of the front panel. Next to the magic eye, there is a pot labeled " Reference Adjust ", and next to it there an attenuator switch, for the reflected input. So I guess adding attenuation of should lower the reading on the scale, from 100% (if it worked that is...) to lower and lower values. That had no effect on the needle, it' still stuck on the left mechanical stop. However the magic eye does react : if I operate the pot, I have a varying degreee of control on the eye : the more attenuation I select, the more I can close the eye.

First I start at 0dB : pot has bugger all effet.
Then I switch to -10dB : pot now allows to close the eye a little bit, enough to be easily noticed.
Then switching to -20dB : I can almost close the eye.
Then switching to -30dB : I can close the eye fully and even beyond : the two bars meet at the center and then I can even make them overlap a bit.

5) Now moving on to a toggle switch in the center of the panel, labelled "Excess Incident Attenuation ", where you can select between 0dB and 10dB... 10dB not minus 10... so looks more like 10 dB BOOST rather attenuation, and the block diagram of the 416A confirms that... there is a 10dB AMPlified in there, and the toggle switch inserts a resistive divider between the input and that amp. So overall the label is misleading...

Anyway, the point is : when I flick this switch, for a split second while it's transitioning from one state to the other, I can see the needle jumping up ! Yeah, it's not dead ! ... except it's camera shy it seems, and when I made the video somehow it refused to move, bastard ! :blah
HOWEVER.... you can see that the magic eye, DOES react : it briefly closes then opens up again. So hopefully it will convince you I did not lie about the needle jumping as well...

6) Ok almost done. Now I power off the instrument, and get closer to the scale to show you a strange little dance that the needled does, 100% repeatable, like clock work...

- Needle violently jumps up a bit, then just as soon and just as violently, moves back to where it was, at the mechanical stop.
- Then the needle rises fast to maybe 40% FSD
- Then immediately does the reverse trip, ending again at the mechanical stop.
- Then the needle is "freed" : it slowly moves up to the Zero mark on the scale, where it was at the power up.






I am now waiting for the service manual. I am willing to do a bit of troubleshooting to see if I can get it working, but nothing major of course, and certainly won't spend considerable money neither.  I had a peek under the chassis with a torch light, I can see a decent number of electrolytic axial caps that I can replace as a no brainer.. the Sprague black beauties also found in my old Tek scopes, and also some Mallory ones in paper tubes... Then some contact cleaner here and there.. then reassess ... check voltage rails... The basic stuff. Any TE deserves at least that much...

I won't bother listing them for sale, waste of time... can't be shipped, and if I can't get them working, worth nothing at all.
So I am thinking of a plan to save them... I can't use them, I can't sell them... and I can't get myself to take them apart and scrap the case.. because they look just so gorgeous and sexy in the flesh, I love them. And this magic eye is the icing on the cake...

So I am thinking :

1) I could put one of them as a decoration in my living room, once the house is in a state that the living room actually looks like a living room and not like a dump.

2) The other one.. as MK said, would make a nice project box. I am thinking I could repurpose the thing to do whatever.. a power supply, my big electronic load project, whatever...  I could get a hobby CNC milling machine to engrave an aluminium plate to make a custom face plate, using the same font and overall looks as HP used, reusing HP knobs and controls, same paint, to make it look like a genuine HP, but repurposed for whatever project I may have. Of course I would save the original 416B face plate and guts...

Wadyathink ?! 

I am trying hard to find ways to save these lovely puppies...

[W6EL]

Vince,

I think I would convert one into a normal SWR/Power meter. The outside is already about there. But you could update the inside and make it very nice, and end up with a very usable piece of gear.

But living room decor is not a bad idea either! Coffee table stands, anyone?

--E
de W6EL

[factory]

I've got the separate SWR meter 415B & power meter 430C, sure I've seen more of those two than the HP 416A/B, advertised for sale over the years.



I've probably got a set of feet & a voltage selector for the other 416B.

Not sure about using the case for a PSU or load either, HP would have used a case with vents for those.

P.S. forgot to mention the other day, with these HP cases the front frame is cast alloy and usually spot welded to the steel or alu outer casing. They suffer in the same way as the later System 1 cases, i.e. bits get broken of bent by delivery companies, picture below from a current ePay listing, my HP 560A digital recorder suffered in this way due to the weight and shipping from Europe.

Thanks for that !
Of course the A and B are bound to be very similar, so will be of great help.... <a few hours later> hell, I finally got a manual for the 416B after all !
.... No PDF online, but strangely on Ebay I found no less than 4 original paper manuals for it !
3 in the US for a fair price but obviously expensive shipping but.... the 4th and last one was in Europe, yeah !
Not in the EU though, sadly... in the UK. But only 5 quid or so ! And only 5 quid for shipping.

https://www.ebay.fr/itm/115081598875

So for 10 quid I will receive that manual.. I can afford that...
Of course I may have to pay customs and shit, but calculated on a 10 quid basis, it can't amount to much can it....

There shouldn't be any customs due, TE manuals are 0% rate if listed in the correct category, also for below 100 euro-ish the fees (if any) are collected by ePay during checkout, a requirement of the EU & UK for imports.

Did you take any pictures of the underneath? virtually nothing on these that I can find, would be interesting to see why it needed such a big case.

David

[factory]

An update on the delivery victim HP 5321A that I intended to post on Sunday, but the computer (web) said no.

As previously mentioned this arrived with the controls smashed due to poor packing & EIS (ePay) rough treatment on it's journey from the US, I've since noticed the panel is bent in where the control passes through, so will need to strip the panel and straighten as some point, but first things were to see if it still works.

A previous user/owner had bodged the PH163 inlet with a soldered on power cord and filled it with hard glue, when the rubber insulation failed it got amputated & a tape-bomb covering. An even worse bodge of two core power cord had been fitted, through the hole for the "external gate" BNC, which was moved slightly to a new (unlabelled) position, there is a mystery switch wire disconnected & flapping about inside too. 



I've no idea what type of glue they filled the inlet with, but it was an absolute PITA to get rid of, didn't melt with heatgun, nor a with a modified (scrap) soldering iron tip, it did turn very slowly into dust at 400°C-ish, it took several hours to remove all of it, but thankfully the inlet socket survived. Not an easy to obtain spare part in the UK. Last one was easy as they used hot-snot. Then I desoldered the cord from inside, might keep the cord as it's Japanese, got a few generators that use the US two-prong plug.






 
Also remembered to set the voltage to 230V and check the fuse fitted, a 3A fuse hope the power transformer isn't cooked like my 5216A.  150mA quickly found & fitted.



Some good news is it still powers up, function switch is very loose from the impact, self check & blanking works OK, next job is the 50Hz modification, it will never give a correct reading until this is done. 



Couple of internal pictures, there is loads of unused space in the back of this counter, unlike the 5321B, very tempted to put this transformer* in the 5216A & use the space for a couple of replacement transformers that won't fit in the 5216A.
* If it's the same part number as the manual suggests, but there are two different numbers for the 5216A depending on age.





David