Test Equipment Anonymous (TEA) group therapy thread

[Robert763]

Oh, I know. But there's this fella "Ohm" that seems to think these two are somehow related.

No, volts ohms and amps aren't simply related. Exception: the special cases in which ohms law is valid.

Don't believe me? Consider the current in tunnelling devices, or where the voltage is outside a device's specifications, or a battery, or etc

Ohms law is still valid in those cases. It's the resistance (impedance) of the devices that is changing.

[tggzzz]

Oh, I know. But there's this fella "Ohm" that seems to think these two are somehow related.

No, volts ohms and amps aren't simply related. Exception: the special cases in which ohms law is valid.

Don't believe me? Consider the current in tunnelling devices, or where the voltage is outside a device's specifications, or a battery, or etc

Ohms law is still valid in those cases. It's the resistance (impedance) of the devices that is changing.

Not really. As it is put in https://en.wikipedia.org/wiki/Ohm's_law , the resistance is the constant of proportionality between voltage and current.

There are many materials that do not obey ohm's law; they are, surprise surprise, termed non-ohmic.

[dxl]

Because there was some discussion about Triax connectors/cable in this thread. I was looking for Triax cables for my HP4156 Semiconductor analyzer, and stumbled accross this:

https://www.ebay.de/itm/155170484470

I sent an offer of 49US$, and it was accepted. I think that is a pretty good price for 4 Triax cables (which are in fact 8 cables, as the 4156A has sense + force triax connectors per SMU). Maybe the plastic housing could be removed and the cable could be used as generic triax cable (without the locking part of the Triax connector of course).

So if anyone needs a few Triax cables, be quick :-)

[factory]

Finally I've got a HP3400A. 

Normally they are selling for 200 to 250 Euros over here. 

This one was some risk, as function 'was not checked' by the heir, who sold it. But I've got it for 85 Euros.



Looks fine with some dust and cat or dog hairs. Inside nothing seems to be missing.

It's from 1982 and has the 66512 A6 assembly, which is the newer opamp solution instead of the separate weird optocoupler.

I didn't expect it to run fine from the start. And so it is:
After switch on, the needle is mooving smoothly, but is running randomly all over the scale.
So there is some research and work to be done. 

That's a bit newer than any of mine, my newest 1605 rev has had the PSU & A6 replaced in the mid 80s, still has the thermocouple & nuvistor. First thing you'll probably need to do is replace the foam on the nuvistor board, every single one of my 3400As had crumbly foam. Only one that doesn't work is the oldest one, with first design of neon photo-chopper assembly.

David

[Peter_O]

Finally I've got a HP3400A. 

Normally they are selling for 200 to 250 Euros over here. 

This one was some risk, as function 'was not checked' by the heir, who sold it. But I've got it for 85 Euros.



Looks fine with some dust and cat or dog hairs. Inside nothing seems to be missing.

It's from 1982 and has the 66512 A6 assembly, which is the newer opamp solution instead of the separate weird optocoupler.

I didn't expect it to run fine from the start. And so it is:
After switch on, the needle is mooving smoothly, but is running randomly all over the scale.
So there is some research and work to be done. 

That's a bit newer than any of mine, my newest 1605 rev has had the PSU & A6 replaced in the mid 80s, still has the thermocouple & nuvistor. First thing you'll probably need to do is replace the foam on the nuvistor board, every single one of my 3400As had crumbly foam. Only one that doesn't work is the oldest one, with first design of neon photo-chopper assembly.

David

Does that microphony really make the reading of no input going over the full range for every range? 

[factory]

Don't know, I usually removed it first, worst case it turns to dust & spreads everywhere. 





David

[Vince]

00H50, worked a little bit this evening.

Managed to fix yet another TV / monitor that a friend gave me a few days ago.  I think I am getting the hang of it.
Since these things are a pain, crap as fuck and worth nothing... in order to not waste my time and sanity on these things, my method is now well established :

- Pop the rear cover
- Measure voltages. Low voltage going to the digital board, and HV going to the backlight.
- If not good, try to fix it, doing only the easy stuff : buzz diodes and electrolytic caps.
- If voltages are good, remove the LCD screen / filters  sandwich, and test the LED strips.
- Bridge any bad LED. Once the screen and diffuser are back in place, you can't even tell if a single, even several, LEDs are not working.
- Test  the device... if still not working, give up and scrap for parts.

Doing that, I have managed to fix the 10 or so TV / monitors I was passed, bar the very first one because the screen was already smashed when it was given to me....which I found out only once I had fixed the backlight issue, of course... 

So yeah, it's incredible. maybe 10 TV / monitors I was given , all of them had either a power board problem, or dead LEDs. This makes it worth sticking to simple things and give up if it resists, because sticking to the simple/quick stuff fixes so far all of them ! 

Well, 90% of them.. as I was writing this I now remember one that had a bad chip. Single board and single chip design,  big BGA chip that does it all. I think part of it was dead... TV was "working" / alive, menus would display and were working, but it failed to detect any signal on any of the inputs. Since all inputs were wired straight to pins of the chip... I declared that BGA chip Kaput and scrapped the TV.

Anyway, I fixed this one today because it's the kind that I could use in the lab to work on various stuff : not too big, not too small, lightweight, and many types of inputs. Old inputs for when I work on my old junk : VGA, SCART, but also modern stuff like HDMI, USB and some slot to stick some type of extension card into it, not sure what it uses and what you can do with it. Maybe a memory card or some kind of SSD to record programs or whatnot. Don't really care as I doubt I will ever use that feature.
Also comes with its remote, that's convenient. I like the menu system as well, looks nice and user friendly.

Only slight issue is that it's missing its feet. Previous owner I guess mounted it on a wall using the VESA mount. Not too bothered with this since I would probably also use the VESA mount myself. And if not, the bottom of the TV case is actually pretty wide and flat, so it's pretty stable as it is.

Well I had already another TV that I fixed to fill this role in the lab, but I guess you can never have too many options. If one doesn't work, take the other ! 
This one looks slightly less cheap and ugly than the other one, so that's another reason to keep it around. Would scrap the other one but it's got a video composite input which can be very handy, which is lacking in the TV I fixed today.

Anyway, feels good to fix stuff, even if it's consumer junk. At least I won't have to spend money for TV / monitors to equip my lab, or as a temporary backup if my computer monitor (also one I fixed !  ) dies.


So what was wrong with this one then ?

I followed my procedure above.... voltages looked good, but no backlight. Removed the LCD screen, tested the LEDs. There are two strips of x11 LEDs, mounted horizontally and wired in series. Fired up the lab power supply to test them. First strip lit up. Second did not, so I scraped the silk screen at every LED, so I could make contact with them. Only one bad LED, the very last one of the strip. Desoldered it, bridged it with a blob of solder. Works like a charm and once all put back together the eye can't tell the missing LED anyway 

Tried it on my TDS 544A scope, works like a charm, mission accomplished 

[Martin.M]

Grundig. found it today at a radio market here 

[capt bullshot]

Nice one, that is!

[Robert763]

So I just bought a measuring instrument on ebay. It's electro-optical and digital but I'm not sure it qualifies as test equipment. It's an item I've wanted to play with for years but new are several thousands for a basic model. It's a Total Station.
They are a theodolite with digital readout, "electronic" distance measurement and trig computation built in. This one is not a big name but is reflectorless, and has 1mm resolution from 1m to over 3km. angular resolution is 1 arc-sec (accuracy 5 arc sec 0.0014 deg).
It turned up on a house clearance type seller listing. Described as not working and it is clearly missing the charger but it looks virtually unused. At under £100 delivered it will be something to play with 

[Neomys Sapiens]

So I just bought a measuring instrument on ebay.
..
It's an item I've wanted to play with for years but new are several thousands for a basic model.

Same here.

[tautech]

So I just bought a measuring instrument on ebay. It's electro-optical and digital but I'm not sure it qualifies as test equipment. It's an item I've wanted to play with for years but new are several thousands for a basic model. It's a Total Station.
They are a theodolite with digital readout, "electronic" distance measurement and trig computation built in. This one is not a big name but is reflectorless, and has 1mm resolution from 1m to over 3km. angular resolution is 1 arc-sec (accuracy 5 arc sec 0.0014 deg).
It turned up on a house clearance type seller listing. Described as not working and it is clearly missing the charger but it looks virtually unused. At under £100 delivered it will be something to play with 

Really, so no prism staff required ? If not that's pretty cool so what do you actually use for a target ?

Theodolite's are cool and great fun. First used one as a teeenager on a big building site.
Spent a bit of time on a staff for both distance measurement and another dumb one that you need do the calcs  and physical measurements.

Now they are smarter again, linked to a GPS base station and providing such good accuracy you don't even need a pin finder. 

[mftaylor]

They don't need anything special as a target, but reflective tape, lighter colors and matte surfaces work best.  The distance accuracy is typically worse than using a prism but good enough most of the time and the range is significantly reduced depending on the model.  That one looks either quite old or is based on an old model so the reflectorless range probably isn't awesome, there isn't a lot of innovation in the total station market outside of Leica and South these days so lots of companies still make them looking pretty much exactly like that, just with Bluetooth added.

I used ones almost exactly like that a number of years ago, and we gradually upgraded until we thankfully got into robotic units after a while.  Now I write software for them and GNSS units instead.

So I just bought a measuring instrument on ebay. It's electro-optical and digital but I'm not sure it qualifies as test equipment. It's an item I've wanted to play with for years but new are several thousands for a basic model. It's a Total Station.
They are a theodolite with digital readout, "electronic" distance measurement and trig computation built in. This one is not a big name but is reflectorless, and has 1mm resolution from 1m to over 3km. angular resolution is 1 arc-sec (accuracy 5 arc sec 0.0014 deg).
It turned up on a house clearance type seller listing. Described as not working and it is clearly missing the charger but it looks virtually unused. At under £100 delivered it will be something to play with 

Really, so no prism staff required ? If not that's pretty cool so what do you actually use for a target ?

Theodolite's are cool and great fun. First used one as a teeenager on a big building site.
Spent a bit of time on a staff for both distance measurement and another dumb one that you need do the calcs  and physical measurements.

Now they are smarter again, linked to a GPS base station and providing such good accuracy you don't even need a pin finder. 

[tonyalbus]

Will be an owner of a Tektronix RFM151 CAI meter aka Spectrum analyzer. 
very cheap guess seller thinks its for tv only.
Does anyone has the CSS151 software that he/she can share with me?

Thanks hope you can help me.

[TERRA Operative]

Apparently that product line was sold to Tempo Communications, so maybe you would have some luck contacting them directly.

Link to a manual if you didn't find it already:
https://www.necrat.us/skippy/RFM151-3000-A.pdf

[tonyalbus]

Apparently that product line was sold to Tempo Communications, so maybe you would have some luck contacting them directly.

Link to a manual if you didn't find it already:
https://www.necrat.us/skippy/RFM151-3000-A.pdf

Thanks Jared!

[Robert763]

Had an RFM151 about 18 years ago. It was OK as I recall. Dynamic range and display are not great but it's nice having proper AM and FM demodulation.
Let us know how you get on.

[Zoli]

They don't need anything special as a target, but reflective tape, lighter colors and matte surfaces work best.  The distance accuracy is typically worse than using a prism but good enough most of the time and the range is significantly reduced depending on the model.  That one looks either quite old or is based on an old model so the reflectorless range probably isn't awesome, there isn't a lot of innovation in the total station market outside of Leica and South these days so lots of companies still make them looking pretty much exactly like that, just with Bluetooth added.

I used ones almost exactly like that a number of years ago, and we gradually upgraded until we thankfully got into robotic units after a while.  Now I write software for them and GNSS units instead.

With the lasers I presented here, I've used orange reflective tape, similar to the one sold by the manufacturer; the longest range I've tested was ~430m, stable readings with cloudy sky and reflective target.
And if lasers, always add: Don't look into the beam with your remaining eye!!!

[tautech]

They don't need anything special as a target, but reflective tape, lighter colors and matte surfaces work best.  The distance accuracy is typically worse than using a prism but good enough most of the time and the range is significantly reduced depending on the model.  That one looks either quite old or is based on an old model so the reflectorless range probably isn't awesome, there isn't a lot of innovation in the total station market outside of Leica and South these days so lots of companies still make them looking pretty much exactly like that, just with Bluetooth added.

I used ones almost exactly like that a number of years ago, and we gradually upgraded until we thankfully got into robotic units after a while.  Now I write software for them and GNSS units instead.

With the lasers I presented here, I've used orange reflective tape, similar to the one sold by the manufacturer; the longest range I've tested was ~430m, stable readings with cloudy sky and reflective target.

Yet IIRC the theodolite and prism I worked with we took shots 700m+ and several more totalling a few km and ended on an OIS (Old Iron spike) some 200m from where we started, both the OIS and starting point pin being formal survey marks and with several shifts and back shots to finish with results of sub 50mm accuracy ! 

All measurements were entered into a handbook and as it was just a dumb theodolite everything had to be longhand calculated as a check against each formal survey mark. We had old survey maps with every legal point and their measurement and with a magnetic pin finder the ability to find them all too.
Interesting it was too to discover all the old boundary 'give and take' adjustments to make the original surveys easier to fence that better suited terrain or access around properties when it was first surveyed a couple hundy years ago. <This was the reason for this informal boundary check as we had a significant disagreement with our neighbor after one day discovering new survey pegs in our property. 
It involved a historical 'give and take' and a modern take take take !
It got settled with a nice payout to each of our children. 

[mftaylor]

I should have also mentioned that these instruments are pretty rugged overall, but they almost always get knocked out of adjustment while being shipped.  There should be somewhere in the menu to adjust the vertical and horizontal, otherwise it will appear to be the correct angle on the display but will in fact be off by some random amount (> 1' is easily possible).  The manual will have more info about the procedure if you have it, but it's not usually complicated.

They don't need anything special as a target, but reflective tape, lighter colors and matte surfaces work best.  The distance accuracy is typically worse than using a prism but good enough most of the time and the range is significantly reduced depending on the model.  That one looks either quite old or is based on an old model so the reflectorless range probably isn't awesome, there isn't a lot of innovation in the total station market outside of Leica and South these days so lots of companies still make them looking pretty much exactly like that, just with Bluetooth added.

I used ones almost exactly like that a number of years ago, and we gradually upgraded until we thankfully got into robotic units after a while.  Now I write software for them and GNSS units instead.

So I just bought a measuring instrument on ebay. It's electro-optical and digital but I'm not sure it qualifies as test equipment. It's an item I've wanted to play with for years but new are several thousands for a basic model. It's a Total Station.
They are a theodolite with digital readout, "electronic" distance measurement and trig computation built in. This one is not a big name but is reflectorless, and has 1mm resolution from 1m to over 3km. angular resolution is 1 arc-sec (accuracy 5 arc sec 0.0014 deg).
It turned up on a house clearance type seller listing. Described as not working and it is clearly missing the charger but it looks virtually unused. At under £100 delivered it will be something to play with 

Really, so no prism staff required ? If not that's pretty cool so what do you actually use for a target ?

Theodolite's are cool and great fun. First used one as a teeenager on a big building site.
Spent a bit of time on a staff for both distance measurement and another dumb one that you need do the calcs  and physical measurements.

Now they are smarter again, linked to a GPS base station and providing such good accuracy you don't even need a pin finder. 

[duckduck]

New acquisition:

HP 403B with Option 01 (dB scale). AC Voltmeter.

Everyone's (OK, some people are) talking about getting TE at hamfests. Now that I'm a ham, I figured I'd give it a shot. I dragged junior out with me and he was happy to eat one of the donuts that are inevitably found where hams gather. We made a day-trip out of it and stopped for lunch and walked on the boardwalk and hit the playground.

The seller said that it came from the local phone company. He had two for sale at USD10 / each. I picked the one with the better looking case. It had a hang-tag on it that read "Poor Batteries". The seller also threw in a PH163 splitter cable, which is probably more valuable to me than the 403B. Whatever feet were included with the unit are long gone. The NiCDs leaked and there is some corrosion on the main PCB. Upon casual observation, I don't see any gross damage to the traces. Without any ICs, I actually have to work to date this unit, I found a couple of the Sprague caps with what might be date codes of 6643L and 6634J. So, 1966. Does that seem right? The USA was bombing Vietnam and the Rolling Stones were coming out with new music. This thing is a tiny slice of history.

EDIT:

Also bought a small cast aluminum project box for USD2 and a small set of Micro-mesh sandpaper + accessories for USD5.

[tggzzz]

And if lasers, always add: Don't look into the beam with your remaining eye!!!

"beam" should really be "beam (or unexpected reflection from a random shiny object)"

[TERRA Operative]

Awwww yisss.

And more bits are still on the way.

[Robert763]

Nice,
Now you need a proper VECTOR network analyser to use it with 
I have a 6GHz 8574 complete kit surplus to needs but shipping might be an issue....

[TERRA Operative]

Working up to it!... I gotta sell a bunch of stuff to make space before I get a proper-sized unit....

Today's impulse buy, a TME brand directional coupler for 1100yen from the local junk store in Akihabara.
Good for 717 - 2200 Mhz, 150W, etc.

Couldn't pass it up at that price, so now all I have to do it think of a use for it.