List your test equipment "scores" here!

[wkb]

Looks like I work for the wrong company these days 

[wkb]

Krohn-Hite model 7500 amplifier

We (our local ham repeater club that is) got this as a donation.
Seems to work fine, save for some dust that smelled funny
during amplifier powerup.

Now what to do with it? 

Wilko

[shakalnokturn]

Use it as the line driving stage for a laser based video display?

[wkb]

Use it as the line driving stage for a laser based video display?

The thought... /me wanders to the garage to look at my stash of HeNe laser tubes..

[Berni]

I certainly wouldn't mind having such a an amplifier laying around, it allows you to basically power anything you want with a signal generator.

You can use it to generate weird mains frequency supplies like 16.6Hz 50Hz 60Hz 400Hz, simulate harmonic distortion on AC power, drive anything with a voice coil from a speaker to galvos. Can make a AM radio transmitter out of it. Can be used as noise injection into DC rails or into metal cases to see if a device is robust to interference. Could probably also drive some piezzo elements for ultrasonic things or sonar...etc

[harrimansat]

yes, I have something similiar in my bench, a bipolar power supply HP6827.

[oz2cpu]

SCORED this.. in mint condition, and all things works 100%
3kW output DC supply, meters also read correctly
one happy camper
Glassman Europe Limited LV80-37
it is also known as : DCS series Sorens model 80-37
incase anyone ever need this : i got schematics and service manual (was hard to find)
mine is now hardwired to one phase 230V mains (it need 3phase for full outout, else i guess i blow a main fuse here)

[Gyro]

Nice.

You might want to dial back on the power a bit with that IEC connector though!    Something like a powerCon would be a safer bet.

[wkb]

I certainly wouldn't mind having such a an amplifier laying around, it allows you to basically power anything you want with a signal generator.

You can use it to generate weird mains frequency supplies like 16.6Hz 50Hz 60Hz 400Hz, simulate harmonic distortion on AC power, drive anything with a voice coil from a speaker to galvos. Can make a AM radio transmitter out of it. Can be used as noise injection into DC rails or into metal cases to see if a device is robust to interference. Could probably also drive some piezzo elements for ultrasonic things or sonar...etc

It found a new caring home in Spain. Better in good hands/use than taking up space unused in my ham shack.

Wilko

[Berni]

You might want to dial back on the power a bit with that IEC connector though!    Something like a powerCon would be a safer bet.

I don't see the problem with 3kW trough a IEC connector. They are rated for 16A so up to 3.6kW

If anything its better than what i do to these big PSUs where i tend to just wire up a spare cut off single phase power cord into the screw terminals and call it a day. Most of these big three phase input PSUs don't come with a connector on the back, but instead just have screw terminals for you to wire into (Much like a 3 phase stove). So getting a IEC connector to fit would often mean ripping out the screw terminal block and cutting the hole to fit a IEC socket. At least the voltage input specs on most of these 3 phase input supplies are usually such that you can wire them in single phase on 230V (Even the american ones as those seam to usually run in delta 3 phase).

But yeah i did also wire a 5kW one this way. That will definitely blow fuses if you try to go full beans with it. In my defense EU Schuko outlets are also rated for 16A so they always have max 16A breakers in the electrical panel, so in theory the breaker will pop before the power cord catches fire.

[wkb]

Another pair of classical HP measurement instruments found their way to my ham shack from Germany.

Another HP3478A now sits next to the one I already owned 
And a HP5385A counter sits next to my HP5342A microwave counter.

Got a box full of HPIB cables for the price of a nice cake to interconnect the whole shebang.

Wilko

[Barbouri]

New for me, a vintage HP 3470 Measurement System from 1976, with a 34750A 5-1/2 digit display module and a 37403A DCV/DCA/Ohm Meter section.
The display module needed some new electrolytic capacitors to operate, but works well now.

Blog post for the display module at: https://www.barbouri.com/2021/11/16/hewlett-packard-34750a-display-module-repair/

[wkb]

Wow.. that looks nice!

Wilko

[xrunner]

New for me, a vintage HP 3470 Measurement System from 1976, with a 34750A 5-1/2 digit display module and a 37403A DCV/DCA/Ohm Meter section.
The display module needed some new electrolytic capacitors to operate, but works well now.

Incredible shape! 

[Neomys Sapiens]

New for me, a vintage HP 3470 Measurement System from 1976, with a 34750A 5-1/2 digit display module and a 37403A DCV/DCA/Ohm Meter section.
The display module needed some new electrolytic capacitors to operate, but works well now.

Incredible shape! 

I knew of it's existence, but never saw one before. Nice catch!

[Berni]

Now that is a really cute looking oldschool DMM. That display is quite something too

[xrunner]

Purchased 8482A power sensor from the field. Attached to hp 437B power meter, calibrated and checked entire range down to -30 dBm. Looks to be in good working order.

 

[Oldtestgear]

I went to buy an HP 8566B spectrum analyser at the weekend. A nice, clean, & fully working instrument sold to me by a calibration lab. Apparently it was their own instrument that had been replaced a while ago. This was a fair price but not a "score".  The seller knows that I have trouble resisting a bargain and also knows how big my car is. This is what he also sold me, which is a score by my reckoning:

8 HP 3478A DMMs ( 6 are complete)
3 HP 3456a  DMMs ( 2 complete & working. 1 faulty & missing the line push button)
1 Tek 2712 SA
4 Tek 494P SA
1 Tek 492P SA
1 tek 475
1Tek 468
2 Tek 2465b ( lots of parts stripped but still useful)
2 Tek 465

This is christmas come early.

These will keep me occupied over the next couple of months.

Phil

[wkb]

I went to buy an HP 8566B spectrum analyser at the weekend. A nice, clean, & fully working instrument sold to me by a calibration lab. Apparently it was their own instrument that had been replaced a while ago. This was a fair price but not a "score".  The seller knows that I have trouble resisting a bargain and also knows how big my car is. This is what he also sold me, which is a score by my reckoning:

8 HP 3478A DMMs ( 6 are complete)
3 HP 3456a  DMMs ( 2 complete & working. 1 faulty & missing the line push button)
1 Tek 2712 SA
4 Tek 494P SA
1 Tek 492P SA
1 tek 475
1Tek 468
2 Tek 2465b ( lots of parts stripped but still useful)
2 Tek 465

This is christmas come early.

These will keep me occupied over the next couple of months.

Phil
(Attachment Link)

Uh oh... why do I never run into this "car too small" problem?   

Wilko

[xmo]

wn1fju wrote: "I used the last counter I bought to count the number of counters I had!"

If someone asks you; "How many multimeters do you have?"  and you have to answer "I haven't counted lately.", you are well on your way to becoming a test equipment addict.

If some one asks the same question about oscilloscopes - or counters - and you have to think about your answer - you are pretty much certifiable.  I know I am.

It's fun to read about people's scores.  A lot of times it's about being in the right place at the right time.

I have had some fun wins over the years.  One from two years ago was a pristine Rohde & Schwarz ZVB-8 network analyzer for less than 4000 USD.  Asking and selling prices on these are still much higher.

When I got it, I figured that, even if it had a problem, I could send it in for flat rate repair and still be OK , but it works perfectly and I also discovered a bonus - it's equipped with the time domain option.

[Jester]

I picked up qty 2 Fluke 8842A's on eBay with make an offer  $180 for both.

Description was display intermittent, ac out of calibration / drifts no further testing done.

The display looks pretty good, definitely quite usable.

I have only had it up an running a couple of hours but so far looks pretty good, DC cal is right on (ran it up to 1000Vdc, and ac is pretty close compared to my three seasoned but uncalibrated 34401A's
34401A    10.0043V
34401A    10.0013V
34401A    10.0029V
8842A        9.9997V

-0.03%  I can live with that if it does not start drifting.   I will let this run for a few days. Hopefully unit #2 works, I do hear some mystery noise inside unit # 2. It has the exact same description.

Of all the non working for parts equipment that I have purchased only three pieces actually had a problem, one bad opamp, one leaky diode, one with two cables swapped. All the others worked perfectly. Total replacement parts cost < $10.

I sometimes wonder if they just want to get new equipment and write up a fake problem to get rid of the old stuff?

[alm]

I sometimes wonder if they just want to get new equipment and write up a fake problem to get rid of the old stuff?

Or it's just that the seller doesn't have the knowledge or doesn't want to invest the time to test them, so they list them as for parts / repair so they won't get any returns.

By the way, I have two 8840A parts units with AC/GPIB boards that are missing their front panel and mechanical parts. So I might be able to help you with parts.

[Jester]

First unit continues to work well.

I opened up the second unit, one of the black plastic board holders was damaged, so little piece of black plastic floating around.

No display on power up. Tapped it on the side and the display started working, tap-on , tap-off, tap-on, tap-off, this should be easy.....
Touched up the solder on pins 14 &16 of the transformer, no more tap-off. Passed the self test, still need to do full test. AC looks close at 10V, I will let it cook with the other one.

The ground screw was also missing on the bottom PCB shield, 4-40x1/4" if yours is missing and need to know what it is.

Front display lens is rough, will be looking for a nice replacement, so if someone has one, please let me know.



After 10 minutes both meters are within 2 counts of each other. I'm really glad I sold the GDM-8251, I'm already getting the warm and fuzzy feeling when taking measurements with this 30 year old fluke.


I now have 4 x Fluke DMM and 3 x HP/Agilent DMM, I think I may have a mild case of DMMitis, heading over to the group therapy thread.

[J-R]

I also recently snagged two 8842A units with both options installed for about $100ea delivered, listed for parts.

On the first the display would flicker and go dim after warm-up, re-soldering the transformer was the fix.  Very bright display, was probably replaced recently as a repair attempt.

The second was labelled "low value volts drifts", found some drift and inaccuracies in the 20mV and 200mV ranges as well as for very low value 4-wire resistance measurements in those ranges.  Was also getting some pretty high non-zero values with the inputs shorted.  All this after hours of warm up.  The internal wire connections to the front terminals were plastered with what I assume is dielectric grease.  Another failed repair attempt?
Ultimately found capacitor C611 was bad, out of circuit it reads a few dozen pF (supposed to be 100uF).  Replaced that and performed a calibration of the 20/200 ranges and things look very good for now.  Will let it cool off overnight and test again to see how it performs.  Maybe that was the culprit.

Checked C611 in the other unit and out of circuit it was ~35uF with ESR of 20 Ohms, so replaced that one too.  When in use the voltage across the capacitor was about 35V and it's rated for 50V.

On both units the small spade terminal connection on the main board going to the AC option board was extremely loose, gave it a little extra crimping force...

Eventually I did go ahead and clean/lube the front/rear switch and hit the transformer with a soldering iron on both units.

199,999 count.

[rsjsouza]

Not as fancy as the big boy test gear around, but I got this brand new sealed Greenlee DM-200A (Brymen BM251S) for less than half the price of a new one.

Since I live in the US, lifetime warranty from Greenlee is quite sweet. Being Brymen, the quality is top notch - this little meter feels incredibly robust and well put together. I risk saying it feels as sturdy as the 87V and the 179.