Test Equipment Anonymous (TEA) group therapy thread

[tggzzz]

Bad timing fail for me in that department. My HP supply is due to arrive on Monday. She’s out tomorrow and in all day on Monday and I’m out.

Ahhh, this is just like "reality" TV (which I don't watch, since I remember "The Year of the Sex Olympics").

[Specmaster]

Bad timing fail for me in that department. My HP supply is due to arrive on Monday. She’s out tomorrow and in all day on Monday and I’m out.

Ahhh, this is just like "reality" TV (which I don't watch, since I remember "The Year of the Sex Olympics").

If you dont watch it, how do you know its like it? 

[WastelandTek]

WastelandTek, it's helpful to add your country in your profile so folks have a sense for things such as, in this case, potential shipping costs when they see your country's flag in your posts.

Those two units look to be in great condition and would work nicely for audio. The 353A patch panel is often found in a three-instrument enclosure between a 200-series oscillator and 400-series AC voltmeter.

sorry, West coast USA

[URI]

Bad timing fail for me in that department. My HP supply is due to arrive on Monday. She’s out tomorrow and in all day on Monday and I’m out.

Reality sometimes strikes without mercy. 
But you have to justify only for one package, lucky man.. 

[bitseeker]

WastelandTek, it's helpful to add your country in your profile so folks have a sense for things such as, in this case, potential shipping costs when they see your country's flag in your posts.

sorry, West coast USA

Cool. Normally, stuff for sale would go into the Buy & Sell forum, but we're pretty flexible in the TEA house. So, add to your original post how much you're looking to get for them, even if it's just the cost of postage (i.e., just get it off my bench!), and people can PM you to make arrangements.

[mnementh]

Awww jeez, guys... now you got me thinking about digging out the Heathkit IM-1202 and Wavetek SAM Jr that have been lost in some unknown box somewhere in the house since we moved 2 years ago...

Damn you. Damn you to hell.


mnem
Another fine day in my Empire of Dirt...

[med6753]

No wife. Girlfriend doesn't live with me. I can get as many packages delivered as I want, when I want. I answer to no one. In fact, my bench is in the living room. Not stuffed away in a closet. Life is good! 

But I've been there in past and totally understand.   

[WastelandTek]

No wife. Girlfriend doesn't live with me. I can get as many packages delivered as I want, when I want. I answer to no one. In fact, my bench is in the living room. Not stuffed away in a closet. Life is good! 

But I've been there in past and totally understand.

GF does live here, but she is a real sport.  Lab is just off the front room...front room that permanently houses rock and roll band.  Life is indeed good.     

[bitseeker]

I don't know if this YouTuber is on the forum, but the beginning of these videos (five months apart, even) sure sounds like he should be in this thread, no?

[bitseeker]

Keithley and/or Triax experts: A few months ago, I got a Keithley 220 which supposedly had a problem. Upon receipt, it would throw an error anytime I enabled the output, regardless how high or low I set the current and compliance voltage.

The problem turned out to be the 2-lug Triax-to-BNC adapter that someone had installed on the output connector. Removing it enabled the supply to operate just fine. On the 220, the center pin is output HI, inner shield is output LO, and outer shield is chassis common.

Other adapters I've seen send the center pin through and tie either the inner (LO) or outer (common) — but not both — to the BNC shield. This adapter sends the center pin through, ties the inner (LO) to the BNC shield, but then has approximately 6.5 MOhms between the inner (LO) and outer (common). What's up with that?

There's also a warning label on the adapter to limit the voltage between LO and common to 30V (~4.6 µA between them). Is this an arrangement that anyone recognizes?

[tggzzz]

Bad timing fail for me in that department. My HP supply is due to arrive on Monday. She’s out tomorrow and in all day on Monday and I’m out.

Ahhh, this is just like "reality" TV (which I don't watch, since I remember "The Year of the Sex Olympics").

If you dont watch it, how do you know its like it? 

You accidentally see snippets while channel surfing. You hear other people droning on about it. Those shows have good PR conslutants (sic).

But this is too far from TEA to be interesting.

[Berni]

Keithley and/or Triax experts: A few months ago, I got a Keithley 220 which supposedly had a problem. Upon receipt, it would throw an error anytime I enabled the output, regardless how high or low I set the current and compliance voltage.

The problem turned out to be the 2-lug Triax-to-BNC adapter that someone had installed on the output connector. Removing it enabled the supply to operate just fine. On the 220, the center pin is output HI, inner shield is output LO, and outer shield is chassis common.

Other adapters I've seen send the center pin through and tie either the inner (LO) or outer (common) — but not both — to the BNC shield. This adapter sends the center pin through, ties the inner (LO) to the BNC shield, but then has approximately 6.5 MOhms between the inner (LO) and outer (common). What's up with that?

There's also a warning label on the adapter to limit the voltage between LO and common to 30V (~4.6 µA between them). Is this an arrangement that anyone recognizes?

Well triax is always a headache. There are also various types of triax and BNC adapters with different wiring inside.

On my Keithley electrometer (Also has the rare 2 lug triax) the outer shield is just earth and is not used for anythyng other than sheilding so in a BNC adapter you would want the inner shield to the the shield of the BNC while leaving the outer shield unconnected.

Then there is my Agilent SMU that also has triax connectors on it but with a different pinout. There center conductor is sense, inner shield is force and outer shield is guard. To convert this to BNC you would need to short the center and inner shield together while sending the outer shield to the BNC shield. If the two are not connected then the SMU can't output any current. And yes having the guard be the outer shield means you can grab on to 100V on the metal connector case, for this reason there is a plastic cover over the triax jacks.

[Specmaster]

Bad timing fail for me in that department. My HP supply is due to arrive on Monday. She’s out tomorrow and in all day on Monday and I’m out.

Ahhh, this is just like "reality" TV (which I don't watch, since I remember "The Year of the Sex Olympics").

If you dont watch it, how do you know its like it? 

You accidentally see snippets while channel surfing. You hear other people droning on about it. Those shows have good PR conslutants (sic).

But this is too far from TEA to be interesting.

I agree TEA is far more interesting, I hardly watch any TV these day, and when I use the TV, I go on YouTube and put on Electronics tear downs and blogs far more entertaining and educational as well to boot 

[bd139]

Haven’t watched TV for about ten years. Would rather be creating or fixing something or whacking F5 on the ten eBay tabs I have open 

[THDplusN_bad]

No wife. Girlfriend doesn't live with me. I can get as many packages delivered as I want, when I want. I answer to no one. In fact, my bench is in the living room. Not stuffed away in a closet. Life is good! 

But I've been there in past and totally understand.

I am blessed with a very understanding spouse, but why is my face showing up a bit envy-green in the mirror right now? 

[bitseeker]

Well triax is always a headache. There are also various types of triax and BNC adapters with different wiring inside.

On my Keithley electrometer (Also has the rare 2 lug triax) the outer shield is just earth and is not used for anythyng other than sheilding so in a BNC adapter you would want the inner shield to the the shield of the BNC while leaving the outer shield unconnected.

Thanks for the info, Berni. Same arrangement with the Keithley 220. When I first checked the adapter for continuity, it seemed to be correct, yet the 220 still threw an error. Then, I measured the resistance between the conductors and discovered the built-in "terminator."

It's good that the adapter was the source of the problem, but a bummer that I now have to find a 2-lug triax cable. It's never ending.

[bitseeker]

I agree TEA is far more interesting, I hardly watch any TV these day, and when I use the TV, I go on YouTube and put on Electronics tear downs and blogs far more entertaining and educational as well to boot

Hanging out with y'all, fixing stuff, and watching electronics videos is so much better than TV.

[neo]

Do you believe in santa? I may have to reconsider my stance, killer deal, delivered a day early, and last callibrated in '96. 

The packaging was well worth the 80 bucks shipping, wrapped in 3 inches of bubble wrap with another 3 inches of polyethylene foam sheet on every side.

All 4 channels in working order, all accurate to each other, and excluding the 2nd 200MHz channel free of bugs. The only glitch on the 200MHz channel 2 is that it constantly says "IDENTIFY" and has its volts/div know missing with the push in/out out vernier broken off.
7A26   calibrated 06/12/96 by STK
7A18   calibrated 07/27/95 by Instrument Repair Labs.
7B85   calibrated 10/24/96 by STK
7B53   calibrated 07/27/95 by Instrument Repair Labs.
7704A calibrated 04/14/96 by STK

The test is a bit of a quick test, same signal going to all channels. I have it sitting on an old typewriter table i bought for 10 bucks, not a perfect fit but it is pretty close.

Excuse the red, it is just what my camera does if you turn off the flash.

[bd139]

I think you won. Nice one 

[Specmaster]

Very nice, but why is the top trace inverted?

[neo]

Because i had the switch to invert it switched by accident and didn't see a need to re-take the picture.

[URI]

The HP 3335A was delivered today. 
BTW: We were having breakfast when the DHL-man rang. I knew it was DHL because I had seen the van in our street short time before.
I told my wife she should't care and went to the door, received three packets, put them in the room next to the front door and returned to the kitchen. I mentioned it was DHL, nothing special. 
I received them so SECRETly, I'm happy! 

My wife left the flat at ~15 o'clock (3 PM.. ) for several hours and that put me to life. Went straight to open the packages and have little christmas!

First packet brought me a PCB holder. Handy, espacially, when only one arm is fully usable.
The second packet held the desoldering station. Yummie!
The third packet that I couldn't barely handle with 1 and 1/8 usable arms had the HP3335A in it, sold for parts.

Quick testing of it showed that the internal OCXO ist so far off the unit won't lock on it. But it immediately locks on my 10MHz GPSDO-Reference and puts out stable frequencies accurate to the 10th digit (mHz)!   
I will have to look for the reason why the OCXO is inaccurate. It's stable on the other hand -that's on the plus side.
The sweep output that the seller described as defective puts out 0.019V at the starting frequency and 1.9V at the stop frequency. On the front there is 0..2V labeled -so that doesn't look too bad, right?
All keys are working, the dial also. Winner!

The 3335A is a real boat anchor and has a really loud fan in it (radial axial, 120mmx120mmx40mm AC-powered,metal chassis and propeller) that pushes vast amounts of air through it in short time.
Not really compatible with my wife trying to work in the same room. That's the downside. 3335Aing only at weekends.     

[neo]

Well i just looked at the price of a knob for it and at that price i would be better off buying another 7A26 as a parts mule. 
The missing knob is going to have to sit on the que for a while at that price.

[bitseeker]

Congrats on your new goodies, neo and URI!

[URI]

Thanks, bitseeker. -Ah, another story:

After I had put the "new" HP 3335A near my bench (not enough room, have to clear things up), I switched my oscilloscope on.
Well, I tried.
In that very moment the power switched lost its latching function. 

Since I didn't want to press down that switch all the time I was testing I had to repair it. Opened the oscilloscope (Philips/Fluke PM3065), pulled out the power supply PCB, identified the broken switch and found two in stock at the local Conrad Electronic store. A march of ~1h later I had two drop-in replacement switches.
Two? You'll never know.. 

I desoldered it with my freshly arrived Solder Peak SP-1010DR desoldering station. What a relief compared to using a desoldering hand-pump! Strange enough: Isn't that a remarkable coincidence: I have to desolder a switch that just became defective on the same day the desoldering station was delivered? 

Well, having the PM3065 open once I threw in a 60mmx60mmx25mm 12V fan as the oscilloscope was always getting rather warm after half an our on or so virtually cooking the electrolytics to death quicker than necessary. Interestingly the PM3065 uses the housing the higher models are also built with -and those have a fan in it; there's a mounting space where the fan can be just clipped in without need for screws. 

To get the 12V fans supply I took a +5V and a -6.4V line out of the same secondary winding of the supply that's unused in the PM3065 because it doesn't have the digital storage functionality of the higher models installed.
Knocked up a little protective circuit using a diode, an electrolytic capacitor and an 22ohms/5W resistor and put that in.

Well after more than three ours on with fan the PM3065s surface is only slightly above room temperature. 

Should never have been shipped without a fan installed, imho.