Test Equipment Anonymous (TEA) group therapy thread

[Zucca]

Just buy a T12, much cheaper and less down the bog each time.

I can't, the Metcal tattoo on my right hand would not match with a T12.

[Specmaster]

Just buy a T12, much cheaper and less down the bog each time.

I can't, the Metcal tattoo on my right hand would not match with a T12.

Wear a glove then

[Specmaster]

Jeez, this thread took an awful turn.

Thats the amazing thing about this thread, it spring off in any direction but always returns to the root in time, its good, I love it.

[med6753]

I find in these circumstances that applying a D.C. voltage to the channel BNC and signal tracing works best. Get another scope on the input stage of each amp and wiggle the input voltage to see if the output moves. Each amp step is a simple differential input and output long tail pair amp with oodles of frequency compensation so it’s easier tracing it through igoring all the compensation caps and stuff that way.

I noticed with scopes that the broken bits are usually right near the front end or right near the plate drivers.

In theory you should be able to isolate the knackered bit before disassembly in system. Once you’ve removed it the circuit is different :

Your suggestion is a good one. I was using a simple sine wave to trace out where channel 2 was not passing signal and causing trace loss. I can press against the board and the signal changes height...sometimes significantly. That tells me there are still issues with the switch deck itself. I suspect it's worn possibly beyond repair but we'll see.

Have you swapped out the obvious failure point, R51 I had a similar thing on a HP1740A and on close up examination the resistor had a fine hairline fracture, replaced it and hey bingo I had a rock solid signal after that.

R51 is not the issue. I am positive of that.

[mnementh]

I have thought about getting a GPSDO for my lab but i have no idea how am i going to get the antenna outside apart from juryrigging it out the window.

I've acquired a GPSDO several weeks ago, and got an antenna and 15 meters of cable last week. What I haven't got is a path for the cable from my lab to the outside. Not much different to your situation, except that I've already thrown out some money.

 
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=flat+rg-6&_sacat=0


What about one of these? Too much loss in the F-connector?

Just buy a T12, much cheaper and less down the bog each time.

I can't, the Metcal tattoo on my right hand would not match with a T12.

Wear a glove then

I can report absolutely zero social adjustment problems for the T12 on my bench; it has been happily cohabitating with my MX-500 for months now.  Of course, both have taken their turns in "tattooing" their owner; but that is to be expected.   

Jeez, this thread took an awful turn.

Thats the amazing thing about this thread, it spring off in any direction but always returns to the root in time, its good, I love it.

I can fix that. 


mnem
"You gotta be fucking kidding me!!!"

[bd139]

 
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=flat+rg-6&_sacat=0


What about one of these? Too much loss in the F-connector?

That's a really cool solution to a problem I have actually as well. Thanks for the heads up. Wonder if you could use a unun on each side and some 300 ohm line as a slightly less lossy method. Although that window frame. Hmm.

I can report absolutely zero social adjustment problems for the T12 on my bench; it has been happily cohabitating with my MX-500 for months now.  Of course, both have taken their turns in "tattooing" their owner; but that is to be expected.   

Yep! Doing those TDS210 BNC's earlier.

[mnementh]

 
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=flat+rg-6&_sacat=0


What about one of these? Too much loss in the F-connector?

That's a really cool solution to a problem I have actually as well. Thanks for the heads up. Wonder if you could use a unun on each side and some 300 ohm line as a slightly less lossy method. Although that window frame. Hmm.

These are meant primarily for Dish Network, etc KU band installation. Standard for this is RG6, so 75 ohm. I know from experience that the connection tends to be pretty fault-tolerant, as it does much of the tuning in the LNB at the dish and sends amplified 1GHz-2.1 GHz signal down the line. I don't know how much loss there is in one of these pass-throughs, but I assume they're probably taking advantage of that fault-tolerant design to keep production costs as cheap as possible. IIRC, the Dish network rig will work and get a stable lock with as much as 24dB loss.

I can report absolutely zero social adjustment problems for the T12 on my bench; it has been happily cohabitating with my MX-500 for months now.  Of course, both have taken their turns in "tattooing" their owner; but that is to be expected.   

  Yep! Doing those TDS210 BNC's earlier.

Amen, brutha! I've a love-nip from my GT7 healing up right now; she gets a little possessive sometimes, and doesn't want to go back in the drawer. 


mnem
"I claim this leftover breakfast in the name of Fat-dwagon-daddy and the Corporation for Public Broadcasting."

[bitseeker]

@bitseeker re the 181
There are a couple of Amphenol connectors I believe fit, I can confirm the first one does (I have it) and it fits nicely.
 
One is readily available, Mouser PN 654-97-3106A-16-11P Amphenol PN 97-3106A-16-11P about USD$20

The other takes a while - I think it is supposedly better from the temp-coeff point of view but is more expensive!
About USD$40 each !   Mouser PN. 654-97-3107A-16-11P. Amphenol PN 97-3107A-16-11P

Expensive as they are they are cheaper than Triax  connectors. **********!!!!!!!

Yeah, tell me about it. Thanks for the references. Now, I'll be less apprehensive the next time a 181 comes by. (Oh, no! )

I plugged it in and it proceeded to blow up 2 of its 4 its Tantalums - I was describing this to my wife and she very astutely nicknamed them "Tantrum" capacitors.

That is an excellent name for them! Bravo Mrs. VK5RC.

I shall have to adopt that.

Replaced them and it works OK I get roughly correct reading on both its ranges and they appear stable - I can't test it further at this stage.
 I have to make a set up to generate a voltage I can then measure down below 1mV and also a "Short" and some test leads, I found some nice pure copper alligator clips and one of Pomona mini-hooks are copper as well. 
Inside it looks like good / real Keithley gear
Regards Rob

Cool. Good find.

I scored a Pomona 5342 cable (3-slot triax to 3 alligator clips) for $40. It currently won't fit any of my Keithley gear, but at that price, I couldn't leave it alone. I'm still hoping I can find either the 2-slot Pomona 4725 and/or a 2-slot to 3-lug adapter (to use with the 5342 cable) at a reasonable (to me) price.

I saw a couple people had posted that they converted the panel-mounted triax connector on their Keithley gear to 3-lug, but it seemed to be a bit of an operation, both electrically and mechanically. So, I've been holding off on going down that path (plus I like to keep my gear as original as possible). I also am not inclined to file off one of the lugs on the 2-lug connector as some have done to make it "universal."

Patience may eventually pay off.

[bitseeker]

Oh, cool. Is that one of the corrected versions? I remember early ones had some jitter issues or something to that effect. (Memory isn't what it used to be...)

I don't know about that, but I have no indication of any issues so far. There is a BG7TBL GPSDO page here on the forum as you know,

https://www.eevblog.com/forum/testgear/bg7tbl-gpsdo-master-reference/

but it doesn't show my model (2017-10-09). Perhaps I need a photo-shoot for it? By the way, BG7TBL is an amateur radio call sign from China, so the guy is a ham.

Yeah, I've periodically checked to see what's going on with his stuff. Some time ago, I got one of those cheap GPS modules with antenna. My plan is to set it up as a simple calibration source to adjust my Racal 1992's OCXO. I don't need super accuracy, yet, so I haven't gotten a GPSDO. But, you know, TEA...

[bitseeker]

Jeez, this thread took an awful turn.

Thats the amazing thing about this thread, it spring off in any direction but always returns to the root in time, its good, I love it.

Interestingly boomerang-like.

[xrunner]

I don't need super accuracy, yet, ...

Yes you do.

You do need it.

You really do need it.

[bitseeker]

 

[Brumby]

You laugh now ........   but then it happens. 

[med6753]

You laugh now ........   but then it happens. 

Sure does, and it strikes when you least expect it. 

[mnementh]

You laugh now ........   but then it happens. 

Sure does, and it strikes when you least expect it. 

[RANDOM MODE]

https://youtu.be/6GEFwiXWieM

[/RANDOM MODE]


mnem
off. slightly.

[bitseeker]

HP 3467A
I have been moderately restrained recently but couldn't resist this, ticks a lot of boxes for me, red LED display,  not really common, of a vintage that you have a fair crack of repair if it breaks, I believe it is based upon a 3466A with switcher and printer.

Rob,

Were you ever successful in locating a legible service manual for your 3467A? One of these interesting meters has surfaced near me, but with some apparent issues and without any docs.

I was also wondering, without GPIB or other interface, do you use yours for logging? Did you find a source for the right size thermal paper?

[Berni]

Yeah, I've periodically checked to see what's going on with his stuff. Some time ago, I got one of those cheap GPS modules with antenna. My plan is to set it up as a simple calibration source to adjust my Racal 1992's OCXO. I don't need super accuracy, yet, so I haven't gotten a GPSDO. But, you know, TEA...

I have two 10MHz rubidium clock modules here that i want to see how good they are. They are pretty close to each other, but what if they are both off?

Just wanting to make sure your oscillator has not drifted off is not time nuttery yet right?

[BravoV]

Not TEA related, by has similarity, its about hoarding electronics components, I'm thinking about creating a new thread called "ECHO" group therapy thread ?

ECHO : Electronics Components Hoarder Organization/Orgy ? 

Any thoughts ?

[Specmaster]

Yeah, I've periodically checked to see what's going on with his stuff. Some time ago, I got one of those cheap GPS modules with antenna. My plan is to set it up as a simple calibration source to adjust my Racal 1992's OCXO. I don't need super accuracy, yet, so I haven't gotten a GPSDO. But, you know, TEA...

I have two 10MHz rubidium clock modules here that i want to see how good they are. They are pretty close to each other, but what if they are both off?

Just wanting to make sure your oscillator has not drifted off is not time nuttery yet right?

Oh yes it is, man with 1 watch knows what time it is, man with 2 or more watches is unsure what the time is without consulting other watches.

[bitseeker]

Yeah, I've periodically checked to see what's going on with his stuff. Some time ago, I got one of those cheap GPS modules with antenna. My plan is to set it up as a simple calibration source to adjust my Racal 1992's OCXO. I don't need super accuracy, yet, so I haven't gotten a GPSDO. But, you know, TEA...

I have two 10MHz rubidium clock modules here that i want to see how good they are. They are pretty close to each other, but what if they are both off?

Just wanting to make sure your oscillator has not drifted off is not time nuttery yet right?

Oh yes it is, man with 1 watch knows what time it is, man with 2 or more watches is unsure what the time is without consulting other watches.

Hence my single OCXO. 

Not TEA related, by has similarity, its about hoarding electronics components, I'm thinking about creating a new thread called "ECHO" group therapy thread ?

ECHO : Electronics Components Hoarder Organization/Orgy ? 

Any thoughts ?

Sounds good. Sounds good. Sounds good. Sounds good. Sounds good. Sounds good.

[Ero-Shan]

I have thought about getting a GPSDO for my lab but i have no idea how am i going to get the antenna outside apart from juryrigging it out the window.

I've acquired a GPSDO several weeks ago, and got an antenna and 15 meters of cable last week. What I haven't got is a path for the cable from my lab to the outside. Not much different to your situation, except that I've already thrown out some money.

 
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=flat+rg-6&_sacat=0


What about one of these? Too much loss in the F-connector?

I can't fix the antenna outside my lab window, and I'm afraid reception wouldn't be good enough. My current plan is to fix it to the porch on my terrace. This means I need to get the cable from the attic to the outside. Would have been a no-brainer some years ago, but I've renovated the house since then, now everything's tightly closed and unaccessible. I plan to take a holiday from my hapless 464 repair and check out the GPSDO and  its antenna placement next weekend.

[Specmaster]

I have thought about getting a GPSDO for my lab but i have no idea how am i going to get the antenna outside apart from juryrigging it out the window.

I've acquired a GPSDO several weeks ago, and got an antenna and 15 meters of cable last week. What I haven't got is a path for the cable from my lab to the outside. Not much different to your situation, except that I've already thrown out some money.

 
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=flat+rg-6&_sacat=0


What about one of these? Too much loss in the F-connector?

I can't fix the antenna outside my lab window, and I'm afraid reception wouldn't be good enough. My current plan is to fix it to the porch on my terrace. This means I need to get the cable from the attic to the outside. Would have been a no-brainer some years ago, but I've renovated the house since then, now everything's tightly closed and unaccessible. I plan to take a holiday from my hapless 464 repair and check out the GPSDO and  its antenna placement next weekend.

I thought that some receivers, like some sat navs, could still get an accurate lock on sat signals indoors?

[bd139]

They can do but the quality of the data depends on how many satellites it can track. The more the better. Indoors my GPS receiver tracks about 4 satellites. Taped to the living room window, about 7, outside somewhere not too crap about 12

[BravoV]

Regarding GPSDOs, all my stuffs are ready, its just my problem still at the lightning protection setup, as I need to install it high above the roof, consulted with lighting protection pros, they're really damn expensive.

Have to wait until I decide to pay the pro to install it, or I do it my self which is quite challenging. 

[Specmaster]

Looks like time nuttery is even worse than volt nuttery [emoji44]

They can do but the quality of the data depends on how many satellites it can track. The more the better. Indoors my GPS receiver tracks about 4 satellites. Taped to the living room window, about 7, outside somewhere not too crap about 12