Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 14551016 times)

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Offline URI

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18400 on: October 19, 2018, 07:25:11 pm »
@URI can hardly breathe here with the suspense of seeing some photos of it up and running in all its glory.

Same here*.   :)


Did they do the repair FOC and you paid for the carriage?

Awesome deal if they did.

Yepp, they repaired it free of charge, I only paid for the transfer to Keysight Germany.
It felt like winning the jackpot when I received the message that the scope would be repaired without further costs for me.  :-+

*- Sure, not photos but the real thing for my part.
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Offline URI

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18401 on: October 19, 2018, 07:39:32 pm »
    I just noticed:

I barely got in under the wire for this service manual on my 3478A; only ~ 2000 units above the cutoff where you have to play the "Which revision is THIS ONE?" game.  :phew:

Depends. With a unit this new you miss out on the fun of retracking all the changes not only of the manual itself but also of the schematic.   ;)

Speaking of -that's something I have to follow further on my 6114A. Well, gained some extra free time this weekend I thought I would be playing with my new toy..
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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18402 on: October 19, 2018, 07:40:50 pm »
The spring contacts are certainly not ferrous and I hazard a guess at them being brass as well, they are very nicely sprung as well so would give a good contact but I take your point about possible wear on the gold plating. I don't have that unique problem that you have so they suit my needs perfectly.  :-+ 
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Offline tautech

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18403 on: October 19, 2018, 08:05:32 pm »
7Mhz. That’s 25W of RF. Enough to burn you (minor RF burn on finger from the LPF  :-DD). I’ve got a Hammond box on the way from CPC. Will chuck it inside that and see if it’s radiation from the PA or up the feed. I haven’t stuffed an RFC on the DC inlet yet. This is very prototype phase stuff so I don’t want to piss on their party until I’m a good citizen :)
Joe's a bit interested to investigate what you observed with the Brymen.
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Offline Housedad

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18404 on: October 19, 2018, 08:21:54 pm »
    I just noticed:

I barely got in under the wire for this service manual on my 3478A; only ~ 2000 units above the cutoff where you have to play the "Which revision is THIS ONE?" game.  :phew:

mnem
*Thanks Ifni for small favors*

Found this on the net about hp serial numbers.  Just a post from someone in 2003.  Don't know if it is true or not, but WTH.  The one I ordered did not have picks of the serial number anyway.   :rant:

So, is this the way the serial numbers are encoded?

 "The serial is: USA 2228A11076

Take the first two digits and at it to 1960 = 1982 (year). The next two digits represent the week in the year = 28. The letter indicates where it was made. A = America, B=Brazil, S=Singapore, etc. The remaining digits tell you that it was the 11,076th  manufactured "
« Last Edit: October 19, 2018, 08:58:04 pm by Housedad »
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18405 on: October 19, 2018, 10:30:55 pm »
Yup. Mine's about due for its midlife-crisis at ~32 years old.

If I see a 1/8 scale Corvette or Porsche parked under the bench with nekkit Barbie passed out in in the back anytime soon, I know where it came from.  :-DD

mnem
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18406 on: October 19, 2018, 10:49:31 pm »
    I just noticed:

I barely got in under the wire for this service manual on my 3478A; only ~ 2000 units above the cutoff where you have to play the "Which revision is THIS ONE?" game.  :phew:

Depends. With a unit this new you miss out on the fun of retracking all the changes not only of the manual itself but also of the schematic.   ;)

Speaking of -that's something I have to follow further on my 6114A. Well, gained some extra free time this weekend I thought I would be playing with my new toy...
Having played that game professionally as an HP AV/PC/SERVER ASP a scant few years ago, you have NO IDEA how happy I am NOT to be playing it here, with a scanned PDF of a paper manual as my only reference resource.  :palm:

The spring contacts are certainly not ferrous and I hazard a guess at them being brass as well, they are very nicely sprung as well so would give a good contact but I take your point about possible wear on the gold plating. I don't have that unique problem that you have so they suit my needs perfectly.  :-+ 
Yup. One of the hardest things to remember, especially as a somewhat jaded IT Mercenary, is that EVERYBODY'S application is different; sometimes in fundamentally unique ways, sometimes in ways that can only be resolved by judicious application of P/N 19511-80014 or equivalent.  :-DD

mnem
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Online xrunner

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18407 on: October 19, 2018, 10:53:54 pm »
So, is this the way the serial numbers are encoded?

 "The serial is: USA 2228A11076

Take the first two digits and at it to 1960 = 1982 (year). The next two digits represent the week in the year = 28. The letter indicates where it was made. A = America, B=Brazil, S=Singapore, etc. The remaining digits tell you that it was the 11,076th  manufactured "

Here's mine -

2301A17122

1983, 01, America, 17122



Been working on a little project for the local repeater. They want to put a GLB preselector on the input, but it was tuned at the factory for 144.570 MHz. So I re-tuned it using my DSA815TG. Not difficult if you have the right tools. You can see in the pic the before curve and where I needed to get it to.

The stated total gain for the unit is +8 dB (it has a pre-amp in it using an MRF 901), but it was actually -10 when I got it. I managed to tweak it up to -1 dB gain while moving the peak response over to 144.730 MHz, but that's all I can get out of it. The transistor is working because if you disconnect power you get barely anything out, but I think it's weak, so I ordered another one to see what happens. Really that's about all I can see that can go wrong, everything else is pretty much intact.

 :-//

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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18408 on: October 19, 2018, 11:15:15 pm »
So you figure being run with badly mismatched output, or some catastrophic event like a nearby lightning strike or having been run from an incorrect power supply in its past?

mnem
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Offline Housedad

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18409 on: October 19, 2018, 11:21:02 pm »
Noob question.

On pictures on the net, I can see on the back (rear) of the HP 5385A is four screw holes.  Did they make rear (bottom) feet for these?
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Offline Housedad

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18410 on: October 19, 2018, 11:29:02 pm »
Darn.  Out of cash for TEA until December.   I guess the GPSDO will have to wait.



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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18411 on: October 19, 2018, 11:30:03 pm »
In Other News...

Looking like the resistance measurement issues with my 3478A are in fact F/R jack switch-related. Cleaning seemed to help; went from fluctuating between .6 ohms and .3 ohms shorted (using banana patch cords, not clips; these measure 0.9 ohm and 0.045 ohm on my Fluke 189 and DE-5000 respectively) down to fluctuating 0.22xx - 0.19xx ohms. After reviewing the schizzmatics, I discovered I could bypass 1/2 of the switch by swapping a couple leads at J107; that dropped shorted resistance to 0.116x - 0.1170 ohms.

Part of me is saying, as I know I'm likely going to really want the rear jacks about twice in my lifetime, that I should just bypass the switch completely and solder the front ports into service; it'll be more accurate and reliable anyways... meanwhile, the purist in me keeps trying to strangle that part.  :-DD We'll see who wins after dinner.  >:D

mnem
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« Last Edit: October 20, 2018, 01:15:44 am by mnementh »
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Online xrunner

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18412 on: October 19, 2018, 11:41:10 pm »
So you figure being run with badly mismatched output, or some catastrophic event like a nearby lightning strike or having been run from an incorrect power supply in its past?

mnem
*Making Shake & Bake pork chops & smashed topatoes for dinner*

So you figure being run with badly mismatched output, or some catastrophic event like a nearby lightning strike or having been run from an incorrect power supply in its past?

mnem
*Making Shake & Bake pork chops & smashed topatoes for dinner*

Good questions mnementh. I attached the spec sheetl for the unit. Unless I am interpreting it wrong, they really mean the system from black box in to black box out has a gain of +8 dB - not the gain of the pre-amp only. If anyone has a different interpretation please chime in.  ::)

What makes a transistor have a "weak" gain? I am not an expert in this type of failure analysis but I have seen it before in other repairs I've made. However, I did order two more off Ebay for $10, just to see. Like I said, the thing is pretty simple and is mostly a bunch of cans and coils. There isn't any damage and it seems to peak up really well and easily. What else can go wrong except the transistor?

 :popcorn:
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Offline Cubdriver

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18413 on: October 20, 2018, 12:10:29 am »
Found this on the net about hp serial numbers.  Just a post from someone in 2003.  Don't know if it is true or not, but WTH.  The one I ordered did not have picks of the serial number anyway.   :rant:

So, is this the way the serial numbers are encoded?

 "The serial is: USA 2228A11076

Take the first two digits and at it to 1960 = 1982 (year). The next two digits represent the week in the year = 28. The letter indicates where it was made. A = America, B=Brazil, S=Singapore, etc. The remaining digits tell you that it was the 11,076th  manufactured "

Pretty much.  I've learned a bit more regarding the encoding - the three or four digit prefix represents the year and week of the engineering revision that the instrument is built to.  The leading two (or one, in the case of three digit prefixes) digits are added to 1960 to determine the year, and the last two represent the week.

The letter is country of manufacture - A for USA, U for UK, G for Germany and J for Japan, for instance.

The digits after the country code are the serial number of the unit.

Its actual manufacture date may be well after what is indicated by the prefix if it was a design that wasn't updated.  I have an 8644B with a prefix of 3546 which indicates a late 1995 rev; it's actually marked as an Agilent unit and based on component date codes looks to be late 2000ish production.  FWIW,

-Pat
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18414 on: October 20, 2018, 01:27:22 am »
So you figure being run with badly mismatched output, or some catastrophic event like a nearby lightning strike or having been run from an incorrect power supply in its past?

mnem
*Making Shake & Bake pork chops & smashed topatoes for dinner*

Good questions mnementh. I attached the spec sheetl for the unit. Unless I am interpreting it wrong, they really mean the system from black box in to black box out has a gain of +8 dB - not the gain of the pre-amp only. If anyone has a different interpretation please chime in.  ::)

What makes a transistor have a "weak" gain? I am not an expert in this type of failure analysis but I have seen it before in other repairs I've made. However, I did order two more off Ebay for $10, just to see. Like I said, the thing is pretty simple and is mostly a bunch of cans and coils. There isn't any damage and it seems to peak up really well and easily. What else can go wrong except the transistor?

 :popcorn:
I'm not the greatest with RF, but with active notch filters like this one, it's my understanding that overall gain is supposed to be relatively small, somewhere between unity and a few dB. But what's important is how much the device lowers the noise floor so that you can receive weak signals being sent at the correct frequency (and only at the correct frequency) with clarity. The lower the noise floor, the less noise gets amplified in the next stage.

I'm sure bd or med can explain it better than I; I'm a bit of a hack as far as RF goes.  :palm:

mnem
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Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18415 on: October 20, 2018, 02:45:21 am »

I'm not the greatest with RF, but with active notch filters like this one, it's my understanding that overall gain is supposed to be relatively small, somewhere between unity and a few dB. But what's important is how much the device lowers the noise floor so that you can receive weak signals being sent at the correct frequency (and only at the correct frequency) with clarity. The lower the noise floor, the less noise gets amplified in the next stage.

I'm sure bd or med can explain it better than I; I'm a bit of a hack as far as RF goes.  :palm:

mnem
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Me explain it? Sorry, you got the wrong person.  :-DD I'm sure bd can explain it but on the whole RF baffles me.  :-//

And over the past few days a lot of the conversation has centered around software and coding which is another subject that I stay away from. So I just keep my pie hole shut.  :P But I will say from experience that most writers of code have NO clue on how to do a proper regression which guarantees that they will fix the problem at hand but screw up something else. 
« Last Edit: October 20, 2018, 02:48:00 am by med6753 »
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18416 on: October 20, 2018, 03:44:03 am »
Forgive me...

I seem to have this repeating brain fart where you and Specmaster and bd139 are concerned; I'm always swapping your "specialties" in my memory. I know it's somehow related to my horrible memory for names. It's like that information is written on different sides of the same brain cell, and I never know which side is going to "click" with which identity. EVENTUALLY I usually get it ironed out... But it is sometimes VERY embarrassing until I do. And it's a lot harder when you don't have a face and voice to associate.  |O

mnem
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Offline bitseekerTopic starter

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18417 on: October 20, 2018, 04:19:01 am »
Every XKCD comic has "mouse over" text with another bit to the joke, which doesn't show when you link to the image here.   This one's mouse over text says:

Quote from: XKCD
I'm working on assembling a combination declinometer, sclerometer, viscometer, aleurometer, stalagmometer, and hypsometer. I'm making good progress according to my ometerometer, a device which shows the rate at which I'm acquiring measurement devices.

Hmm, an ometerometer might break in the hands of some TEA members. :-DD
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Offline bitseekerTopic starter

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18418 on: October 20, 2018, 04:29:14 am »
9 pages....!

You get busy for a couple of days and then there's 9 pages on which to catch up.

Yeah, I know. I'm trying to catch up now after a busy few days.
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Offline bitseekerTopic starter

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18419 on: October 20, 2018, 04:42:43 am »
I'm eagerly awaiting the arrival of my latest acquisition, another Tek TDS210, not that I need another but it comes with a differential probe, something I have been looking for at a sensible price.

Wow, isn't that probe worth more than the scope? Nice score.
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Offline bitseekerTopic starter

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18420 on: October 20, 2018, 04:56:22 am »
Found this on the net about hp serial numbers.  Just a post from someone in 2003.  Don't know if it is true or not, but WTH.  The one I ordered did not have picks of the serial number anyway.   :rant:

So, is this the way the serial numbers are encoded?

 "The serial is: USA 2228A11076

Take the first two digits and at it to 1960 = 1982 (year). The next two digits represent the week in the year = 28. The letter indicates where it was made. A = America, B=Brazil, S=Singapore, etc. The remaining digits tell you that it was the 11,076th  manufactured "

Pretty much.  I've learned a bit more regarding the encoding - the three or four digit prefix represents the year and week of the engineering revision that the instrument is built to.  The leading two (or one, in the case of three digit prefixes) digits are added to 1960 to determine the year, and the last two represent the week.

Exactly. Some take the date coding to be the manufacture date, but it's not. Like you, Pat, I've run into examples where the date codes inside debunk the manufacture date hypothesis.
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Offline Housedad

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18421 on: October 20, 2018, 05:15:18 am »
I'm eagerly awaiting the arrival of my latest acquisition, another Tek TDS210, not that I need another but it comes with a differential probe, something I have been looking for at a sensible price.

Wow, isn't that probe worth more than the scope? Nice score.

 'The TEA is strong with this one.' ------> Speckmaster  ☕
« Last Edit: October 20, 2018, 05:47:07 am by Housedad »
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Offline Martin.M

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18422 on: October 20, 2018, 05:17:09 am »
 :bullshit:

 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18423 on: October 20, 2018, 06:04:22 am »
Martin, you have my sympathy and understanding. I have the military version of the Tek 7603N called the OS 245(P)/U. I did find a manual for it but it is missing sections including the Z-Axis and CRT schematics. In fact, I found several sources but it turns out that they apparently are from the SAME master copy. So you would think I could use the manual for the civilian 7603N. Not quite. Tek made so many changes and updates over the life of the 7603 series that it's almost like a different scope on the inside. My scope is an early version and just about all the manuals available are for the later versions. And of course I had a problem with the CRT blanking circuit so I was troubleshooting blind. It can be very frustrating and annoying.  |O     
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #18424 on: October 20, 2018, 06:09:09 am »
I'm eagerly awaiting the arrival of my latest acquisition, another Tek TDS210, not that I need another but it comes with a differential probe, something I have been looking for at a sensible price.

Wow, isn't that probe worth more than the scope? Nice score.

Yeah, if the probe's salvageable, I'm afraid he may be getting The Jammy back before it ever even officially goes to URI...  :-DD

mnem
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