Re: 2465A (ch.1-ch2) output
Thanks,
? I wonder if I could extract the A-B output from one of the plug-in difference amplifiers. ?I would like to have the A, B, A-B voltages to send to my wave analyzer.
mike
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Re: 2465A (ch.1-ch2) output
Bonjour, bravo for the good question.
Depending on he signal levles, desired CMRR and BW, may options are avaialble for a diff amp, CH1-CH2.
But The external VERT output of all 2465/7x TEK are CH 2 SIG OUT and a side chan of the CH2 amp.
CH1-CH2 is derived in the Ch mux hybrid and is NOT sent to the CH 2 SIG out.
Main use of CH 2 SIG is to monitor on ext device eg counter, or to strap to CH 1 in for additional gain.
Even if you obtained an ext CH1-CH2, the accuracy and CMRR will give some error, perhaps 2..5%.
See TEK service and op manual for your model and SN.
We use TEK 7000 MF and plugins designed for diff ue eg 7A22. Also suggest TM500 plugin AM502, excellent diff amps with BW limit controls.
Finally external diff amps are useable, such as our old friend Greg LEYH instruments #29 amp, x1/10/100/500 full diff. see lod.org.
Bon Chance
Jon
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I have a 2465A and hoping I can get an output for Ch. 1 - Ch2, much like the old 1A1 preamplifier. If I invert ch.2 and add to ch.1 will the output on the back bnc (ch. 2 output)
give me the ch1 - ch2.? ?
Is there any more modern preamp than the 1A1 that has that function?
Regards,
mike zias / W3JRR
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Just found my 7CT1 plugin curve tracer. Used In a large CRT MF like 7603 its great.
Needs a vert PI in the H slot or H PI with X (ext) input.
Only 50V but small and handy compared to the giant 576, 577 and 500 tube tracers.
Finally the TEK test fixtures are rare but very handy, only diff the 577/576 test adapters is they are 5 terminal Kelvin, but still can work on the 7CT1.
Jon
PS: 7CT1 have a pair of axial lytics C30, C32 100 uF that were 25V rated on 30V bus.
A TEK mod later replaced them with 100 uF 50..100V.
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On 12/21/23 20:10, Froggie the Gremlin wrote: A novice tweaker can spend hours at first but after a few time you will get the "feel" of the controls.
The experienced pilot has it all in memory, the work becomes a pleasure... Thanks Jon, made me smile :-)
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Raymond! Fine to hear from you,
The RT and BW on many TEK are conservative (unlike the Chinese scopes) and are often exceeded IF the test setup is optimized.
tips for optimized RT :
1/ Use direct connection , no cables , minimize adapters
2. Use high quality connectors eg BNC T, terminations, atten eg Mini Circuits HAT-20.
3. Use scope internal 50 Ohm term
4. Best pulser I found is Leo Bodnar 40 pS
5. Add 10..20 db 50 Ohm pad after gen to minimize back reflections and VSWR issues
6. Check many PU to see if aberration is in MFor PI.
7. Follow PU and MF align with NO extenders, eg remove scope side covers.
8. Be PATIENT, transient tweaking is NEVER perfect and is an INTEATIVE INTERACTIVE process.
9. The BW will "fall out" correclty IF the transient response is tweaked ......
A novice tweaker can spend hours at first but after a few time you will get the "feel" of the controls.
The experienced pilot has it all in memory, the work becomes a pleasure...
Hope to meet you in Netherlands sometimes 2024! \\
Amicalment,
Jon
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Thanks for the explanation, Jon and yes, it's Raymond from the Netherlands.
My remark about the rise time: I see a rise time of 200ps in your photo, which is quite surprising, even for a 7104 with 7A29. It equates to around 1.75GHz bandwidth... I guess a direct-to-plate connection in a 7104 could provide that, but with internal amp and vertical plugin like a 7A29?
Raymond
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John and Raymond (in Holland?)
to clarify:
1/ Scope shots are NOT 7104 /7A29
They are 7904/7A26
2/ Lower readout is delay time of B sweep of 7B92A hor plugin (excellent for all 7xxx except 7104)
3/ Risetime/aberrations....we have special needs to qualify high FS digital audio cables and transromers for low abberation and RT.
Our transformers are carrying up to 24.576 MHz Manchester coded AES/EBU, AES-3id and SP/DIF with FS to 192/384 thus half bit rate to 24.576 MHz and need at least 5th harm.
setup: Leo Bodnar 40 pS>>Mini ckts HAT-20 50 Ohm attn >>7A24 (or 7A29) 50 Ohm inoput
NO cables, direct connections.
Followed TEK serv on Vert plugin 7A24 and on Vert amp transient CAL.
As Chuck Harris once said, transient cal is more of an art than a science.
4/ The aberrations are all in the Leo B 10 MHz wave first few uS and slower Waves freq only reduces the trace intensity.
5/ Of course the plugin and Vert amp of the scope all contribute to RT and aberrations, so each channel of each PU and the Vert in the scope have separate CAL proceedures!
Enjoy,
Jon
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On Thu, Dec 21, 2023 at 04:48 PM, Raymond Domp Frank wrote:
Come to think of it: The full character scan of the Readout module could perhaps benefit from a little adjustment: The "tails" are a bit short in the "n" and "p".
BTW, very nice edges! Did you check some slower edges too (say between 1ns and 10us), after this adjustment? In my experience, these often show some overshoot after adjusting the fastest edges, somehow.
Raymond
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On Thu, Dec 21, 2023 at 04:14 PM, John Griessen wrote:
What is the lower right 00.79pS from? I see 10nS 200pS on top line and seem to be from the left right timebases.
I think that says 0.79ns. The 200ps rise time surprises me... Raymond
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On 12/21/23 00:14, Froggie the Gremlin wrote: New photos:
/g/TekScopes2/album?id=291760
1/ 7104/7A29/7B10/7B15 with leo Bodnar 40 pS pulser after transient allignment /g/TekScopes2/photo/291760/3725151What is the lower right 00.79pS from? I see 10nS 200pS on top line and seem to be from the left right timebases. My 7104s are not fully working at the moment...( I could not fiddle with same setup to figure it out).
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New photos: /g/TekScopes2/album?id=2917601/ 7104/7A29/7B10/7B15 with leo Bodnar 40 pS pulser after transient allignment 2/ Bench with 7703/7L5, 7904, usual PUs Many 7000 and TM500 PU on top shelf Lots more ! Enjoy! Jon
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On Tue, Dec 19, 2023 at 08:31 PM, David C. Partridge wrote:
> What do you recommend using to clean switch contacts
?
For all the ¡°finger¡± to pad cam switches, only ever use cartridge paper strips (say 1/8¡± by 1.5¡±) dampened with isopropyl alcohol.? Turn the cam so the finger lifts off the pad, insert the paper slip, turn the cam to drop the finger again, then slide the paper out.? Repeat as necessary.
?
David
Sounds exactly like the process I use to clean floppy drive heads on my vintage computers, just a tad more delicate. - David
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I'd agree with that 100%. When I've done it, I've just used regular
laser printer paper.
Paul
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On Tue, Dec 19, 2023 at 06:40:22PM -0800, Radu Bogdan Dicher wrote: This is probably one of the most finicky restoration/maintenance tasks of
any piece of equipment I am aware of. Not to discourage anyone, but it
requires clean, careful and deliberate work.
Radu.
On Tue, Dec 19, 2023 at 6:31?PM David C. Partridge <
david.partridge@...> wrote:
What do you recommend using to clean switch contacts
For all the ¡°finger¡± to pad cam switches, only ever use cartridge paper
strips (say 1/8¡± by 1.5¡±) dampened with isopropyl alcohol. Turn the cam so
the finger lifts off the pad, insert the paper slip, turn the cam to drop
the finger again, then slide the paper out. Repeat as necessary.
David
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows
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Had 7000 scoles and pluguns since 1990s, perhaps 4 scopes and 120 PU...
Fast notes:
Attn.contact clean :
Paper: We use business cards and 99% Iso Achol.
Beware some wideband PI like 7A29 use polysolfone substrate attn and need special cleaning precaution
7L5/12/13/18 All the TEK 7K SA have VERY difficult repair and service, and usually dead shaft encoder controls and sometimes burned out atten/mixers. Beware.
The sampling units are hard to use and finicky. Easier to just get a modern digital scope for plots, one shot, averaging.
The curve traced 7CT1 is rare and costly and hard to sue. Avoid unless a junker low cost.
Bon chance
Jon
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On 12/19/23 20:40, Radu Bogdan Dicher wrote: This is probably one of the most finicky restoration/maintenance tasks of any piece of equipment I am aware of. Not to discourage anyone, but it requires clean, careful and deliberate work.
Radu.
On Tue, Dec 19, 2023 at 6:31?PM David C. Partridge <david.partridge@... <mailto:david.partridge@...>> wrote:
> What do you recommend using to clean switch contacts
So, what IS cartridge paper? "Quality cartridge paper will have a slight texture to it ¨C this is known as grain or tooth, and provides the resistance needed to hold marks in place and increases the depth of range achievable in graphite or charcoal." Art supply.
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This is probably one of the most finicky restoration/maintenance tasks of any piece of equipment I am aware of. Not to discourage anyone, but it requires clean, careful and deliberate work.? Radu.?
> What do you recommend using to clean switch contacts ? For all the ¡°finger¡± to pad cam switches, only ever use cartridge paper strips (say 1/8¡± by 1.5¡±) dampened with isopropyl alcohol.? Turn the cam so the finger lifts off the pad, insert the paper slip, turn the cam to drop the finger again, then slide the paper out.? Repeat as necessary. ? David
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> What do you recommend using to clean switch contacts ? For all the ¡°finger¡± to pad cam switches, only ever use cartridge paper strips (say 1/8¡± by 1.5¡±) dampened with isopropyl alcohol.? Turn the cam so the finger lifts off the pad, insert the paper slip, turn the cam to drop the finger again, then slide the paper out.? Repeat as necessary. ? David
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I have a 7904.
One of my favorite combinations is a 7A26 (or 7A24 if I need the bandwidth), a 7D12 with sampling plugin, a 7D15 225 Mhz counter, and a 7B92A timebase.? The 7B92A does have a trace separation on the two traces.
An interesting use of the 7D12 is to use the A intensified by B function, take the B gate out, and run it to the trigger in on the 7D12.? It then samples the voltage on the intensified area of the race, allowing the equivalent of a cursor read.
Harvey
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On 12/19/2023 4:51 PM, dkarguth wrote: On Tue, Dec 19, 2023 at 03:13 PM, <Zentronics42@...> wrote:
EVERYTHING that I have gotten in to the lab in the 7K hardware has
needed some kind of servicing. It could be as simple as cleaning
the attenuator contacts to as complex as a full rebuild of the
plugin followed by a calibration.
What do you recommend using to clean switch contacts that won't hurt the plastics? I know some contact cleaner sprays can soften some types of plastic.
The listed plugins 7a26, 7B70, and 7B71 are a good match for the
frame though you might want to be on the lookout for a
7B53A(100Mhz Dual) or a 7B92 / A (500Mhz) the dual time bases will
free up a Horz bay for another plugin. I was not a fan of the 7B7X
plugins for the way they implemented the trigger control. Lots of
plastic and when it cracks it is REALLY hard to get something
working again. If you still want to run dual plugins kick up to
the 7B80 and 7B81 . DO NOT grab a 7b87. The 7B87 is kind of a
special time base for the 7854 to allow single shot capture.
I was originally going to order a 7B92 from the seller I got the scope from, but was told that while it will technically work in the 7704, the original 7704 does not have provisions to vertically separate timebases from the same plugin. Not really a huge deal, but that's the main reason I chose the 7B7x plugins instead of a dual timebase one. I might pick up a pair of the 7B80/81 plugins at some point in the future if I have problems with the 7B7x ones.
Thanks for the info, I'll keep the plugins you listed in mind!
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On Tue, Dec 19, 2023 at 03:13 PM, <Zentronics42@...> wrote:
EVERYTHING that I have gotten in to the lab in the 7K hardware has needed some kind of servicing. It could be as simple as cleaning the attenuator contacts to as complex as a full rebuild of the plugin followed by a calibration.
What do you recommend using to clean switch contacts that won't hurt the plastics? I know some contact cleaner sprays can soften some types of plastic.
The listed plugins 7a26, 7B70, and 7B71 are a good match for the frame though you might want to be on the lookout for a 7B53A(100Mhz Dual) or a 7B92 / A (500Mhz) the dual time bases will free up a Horz bay for another plugin. I was not a fan of the 7B7X plugins for the way they implemented the trigger control. Lots of plastic and when it cracks it is REALLY hard to get something working again. If you still want to run dual plugins kick up to the 7B80 and 7B81 . DO NOT grab a 7b87. The 7B87 is kind of a special time base for the 7854 to allow single shot capture.
?
I was originally going to order a 7B92 from the seller I got the scope from, but was told that while it will technically work in the 7704, the original 7704 does not have provisions to vertically separate timebases from the same plugin. Not really a huge deal, but that's the main reason I chose the 7B7x plugins instead of a dual timebase one. I might pick up a pair of the 7B80/81 plugins at some point in the future if I have problems with the 7B7x ones. Thanks for the info, I'll keep the plugins you listed in mind!
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mike zias / W3JRR
Froggie the Gremlin
David C. Partridge