Timebase Question : Auto vs Norm Mode
I'm working on an 7B53N but I think this question applies to many/most scopes and/or time-bases.
In AUTO mode, the time-base is in a "free-run" mode which generates a ramp at the selected sweep rate and, at the end of the ramp, generates another ramp. This continues whether a trigger is present or not.
In NORM, the time-base waits for a triggering signal before executing a sweep and, at the end of the sweep, waits for another trigger signal before generating another ramp.
My question is with respect to triggering in AUTO. Since the ramp will be generated regardless of a trigger, how does the system perform triggering when in AUTO mode?
I know this is a very basic question, but I don't seem to be finding a good explanation in the manual so I thought I'd ask here.
Thanks,
Barry - N4BUQ
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Re: Looking for part 155-0042-03 Miller integrator to Japan
On Sat, Dec 11, 2021 at 04:33 AM, Jeff Dutky wrote:
I saw that in the Tek ICs RPR, almost every instrument that used the
155-0042-03 parts is indicated to use the 155-0028-00 as a replacement
I just saw that TekWiki contributor Peter on 22 November has merged the 155-0042 into the 155-0028 article and included redirection. Thanks, Peter, if you read this! Raymond
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Re: 1502 TDR RECORD functions
If you have a 1503 you might want to give it a try.? Less fragile and I think, more of a pulse amplitude.? It'll handle a 10 Km string of lights.? Would that be long enough?
Harvey
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On 12/11/2021 6:08 PM, Paul Amaranth wrote: I had a few moments and tried this with a dead string of LED lights.
I can see the end of the string when I short the socket for the
next string, but I can't see any difference when pulling LEDs out.
If I pull out the first LED and short the socket with a screwdriver,
I can see that on the screen, but not for the second LED.
I would think the pulse magnitude is insufficient to cross the LED
semiconductor junction. Obviously not an issue with incandescant
lamps.
Pity, I have a ton of dead strings.
Paul
On Thu, Dec 02, 2021 at 10:17:24PM +0000, Tom Gardner wrote:
To a first approximation the transition wouldn't matter. I'd just use any
old BNC-to-croc clips cable, and then ignore any reflections at the
beginning of the trace.
I wonder if intact bulbs would appear as inductive blips on the trace, which
would make counting along to the failed/short bulb easier.
If I have time, I might have a play, but I'm busy plus An Event occurred today :(
On 02/12/21 09:28, David C. Partridge wrote:
I have to ask how you handle the transition from coax to the Xmas lights? And how you interpret the results.
A picture of two may be worth a 1000 words.
D.
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Glydeck via groups.io
Sent: 02 December 2021 05:23
To: [email protected]
Subject: Re: [TekScopes] 1502 TDR RECORD functions
Good question. I don¡¯t think it matters. An interruption in the transmission line does not care if it¡¯s a LED or a bulb. I¡¯m so trying this on some recalcitrant light strings.
Glydeck KD6NEW
On Dec 1, 2021, at 6:32 PM, Paul Amaranth <paul@...> wrote:
?Was that incandescant or LED lights?
I have an entire bin full of LED strings that are dead and that might
be worth a try.
Paul
On Wed, Dec 01, 2021 at 01:51:54PM -0800, fiftythreebuick wrote:
Tom, the 1502 is one of the most useful instruments around!
I just finished finding the fault in a long string of Christmas lights with mine! :-) Definitely something essential to have around...
Tom --
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows
!DSPAM:61a945ff152291116790165!
|
With help from here and in particular John Miles, Didier (KO4BB) I. Yrj?l? & Dr Luis Cupido I tackled a so so 492BP and have whipped it into shape. Many new caps in power supply, fan, other leaking caps found under RF cages, new battery etc and a good cleaning, case straightening and a partial alignment - it looks and works so nice now. I would not have even considered it - without this support. Had a blast. Thank you.
p.s. I have posted a couple GHz traces just to prove these instruments are not to be ignored.
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Re: 1502 TDR RECORD functions
I had a few moments and tried this with a dead string of LED lights.
I can see the end of the string when I short the socket for the
next string, but I can't see any difference when pulling LEDs out.
If I pull out the first LED and short the socket with a screwdriver,
I can see that on the screen, but not for the second LED.
I would think the pulse magnitude is insufficient to cross the LED
semiconductor junction. Obviously not an issue with incandescant
lamps.
Pity, I have a ton of dead strings.
Paul
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Show quoted text
On Thu, Dec 02, 2021 at 10:17:24PM +0000, Tom Gardner wrote: To a first approximation the transition wouldn't matter. I'd just use any
old BNC-to-croc clips cable, and then ignore any reflections at the
beginning of the trace.
I wonder if intact bulbs would appear as inductive blips on the trace, which
would make counting along to the failed/short bulb easier.
If I have time, I might have a play, but I'm busy plus An Event occurred today :(
On 02/12/21 09:28, David C. Partridge wrote:
I have to ask how you handle the transition from coax to the Xmas lights? And how you interpret the results.
A picture of two may be worth a 1000 words.
D.
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Glydeck via groups.io
Sent: 02 December 2021 05:23
To: [email protected]
Subject: Re: [TekScopes] 1502 TDR RECORD functions
Good question. I don¡¯t think it matters. An interruption in the transmission line does not care if it¡¯s a LED or a bulb. I¡¯m so trying this on some recalcitrant light strings.
Glydeck KD6NEW
On Dec 1, 2021, at 6:32 PM, Paul Amaranth <paul@...> wrote:
?Was that incandescant or LED lights?
I have an entire bin full of LED strings that are dead and that might
be worth a try.
Paul
On Wed, Dec 01, 2021 at 01:51:54PM -0800, fiftythreebuick wrote:
Tom, the 1502 is one of the most useful instruments around!
I just finished finding the fault in a long string of Christmas lights with mine! :-) Definitely something essential to have around...
Tom --
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows
!DSPAM:61a945ff152291116790165!
--
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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Re: Humor, I didn't know HP made one of these (465)
Hi,
If memory serves me correctly, "onsale.com" was first, eBay used a slightly different model.? I did buy from the folks but thy closed shop in 1999 +/-
Be well,DBN aka John
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On Friday, December 10, 2021, 10:23:59 PM EST, Jeff Dutky <jeff.dutky@...> wrote:
Stefan,
Amazon actually attempted to take the on-line auction market from eBay way back in 1999, and threw in the towel only two years later:
-- Jeff Dutky
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Re: Tek 577 restoration -- help needed
Hi Roger,
There is a separate calibration procedure for the 177. There are 2 op-amps in there that need to be adjusted. It has been a while since I have made the 577 videos but if I remember correctly what is causing the issue is the dc balance step in the 177 calibration. The good news is the 177 calibration is I believe only 3 steps. However the calibration is in a totally different document. You also do not need an in cal 577 to cal the 177 so you can do that on any frame with good power rails.
Zen
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-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Rogerio O Sent: Saturday, December 11, 2021 6:32 AM To: [email protected]Subject: [TekScopes] Tek 577 restoration -- help needed Hi folks. I managed to buy a 577 D (ser# B105061). The unit turned on and there was a bright trace on the display - good news! Since the equipment had been left in storage for a long time, there was dirt everywhere so I decided to start by washing and drying. After this procedure the unit turned on again -- good, no damage done. Then, I pulled out every IC and applied a little of deoxit to the pins since most of them where really black and I don't know if this stuff would cause any contact issue. I did the same with all the pushbuttons and rotary switches Next step was to start the calibration procedure All voltages on main PSU were present and within tolerance. I decided not to do step 8 in this first pass since it related to storage operation. However I could not complete step 9 ( Vertical gain adjustment). I suspected of the 177 unit so i tried a spare one that I have, just in case. The behavior of the trace changes, but I can't complete the step successfully. So my questions are: 1 - Is there any known fault on this circuit that I should look? 2- Is it possible that the fault is on the 177 instead of the 577? 3 - If the previous answer is yes, how can I determine if the fault is on the 177 or in the 577? 4 - will the 177 performance check/ calibration procedure work on a faulty 577? I decided to build an extension cable so I can measure the signals in/out the 177 to see if it helps me to identify the problem, but the parts have not arrived yet. Meanwhile every comment/suggestion would be greatly appreciated. Thank you all in advance Roger
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Tek 577 restoration -- help needed
Hi folks.
I managed to buy a 577 D (ser# B105061).
The unit turned on and there was a bright trace on the display - good news!
Since the equipment had been left in storage for a long time, there was dirt everywhere so I decided to start by washing and drying.
After this procedure the unit turned on again -- good, no damage done.
Then, I pulled out every IC and applied a little of deoxit to the pins since most of them where really black and I don't know if this stuff would cause any contact issue.
I did the same with all the pushbuttons and rotary switches
Next step was to start the calibration procedure
All voltages on main PSU were present and within tolerance.
I decided not to do step 8 in this first pass since it related to storage operation.
However I could not complete step 9 ( Vertical gain adjustment).
I suspected of the 177 unit so i tried a spare one that I have, just in case.
The behavior of the trace changes, but I can't complete the step successfully.
So my questions are:
1 - Is there any known fault on this circuit that I should look?
2- Is it possible that the fault is on the 177 instead of the 577?
3 - If the previous answer is yes, how can I determine if the fault is on the 177 or in the 577?
4 - will the 177 performance check/ calibration procedure work on a faulty 577?
I decided to build an extension cable so I can measure the signals in/out the 177 to see if it helps me to identify the problem, but the parts have not arrived yet.
Meanwhile every comment/suggestion would be greatly appreciated.
Thank you all in advance
Roger
|
Re: Looking for part 155-0042-03 Miller integrator to Japan
I saw that in the Tek ICs RPR, almost every instrument that used the 155-0042-03 parts is indicated to use the 155-0028-00 as a replacement (except for a few SN ranges of the 5B12N and 7B52 which use 050-0962-00 and 050-0518-00 respectively. What are 050-xxxx-yy parts? I'm not familiar with that prefix)
I'm going to swap the 155-0028-00s from my parts mule into a known good 7B53A to verify if they are working.
-- Jeff Dutky
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Re: Humor, I didn't know HP made one of these (465)
Stefan,
Amazon actually attempted to take the on-line auction market from eBay way back in 1999, and threw in the towel only two years later:
-- Jeff Dutky
|
Re: Humor, I didn't know HP made one of these (465)
Saw that one and rolled my eyes. Got another one on CL: listing a 2246 & 7854. Amazon price: $200 & $950, Your price: $125 & $825. Wow, didn¡¯t know Amazon carrier obsolete lab equipment!
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Re: Looking for part 155-0042-03 Miller integrator to Japan
On Fri, Dec 10, 2021 at 05:56 PM, Jeff Dutky wrote:
The Miller Integrators that I have in the parts mule 7B53A are 155-0028-00, but
I also have a 5B10N parts mule in the right serial number range to be using a
155-0042-03 part.
155-0042-0x was used in several plugins and a few scopes. For all prefixes in all instruments except 7B52 below B020000 and 5B12N below B065802 155-0028-00 is a direct replacement. /H?kan
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Jean-Marc,
I downloaded the 7B52 manual and that does indeed help. Thanks for the suggestion!
Unfortunately, I think my signals stop at TP470 which makes me fear a TD (or TDs) is bad. I think someone has already been in that area and may have either replaced or resoldered one of them; however, Q466 could be the issue. Either HoldOff is enabled or it may be bad. I just haven't gotten that far with troubleshooting yet.
Thanks again,
Barry - N4BUQ
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----- Original Message ----- From: "Jean-Marc Imbert" <jmimbert@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 10, 2021 1:50:49 PM
Subject: Re: [TekScopes] 7B53N sweep repair Barry,
Barry,
Yes same for U750 , it is also a 155-0042-03 IC on mine.
I will buy an Artek copy, thanks.
For your trigger, the 7B52 wil be a good reference for trigger voltages and
waveforms and trigger schematics as well. Fetch it from the tekwiki, as well
as the troubleshooting manual here from the same tekwiki :
.
Regards
Jean-Marc.
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Barry,
Barry,
Yes same for U750 , it is also a 155-0042-03 IC on mine.
I will buy an Artek copy, thanks.
For your trigger, the 7B52 wil be a good reference for trigger voltages and waveforms and trigger schematics as well. Fetch it from the tekwiki, as well as the troubleshooting manual here from the same tekwiki : .
Regards
Jean-Marc.
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Re: Help required finding a Tek 466 power rail short
James,
The 1.5A bridge rectifiers are suspect. It is recommended to use 4A types. I have done this by the advice on this group. The 4A types run cooler due to not being run near it's current capacity. The rectifiers for the lower voltage supplies are 200V. You can use a higher voltage type if you want. If you will need bridge rectifiers for other things at a higher voltages, get ten of a higher voltage at 4A to get a price break. The price break is usually ten of an item.
It sounds like you have number of shorted tantalums by your description. Keep testing each one with one leg unsoldered. Those that are bad, leave the one leg up and note what you need to replace. With one leg left up, you know that one is bad.
You may have bad transistors. If any are 151-0367-00, check C to E. Any that show leakage, replace with KSP10BU. These have a pinout of BEC.
Mark
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Re: Help required finding a Tek 466 power rail short
Just to clarify.
On the A10 Storage board, there are three tantalums which all read short when connected, yet fine with one leg disconnected.
They are, C1846 C1826 and C2097.
I am presuming that one leg of each is to ground and that the other must be to the 5v rail, so probably all ok (apart from the 5v rail short)
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Re: Looking for part 155-0042-03 Miller integrator to Japan
The Miller Integrators that I have in the parts mule 7B53A are 155-0028-00, but I also have a 5B10N parts mule in the right serial number range to be using a 155-0042-03 part. My notes say "the main selector switch needs cleaning, entire blocks of sweep speeds no working" which suggests that some sweep speeds are working, and hence that the Miller integrator is working. I can double check that instrument to be sure that it is working.
-- Jeff Dutky
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The serial number for my 7B53N is B052213 and U750 in it is a 155-0042-03. I haven't found a serial number range in the manual and presumed it covers all serial numbers for that model.
I'm not sure of all the differences, but comparing my 7B53N to a 7B53A or 7B53AN shows quite a bit of differences. For example, the trigger board in the N model has mostly discrete components whereas the A or AN models have several ICs there. There are other differences - mostly due to layout - but the schematics seem to be quite different as well.
I presume signals at similar (but differently-named) TPs should be close to the same between models but I haven't tried to correlate those yet.
Mine will display a trace in AUTO mode but won't trigger and, of course, won't display anything in NORM due to the same problem. It also won't sweep in the 5ms, 2ms, or 1ms positions. I've cleaned the finger switches but that didn't help and I suspect one of the timing resistors or capacitors is either bad or still not getting connected in those modes. I tested the timing caps while I had it apart and those looked good.
I'm still trying to determine where the problem(s) are in mine.
Thanks,
Barry - N4BUQ
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----- Original Message ----- From: "Jean-Marc Imbert" <jmimbert@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 10, 2021 9:24:33 AM
Subject: Re: [TekScopes] 7B53N sweep repair Thanks Barry ! this is useful information. I'd buy it from Artek asap;: can you
please check if it suits my serial number B051276 ?. Then I think I can work
out the voltage levels similarities with the 7B84, 7B92 which use the same
155-0049-00 sweep control IC. Regards .Jean-Marc
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Thanks Colin but it seems the 7B3N trigger part (and front face) is 90% inherited from the 7B52 in all cases.
For the sweep part, I can't generalize but mine (SNB051276) has a sweep part with a sweep control IC, 155-049-00, similar to the 7B53A. But the apart from this IC the 7B53N and 7B53A sweep boards have very different layouts and overall very different schematics and numbering.
So I dont think the trigger part of the 7B53A can help for the strangely named 7B53N. (everybody agrees that the sequential name should have been 7B52N).
But thanks for the offer.
I'm in France, Tours :)
Barry might be yes in North America.
Jean-Marc
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Re: Help required finding a Tek 466 power rail short
Hi Mark and thank you for your advice.
Any components from Mouser shall probably have to wait until I next go to Europe, as unfortunately the postal services here simply cannot be trusted to deliver any international item. Quality components such as low ESR caps are extremely difficult to find in Brazil so my goal is to just get the scope back to a working condition. I have repaired various of this series, which have always been just fairly simple component replacement. By the tme this one is back up and running I shall certainly have a much deeper understanding on analogue scope repair. :)
Anyway, CR1767 is fine although VR1726 is indeed open. So that is progress.
I have been primarily looking for shorted tantalums and diodes, and mainly on the A6 Interface board. So far, I have found three or four but seem to have run out of tantalums to test on that board.
On the A10 Storage board however, I do find that across certain caps it reads short, only for the caps to test good with one leg removed, although across the traces still reads short. C1846 being one of these.
@ Harvey...
It has been on my mind that perhaps there is a bridge rectifier issue because some of the readings are not as they were, and they are not consistent across all rectifiers. I have just been putting it down to something further along being shorted, however I shall have a deeper look just to clarify. It would be nice to remove the rectifiers but it was such a ball-ache changing the ones I replaced that I must say, it doesn't really fill me with desire to do it again.
There was a video I saw where the tech just used a pair of pliers to literally twist the rectifier off the board before desoldering the remaining legs/pins, it's just I can no longer find the vid and don't want to risk destroying the A6 board...
As for ESR testers, I have an MK 328 which stopped working this week. Having said that I found an old Wayne Kerr 4225 ESR/LCR tester yesterday in a junk shop for under 20 USD. It switches on and a quick look inside shows it's complete, so once I clean the contacts which hold the components under test, I'll give it a spin.
Need to head into town for components.
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Raymond Domp Frank
zenith5106
James55