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Re: 2465 Calibration
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Ross -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of jimbert4 via groups.io Sent: Friday, April 29, 2022 3:48 PM To: [email protected] Subject: Re: [TekScopes] 2465 Calibration Well I really messed up the vertical calibration today after getting limit errors on all the ranges. But I figured out the problem. My signal generator output was only 1/2 of what it was supposed to be. It's a Juntek PSG9080 that I bought on Amazon. It's supposed to have a 50 ohm output impedance and I discovered that when I connect it to a 50 ohm load (i.e. the oscilloscope) the output voltage is cut in half. Is that expected? I thought the 50 ohms on each end would be in parallel and not affect the output voltage. Ross - That is correct. If the source Impedance is 50 Ohms, when you load it with 50 Ohms, the voltage division node will be 1/2 of the voltage specified on the instrument. There is also a notification on the front of the Tektronix PG506 in Red that states the same condition. When doing the CAL 02 Vertical calibration, you are not doing that into a 50 Ohm Load, it is High Impedance. Also make sure that your Signal Generator is producing a Square Wave waveform with the requested Voltage Level being the High Level "Referenced to Ground". It can't be just a DC Level equivalent to the requested Voltage Level. Also verify that the Signal Generator does not have any ripple on the lower Voltage Levels. Any of these conditions will cause LIMIT errors and you won't complete calibration. Once again, using the Tektronix specified equipment is preferred. Also, using the PSG9080 is a pain in the neck because whenever I change the output voltage, I also have to change the offset to 1/2 of the new peak-peak to set the low end (approximately) at ground level. Ross - See above comment "Referenced to Ground" comment. How critical is the frequency used during the vertical calibration? I have seen both 1 KHz and 100 KHz mentioned as the frequency to use. How about 400 Hz? Then maybe I could use my DMM AC RMS meter with some conversion factor to get the peak value? Ross - I just measured mine and it is 1kHz for all of the requested Output Voltages of the PG506. They use other frequencies for the Fast Rise Waveform Tests the 1ookHz is used for that. |
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Re: Need Help With Tek 453 Weird Problem
On Fri, Apr 29, 2022 at 01:37 PM, diyguitarist wrote:
Then later I was analyzing the PS and Horiz Amp schematics and noticed thatBut did you measure the ripple? It's EASY to do with your DVM: Just switch to ACV So, check the voltage with the DVM set to DCV, then switch to ACV and you've got the ripple. Your DVM probably won't give good ripple measurements if this is a switching PS, but if it's running off anything from 25-400 Hz, the numbers will be useful. |
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Re: 2465 Calibration
Well I really messed up the vertical calibration today after getting limit errors on all the ranges. But I figured out the problem. My signal generator output was only 1/2 of what it was supposed to be. It's a Juntek PSG9080 that I bought on Amazon. It's supposed to have a 50 ohm output impedance and I discovered that when I connect it to a 50 ohm load (i.e. the oscilloscope) the output voltage is cut in half. Is that expected? I thought the 50 ohms on each end would be in parallel and not affect the output voltage.
Also, using the PSG9080 is a pain in the neck because whenever I change the output voltage, I also have to change the offset to 1/2 of the new peak-peak to set the low end (approximately) at ground level. How critical is the frequency used during the vertical calibration? I have seen both 1 KHz and 100 KHz mentioned as the frequency to use. How about 400 Hz? Then maybe I could use my DMM AC RMS meter with some conversion factor to get the peak value? |
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Re: 2465 blower
It's painful but you can rebuild the Siemens motors. You have to unwind them to get at the bearings which is a massive pain and when reassembling take great care of the fragile hall effect sensors. The bearings are standard cylindrical oilite bushes which you can re-impregnate with oil by heating to about 80 degrees C in a vacuum chamber (I have a heath-robinson contrivance made of a lump of old brass and using an old model engine spark plug as a feed through). I must confess I tend to turn new tiny oilite bushes from big ones(!) just remember not to ream the bore (they recommend single point boring, but it's a pretty small tool). There is a very nice collet drawing (Fan Collet - Tek 2465 O-scope) in the files section of this group which is ideal for making a new one. I made one out of aluminium ages ago. I needed a little jig to hold it to turn the thread but generally it was OK!
Alan |
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Re: 2465 tube & focus question
Just bought the Kitsune-Denshi Battery Kit anyway. It's a good investment.
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I really like the portability of the Oscilloscope and it works well for that. Ross -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of si_emi_01 Sent: Friday, April 29, 2022 2:05 PM To: [email protected] Subject: Re: [TekScopes] 2465 tube & focus question You make mention that the Tek 222 Digital Oscilloscope is isolated. That is correct and the AC-to DC Adapter provides pretty good Isolation as well. I have used the 222 Oscilloscope many times in high Impedance, high Common Mode Noise environments up to 1 MHz with good results. I have had to replace the batteries a few times because I don't use it all of the time. I should buy the Kitsune-Denshi 18650 Battery kit for it. That would help with the batteries failing. Another project for another day. Ross -----Original Message----- From: [email protected] <[email protected]> On Behalf Of alan.bain@... Sent: Friday, April 29, 2022 12:36 PM To: [email protected] Subject: Re: [TekScopes] 2465 tube & focus question Sorry should have said UK. That's a good point! I still like the old phosphor scopes. I used a 465 for a long time and them moved to the more versatile 2465 after a try with HP scopes which I didn't like so much. There's also handy 222 for scope troubleshooting (despite its low bandwidth it is isolated which can be handy!) but the only proper size Tek is a 575! Tube is a 154-0850 (cannot see if -00 or -01 until I remove it!) Alan |
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Re: 2465 tube & focus question
You make mention that the Tek 222 Digital Oscilloscope is isolated. That is correct and the AC-to DC Adapter provides pretty good Isolation as well.
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I have used the 222 Oscilloscope many times in high Impedance, high Common Mode Noise environments up to 1 MHz with good results. I have had to replace the batteries a few times because I don't use it all of the time. I should buy the Kitsune-Denshi 18650 Battery kit for it. That would help with the batteries failing. Another project for another day. Ross -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of alan.bain@... Sent: Friday, April 29, 2022 12:36 PM To: [email protected] Subject: Re: [TekScopes] 2465 tube & focus question Sorry should have said UK. That's a good point! I still like the old phosphor scopes. I used a 465 for a long time and them moved to the more versatile 2465 after a try with HP scopes which I didn't like so much. There's also handy 222 for scope troubleshooting (despite its low bandwidth it is isolated which can be handy!) but the only proper size Tek is a 575! Tube is a 154-0850 (cannot see if -00 or -01 until I remove it!) Alan |
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Re: Need Help With Tek 453 Weird Problem
On Mon, Apr 25, 2022 at 04:29 PM, Ozan wrote:
Finally got around to working on this some more after a very busy work week. Yes, the noise was there full time, you could kinda see it on the waveforms a little bit when not in x10 mode, was most obvious on a sine wave. I always assumed that was just normal as it was almost perfectly stable. It was more much obvious when you used the Beam Finder - the noise at each end of the sweep became very obvious. I never really used the Beam Finder and I never tried using X-Y mode until I learned about this other way of using a scope it a few months ago, and that is when I discovered the scope had these problems. Anyway, I have made more progress this week. I tried to look at the +75 PS ripple with my other scopes (Heathkit IO-4560 & SO-4541) but they would not display a waveform, just a nebulous fuzzy mess (not sure why, they should have plenty of bandwidth for that). Then later I was analyzing the PS and Horiz Amp schematics and noticed that the Horiz Amp uses+12V, -12V, +75V AND +150V. So I went snooping around in the filter cap area. Tested all of the rectifier diodes, they checked out OK. I checked the filter caps and they seemed to be OK. I didn't find anything obviously wrong. However, on a hunch, I surmised that that either the +75V and/or the +150V filter caps were not doing a good job of smoothing the PS ripple even though they seemed to be OK when I checked them with ESR meter and octopus curve tracer. So I decided to change C1172 (+75V), C1202 (+150V) & C1204 (+75V/+150V) to see what happened. I used caps from a 1970 donor scope that I've had sitting around for a long time. When I powered it up after the change I was disappointed because it appeared that the problem in x10 mode remained, but then after warming up for a few minutes it went away! Powered it up again this morning and same thing happened, noise is there and then goes away in a few minutes. Now in x10 mode there's still a tiny bit of noise but the fishbone hash is not an issue, it's quite usable and the small amount of noise that you can see is also dependent on the setting of the Time/Div switch. I have to say, it is a major PITA changing those filter caps. Didn't really want to have to do that. Changing C1112 & C1142 would be a real nightmare with all those rectifier diodes to deal with. Tektronix probably didn't envision people still using these 453s 50+ years after they were made, so ease of repair in that area probably wasn't too much of a concern in the design of the thing. Now my only remaining issue is that in X-Y mode I can't get a sharp image, it's kinda blurry. And still no dot, it's a still side view of Saturn. However it is much improved. I have checked the functionality of the Horiz Display switch, all of the wiring connections to the B Sweep/Trigger PCB, etc and can't really find anything wrong. +12V & -12V supplies don't seem to be a problem as far as I can tell. All of the LVPS voltages are stable. Still have a nice dot when Horiz Display switch is in between Delayed Sweep (B) and Ext Horiz positions. Hard to tell where the problem may be on that. Not sure where else to look. |
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Re: 2465 tube & focus question
Sorry should have said UK. That's a good point!
I still like the old phosphor scopes. I used a 465 for a long time and them moved to the more versatile 2465 after a try with HP scopes which I didn't like so much. There's also handy 222 for scope troubleshooting (despite its low bandwidth it is isolated which can be handy!) but the only proper size Tek is a 575! Tube is a 154-0850 (cannot see if -00 or -01 until I remove it!) Alan |
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Re: 2465 tube & focus question
Where are you located as shipping a CRT is a major cost factor.
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Regards On 4/29/2022 1:43 PM, alan.bain@... wrote:
A topic from long time ago; just thinking of some old puzzles. --
This email has been checked for viruses by Avast antivirus software. |
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2465 tube & focus question
A topic from long time ago; just thinking of some old puzzles.
I have a 2465 (not A or B) which works except for a focus problem. Focus amp seems to work fine (voltages match my calculations / values on schematic, ditto X and Y amps at test points 56,57,65 and 66). Doing various tests show focus problem still in X-Y mode and focus knob hard ccw for best focus (adjusted together with astig). If I short together the vertical plates (after disconnecting the hybrid and power) then I can get a perfectly focussed horizontal trace (focus and astig mid travel) and in X-Y mode a perfectly focussed dot which moves left to right, but if with plates shorted I apply a voltage of 30V to both vertical plates the trace defocusses badly and the best compromise focus is the same as the one achieved above. I'd expect minor dynamic focus adjustment to be needed if I actually deflected the trace, but not for equal voltages on both plates. This seems to suggest to me an inter-electrode leakage inside the tube? Does this really seem like the only conclusion and time to begin a hunt for a new CRT...? Alan |
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Help Needed - 547 Horizontal Timing/Trace
I¡¯ve come quite a long way into repairing this early 547. All the TD¡¯s are replaced and working properly, all the electrolytics have been replaced, a few out-of-spec resistors have been replaced too, as well as a few transistors, mainly the AF118. I had ordered a few AF118 (4.5€ a pop), but those that arrived were not the regular TO-7. They were instead in a TO-92 package. If you see those, don¡¯t even bother, they don¡¯t work as expected. I returned them and did find the proper NOS TO-7 ones that worked right off the bat as expected, albeit a bit pricier at 5.8€ a pop!
Anyways, the problem I¡¯m facing concerns the horizontal amplifier. For starters, the trace is always moving a bit right and left. Also, it is just impossible to adjust the timing. It¡¯s completely off even with the X1 and X10 all the way CCW. It¡¯s still way to wide. I replaced what I found to be out of spec, but there is still no change. I haven¡¯t measured the 30K and 18K 8W precision resistors though¡ Here¡¯s a short video of a 1KHz from a Type 184. You can clearly see the trace moving right and left, as well as the timing being off, and I can¡¯t adjust it any further. Any help would be appreciated. |
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Re: Leo Bodner Fast Rise Pulse Generator for 453 & 547?
IIUC, the Bodnar pulser does not output a flat waveform ¨C all design effort went into getting the fastest possible rise. 067-0521 and 106 put out a flat waveform.
Dave Wise From: [email protected] <[email protected]> On Behalf Of PMF via groups.io Sent: Thursday, April 28, 2022 1:59 PM To: [email protected] Subject: [TekScopes] Leo Bodner Fast Rise Pulse Generator for 453 & 547? I started to use my recently received Leo Bodner Fast Rise Pulse Generator (BNC) on my Tek 547/1A1 before wondering if I should seek advice here. I will stipulate that I had looked through the archive for hints as to how to set it up to adjust the H.F. response of the vertical amplifier and will also stipulate that I had remembered to install a 50-ohm terminator between it and the 1A1 input. While reading many interesting tangents and helpful hints, I didn't see anything about using the Bodner on lower bandwidth scopes such as mine. Perhaps, this is an important hint, come to think of it. . . Would my trying to flatten the top of the square wave with the input Volts/Div. set at 0.2, sweep at .1 microsecond, which is the fastest on this dear old beast, and magnifying the sweep by 5 yield valid results? The test result sheet included with the Bodner shows the amplitude at 0.891 volts, Risetime at 36.02 pS, Falltime at 31.14 pS, overshoot at 3.2%, and undershoot at 5.6%. (Risetime of the 547/1A1 is supposed to be 7 nS.) Viewing the waveform with these settings showed some problems with the top of the square wave that did not appear when I put the Volts/Div. at .5 or 1 (don't quite remember which, now). Not magnifying the sweep made the wave form look like that of the Tek 106 output on a 310A scope. I would also note that the only 547 manuals that I have or have seen on TekWiki show this step only using the 067-0521-00/TU-7/1M1, rather than the 106 and a 1A1. While I have a 067-0521-00 and think that it has allowed me to peak the HF response fairly well, it could be well out of calibration. It also does not check the whole signal chain as would using the Bodner or the 106 with the 1A1 would - not to state the obvious. Also, I have no way of confirming the accuracy of the 067-0521-00 output because the 453 and 547 are my fastest scopes. Only other ones that I have are the 310As, which I would like to calibrate, too. (Like others here, I work in the AF range, admire the quality of these scopes, and haven't really needed anything modern, although the maintenance of these antiques has tried my patience a few times in the last few months.) My rationale for using the Bodner is to confirm function of this and my 453 vertical amplifiers before undertaking any (additional) attempts to adjust the output of my 106 and 107 Square Wave Generators. (I had chimed in on attempts to repair another party's 106 earlier this year.) I cannot tell if both of those generators are the source of various waveform distortions or if both of my scopes are the culprit. Initial adjustments on the 547 did allow me to almost flatten the top of the square wave, but I would like to try to improve the results - if I am on the right track. PMF |
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Re: DM501A Input Leakage Source
Greg, Tom, Ed
Thanks for your inputs, guys. Tom, I tried your antenna thing but it made no visible difference, Ed, I worked on your idea of inter-switch leakage. You are right, there is a lot of +5V switching going in in poles physically adjacent to the sensitive input node. In particular, switching back and forth rapidly between Temp and 200mV had an appreciable (temporary) effect, so I liberally squirted pcb cleaner into that particular switch. After drying out, the offset was reduced from around 11mV to around 4mV. This suggests that the cause, at least, has been identified, if not the complete solution. Given what Greg reported in his units, and the closeness of so many 5V switching nodes, this is probably as good as it gets. Looks like the designers didn¡¯t try too hard to guard the input node, but that¡¯s probably a bit harsh coz of course 400pA is probably not too shabby for this class of DVM. That Tek article that Gudjon refers to in his post is great if the switch is on its own on the bench, but quite impossible if the switches are still in the instrument. Maybe I¡¯ll have another go one day¡.. Thanks again, guys. Roman |
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Re: Leo Bodner Fast Rise Pulse Generator for 453 & 547?
In looking at the type 107 it looks like there is not much that will fail in it other than the normal power supply caps. The 106 has a lot more going on in it. If I can capture some waveforms from a working 106 let me know. I have one in the lab. I also have 2 leo pulsers in the lab so I can take some pictures on a 7k frame of what it looks like. But I think my slowest plugins are 75Mhz. but that would get close to the 1a1.
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Also when doing the HF alignment the only thing of interest in the wave form is the rise and transition to the flat top of the wave form. Nothing in wave shape matters after that. The way the alignments go is to start out slow and long flattening out the waveform working forward to the rising edge sharpening up the corner as the steps progress. The deeper in to the process the more zoomed in on the corner. The more zoomed in on the corner the less the rest of the wave form matters. That being said I have had some plugins that were very badly miss aligned (from the Ebay) that took 4-5 passes of the compensation procedure to get them to rights. If I can help out in any way let me know Zen -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of PMF Sent: Thursday, April 28, 2022 11:09 PM To: [email protected] Subject: Re: [TekScopes] Leo Bodner Fast Rise Pulse Generator for 453 & 547? Zen, In that case, I might return to the 067-0521-00 to see what the waveform looks like after I blundered into adjusting the whole system with the Bodner. You make a very good point anent standardizing, so to speak, the mainframe so that all plugs-in behave, and I will return to this MO, even though I have but one 500 series scope. Fortunately, I had two or three bumps well beyond 10 nS in the waveform, at least as I left it, so I probably did not attenuate the bandwidth too much. I am also glad you replied, for this is the only 'scope whose vertical amplifier I 'adjusted.' Unfortunately, this probably indicates that my 106 & 107 square wave generators are faulty, but at least it is good to know where to start. Somehow. PMF |
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Re: Leo Bodner Fast Rise Pulse Generator for 453 & 547?
Zen,
In that case, I might return to the 067-0521-00 to see what the waveform looks like after I blundered into adjusting the whole system with the Bodner. You make a very good point anent standardizing, so to speak, the mainframe so that all plugs-in behave, and I will return to this MO, even though I have but one 500 series scope. Fortunately, I had two or three bumps well beyond 10 nS in the waveform, at least as I left it, so I probably did not attenuate the bandwidth too much. I am also glad you replied, for this is the only 'scope whose vertical amplifier I 'adjusted.' Unfortunately, this probably indicates that my 106 & 107 square wave generators are faulty, but at least it is good to know where to start. Somehow. PMF |
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Re: Leo Bodner Fast Rise Pulse Generator for 453 & 547?
PMF,
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Please disregard the second message as I missed the part about the 50 Ohm terminator. What I get for typing out emails and getting interrupted. I will base what I am about to say out of the 7K world as that is my strong spot. Typically when adjusting a 7K Frame and associated plugins the order is frame -> then plugins. The use of the calibration plugin is to make sure the HF response of the port is correct before adjusting the HF of the plugin. If the port response is off this offset will then also be tuned in to the plugin. If the plugin is moved to another frame it is out now due to the HF of the frame The calibration plugin has a known step response to adjust the frame. There are notes in the 7k frame manual that say you can do the adjustments with out the calibration plugin. But if this is done then there is no guarantee that the plugin will meet spec if it is moved to another frame. After digging in to the adjustment document of the 1a1 like in the 4xx and 7xxx gear there is a frequency compensation in all voltage ranges 0.05 all the way through 20V it is adjustment capacitors C104-112 both C and B one of the reasons for good waves forms on some ranges and bad on other could be some miss adjustments or faults in the attenuator for the ranges. Referencing table 7-2 on page 7-24 of the late serial number manuals. This creates a chicken and egg problem. Is the attenuator out or is the frame out? Given that the waveforms look good on some ranges but bad on the other leads me to believe that it is the attenuator that is out rather than the 547 but I can not say for sure. Another thing to note in doing these types of adjustments is the leo pulser may only be flat for a specified time. TD pulsers that tech made have this problem. Only flat for 10ns. A type 106 is used for the low and mid frequency compensations and a TD pulser is used for just the HF comp. the waveform of the TD pulser slowly fall off after 10ns and is no longer flat. If needed I can check flatness of a leo pulser I have 2 available in the lab. Zen -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Zentronics42 via groups.io Sent: Thursday, April 28, 2022 9:27 PM To: [email protected] Subject: Re: [TekScopes] Leo Bodner Fast Rise Pulse Generator for 453 & 547? PMF one other thing to note after looking up the 1a1 you will need a 50 Ohm terminator to get the rise time out of the Leo pulser. These can be had for $20.00 an example is here Zen -----Original Message----- From: [email protected] <[email protected]> On Behalf Of PMF Sent: Thursday, April 28, 2022 4:59 PM To: [email protected] Subject: [TekScopes] Leo Bodner Fast Rise Pulse Generator for 453 & 547? I started to use my recently received Leo Bodner Fast Rise Pulse Generator (BNC) on my Tek 547/1A1 before wondering if I should seek advice here. I will stipulate that I had looked through the archive for hints as to how to set it up to adjust the H.F. response of the vertical amplifier and will also stipulate that I had remembered to install a 50-ohm terminator between it and the 1A1 input. While reading many interesting tangents and helpful hints, I didn't see anything about using the Bodner on lower bandwidth scopes such as mine. Perhaps, this is an important hint, come to think of it. . . Would my trying to flatten the top of the square wave with the input Volts/Div. set at 0.2, sweep at .1 microsecond, which is the fastest on this dear old beast, and magnifying the sweep by 5 yield valid results? The test result sheet included with the Bodner shows the amplitude at 0.891 volts, Risetime at 36.02 pS, Falltime at 31.14 pS, overshoot at 3.2%, and undershoot at 5.6%. (Risetime of the 547/1A1 is supposed to be 7 nS.) Viewing the waveform with these settings showed some problems with the top of the square wave that did not appear when I put the Volts/Div. at .5 or 1 (don't quite remember which, now). Not magnifying the sweep made the wave form look like that of the Tek 106 output on a 310A scope. I would also note that the only 547 manuals that I have or have seen on TekWiki show this step only using the 067-0521-00/TU-7/1M1, rather than the 106 and a 1A1. While I have a 067-0521-00 and think that it has allowed me to peak the HF response fairly well, it could be well out of calibration. It also does not check the whole signal chain as would using the Bodner or the 106 with the 1A1 would - not to state the obvious. Also, I have no way of confirming the accuracy of the 067-0521-00 output because the 453 and 547 are my fastest scopes. Only other ones that I have are the 310As, which I would like to calibrate, too. (Like others here, I work in the AF range, admire the quality of these scopes, and haven't really needed anything modern, although the maintenance of these antiques has tried my patience a few times in the last few months.) My rationale for using the Bodner is to confirm function of this and my 453 vertical amplifiers before undertaking any (additional) attempts to adjust the output of my 106 and 107 Square Wave Generators. (I had chimed in on attempts to repair another party's 106 earlier this year.) I cannot tell if both of those generators are the source of various waveform distortions or if both of my scopes are the culprit. Initial adjustments on the 547 did allow me to almost flatten the top of the square wave, but I would like to try to improve the results - if I am on the right track. PMF |
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Re: Leo Bodner Fast Rise Pulse Generator for 453 & 547?
PMF one other thing to note after looking up the 1a1 you will need a 50 Ohm terminator to get the rise time out of the Leo pulser. These can be had for $20.00 an example is here
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Zen -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of PMF Sent: Thursday, April 28, 2022 4:59 PM To: [email protected] Subject: [TekScopes] Leo Bodner Fast Rise Pulse Generator for 453 & 547? I started to use my recently received Leo Bodner Fast Rise Pulse Generator (BNC) on my Tek 547/1A1 before wondering if I should seek advice here. I will stipulate that I had looked through the archive for hints as to how to set it up to adjust the H.F. response of the vertical amplifier and will also stipulate that I had remembered to install a 50-ohm terminator between it and the 1A1 input. While reading many interesting tangents and helpful hints, I didn't see anything about using the Bodner on lower bandwidth scopes such as mine. Perhaps, this is an important hint, come to think of it. . . Would my trying to flatten the top of the square wave with the input Volts/Div. set at 0.2, sweep at .1 microsecond, which is the fastest on this dear old beast, and magnifying the sweep by 5 yield valid results? The test result sheet included with the Bodner shows the amplitude at 0.891 volts, Risetime at 36.02 pS, Falltime at 31.14 pS, overshoot at 3.2%, and undershoot at 5.6%. (Risetime of the 547/1A1 is supposed to be 7 nS.) Viewing the waveform with these settings showed some problems with the top of the square wave that did not appear when I put the Volts/Div. at .5 or 1 (don't quite remember which, now). Not magnifying the sweep made the wave form look like that of the Tek 106 output on a 310A scope. I would also note that the only 547 manuals that I have or have seen on TekWiki show this step only using the 067-0521-00/TU-7/1M1, rather than the 106 and a 1A1. While I have a 067-0521-00 and think that it has allowed me to peak the HF response fairly well, it could be well out of calibration. It also does not check the whole signal chain as would using the Bodner or the 106 with the 1A1 would - not to state the obvious. Also, I have no way of confirming the accuracy of the 067-0521-00 output because the 453 and 547 are my fastest scopes. Only other ones that I have are the 310As, which I would like to calibrate, too. (Like others here, I work in the AF range, admire the quality of these scopes, and haven't really needed anything modern, although the maintenance of these antiques has tried my patience a few times in the last few months.) My rationale for using the Bodner is to confirm function of this and my 453 vertical amplifiers before undertaking any (additional) attempts to adjust the output of my 106 and 107 Square Wave Generators. (I had chimed in on attempts to repair another party's 106 earlier this year.) I cannot tell if both of those generators are the source of various waveform distortions or if both of my scopes are the culprit. Initial adjustments on the 547 did allow me to almost flatten the top of the square wave, but I would like to try to improve the results - if I am on the right track. PMF |
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Re: Leo Bodner Fast Rise Pulse Generator for 453 & 547?
PMF
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I have a bunch of calibration videos out on you tube about doing these adjustments. Not on a 547 but 465's and 485's I have also been told that 475's are on the way. The adjustment display is the same for the 500 series as for the 4xx series. It is critical that the rise time not be over damped if this is the case the scope will lose bandwidth. If you make the square wave look nice and clean the vertical will come out slow. In a 4xx you can loose 25-30Mhz in the high frequency compensation. The channel is linked below. The HF comp procedure is pretty much the same just with faster or slower edges. Of specific interest 7a26 - 7A15A - 465B Vertical section - 485B Vertical Section - Zen -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of PMF Sent: Thursday, April 28, 2022 4:59 PM To: [email protected] Subject: [TekScopes] Leo Bodner Fast Rise Pulse Generator for 453 & 547? I started to use my recently received Leo Bodner Fast Rise Pulse Generator (BNC) on my Tek 547/1A1 before wondering if I should seek advice here. I will stipulate that I had looked through the archive for hints as to how to set it up to adjust the H.F. response of the vertical amplifier and will also stipulate that I had remembered to install a 50-ohm terminator between it and the 1A1 input. While reading many interesting tangents and helpful hints, I didn't see anything about using the Bodner on lower bandwidth scopes such as mine. Perhaps, this is an important hint, come to think of it. . . Would my trying to flatten the top of the square wave with the input Volts/Div. set at 0.2, sweep at .1 microsecond, which is the fastest on this dear old beast, and magnifying the sweep by 5 yield valid results? The test result sheet included with the Bodner shows the amplitude at 0.891 volts, Risetime at 36.02 pS, Falltime at 31.14 pS, overshoot at 3.2%, and undershoot at 5.6%. (Risetime of the 547/1A1 is supposed to be 7 nS.) Viewing the waveform with these settings showed some problems with the top of the square wave that did not appear when I put the Volts/Div. at .5 or 1 (don't quite remember which, now). Not magnifying the sweep made the wave form look like that of the Tek 106 output on a 310A scope. I would also note that the only 547 manuals that I have or have seen on TekWiki show this step only using the 067-0521-00/TU-7/1M1, rather than the 106 and a 1A1. While I have a 067-0521-00 and think that it has allowed me to peak the HF response fairly well, it could be well out of calibration. It also does not check the whole signal chain as would using the Bodner or the 106 with the 1A1 would - not to state the obvious. Also, I have no way of confirming the accuracy of the 067-0521-00 output because the 453 and 547 are my fastest scopes. Only other ones that I have are the 310As, which I would like to calibrate, too. (Like others here, I work in the AF range, admire the quality of these scopes, and haven't really needed anything modern, although the maintenance of these antiques has tried my patience a few times in the last few months.) My rationale for using the Bodner is to confirm function of this and my 453 vertical amplifiers before undertaking any (additional) attempts to adjust the output of my 106 and 107 Square Wave Generators. (I had chimed in on attempts to repair another party's 106 earlier this year.) I cannot tell if both of those generators are the source of various waveform distortions or if both of my scopes are the culprit. Initial adjustments on the 547 did allow me to almost flatten the top of the square wave, but I would like to try to improve the results - if I am on the right track. PMF |
diyguitarist
PMF
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