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New (to me) 2465 Power On State
I just got a 2465 in pretty good condition (one sharp dent in the case, a broken corner on the rear bezel, disintegrated rear cord-wrap feet, and a bent shaft on the SEC/DIV VAR knob) but after a bit of struggling, an application of pliers, and some minor metal work, it's almost as good as new. I ran through a bunch of functions, somewhat haphazardly, and checked that I could see traces on all four channels, all of which seemed to work, within the limits of my equipment and skill. The main SEC/DIV knob seems to have some trouble when setting a delayed sweep more than a few positions in advance of the main sweep, but I haven't investigated enough to really understand what's happening.
When I first got it it would show a diagonal line on the screen on power up with the messages "DIAGNOSTIC. PUSH A/B TRIG TO EXIT" and "CT TEST 81 FAIL 03 BU<F110>". When I opened it up I found a cable had been rudely disconnected from the control board (J502 which transmits some EAROM signals to the option boards). I straightened the bent pins and reconnected the cable before addressing the dented case and reassembling the unit. When it was reassembled it still showed the diagonal line on the screen, but now the message at the bottom of the screen reads "ALL 00 PASS BU<F110>". Is the instrument always supposed to start up in diagnostic mode? Do I need to do something to take it out of diagnostic mode? -- Jeff Dutky |
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7633 no high voltage -1475V on test point
I just repaired the time base 7B53A and a new problem appears.
An acrid smell came from the oscilloscope so decide to test the scope for 3 hours and the trace and readout disappeared. I measured the low voltages and are all ok but is missing the high voltage (-1475V) on the test point. Where is the problem? Fabio |
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Re: Tek 576 step generator problem
I will check it later with mine
-----Mensaje original----- De: [email protected] [mailto:[email protected]] En nombre de Dave S. Enviado el: lunes, 11 de enero de 2021 19:23 Para: [email protected] Asunto: Re: [TekScopes] Tek 576 step generator problem Hi, thanks for ur help! What about the 50uA and 100uA (.1mA) waveform with the 100k paralell? Maybe you can check it on your 577 or someone else could check it on a 576 if it looks strange aswell. Thank you! David Scanned by McAfee and confirmed virus-free. Find out more here: |
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Update on the Location of 3 International Orders for Peter Keller's books
One book left Narita Airport in Japan on January 11, 2021 at 3:26 pm and is
currently in transit to the destination. This will come as no surprise to our members in Japan. According to my friends at the USPS Japan holds the record for the fastest and most reliable mail system in the world. They are so far ahead of every other country that there is no hope of any one catching up to the level of service they provide to their citizens. Two books have already departed a transfer airport in Heathrow, London on January 11, 2021 at 8:28 am. These two books are currently in transit to their destination. All of the other international orders departed the USPS SAN FRANCISCO CA INTERNATIONAL DISTRIBUTION CENTER between January 9, 2021 at 8:32AM and January 10, 2021 at 4:07PM Dennis Tillman W7pF |
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File /AM503B AM5030 Calibration Adapters.pdf uploaded
#file-notice
[email protected] Notification
The following files have been uploaded to the Files area of the [email protected] group. By: Dennis Tillman W7pF Description: |
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Re: Update on Domestic US Book Delivery Dates
I received my book today in Orlando Florida. It arrived in great shape and looks like a great book. Beautiful hardcover text. Thanks Dennis for your work on this.
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Steve Kb4irb On Jan 11, 2021, at 12:02 AM, Dennis Tillman W7pF <dennis@...> wrote: |
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Re: FS: TM500 stuff for parts/repair
Sorry, this sold very shortly after I posted the message.
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Tom On 1/11/2021 12:53 PM, Jared Cabot via groups.io wrote:
Are you willing to post the scope to Japan, if so how much? |
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Re: Alternative for Snap-On knobs on 22XX and 24XX scopes??
Hi Jeff, Tam,
These knob don't break beyond use, sometimes the little latch inside comes loose. But this is an easy fix using silicone kit. As it turns out, these knobs are made already using a 3D printer, I think. I found this: I don't have a 3D printer, so that's no option for me. Saludos, Leo |
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Re: [dead tek 485] Can i fix it ? (newbie here)
Jeff, the Tek probe cross reference from TekWiki says P6101A for passive 1X, P6106A for passive 10X, P6063B for passive 1X/10X, P6009 for high voltage 100X, P6015 for high voltage 1000X, and P6201 for active.? None indicated as being originally shipped with the 485 scope.? TekWiki is your (and my) best friend.? ? Jim Ford?Sent from my Verizon, Samsung Galaxy smartphone
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-------- Original message --------From: Jeff Dutky <jeff.dutky@...> Date: 1/10/21 8:39 PM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] [dead tek 485] Can i fix it ? (newbie here) Tom,I've been reading everything that I could find about the 485 since this discussion started, and the one thing that I can't find is any mention of what probe would have been standard with the scope. The 485 was released the same year as the 475 (with which I am quite familiar). The 475 would have shipped with P6075 probes (or maybe P6063 probes? My father's scope, which he started using in 1975, was shipped with P6075A probes).The manuals for the 475 clearly list what kind of probe would have been standard equipment with (and, apparently, were specifically designed for) the scope. Depending on which manual you look at the 475 manuals list either the P6075 or the P6106, but I haven't found any such listing in the 485's manual.I've been using cheap Chinese 200 MHz probes to test my new (to me) 2465, and the effects of the probes' bandwidth are evident. What probes would have been used on a new 485 in the early to mid seventies?-- Jeff Dutky
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Re: 7904 Power Supply Capacitors
Hi, Jose'.? I haven't seen Dave Hess post on TekScopes for a long time.? Try eevblog; he seems to be more active there lately.? ? ?GL.? ?Jim Ford?Sent from my Verizon, Samsung Galaxy smartphone
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-------- Original message --------From: Jose Luu <jose.luu@...> Date: 1/11/21 6:14 AM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] 7904 Power Supply Capacitors On Thu, Nov 24, 2016 at 02:21 PM, David Hess wrote:>> I need to start thinking about rebuilding my 7000 power supplies. I> think I will start on a spreadsheet showing the parts used in each> model.>I just fixed a 7904 where 3 of these capacitors had failed (2 in the suppy, one on the main board), I was wondering if you ended up doing the capacitor replacement spreadsheet you mentionned.RegardsJose
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Re: Alternative for Snap-On knobs on 22XX and 24XX scopes??
Leo,
These pre-made knobs are very nice. I have ordered a few score, of different types, to see how they will work. I have also (because I am an American who does not understand thrift) ordered several of the $5 original manufacture press-on knobs. I have not installed them yet because I would like to try making replacement resin knobs from a silicone cast of the originals. I will report back on both experiments. -- Jeff Dutky |
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
It occurred to me that if one were to successfully use a 7000 series plugin frame, the frame would stick out significantly, and allow you to have extra (and ventilated) room.? It wouldn't be workable with the current board set, but might be useful for a "checkout" style project.
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Harvey On 1/11/2021 5:37 AM, John Kolb wrote:
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Re: Tek 576 step generator problem
Step-Amplitude: .5V (no resistor)The staircase looks ok! it's not broken trace issue. The design of step generator circuit is different between 576 and 577. In case of 577 the traces synchronize with the collector supply 4 traces per period(one trace per 90 degree). This could be seen by the timing between collector supply and staircase. </g/TekScopes/photo/255563/29?p=Created,,,100,1,0,0> </g/TekScopes/photo/255563/30?p=Created,,,100,1,0,0> Hope it helps. Jack |
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Re: [dead tek 485] Can i fix it ? (newbie here)
Jose,
Nice scope! All of these 4xx series scopes are favorites of mine. I have not read back through the entire thread of posts. One minor issue that I see in the pictures, besides those already mentioned is the lack of illumination of the 1X or 10X indicators on the Ch1 Or Ch2 input. In addition, the 1M or 50Ohm indicator illuminators do not appear to be working. Not at all being picky, just mentioning them so you can add them to the list of things to fix. I bought a very similarly ¡°nice¡± 485 in Dallas, TX. As many have suggested, a thorough cleaning of every switch is one of the very first items on your list. Mine had similar issues and almost all went away after a careful switch cleaning. Mine had a very dirty beam finder switch that was causing the trace to wander off the screen from time to time (among other things). Looking forward to hearing more of your adventure with this fine scope. -- Michael Lynch Dardanelle, AR |
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Re: Type 503 ¡ª power supply question
Dan,
Thanks for these links and recommendations. Fantastic stuff! I love all the old audio equipment! Those machines are great for teaching the history of sound recording, radio, etc. with it. I've worked on both wire recorders and on a few old record cutters. I did a course on sound art where we restored a bunch of old Meissner record cutters and had the students cut their own discs. The challenge with those units is that the crystal cutting heads are all dead and have to be rebuilt. Anyway, I'm happy to talk about any of those projects if you (or anyone else) is interested. (Or just email me off list.) And I did use a Tek scope on them--my normal bench oscilloscope--but I wish I had the 503 back then! All best, Brian |
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Re: [dead tek 485] Can i fix it ? (newbie here)
On Mon, Jan 11, 2021 at 07:15 AM, dnmeeks wrote:
I guess to clean all contacts, some disassembling is required to access certain contacts (acces to intensity potentiometer is quite easy) |
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Re: [dead tek 485] Can i fix it ? (newbie here)
Jose,
Jeff is correct, the non-flatness of the Ch1 signal in AC coupling should be correctable as part of the Ch1 calibration procedure. Your first picture of the Ch2 signal has the vertical sensitivity set to 0.1V/div instead of 1.0V/div! The trace shows something that looks a lot like the noise I mentioned in the previous post. The next picture, which I believe has the input set to 50 ohms shows the correct display since the calibrator output drops to 0.5V when terminated by 50 ohms. With no trigger signal and 'normal' mode selected the beam spots should be on the left hand side and not visible until you turn the intensity up beyond its normal level. The electron beam should be blanked off by the Z axis circuitry, waiting to be unblanked when the time base is triggered. There is a 'holdoff' circuit which makes the timebase wait a set amount of time before retrace and the next trigger - maybe this is not working properly. Try rotating the 'A trigger holdoff' knob back and for several times in case it has developed bad contacts. Regards, Roger |
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Re: [dead tek 485] Can i fix it ? (newbie here)
Jose,
I am just going to give a quick reply to the first issue. It looks to me like there is a problem with the calibrator output. I think you have another scope so can you feed the calibrator output into the second scope. I looks like there is some noise on the calibrator output just before it switches - both from high to low and from low to high. I would try pressing the 1kHz / 1MHz switch many times while displaying the signal on the second scope. While at 0.2msec/div see if you can make the trace move sideways by adjusting the trigger level control, it may be that the scope is triggering from the first 'noise' pulse rather than the main low-high transition. Looking at your pictures and even allowing for some over-exposure effects you seem you seem to have the single trace both high and low at the same time which is a physical impossibility, hence my suggestion of noise. This could also explain why the scope seems to be triggering around the half-way point at 0.2msec/div. More later! Regards, Roger |
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