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Re: SG503 amplitude precision
I'm very sorry that I emailed the wrong group!
I'm little desperate and it shows! I hope your group will forgive me and I'll try not to repeat my mistake! Have a great weekend! Thank you. Tony On Fri, Apr 26, 2019 at 11:34 AM Dennis Tillman W7PF <dennis@...> wrote: Hi Tony, |
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Re: [Test-Equipment] Suggestions for going through Tek2465DVS/DMM?
Thank you very much for comprehensive email, that is pointing me to the
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right direction! It seems to me that the Beam Switch is sticking for sure and could cause most of my problems. I'll try to update the videos as soon as I make some progress. Should I also replace some of the square caps that are something like 0.006xx nF? Many people do this ASAP, since these caps are not a good quality - despite most of the parts are very good quality. Where should I buy the caps and other parts, if I'll need them? I'm sure, China and eBay should not be on my list for caps - right? Anyway, Have a great day and I'll post videos so you can see what I did and the results that happen. Have a great day and weekend! Tony On Fri, Apr 26, 2019 at 9:05 AM Siggi <siggi@...> wrote:
Hey Tony, |
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Re: SG503 amplitude precision
Hi Tony,
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The subject line of a thread tells our 8,000 members around the world whether this is a topic that is relevant to them. In this case the thread is about the SG503 amplitude precision. It makes it simple for anyone who doesn't own an SG503 to delete this email without spending any time reading it. When you used this"SG503 amplitude precision" topic to ask for help with your 2465 two things happened: 1) You annoyed the members who are having a conversation about the SG503. It is as if you are butting into a conversation among many people, you interrupted what they were talking about, and you asked an irrelevant (to them) question that has nothing to do with their conversation. 2) No one who owns a 2465 is paying attention to a conversation about the SG503 so you will not reach the very people who can help you. The proper thing to do is to start your own topic with a subject line that clearly and succinctly states what you want. For example the subject line might say "I need help troubleshooting my 2465". So feel free to send a new email to TekScopes with a new subject line and in the email state as clearly and succinctly as you can what the problem is with your scope. Dennis Tillman W7PF -----Original Message----- -- Dennis Tillman W7PF TekScopes Moderator |
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Re: Tek485 - a quick question on disabling/bypassing power supply protection
Thank you very much!
On Fri, Apr 26, 2019 at 9:43 AM Roger Evans via Groups.Io <very_fuzzy_logic= [email protected]> wrote: Is the Y scaling per small division (+/- 5 within the box) or something |
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Re: SG503 amplitude precision
Thank you very much!
On Fri, Apr 26, 2019 at 1:52 AM David C. Partridge < david.partridge@...> wrote: Please start a new thread about this - IOW please don hi-jack threads. |
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Re: Tek485 - a quick question on disabling/bypassing power supply protection
Here's a link to the album: /g/TekScopes/album?id=89902.
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On Fri, Apr 26, 2019 at 5:51 AM Lorenzo <ltcrocs@...> wrote:
Hi Roger. Reminded myself how to add photos and have uploaded three |
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Re: Tek485 - a quick question on disabling/bypassing power supply protection
Is the Y scaling per small division (+/- 5 within the box) or something else? Either way it doesn't look like the -5V is decaying to 0V and is Ch3 inverted?
There is a very clear signal on LIMIT which could cause the shutdown. If you do the same test with comb U3 removed and LIMIT is still active then the fault is probably around Q1544, Q1546 where the beam limit signal is generated. The manual suggests you ground TP1544 to disable the LIMIT signal in order to troubleshoot (with care of course). If the fault really is in the -5V overcurrent then the only thing I can think of is that an IC or a transistor is biassed into conduction when all the power rails are up but not when only -5V is present. You can look for likely candidates (-5V bias into linear ICs and transistors with very low load resistors between -5V and ground) and isolate boards by removing combs / pins as necessary. Best of luck, Roger |
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Re: [Test-Equipment] Suggestions for going through Tek2465DVS/DMM?
Hey Tony,
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welcome to the group. I watched the videos you posted in another thread detailing your 2465 CTS troubles < >. Here's my advice for how to proceed: 1. Get a service manual for your scope. You can download one from here < >, or if you're not satisfied with the scan quality you can buy a very good quality scan from Artek Manuals < >. 2. Get familiar with the controls of your scope. Alan Wolke has a bunch of tutorial-like videos on coupling and trigger setup and such, there's a list of his YouTube videos here < >. 3. Read this document < > on how to troubleshoot oscilloscopes. Now looking through your videos, I think you one problem for sure, and possibly one more. 1. Your beam finder button sticks or glitches. 2. Something else, possibly more than one other problem. It's very hard to reason about what the CRT is displaying while the beam finder is bad, but it's easy to fix. You can probably get by with isopropyl alcohol - just squirt some into the switch and work it several times. If that doesn't do it, get yourself some kind of contact cleaner (Deoxit D5 is what I use), and clean the switch with that. What makes me think that you may have a second problem is the fact that the readout would sometimes shrink only in the horizontal, but it's possible that this is simply due to a high-resistance beam finder switch, so fix that first. Once the beam finder switch is good, it's possible to move forward to diagnose whatever else is wrong, if anything. A key question I found myself asking while watching your videos was whether the intermittent shrinking affects only the readout, or whether it also affects the traces. Unfortunately I didn't see the shrinkage occur while traces and readout were both displayed. Note that for the traces to be displayed, your triggering controls have to be set up right. If you set the trigger to AUTO & CH1, then set the CH1 coupling switch to GND coupling, you should be able to display all traces reliably. Siggi On Fri, Apr 26, 2019 at 1:12 AM Tony Fleming <czecht@...> wrote:
I have the same oscilloscope. It is also listed under (at least that is |
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Re: I wonder if there is much interest in vacuum tube oscilloscopes such as the 500 series
I have a 551 and 535a I'm working on restoring. I want to use them especially on tube audio amplifiers. My thought is if I mess up and expose them to high voltage they're likely to be more forgiving than my 7104, 7603A or 2456B.
John |
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Re: I wonder if there is much interest in vacuum tube oscilloscopes such as the 500 series
Some space heaters eat up a lot of electricity like that too. When my
basement lab gets cold, I have this cool retro-looking space heater, a model Tektronix 547, that takes the chill off. Best part is the giant heat wave indicator light. My wife says it's the most reliable heater we have and has suggested that I try to find another one for the garage. So, reluctantly... On Thu, Apr 25, 2019 at 4:02 PM Gary Robert Bosworth <grbosworth@...> wrote: Nearly all of the Tektronix products from the 1960's were a marvel of |
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Re: Tek485 - a quick question on disabling/bypassing power supply protection
Hi Roger. Reminded myself how to add photos and have uploaded three tonight that should help answer your queries. They're under a new album with the same name as this post thread. The 'white' screenshot is an old one done when I was digging into the problem months ago. Shows the spiking on U1624 pin 3 as the -5V supply starts to come up and then tracks upwards towards GND as it fails/shorts. Also shows +5V supply that also comes into U1624 Pin 3. The 'yellow' ones I did tonight - show voltage directly across CR1958 using my differential probe, and activity on BAL node, LIM node and HV node. LIM node shows no -ve excursions so looks OK. HV node also appears OK - these were done with comb U3 connected, so HV active. CR1958 is conducting as the -5V supply fails and doubtless explains the shutdown. I've tested all the resistors and supply voltages going to the balance node - all look good. All the other LV supplies behave fine and rise or fall uniformly towards their final values before the inverter shuts down - and pretty much in proportion to one another. I've done lots of testing with U3 in as well as with U3 out. Perhaps this will suggest some further tests I should focus on.
I also checked on the current drain readings I took last night with scope off - but this time with U3 connected. Made no difference at all to the readings. |
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Re: SG503 amplitude precision
Sorry for the typo, the correct number for the cable is 012-0482.
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Jack On 4/26/2019 2:49 AM, Kerry Burns wrote:
Hello All |
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Re: SG503 amplitude precision
Please start a new thread about this - IOW please don hi-jack threads.
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David -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Tony Fleming Sent: 26 April 2019 04:56 To: [email protected] Subject: Re: [TekScopes] SG503 amplitude precision I'm new here and I'm looking for someone to help me with my Tektronix 2465 DNS (aslo known as 2465 CTS ) |
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Re: SG503 amplitude precision
Hello All
My SG503 front panel specifies a slightly different cable number - 012-0482-00 ( I do have one of these). Not sure how this differs from the 012-0480-00 but it does have a metal rather than plastic strain relief collar. Kerry ?On 26/4/19, 2:41 pm, "Jack Reynolds" <[email protected] on behalf of jackandladyreynolds@...> wrote: Hello Jared and Rick, Before you make an investment in this enterprise you are considering, you may want to go back to the beginning of these posts from 2015. It was categorically stated the the real 012-0480-00 is made from RG 223 although some discussion was given to improving it using RG 400. I own a genuine 012-0480-00 and it is stiffer than RG 58 (presumably because of the double shield in RG 223) and slightly larger in diameter .210 vs .200 for RG 58. Having made some cables from RG 223, I can also tell you that RG 223 takes a different BNC connector than RG 58 to do a workmanlike job. I am not trying to discourage you, simply to help you to avoid some missteps. I might even get one myself. By the way, the Tek cable is also very well made as you would expect with molded on plastic strain reliefs at either end. Jack Reynolds |
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Re: SG503 amplitude precision
I'm new here and I'm looking for someone to help me with my Tektronix 2465
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DNS (aslo known as 2465 CTS ) I made few videos here: about my sick scope. Can anyone tell me where is a special group for my scope? Thank you all for helping me and each others! Have a great day! Tony On Thu, Apr 25, 2019 at 9:17 PM Rick <rpbale@...> wrote:
I may be a little late to the game but I posted this question to a Tek |
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Re: [Test-Equipment] Suggestions for going through Tek2465DVS/DMM?
I have the same oscilloscope. It is also listed under (at least that is what I found today) as Tektronix 2465CTS (or 2465 CTS) .
Mine has some problems, sometimes I loose the text on top and bottom of the display and also the FIND BEAM gets stuck, so I don't know exactly where to find the solution. Anyway, I hope your scope is working. Tony Fleming |
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Re: SG503 amplitude precision
Hello Jared and Rick,
Before you make an investment in this enterprise you are considering, you may want to go back to the beginning of these posts from 2015. It was categorically stated the the real 012-0480-00 is made from RG 223 although some discussion was given to improving it using RG 400. I own a genuine 012-0480-00 and it is stiffer than RG 58 (presumably because of the double shield in RG 223) and slightly larger in diameter .210 vs .200 for RG 58. Having made some cables from RG 223, I can also tell you that RG 223 takes a different BNC connector than RG 58 to do a workmanlike job. I am not trying to discourage you, simply to help you to avoid some missteps. I might even get one myself. By the way, the Tek cable is also very well made as you would expect with molded on plastic strain reliefs at either end. Jack Reynolds |
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Re: SG503 amplitude precision
I may be a little late to the game but I posted this question to a Tek expert on Youtube:
This comment/request might be a little out of scope, to calibrate a Tek SG503 Tek says a special cable is required, Tek part 012-0482-00. This is an extremely expensive 3 foot 50 ohm BNC cable, $200+ on ebay. There's a discussion going on at TekScopes@... about the need for this cable and thought this was right up your alley for a video. How do you make a precision application cable in the home workshop? What is this cable doing that another 3 foot 50 ohm terminated cable can't do? I'm a m addicted to collecting Tek 500 series plugins for my home lab and have a SG503 and would love to make one. Thanks and love your videos. His reply: w2aew I looked up the engineering specs for that cable - doesn't look like anything super special. 012-0482-00 refers to a 36" +/-0.5" long RG-58C/U cable with BNC connectors and strain reliefs. The BNC connectors are to be per MIL-C-39012 spec, which basically applies to most high-quality (reputable manufacturer) connectors, rated to 4GHz, max insertion loss of 0.2dB at 3GHz, VSWR of 1.3:1 max with TFE insulation. Nothing super special, just a 3' 50ohm coax made with quality materials. |
David C. Partridge
Jared Cabot
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