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Re: 577 D2 Display Issues
Have you checked the IC sockets? Most 577s were built with Texas
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Instruments edge contact DIP sockets that proved unreliable and were later replaced. If re-seating any of the IC's makes a difference, it might be time to swap the sockets in your 577. Dave Casey On Fri, Oct 29, 2021 at 8:25 PM <gmilliorn@...> wrote:
It took about 30 minutes of prying around the rubber gasket to free the |
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Re: 577 D2 Display Issues
It took about 30 minutes of prying around the rubber gasket to free the '577 tube. I broke the gasket
too. On the other hand the 5110 tube came out very easily. On swapping it I get a pretty stable display now. After running through the calibration procedures, I used it to measure the beta of a 2N4403 at 185, which seems pretty reasonable (once I realized the lamp behind the step knob is burned out - initially I was worried it was indicating 1850). The only issue left is when the number of steps is even, the step waveform is very steady. When odd (and >= 5), it shimmers vertically quite a bit. Something odd in the step generator board up next I guess. |
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Lots of Tek/HP and Cal goodies added to the stuff page
walter shawlee
The elves have been busy, and there are all kinds of interesting items uploaded including BITE indicators, Hp/Tek knob assortments, and great first/cheap instruments in the surprises section.
Hopefully you will find some fun stuff to look at this weekend. There's also a spectracom 8140 10MHz distribution amp I have modified with its own OCXO so it's a self-contained bench standard that has 5 outputs. Look in the CAL section. Think of it as electronics trick or treat. all the best, walter (walter2 -at- sphere.bc.ca) sphere research corp. |
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P6009 100x Probe with GR-874 Adaptor
I've been wanting a good 100x probe with low capacitance, and a P6009 showed up on ebay for a reasonable price. It seemed to have something attached to it that wasn't mentioned by the seller, something that looked GR-874-ish. So I took a chance and bought it. It turned out to be a perfectly good P6009 with a rather nice homemade GR-874 adaptor. Photo here:
/g/TekScopes/photo/262268/3327732 closeup here: /g/TekScopes/photo/262268/3327733 exploded view: /g/TekScopes/photo/262268/3327736 end view: /g/TekScopes/photo/262268/3327737 This appears to have been made from part of a GR-874 connector, with a brass ring pressed inside one end and three #2-56 holes around the sides to contact the three ground contacts on a standard #6-32 Tek monolithic probe. The exploded view shows the short brass spacer that is tapped #6-32 in one end, to mate with the probe, and #8-32, to mate with the 874 center pin, in the other. I have replaced the original #2-56 flat head screws with non flatheads. This probe came with the optional BNC 100x readout connector on the scope end, but that appears to be broken. You can see the end view here: /g/TekScopes/photo/262268/3327735 Whatever readout pin was there is gone. I don't have a scope that could have used that feature, so that's not a problem for me. It appears that this special end could be replaced with the end shell of some standard BNC. Does anyone know which variety I should look for? The P6009 manual calls that part a 134-0044-00; anyone got one? If I manage to replace this end, would the broken part be useful to anyone else? thanks, |
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Re: Need 20 Meg Switch for 465B
Okay - I see that now on the Trigger View button. I thought it strange that it wasn't on the 465 but overlooked it from the pictures I was viewing. Hope you find a suitable switch.
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Regards, Barry Thanks, Barry - N4BUQ ----- Original Message -----
From: "Robert Simpson via groups.io" <go_boating_fast@...> yes, the 465 has pull to activate (like my 465M) limit whereas the 465B is push. |
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Re: Newbie with a 466 that won't sweep
Thanks everyone for your insight so far! I haven't had a chance to dig much further, but I thought I'd drop in with some more observations and responses to your questions:
As far as diagnostic equipment goes, yes, I do have another scope at my disposal, and a signal generator and multimeter. The power rail ripple isn't as bad as I first thought - that 20mV figure I quoted earlier was a combination of measurement error and a rather electrically noisy environment. Taking a bit more care about the measurements, I think I'm hitting the noise floor of my cheap modern scope and probes at around 3mV. So it may not be quite within spec, but close. Voltages all seem to be stable and within tolerance. The connections to the deflection plates appear to be OK. With the the horizontal amp common-moded and X-Y mode selected to un-blank the trace, I see a centered dot, so I think we can sign that section off as OK for now. I've noticed that the horizontal position in X-Y mode is influenced by the sweep mode, which seems a bit odd to me: - A Sweep (also A intensified by B): trace is offset far to the right, can be brought partially on-screen with the horizontal position control, but not fully. - B Sweep: trace is offset by approximately one division to the left with the horizontal position control centered - Mix: When pressed, the trace starts at B sweep position and then sweeps to the A sweep position at the rate set by the B timebase (and then stays there) To me this lends credence to the hypothesis that the A sweep generator is 'stuck' - Andreas, thanks for digging that info out of your notes! I'll definitely take a look at that capacitor on the timing board. However, right now the timing board is out of reach. I'm having some trouble removing the B trigger slope knob; no matter how much persuasion I apply, that grub screw isn't budging. Even with regular dousings of penetrating oil over the past few days, it's resolutely stuck, to the point where I've wrecked a couple of hex keys trying to turn it. Anything else I should try before I do some violence with a left-handed drill bit? Thanks again, Richard |
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Re: Need 20 Meg Switch for 465B
Bob,
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I haven't torn into a 465B in detail yet. But from the listings just posted this does look like a switch type I have disassembled several times now. The first was for a broken plunger just as you've described. The white (or grey) plastic plunger has a very small cross section inside the switch. There are two spring slides that are the switch contacts that live inside this plunger. It gets very narrow and is easily broken. Rather than desoldering the entirety of the switch you can disassemble your broken switch, the new replacement one, and then swap plungers for a simple solderless fix. It only takes some care, and three hands. Just gently pry the front brass clip from the plunger and set the spring aside. Depending on the details of the switch there may be some toggling mechanisms that need to also be carefully removed and set aside. Some switches require a slider to be held aside while pushing the plunger through the switch body and out the back. At this point you need to be careful and observant about how the contacts are placed inside the plunger and switch body. As it comes out the back they're going to want to fly out and get lost. Now you should find how the back of the plunger has broken off. Slide the entire plunger out the back of the switch body. Do the same for the new switch. Clean everything up well and reassemble. You shouldn't need to lube anything. Still, I put a tiny amount of silicon grease on the top and bottom of the new plunger. But it's probably not necessary, and may be a long term dirt collector. To each their own. I use a tweezers to hold the contact springs in the new plunger as I slide it into the switch. Once that's in it's a pretty easy job to reassemble the front of the switch. If the brass spring holder clip is a bit stretched from removal it may need an ever so gentle squeeze to close it up a tad. Also be careful getting the push button shaft off the plunger. They can get stretched out being pried off. Then it'll always pop off the plunger if the switch is a pop-out type. Hope that helps! Good luck! Dave On Friday, October 29, 2021, 11:49:55 AM PDT, Robert Simpson via groups.io <go_boating_fast@...> wrote:
Looks like I need a new 465B 20 Meg bandwidth limit switch if there is one available. So far, no luck. Neither Sphere nor Qservice have one. It is S1414, part number 260-1486-00. It has been stuck in the ON position, and after several tests, I just confirmed it's broken. The front panel external part of the switch moves in and out smoothly, but it stays ON.? I can get it to turn off by poking the back side with a hooked dental probe. This pushed the inner slide forward and turns the switch off. Does anyone have or know where I can obtain a working switch? Bob |
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Re: Need 20 Meg Switch for 465B
What I meant to say was that I think the BW Limit switch was added to the B model so a 465 parts unit may not have what you're looking for.
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Thanks, Barry - N4BUQ ----- Original Message -----
From: "n4buq" <n4buq@...> On second thought, that's a 465 and I don't think the BW Limit switch was added |
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Re: Need 20 Meg Switch for 465B
On second thought, that's a 465 and I don't think the BW Limit switch was added to the B model. Sorry about that.
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Thanks, Barry - N4BUQ ----- Original Message -----
From: "n4buq" <n4buq@...> You might try here: |
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Re: Need 20 Meg Switch for 465B
Here:
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Five bucks. Paul On Fri, Oct 29, 2021 at 11:49:48AM -0700, Robert Simpson via groups.io wrote:
Looks like I need a new 465B 20 Meg bandwidth limit switch if there is one available. So far, no luck. Neither Sphere nor Qservice have one. It is S1414, part number 260-1486-00. --
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: Need 20 Meg Switch for 465B
You might try here:
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Thanks, Barry - N4BUQ ----- Original Message -----
From: "Robert Simpson via groups.io" <go_boating_fast@...> Looks like I need a new 465B 20 Meg bandwidth limit switch if there is one |
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Need 20 Meg Switch for 465B
Looks like I need a new 465B 20 Meg bandwidth limit switch if there is one available. So far, no luck. Neither Sphere nor Qservice have one. It is S1414, part number 260-1486-00.
It has been stuck in the ON position, and after several tests, I just confirmed it's broken. The front panel external part of the switch moves in and out smoothly, but it stays ON. I can get it to turn off by poking the back side with a hooked dental probe. This pushed the inner slide forward and turns the switch off. Does anyone have or know where I can obtain a working switch? Bob |
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Re: tek 2215 trace position issues
Tom, Harvey,
This problem has threads running in parallel on eeVBlog and the UK Vintage Wireless Forum. On eeVBlog the generic component tester shows two back to back diodes, one with Vf ~ 700mV and the other with Vf ~ 1.2V, actually quite an informative result if you know what you are about. Roger |
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Re: Parts for a Tek 920 or 922?
Dan I have 2 900 series that I do not thing I will have time to get to. I
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know they both have HV issues however the tubes seem to be good and they are complete units. Then are a 922 and a 912. Both are known BAD. Let me know if you are interested? Zen -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Tom Lee Sent: Thursday, October 28, 2021 8:10 PM To: [email protected] Subject: Re: [TekScopes] Parts for a Tek 920 or 922? I can confirm that the attenuator does not to be swapped out. Tom Sent from my iThing, so please forgive brevity and typos On Oct 28, 2021, at 17:01, John Gord via groups.io<johngord@...> wrote: The shaft can probably be just pulled out, and the whole knob/shaft piece replaced without changing the attenuator. --John GordforOn Thu, Oct 28, 2021 at 02:59 PM, Daniel Koller wrote: Channel 1 of a 922. The plastic knob broke off. |
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Re: tek 2215 trace position issues
Generally, the algorithm is to run each pin of the device through two resistors, one about 680 ohms, one about 470K.? Each of the ends of those resistors goes to a separate I/O pin.? Each device pin also goes directly to the A/D converter.
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Depending on which pin is connected, (with an active pullup, or not, or with an active pulldown or not (IIRC),? you can measure the forward voltage drop of a diode through either about 8 ma or about 10 ua. Once you identify the base by diode tests, you likely pick the collector (10 ua into the base, 680 ohms collector, likely ground the emitter), as the lead that gives the highest beta. Clever.? The schematics are on the web, but the algorithms are not. Not super accurate, but useful... Harvey On 10/28/2021 10:08 PM, Tom Lee wrote:
Wouldn¡¯t tell me much anyway! Need to know how it tests. |
Dave Peterson
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