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Re: 2235 display problem
Chuck Harris
Put the scope in X-Y mode, with no input signal, and
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measure each vertical deflection output to ground. They should be about the same voltage. If one is at zero, or the supply voltage, that driver is burned out. A very common problem that often comes from shorting one output to ground. -Chuck Harris Pmccandless via Groups.Io wrote: Beamfinder is working properly. When pressed, the display compresses to a single position on the x-axis, but the amplitude remains. Here is a helpful hint...I pulled (disconnected) the upper and lower plate deflector wires from the CRT and turned the unit on again... without any vertical input connected, the CRT display was exactly the same as before...just a big rectangle-appearing image at all sweep speeds. This tells me that something is amiss in the CRT or associated electronics. Still scratching my head on this one. |
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2019 Sphere Stuff Day event preview
walter shawlee
those of you that have come to one of our previous stuff day events know that there is a great mix of free and cheap electronic "stuff" for everybody to snorkel through. it is a true BYOB (bring your own boxes) affair. usually we get rid of at least 2 tons of gear at each event.
This year will be a bit different, as both susan and I are turning 70, and we need to totally clear out at least one of our off-site storage units (about 5 tons). We will be running the event for a full week, to fit as many of your schedules as we can, and whole bankers boxes of stock will go for just a few bucks. Boxes filled with new fans, terminal blocks, pots, tek and hp spares, breakers, switches, LEDS, displays, pots, power resistors, capacitors, motors, smd parts, transformers and CRTs. We have at least 50 CRTs that really need to go, to make some space. Also about 100,000 primo Osram SMD LEDs, new in reels. There will also be a huge pile of Tek, HP, Fluke, Boonton and other test gear and parts to go. Susan wants at least half of the stuff cleared out of rooms, aisles, our sauna, and storage, so this will really work to your benefit. We are located 4 hours NE of Vancouver in BC, close to Washington, Oregon and Alberta by highway. We are happy to put up guests overnight if the room is free, and we are looking for "best dates" for the event. To some degree, it is linked to weather, best with no rain for a week before, and clear highways. Usually it is within 2 weeks of the Easter long weekend. You can get more details from our website at: Our goal is to clear out all the bulky stuff, gear we are never going to get around to fixing, and extra stock that should really be home with somebody else! No, Sphere is not closing, but we REALLY need to clear out many things that nobody even knows we have. please feel free to email off list with any special requests (walter2 -at- sphere.bc.ca), and let us know if you can come up in 2019! all the best, walter sphere research corp. |
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Re: 466 Channel 2 problem
I have had another snoop around with my multi-meter and I find that test-points 4 and 7 on channel 1 both show +5.7V, the equivalent ones on channel 2 show +3.37V (TP 11) and +7.31V
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(TP 14). What does this show, I wonder? Colin. -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Colin Herbert via Groups.Io Sent: 08 December 2018 14:42 To: [email protected] Subject: [TekScopes] 466 Channel 2 problem Hi, I have been faffing about with a 466 with a channel 2 problem for a few weeks, and though I might eventually sort it, I thought I would consult the experts and possibly save a bit of time. The scope came with a non-operational delayed time-base and an intermittent graticule illumination light. I have fixed both of these now, but the channel 2 problem is bugging me. The scope works on channel 1 alone fine, so it can't be anything after the diode-switching circuitry (can it?), but channel 2 doesn't display normally. If I push the beam-finder switch, I see channel 2, but the position control does nothing. If I use a slow time-base setting and switch to "alternate", I can see channel 1 and there is a period when channel 2 would be displayed, but no channel 2 shows. I have checked voltages and signals for channel 2 from the end of the attenuator through to the diode channel switching (possibly not comprehensively) and mostly cannot see anything untoward. I have also checked to see that the "position" control does change the voltages on the two nominal +2.8V rails, but rather asymmetrically (-0.6 to +2.8V on one rail and 2.79 to 2.8V on the other). I am suspecting that there is something wrong with the "position" control circuitry, but changing Q262 didn't solve the problem. I also noted that I cannot trigger the time-base from channel 2. Am I missing something obvious? I would like to get this 466 working, as it is one of three that I have, one of which has already become a parts-donor. I might even try fixing the other one sometime. TIA, Colin. |
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Re: How Many Scopes?
Craig Sawyers
Dual amplifier in left and right vertical (set to chop or alternate) and dual timebase (such as a
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7B92A) in each horizontal compartment. Select vertical mode beam 1 right, beam 2 left. Set horizontal mode to beam 1 right, beam 2 left Set each 7B92A to intensified and delayed sweep ,and set trace separations to suit. Gives a total of 16 traces. Craig -----Original Message----- |
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Re: 2235 display problem
Beamfinder is working properly. When pressed, the display compresses to a single position on the x-axis, but the amplitude remains. Here is a helpful hint...I pulled (disconnected) the upper and lower plate deflector wires from the CRT and turned the unit on again... without any vertical input connected, the CRT display was exactly the same as before...just a big rectangle-appearing image at all sweep speeds. This tells me that something is amiss in the CRT or associated electronics. Still scratching my head on this one.
Phil |
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Re: What have i here ? (Tek TDS 540 )
On 12/8/2018 3:26 PM, mattko87 wrote:
I has a TDS540, scussefully repaired.Hello, Matt-- As a guess... VER2 = version 2 73-- Brad AA1IP |
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Re: How Many Scopes?
Hi all?I for one have more scopes than i can or will ever use , but for some strange reason i keep getting them . For me it just fixing them that i enjoy and once fixed it goes in the pile that i have , speaking of pile i am looking for one last tek to complete my dual beam collection,? 7844 is the last tek needed for dual beam collection,? if anyone has one reasonable please let me know,? thanks and keep the hobby going .
On Sat, Dec 8, 2018 at 1:39 PM, TomC<tomc@...> wrote: On 12/7/2018 3:15 PM, Craig Sawyers wrote: How?Now just what do I do if I have to display more than 12 waveforms at once ?Ah - you can do that with a single 7844 |
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Re: How Many Scopes?
On 12/7/2018 2:04 PM, Vincent Trouilliez wrote:
I guess it's like asking a women why does she have 564 different pairs of shoes, but only one pair of feet to use them with....Most men will know that is a question best not asked. My scopes: 2232, 2246 2445, 2465 7704, 7844, 7854, 7904 TDS210 |
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Re: Tek 371 test fixture
Hi Bob??Thanks for your reply that you sent to me with pictures I would like to ask you if you could possibly let me know the gauge of the wires there and the possible length of the cord coming from the plug that goes to the Tracer to the test fixture. Once again thank you Neil
On Sun, Nov 4, 2018 at 6:07 PM, Bob Koller via Groups.Io<testtech@...> wrote: Oliver, I have uploaded some pictures to the Photos section. A few notes: The fixture pictured is missing the clear safety cover. There are three microswitches in the fixture; two in front that are actuated when the cover is closed, and one at the hinge that is actuated when the cover is open. There is a? 10nf cap connected as shown in the main housing. The resistor shown in the removable section is 1k. There is a schematic in the 371A service manual available at Tek.co, and on the Tek wiki. |
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Re: Probe bags ...
On Sat, Dec 8, 2018 at 6:07 AM David Slipper <softfoot@...> wrote:
Has anyone come across a source of probe/manual bags - or a workableI'd say you've found the best source already. A lot of us use our scopes on the bench, and take the probe pouches off so we can stack things on top of the scope. So, post your requirements here. |
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Re: A cautionary tale ...
Mine actually has 3 in that position - I had assumed that was their
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purpose - thanks for the warning, though. Dave On 08/12/2018 13:56, george edmonds via Groups.Io wrote:
Hi Dave |
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Re: Probe bags ...
Yes, that may work with the application of some self-adhesive Velcro.
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Dave On 08/12/2018 15:28, Richard Solomon wrote:
How about heavy duty, large |
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Re: Smashed CRT on a 2215 - where to find a substitue?
If there were an included thread to even SKIM 8^(
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On 12/8/2018 10:40 AM, Carsten Bormann wrote:
On Dec 8, 2018, at 16:17, Carsten Bormann via Groups.Io <cabocabo@...> wrote:Well he did give it away, no?(No, he didn¡¯t. That¡¯s what you get for replying after just skimming a thread. Promise to better myself.) --
Dave Manuals@... www.ArtekManuals.com |
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Capacitor sniffing
Old devices often have a characteristic smell, e.g., from the dust that is being cooked inside the device.
Some of this smell unfortunately stems from leaking capacitors. Is there a guide somewhere that allows mapping a specific smell to a specific kind of capacitor? I know we don¡¯t have smell-o-vision in the Internet, but it should still be possible to verbally describe smells. I¡¯m asking because I have an FG501A with some performance problems, as well as a characteristic smell. Soapy, perfumy, I¡¯d say. I don¡¯t ¡°see¡± which capacitors are leaking, so I would love to use the smell to point to potential culprits. (Of course, the performance problems could be unrelated to the smell, and the smell could also come from other components cooking themselves. In any case, it would also be nice to know how toxic that smell is¡) Gr¨¹?e, Carsten |
Gary Robert Bosworth
Craig Cramb
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