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Re: replacement part?
--- In TekScopes@..., Hong F Du <feng@s...> wrote:
Hi All,from the power supply of Tek scope 7603? Many thanks.December 14, 2000. The transister is Silicon...NPN.......2N3773...151-0487-00 Regards, Bernard Lee |
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Re: Tek HV parts (570)
Stan or Patricia Griffiths
spam@... wrote:
My Tek model 570 vacuum tube curve tracer seems to haveHi John, You can use just about any scope as a high voltage capacitor checker. You just set the vertical input to DC coupling and some fairly sensitive range like 0.1 volts/division. You then (carefully) connect some low ripple DC (like the +500 volts from an older Tek scope) to one end of the cap and touch the other end to the scope input. A very good cap will not leak DC and the scope trace will return to the screen when the cap is charged. A leaky cap will cause the trace to remain off screen. You can actually measure the amount of leakage by realizing the scope is putting 1 megohm on the end of the cap to ground and forming a DC divider with it. By measuring the amount of DC deflection on the scope and knowing how much DC you are applying to the cap, you can actually make a pretty good calculation of the internal DC leakage resistance of the cap. It should be very very high in a good cap . . . To get familiar with this testing technique, try some known good mylar caps (very low leakage) and then try some older "black beauty" type caps (usually quite high leakage). Make sure you don't apply more DC than the cap is rated for. Less is OK but won't give you as good a test as testing it near its rated voltage. The 500 volt supply in an older Tek scope is DEADLY. BE CAREFUL. I know of no source of good 570 High Voltage transformers although I know one guy who rebuilds certain old Tek HV transformers. I am not sure he does 570 transformers, though. He is: Bill Schell, 10102 Winder Trail, Orlando, FL 32817 Phone: (407) 282-4289. I had a HV transformer failure in my early 570 and found that I could substitute a HV transformer from an RM15. It provides a slightly different CRT cathode voltage than the original but it was close and I think I can make it work OK if I adjust it to keep the total CRT accellerating voltage the same as it was originally. I have only partially restored my 570 so I don't really know if this is a good solution or not. Stan w7ni@... |
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Re: Tek HV parts (570)
Michael Dunn
At 5:07 PM +0000 2000/12/07, spam@... wrote:
know where to get small quantities of the 1,2,3, and 4Digikey has a limited number of HV caps. You can always make series/parallel combinations too... You'd probably want equalizing resistors in the case of series strings. p.s., I've probably asked before, but does anyone have an 8608 tube to spare? ----------------------------------------------------------------- Michael Dunn | Surround Sound Decoder & Stereo Enhancer Cantares | Self-Amplified Speakers, Test Equipment 74 George St. | Ambisonic Surround Sound CDs and Recording Waterloo, Ont. | (519) 744-9395 (fax: 744-7129) N2J 1K7 | mdunn@... Canada | ----------------------------------------------------------------- |
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Re: Tek HV parts (570)
spam@... wrote:
If this unit uses those little oil-filled caps in the HV supply, try hitting them with some freeze spray. My RM545B did this (as well as smoking the 6AU5 cathode resistor) due to electrical leakage in the .001 uF 1KV oscillator tank cap. Chilling this cap made the problem go away temporarily. I replaced it with a ceramic disc with the same value and rating. -- Dan Kerl dlkerl@... PS- looking for a 577 |
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Tek HV parts (570)
My Tek model 570 vacuum tube curve tracer seems to have
lost the ability to keep the high voltage running. When it is first powered on, I get a nice trace, but the HV oscillator tube (6AQ5) looks like it's really unhappy about it. In a minute or so, the high voltage goes away with the usual dim expanding trace. I've replaced the tubes, and don't see anywhere the supply is overloaded, so I'm guessing a failed capacitor or shorted turn in the transformer. Anyone know where to get small quantities of the 1,2,3, and 4 kilovolt capacitors? I've found about half of them, a couple apiece at five different vendors (I'd end up spending 10 times more in shipping than in parts). Are some capacitors more likely to fail than others? I don't have a high voltage capacitor tester, though I plan to go through it with the one I do have if I can't just replace 'em all. And if I'm really unlucky, anyone know where I can obtain a replacement HV transformer? Failing all the above, can anyone recommend a place to have classic Tek gear repaired? -- Thanks, John Rehwinkel spam@... |
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Re: 1A5, 1A7
Stan or Patricia Griffiths
I was going to suggest that maybe, with questions like that, you could use a
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copy of my book (OSCILLOSCOPES--Selecting and Restoring a Classic) that is full of such descriptions and includes both the 1A5 and 1A7. However, I see that Bernard Lee has written you a response that is almost an exact copy of what I wrote so I can say that you can rely on his answer. Stan w7ni@... Michael Dunn wrote: Does anyone know the difference between the 1A5 and 1A7 |
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Re: 1A5, 1A7
--- In TekScopes@..., Michael Dunn <mdunn@c...> wrote:
Does anyone know the difference between the 1A5 and 1A71A5 is an amplifier with differential inputs and up to 50 Mhz bandpass, depending on sensitivity. It has an input for a special differential probe P6046 and also has a comparison power supply built in which may be connected to one of the differential inputs and subtracted from the signal connected to the other differential input. 1A7 is an extremely high gain differential amplifier. It has a bandpass of 500 Khz and a maximun sensitivity of of 10 uv/ division. Regards, Bernard Lee |
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1A5, 1A7
Michael Dunn
Does anyone know the difference between the 1A5 and 1A7 differential plug ins?
thx ----------------------------------------------------------------- Michael Dunn | Surround Sound Decoder & Stereo Enhancement Cantares | Self-Amplified Speakers, Test Equipment 74 George St. | Ambisonic Surround Sound CDs and Recording Waterloo, Ont. | (519) 744-9395 (fax: 744-7129) N2J 1K7 | mdunn@... Canada | ----------------------------------------------------------------- |
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Re: What to do with a pile of 7A16P's? CADC?
Michael Dunn
At 4:24 PM +0000 2000/11/09, walter shawlee wrote:
We have a pile of 7A16P's, the programmable version of the 7A16, usedStrip off any easily strippable parts, hardware, knobs, etc, and sell grab bags of Tek parts. Also have about 150 pounds of partial and failed 5K/7K plug ins weTempting :-) Could you post a rough list of 7000 modules...? Any particularly "interesting" ones? (7C,D,L,M,Snn) BTW, is the 5000 series a successor to the 7000, or concurrent? What's the difference? I'm quite amazed at the tube/SS overlap - the 7000 series started to happen in the late 60s, yet tube units were produced till perhaps 1973(?). Semi-related question for Canadians out there: Anyone know if CADC (Crown Assets Disposal Corp) or a successor is still in operation? I used to get all sorts of interesting junk through them. ----------------------------------------------------------------- Michael Dunn | Surround Sound Decoder & Stereo Enhancement Cantares | Self-Amplified Speakers, Test Equipment 74 George St. | Ambisonic Surround Sound CDs and Recording Waterloo, Ont. | (519) 744-9395 (fax: 744-7129) N2J 1K7 | mdunn@... Canada | ----------------------------------------------------------------- |
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What to do with a pile of 7A16P's?
walter shawlee
We have a pile of 7A16P's, the programmable version of the 7A16, used
in waveform digitizers like the 7912D and 7612AD. Unfortunately, we have no digitizers, so these are worthless to us, and do NOT work in regular frames. Rats. Other than landfill, any suggestions? Note that we have lots of other mor useful Tek items, parts and CRTs on our website here: Also have about 150 pounds of partial and failed 5K/7K plug ins we are scrapping. Free to anybody that wants to pay the freight. We are also looking for CRT's, nixie tubes and HP repair parts. all the best, walter walter2@... |
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Re: Tek 7B87 Question
Stan or Patricia Griffiths
HI Don,
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The 7B87 can be used in any 7000 series main frame, including the 7904. Stan w7ni@... Don Crano wrote: I know the 7B87 plug in is designed to support the features of the 7854 |
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Re: Tek 7B87 Question
Dear Don!
The 7B87 is a timebase that features a pretrigger aquire clock to enable a pretrigger otion in the digital storage mode of the 7854. It works in all other 7k scopes i own. The main disadvantage of this timebase is that it does not have the delta delay or normal delay for a delayed timebase. Also the independent/runs after delay/triggerable after delay button is not available because it will control the pretrigger operation. When You use it as delayed timebase (eg with a 7B15 or 7B85) it will work fine. (similar to a 7B80) Michael B. Haubmann mhaubmann@... --- In TekScopes@..., "Don Crano" <donc@s...> wrote: I know the 7B87 plug in is designed to support the features of the7854 frame, but can it be used in a 7904 frame, or is it strictly forthe 7854 frame? |
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Re: FS/For Trash? Type 502 Dual Beam Oscilloscope
In a message dated 11/03/2000 9:56:55 PM Eastern Standard Time,
w7ni@... writes: It is hard to guess what will happen on eBay. Here is my guess atit just for picking it up.My experience is about the same. I have 5 or 6 502s and would really like to have one operating on each bench that I use for audio work, but they really need thorough servicing and recapping. I burned out two transformers before I learned not to turn them on. I have paid $0.00 to $25.00 for them. I would pick up any similar vintage Tek equipment that are available for the hauling within 50 miles of Rochester, NY or $5 to $15 for one that sits in front of me at a Hamfest. At that rate I get about all I can handle. Mike Csontos |
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Re: FS/For Trash? Type 502 Dual Beam Oscilloscope
Stan or Patricia Griffiths
Hi Jeramy,
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An old Tek scope like a 502 always has SOME value but whether it is worth the cost the box and ship it is a good question. It is always a good idea to offer these things to the list but it would be helpful to know WHERE it is located to know if one could pick it up without boxing and shipping. As to what it might be worth on eBay . . . good question. I have sold tons of stuff on eBay and I have really been surprised at what some of it went for. I have also put some stuff up for auction that never got a single bid . . . sometimes I have relisted a "no bid" item and gotten good bids on the second try. It is hard to guess what will happen on eBay. Here is my guess at what it is worth: If it looks dead with no trace when you plug it in and turn it on: $10.00. If it has a trace and appears to work: $25.00. A little more if it has a manual and/or probes or a scope cart. I already have two of them plus two 502A models but I would still find a place for it here to save it from the landfill if it was close to here and I could get it just for picking it up. Stan w7ni@... Jeramy Ashlock wrote: Hello, I just rescued an old 502 Dual Beam Oscilloscope that |
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Re: FS/For Trash? Type 502 Dual Beam Oscilloscope
Michael Dunn
At 2:30 PM -0700 2000/11/03, Jeramy Ashlock wrote:
Hello, I just rescued an old 502 Dual Beam Oscilloscope thatNot sure what you could get on eBay, but don't trash it! I'll pay you a reasonable amount for stripped parts if you don't want to keep it together. Shipping intact might be prohibitive. Does it have PCB vertical amps, or little sub-chassis with ceramic strips? ----------------------------------------------------------------- Michael Dunn | Surround Sound Decoder & Stereo Enhancement Cantares | Self-Amplified Speakers, Test Equipment 74 George St. | Ambisonic Surround Sound CDs and Recording Waterloo, Ont. | (519) 744-9395 (fax: 744-7129) N2J 1K7 | mdunn@... Canada | ----------------------------------------------------------------- |
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FS/For Trash? Type 502 Dual Beam Oscilloscope
Jeramy Ashlock
Hello, I just rescued an old 502 Dual Beam Oscilloscope that
was about to be thrown out, tubes and all. It is in slightly beat up shape. I am wondering if it would have any value to anyone here, or should I just trash it? What do you think I could I get for this thing on ebay? |
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