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Re: [dead tek 485] Can i fix it ? (newbie here)
Jeff,
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According to the 1976 Tek catalog, the recommended probes for 50 ohm mode were P6056 (10x), P6057 (100x), and P6201 (FET). The P6202A (FET) would also be fine. For 1M ohm input, the recommended probes were P6053B (10x) and P6063A (1x/10x). Bandwidths varied. The 485 has power connectors for the FET probes. You can download the catalog from: --John Gord On Sun, Jan 10, 2021 at 08:39 PM, Jeff Dutky wrote:
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Re: [dead tek 485] Can i fix it ? (newbie here)
Hi, Jeff,
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The manual I have lists several probes on page 1-3, with the P6053 being the only 10:1, 1 megohm probe mentioned. The P6106 was (and is) commonly found connected to the 485, too, though. In the 1 meg mode, the bandwidths of the 485 and 475 are both around 250MHz with either of those probes, as long as they're 2m or less in length. And yes, the el cheapo Chinese probes often found on eBay are pretty rough at 200MHz (you can already see significant pulse response aberrations at 100MHz). The ones I've disassembled don't use resistance wire at all -- just something resembling ordinary RG-174 and a couple of damping resistors. I was actually impressed that they worked as well as they did, but that's only because my expectations were even lower. -- Cheers, Tom -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 350 Jane Stanford Way Stanford University Stanford, CA 94305-4070 On 1/10/2021 20:39, Jeff Dutky wrote:
Tom, |
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Re: Update on Domestic US Book Delivery Dates
Sorry to disagree with all the naysayers but from the emails I have received so far the books are arriving ON or AHEAD of the estimated dates on the receipt I got from the post office.
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I don't expect every one of the 76 books to arrive by Monday evening but I would not be surprised if at least 85% to 90% of them arrive with the remaining 6 to 10 books arriving a day or two later. I predicted they would all arrive 10 days after I shipped them on 1/2/2021. That gives me until Tuesday evening for the last one to arrive. It will be close but I think my chances are better than 50/50 that they will all arrive by then. If I focused on all the things that could go wrong including, as you suggested the USPS being unable to process the deliveries, I never would have called Peter Keller in the first place. I do not know whether the USPS will be able to deliver every book exactly when they say they will after having so many of their sorting machines destroyed this summer to intentionally slow down the mail. From what I can tell so far I would say they are doing an excellent job delivering the least important, lowest class media mail books, I entrusted to them. I don't know about you but I am very impressed with the job the United States Postal System is doing delivering Peter's books to you everywhere in the United States. Dennis Tillman W7pF -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Gordon Smith Sent: Friday, January 08, 2021 5:37 PM To: [email protected] Subject: Re: [TekScopes] Update on Domestic US Book Delivery Dates On Fri, Jan 8, 2021 at 02:45 PM, Dennis Tillman W7pF wrote: Hi Dennis, My apologies, but I would take any estimated delivery dates by the Post Office with a grain of salt. Because of changes made to the US Postal service over the last year, mail delivery is lagging massively. It is so bad that I personally know of Priority mail items that were mailed 2 weeks before Christmas and some are just now getting to their recipients. I ordered two aluminum roll up shade aluminum tubes last week and the business flat out stated that they would NOT ship via USPS because of delivery issues. YMMV but just thought I would give a warning. Thank You, Gordon -- Dennis Tillman W7pF TekScopes Moderator |
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Re: [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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Tracking your Peter Keller book (and anything else) Internationally
This web application called Package Radar may be helpful in tracking your
book. This is the specific web page to track a USPS (US Postal Service) shipment: Package Radar has 230 other worldwide carriers they track. You may find a few of them useful as well. The complete list of 230 carriers they track is here: Dennis Tillman W7pF |
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Re: Tek 2712 GPIB board
One way to check is use a terminal program to connect to the prologix controller and try talking to the 2712. Sending the command ?ID should give you the model number and a bunch of other info.
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Vince. On 01/10/2021 03:02 PM, Howard Hoyt wrote:
Hi! --
K8ZW |
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Tek 2712 GPIB board
Hi!
Does anyone have a spare 2712 GPIB board available? I am using a Prologic GPIB to USB converter, and the setup had been working great for a few years. Abruptly it ceased communicating, so I tried a spare Prologic converter, but that did not fix the issue. At that point I assumed a power issue with chassis differential (power spike?) between the PC and 2713 was the culprit. I replaced the two GPIB interface ICs U170 and U370 as well as the dead battery, but I still cannot plot through it. When Plot is pressed I get a No Listener message, even though the PC sees the Proligic, and I know it is good, so I suspect some other GPIB board issue. I tried ordering a TMS9914A GPIB IC, but the only version available is a really small SMD (I forget the case outline style) which is not pin-for-pin compatible with the much larger one on my board and I don't have time to make an adapter PCB....if that is even the problem I hope someone has a spare board #671-1859-01 to sell? Thank you for the bandwidth, Howard Hoyt |
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Re: [dead tek 485] Can i fix it ? (newbie here)
Hi Gary,
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Jim was very good about citing references. His remarkable AN-47 (how many 132-page app notes do you run across?), where he debuted his pulser, cites the Tek 111 pre-trigger pulse gen as an inspiration. Unfortunately, he sort of misapplies the rise time-bandwidth relationship in the notes, leading readers to think that they could infer bandwidth from a narrow pulse's rise time using the same formula as for a step. I'm sure that the application for which you built your avalanchers at GE had, er, other purposes. -- Cheers, Tom -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 350 Jane Stanford Way Stanford University Stanford, CA 94305-4070 On 1/10/2021 16:45, shalopt via groups.io wrote:
Don't known where Jim got the idea for the pulser but in 1962 |
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Re: [dead tek 485] Can i fix it ? (newbie here)
Don't known where Jim got the idea for the pulser but in 1962
I built this circuit with the delay line as an engineering technician. While at GE Comm Products Lynchburg, Va Military Engineering Dept long forgotten why we were doing this. We where not testing "o" scope. Gary G |
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Re: File /Tek 5S14N Sampler Instruction & Service Manual sm_OCR.pdf uploaded
#file-notice
Dennis, no problem. I already uploaded it to TekWiki here
Next up will be a post for assistance on the repair I need to do on it. Rick |
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Re: File /Tek 5S14N Sampler Instruction & Service Manual sm_OCR.pdf uploaded
#file-notice
Rick,
Thank you for creating an OCR scan of the 5S14 Sampling plugin Service Manual and uploading it to our Files section. Unfortunately TekScopes has limited storage on Groups.io and we are not the first place people would think to look for this manual. TekWiki is the more logical place people would look for it. Since Kurt Rosenfeld needs a 5S14 manual for TekWiki (it even says so on his 5S14 web page) your 5S14 OCR scan of this manual will be a welcomed contribution to TekWiki. Could you transfer the manual to Kurt Rosenfeld to host on TekWiki instead of on TekScopes. TekWiki has virtually unlimited storage and TekWiki already has an enormous collection of scanned manuals that Kurt is maintaining for collectors of Tek products. Thank you Kurt!!! On TekWiki¡¯s home page () it says ¡°If you want to add to Tekwiki or improve existing Tekwiki pages, please email the administrator for an account.¡± Three lines below where it says ¡°Main Page¡± in big letters on the TekWiki home page is the link to Kurt¡¯s email address. I know Kurt will be very glad to finally get this manual to host on TekWiki. Dennis Tillman W7pF From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Notification Sent: Sunday, January 10, 2021 2:11 PM To: [email protected] Subject: [TekScopes] File /Tek 5S14N Sampler Instruction & Service Manual sm_OCR.pdf uploaded #file-notice The following files have been uploaded to the Files area of the [email protected] <mailto:[email protected]> group. * /Tek 5S14N Sampler Instruction </g/TekScopes/files/Tek%205S14N%20Sampler%20Instruction%20&%20Service%20Manual%20sm_OCR.pdf> & Service Manual sm_OCR.pdf By: Rick Description: Tek 5S14N Instruction & Service Manual |
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Hi Larry,
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I would like to thank you for your foolhardy volunteer spirit and diligence so far.? It would appear that you are trying to approach Dennis's record for having taken the worst one for the team!? I believe that his index for pain and suffering peaked at just over a hundred books.? In the event that you begin to approach that milestone, we will probably have to form a committee to determine the (winner?).? I believe that part of his success involved the delivery of chocolate to the post office ladies over a long period of time.? You may want to begin that process.? Good Luck and Thanks, Jack On 1/10/2021 5:32 PM, Larry McDavid wrote:
This is another update on the group order for circuit board sets for Jared Cabot's TM500 power supply tester. |
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Re: Type 503 ¡ª power supply question
Ah, really cool!
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Getting a wire recorder is on my list of things to do!! Also, getting one of those old tube-based portable record recorders. But I haven't got time for my active projects. Would love to hear more about the wire recorders, and I suspect others here would too, except that it's off-topic, unless you used Tek scopes to fix them! You might also find the folks over at the funwithtubes ([email protected]) very interesting. It's also a moderated group filled with wisdom. Also, regarding your research project, I think you will find sparkbangbuzz.com EXTREMELY interesting, particularly in light of the guy who made that website. If you could get an interview from him, I think you'd hit a goldmine. Dan On Sunday, January 10, 2021, 05:48:51 PM EST, <brian.kane@...> wrote:
Thanks to all for your advice and wisdom. My previous experience with this kind of thing has been working on restoring radios, test equipment, wire recorders, etc. This is my first oscilloscope. I have a good sense now of what's involved in putting in a filment transformer for the CRT. I appreciate all the advice, pro and con, about whether it is worth doing. Regarding Dan's question: I'm a professor at Yale. I teach in the Department of Music and in the Program in Film and Media Studies. I have a strong background in electronic music, but nowadays I'm mostly an historian and theorist. I'm involved in a research project that involves radio and the roots of do-it-yourself electronics. I'm very interested in the informal ways that a whole generation or two of musicians (both popular and avant-garde) learned about electrical engineering and audio engineering through tinkering with radio, hanging out at radio repair shops, reading magazines and Rider manuals, etc. etc. This is an amazing forum. Thank you for all of your help. --Brian |
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Re: [dead tek 485] Can i fix it ? (newbie here)
Hi Jeff,
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Yes, the 2465 targeted the same market segment as did the 485 ("Give me the highest BW in a portable; I've got the budget for it"), and there was some continuity in engineering: Wink Gross, who had partnered with John Addis on the 485, designed the 2465's vertical amp. The 2465 team aimed for higher precision, a modest increase in bandwidth, and far fewer factory adjustments, by taking full advantage of them newfangled 1's and 0's. The 485's fast cal gen is a very useful feature. It's also a nice little circuit for illustrating to students how one approaches the design of a special-purpose pulse amplifier differently from that of a general-purpose linear amplifier. There are other things, too, such as John implementing a 4.3k resistor as a series connection of two 2.15k resistors to realize a higher-wattage resistance with lower capacitance, the choice of very low output-capacitance transistors, etc. --Cheers, Tom -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 350 Jane Stanford Way Stanford University Stanford, CA 94305-4070 On 1/10/2021 14:11, Jeff Dutky wrote:
Tom, |
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Re: Tek 576 step generator problem
Chuck Harris
The filter capacitor for the 5V logic section is
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known to be bad, almost always, with these curve tracers. It is about 10K uf, and fairly low voltage, and it becomes open circuit. When the 5V supply capacitor is bad, it causes very erratic operation. -Chuck Harris hifi-workshop@... wrote: Hello Guys, |
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Re: Type 503 ¡ª power supply question
Thanks to all for your advice and wisdom. My previous experience with this kind of thing has been working on restoring radios, test equipment, wire recorders, etc. This is my first oscilloscope.
I have a good sense now of what's involved in putting in a filment transformer for the CRT. I appreciate all the advice, pro and con, about whether it is worth doing. Regarding Dan's question: I'm a professor at Yale. I teach in the Department of Music and in the Program in Film and Media Studies. I have a strong background in electronic music, but nowadays I'm mostly an historian and theorist. I'm involved in a research project that involves radio and the roots of do-it-yourself electronics. I'm very interested in the informal ways that a whole generation or two of musicians (both popular and avant-garde) learned about electrical engineering and audio engineering through tinkering with radio, hanging out at radio repair shops, reading magazines and Rider manuals, etc. etc. This is an amazing forum. Thank you for all of your help. --Brian |
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
This is another update on the group order for circuit board sets for Jared Cabot's TM500 power supply tester.
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I just yesterday remembered there is a Tek500 groups.io Group specifically for TM500 equipment. I asked there for interest in the board sets and got several requests to be included; that has expanded the list to 63 committed and still 2 more with incomplete information or lack of commitment. Please check the two lists of name initials below to ensure you are shown correctly. These 63 have committed to order board sets: ML ML ML PA SM DC HB GL MH JR WR JT EW EW EW EW RD AW SG DS JF MU PE SN SC AA BH EPa WS KT RDD PM GM CC BH BK LR MP MP MP SA BG JK AA PTC PD MU BO JG EP BL CT MD RG CB CH DM AD JR JR CR PM LM These 2 are not committed at this time: rrrr MK It is interesting that, while most of these are in USA, there are also members in UK, Canada, Australia, Spain and Germany. In light of the size of the circuit board order remember that I must ask for prepayment by PayPal Friends and Family before I can place the board order. If you have any problem using PayPal Friends and Family as a means of payment, please contact me off-list. Final board set cost is still being worked but the estimate is $38. Packaging and shipment to CUSA will be $10; international shipping will be higher and I have discussed that with those several. Note that Jared has released another update to the Gerber files. Larry McDavid On 12/31/2020 11:27 AM, Jared Cabot via groups.io wrote:
Hi all, --
Best wishes, Larry McDavid W6FUB Anaheim, California (SE of Los Angeles, near Disneyland) |
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Re: [dead tek 485] Can i fix it ? (newbie here)
On Sun, Jan 10, 2021 at 11:11 PM, Jeff Dutky wrote:
I guess a lot of people went the Jim Williams pulser-way and drew conclusions that weren't warranted, especially before Leo's pulser became available (not too many years ago). It's a waste of effort as a replacement tool for adjusting a 'scope's BW by step response, especially without a charge line which, as Tom indicates, needs to be adjusted to be useful - and for that you need a fast 'scope! OTOH, looking at Jim Williams' pulse is about as much fun to see on a not so well-adjusted 'scope as on one that is, unless you know what the pulse really is like, in amplitude and shape. Raymond |
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Re: [dead tek 485] Can i fix it ? (newbie here)
On Sun, Jan 10, 2021 at 11:11 PM, Jeff Dutky wrote:
The 2465's calibrator is nothing like the 485's. It doesn't generate a fast edge and modifies its frequency, depending on the time base speed selected. This in most cases (and in all mine) is just a nuisance. Raymond |
Raymond Domp Frank
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