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Digitizer on eBay
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Lynn Lewis
I guess that conversation took place before I joined. Could someone tell
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me - briefly - what the digitizer is good for? And what else would one need to go with it to make it useful? P.S. I recently bought a box called an Auto-Cal Steering Unit. I actually bought it for the box ($5 + S&H) but now that I've looked inside, I find it intriguing. I'm especially curious as to what connects to the two centronics-like connectors on the back. Any background would be appreciated. -----Original Message-----
From: Craig Sawyers [mailto:c.sawyers@...] Sent: Tuesday, January 15, 2002 2:57 AM To: TekScopes@... Subject: [TekScopes] Digitizer on eBay Hi A heads-up for anyone wanting a 7912 digitizer that we were discussing on the list a few days ago. There is one listed on eBay, item 1690813203 with a $19.99 start bid. It weighs 70lb, so it is not one for me - shipping costs to the UK would be astronomical. Craig Yahoo! Groups Sponsor ADVERTISEMENT To unsubscribe from this group, send an email to: TekScopes-unsubscribe@... Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. |
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Stan or Patricia Griffiths
Lynn,
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If you are talking about the 7912, it is good for making extemely fast, single-shot measurements. Very handy for things like nuclear explosions . . . when you need to catch the EMP on your screen. Is this "Auto-Cal Steering Unit" a Tektronix item? Does it have anything like a Tek part number on it? Is it a rackmounted item with a hinged door on the front? Stan w7ni@... Lynn Lewis wrote: I guess that conversation took place before I joined. Could someone tell |
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Hi,
here is some hands-on experience with buying a 7912AD at ebay: Half a year ago i got a 7912AD at ebay for US $ 50. It was shipped from US to Germany by USPS surface for about US $ 90. When it arrived it was in good shape, though the processor hang on powerup self tests. Anyway it is a really interesting device: Its circuits are about 3 times more complex than a normal 7000 scope. It has everything inside that was high-tec in the 80s, from ECL to AM2900 bit slice processor. Its modular switched 350 W power supply must have been a shock for Tek competitors (appears to be prototype of modern PC power supplies). So i decided to buy service manuals and fix it. This was another US $ 300 + about 20 hours of work. In addition i bought a programmable amplifier 7A16P and a programmable time base 7B90P for about US $ 120 + shipping. Later i noticed, that 7A16P is the proper amplifier for a 7612 digitizer and i needed a 7A29P instead. That one i got for another US $ 170 + shipping. You also need a black and white TV monitor to do adjustments. So you see: Owning such a device is not for the fainthearted and the impression you get, when somebody buys something cheap at ebay may be completely misleading. For me the total was about $ 1000. You also see: For an educated engineer a 7912AD is still maintainable. Now i have a scope that dumps its electron beam into a semiconductor target of about 1" by 1". The target serves as realtime storage and is read out by a second beam in three different modes: - TV scanning - xy intensity scanning - xy intensity scanning with analog to digital conversion, storage and data transfer via HPIB. The images i get are perfect, including a grid written by the beam! Bandwith is about 500 MHz. The sampling rate equivalent to the risetime of about 0.6 ns would be 1.6 Gs/s. Now the drawback: it does only about 512 samples total! This is why everybody wants to have one of these modern digital storage scopes with megabytes of memory and why the concept of 7912AD is history. Anyway, for applications where the small number of samples doesn't matter, a 7912AD still competes with modern $ n0 000 scopes. This is in the area of scientific measurements, where you know when you expect an interesting event to happen, so you can catch it inside your 512 samples record. In the world of digital communications a 7912AD gets lost and you better buy a used TDS scope for the same price. Owning such a superb device as a private person may be an interesting experience, especially for a true Tek freak. I bought another one in the meantime.. mmm, because each one has only one input channel! Best regards Dieter Teuchert |
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Don Black
Once I had a little problem with my septic tank (sewerage system) and needed to get
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some air into it. I went to the local pet shop and bought a fish tank pump that did the job just fine. However, they also had a special; a free gold fish with every purchase. Terrific. Then of course, I needed a tank, filter, gravel, underwater toys and Doo Dads. I already had the pump (when not otherwise in use, it had two outlets anyway). So after getting all the accessories all was well, with fishy happily swimming round in his new home, until one day he went to the great fish tank in the sky. A friend finally got the tank, etc. Now if I go to buy a reel of solder and the day's special is a Tek. Digitizer, well perhaps I'll just pass it up. Still, if ever I need to conduct any underground tests? I know how you feel Dieter. At least you won't have to buy a manual for the next one. Cheers, Don Black. Dieter Teuchert wrote: Hi, |
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Lynn Lewis
I've decided to pass on the digitizer. I've bought enough "toys" already
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(toy=something to take apart to see if there is anything useful in it), including an HP1630D. Right now, I have a 7704A scattered across my workbench. I've always worried about those EMPs. I've though about adding ferrous shielding around my hard drive in case a nuke hit close by <:-) Here is the link to the Auto-Cal Steering Unit on ebay: 720 I'll check for a part number when I get back to the office later today. It's made by Tektronix. It's rack mounted but no hinged door. It has a multitude of BNC connectors. Inside (besides lots of room, which I find unusual for Tektronix) there is a horizontal metal partition between the top section and the bottom section to which the circuit boards are attached, also horizontally. On the bottom of the partition is a (well made, easy to get to) power supply that provides +5, +15, -15, and -5.2vdc. The other boards are on top of the partition. Most of the cables from the BNC connectors go to a board with a bunch of flat "relays". Each relay has one input and (I forget) maybe 4 outputs. It's purpose is obviously to "steer" a signal from one input to one of several outputs, depending on instructions sent by the other (logic?) boards. The logic boards apparently attached to something via the centronics like connectors and that something determined the "route" of the signal. I'm thinking that it may have routed several calibration devices to an output so that once hooked up, you could change inputs automatically without having to unplug and replug cables all the time. In any case, it's a very nice box but I'm going to explore it a while before I decide whether to gut it or not. Lynn -----Original Message-----
From: Stan or Patricia Griffiths [mailto:w7ni@...] Sent: Wednesday, January 16, 2002 12:43 AM To: TekScopes@... Subject: Re: [TekScopes] Digitizer on eBay Lynn, If you are talking about the 7912, it is good for making extemely fast, single-shot measurements. Very handy for things like nuclear explosions . . . when you need to catch the EMP on your screen. Is this "Auto-Cal Steering Unit" a Tektronix item? Does it have anything like a Tek part number on it? Is it a rackmounted item with a hinged door on the front? Stan w7ni@... Lynn Lewis wrote: > I guess that conversation took place before I joined. Could someone tell > me - briefly - what the digitizer is good for? And what else would one need > to go with it to make it useful? > > P.S. I recently bought a box called an Auto-Cal Steering Unit. I actually > bought it for the box ($5 + S&H) > but now that I've looked inside, I find it intriguing. I'm especially > curious as to what connects to the two > centronics-like connectors on the back. Any background would be > appreciated. > -----Original Message----- > From: Craig Sawyers [mailto:c.sawyers@...] > Sent: Tuesday, January 15, 2002 2:57 AM > To: TekScopes@... > Subject: [TekScopes] Digitizer on eBay > > Hi > > A heads-up for anyone wanting a 7912 digitizer that we were discussing on > the list a few days ago. There is one listed on eBay, item 1690813203 > with > a $19.99 start bid. It weighs 70lb, so it is not one for me - shipping > costs to the UK would be astronomical. > > Craig > > Yahoo! Groups Sponsor > ADVERTISEMENT > > To unsubscribe from this group, send an email to: > TekScopes-unsubscribe@... > > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. > > > > > To unsubscribe from this group, send an email to: > TekScopes-unsubscribe@... > > > > Your use of Yahoo! Groups is subject to Yahoo! Groups Sponsor ADVERTISEMENT To unsubscribe from this group, send an email to: TekScopes-unsubscribe@... Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. |
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Stan or Patricia Griffiths
Hi Lynn,
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After taking a look at the eBay pictures, I have to admit that in my 26+ years at Tek, I have never seen this thing. Tek made a lot of LARGE systems of 7912's (digitizers, like we have been discussing here) for the military. I think many of those systems have been broken down into pieces for sale on the surplus market. This looks like one of the pieces of such a system for routing standard signals to the individual 7912's (or maybe 7612's) to verify system performance prior to using the system to gather data during a test. No doubt, there are many coaxial relays inside the box and the two blue connectors are used to control the opening and closing of those relays for routing signals. Most of these types of equipment never appeared in any catalog since they were custom-made in very low quantities. Stan w7ni@... Lynn Lewis wrote: I've decided to pass on the digitizer. I've bought enough "toys" already |
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Lynn Lewis
Stan
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I forget to look for a part number. What you said sounds right to me. I like the idea of a coaxial relay. Are they used in anything else? I'll probably be asking about pinouts later. Thanks. Dick, I solved my power supply problem, except it wasn't actually the power supply. One of the cables going to the calibration board was plugged in backward (P10D, I think). They symptoms were, nothing worked except the little bulb in the power supply (??19). You could here it going tik, tik, tik but the graticule lights didn't even come on. I got pretty intimate with the schematic but I'm afraid you didn't give me much to go on. By the way, with mine, the 5 volt supply was also less than a volt. More to come. -----Original Message-----
From: Stan or Patricia Griffiths [mailto:w7ni@...] Sent: Thursday, January 17, 2002 12:46 AM To: TekScopes@... Subject: Re: [TekScopes] Digitizer on eBay Hi Lynn, After taking a look at the eBay pictures, I have to admit that in my 26+ years at Tek, I have never seen this thing. Tek made a lot of LARGE systems of 7912's (digitizers, like we have been discussing here) for the military. I think many of those systems have been broken down into pieces for sale on the surplus market. This looks like one of the pieces of such a system for routing standard signals to the individual 7912's (or maybe 7612's) to verify system performance prior to using the system to gather data during a test. No doubt, there are many coaxial relays inside the box and the two blue connectors are used to control the opening and closing of those relays for routing signals. Most of these types of equipment never appeared in any catalog since they were custom-made in very low quantities. Stan w7ni@... Lynn Lewis wrote: > I've decided to pass on the digitizer. I've bought enough "toys" already > (toy=something to take apart to see if there is anything useful in it), > including an HP1630D. Right now, I have a 7704A scattered across my > workbench. > > I've always worried about those EMPs. I've though about adding ferrous > shielding around my hard drive in case a nuke hit close by <:-) > > Here is the link to the Auto-Cal Steering Unit on ebay: > > 720 > I'll check for a part number when I get back to the office later today. > > It's made by Tektronix. It's rack mounted but no hinged door. It has a > multitude of BNC connectors. Inside (besides lots of room, which I find > unusual for Tektronix) there is a horizontal metal partition between the top > section and the bottom section to which the circuit boards are attached, > also horizontally. On the bottom of the partition is a (well made, easy to > get to) power supply that provides +5, +15, -15, and -5.2vdc. The other > boards are on top of the partition. Most of the cables from the BNC > connectors go to a board with a bunch of flat "relays". Each relay has one > input and (I forget) maybe 4 outputs. It's purpose is obviously to "steer" > a signal from one input to one of several outputs, depending on instructions > sent by the other (logic?) boards. The logic boards apparently attached to > something via the centronics like connectors and that something determined > the "route" of the signal. I'm thinking that it may have routed several > calibration devices to an output so that once hooked up, you could change > inputs automatically without having to unplug and replug cables all the > time. In any case, it's a very nice box but I'm going to explore it a while > before I decide whether to gut it or not. > > Lynn Yahoo! Groups Sponsor ADVERTISEMENT To unsubscribe from this group, send an email to: TekScopes-unsubscribe@... Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. |
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I believe that those digitizers were used to measure all sorts of parameters
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during test, so a number of them was consumed for a single test. My understanding was that they were lowered down the hole, but somehow digitizers lived until data was transmitted to a safe location. I remember talking with Tektronix salesman in Orange County who was covering company that I worked for and, must have been, EGG also. Much later in time, I found out that EGG was a major contractor for Nevada site and frequently a front company for ordering long lead time supplies. In that conversation I was lamenting about problems of failures in field and Tek guy laughed and said how he never gets service calls, just another order. He never said who was his customer, I guessed that after reading about testing. There also seems to have been test parameters recorded photographically from screens of 7903, blue phosphor and reduced deflection options. I bought one of those to cheaply get hold of 7A19s; guy was selling those scopes for less money than asking price for a single 7A19, at the time, and would not hear of selling just plug ins. I had to take the whole thing; something like Stan's venture in government auctions. The camera mount adapter was hard bolted to scope frame. I have never seen something like that before: the screws that hold CRT in place were replaced with longer ones so that camera mount adapter was grabbed, too. I guess, camera falling of the scope was not considered an acceptable event. Guy who was selling those 7903s would bring two or three at the time to swap-and-meet at the TRW. He was probably hoping that tea-spooning would hold up price, but he did not have many takers. I saw him asking $450 for a scope, two pieces of 7A19 and 7B80 and after several months at the other swap-and-meet asking price was down to $250. I am pretty inept at bargaining, but I got a unit for $200. The 7A19 were option WF, something not shown in a Tek catalog; comparing physical unit with description in catalog makes WF a recessed control mod. In the case of 7A19 it was trace position that was recessed; there was no trace ID, either, but that must have been incidental to recessed control. The mainframe (7903) was also WF option and that was intensity control that was recessed. Time base was kind of a standard unit, though serial number indicated Guernsey (numerals only). Regards Miroslav Pokorni ----- Original Message -----
From: "Stan or Patricia Griffiths" <w7ni@...> To: <TekScopes@...> Sent: Tuesday, January 15, 2002 10:42 PM Subject: Re: [TekScopes] Digitizer on eBay Lynn,. . when you need to catch the EMP on your screen.like a Tek part number on it? Is it a rackmounted item with a hinged door onthe front?need actuallyto go with it to make it useful? onbought it for the box ($5 + S&H) shippingthe list a few days ago. There is one listed on eBay, item 1690813203 costs to the UK would be astronomical. |
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ghpicard
--- In TekScopes@y..., "Miroslav Pokorni" <mpokorni2000@y...> wrote:
I believe that those digitizers were used to measure all sorts ofparameters during test, so a number of them was consumed for a single test. Myremember I think it's more probable that the units could reliabily withstand just one EMP, so why to risk a second EMP with a total data loss when you could buy a new one... If the unit become damaged *during* the test, the data, if you could recover anything at all, would be either garbage or unreliable at all. Memory circuits (except perhaps ferrite cores) are most sensitive to gamma rad. Anyway, if using ferrite cores, the M part of the EMP could make a nice mess with the contents... Regards Gaston |
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ghpicard
--- In TekScopes@y..., "Miroslav Pokorni" <mpokorni2000@y...> wrote:
I believe that those digitizers were used to measure all sorts ofparameters during test, so a number of them was consumed for a single test. Myremember I think it's more probable that the units could reliabily withstand just one EMP, so why to risk a second EMP with a total data loss when you could buy a new one... If the unit become damaged *during* the test, the data, if you could recover anything at all, would be either garbage or unreliable at all. Memory circuits (except perhaps ferrite cores) are most sensitive to gamma rad. Anyway, if using ferrite cores, the M part of the EMP could make a nice mess with the contents... Regards Gaston |
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Gaston,
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The EMP is a very wild beast. One of the first tests where effects were to be measured was a test named Starfish. It fired a bomb about 200 miles above Johnson Island (do not know how far on the side). As result, parts of Hawaii lost electricity and no one expected that. A nuclear caused EMP is always associated with high altitude shots. I am not sure, but it looks like lack of atmosphere is important, possibly not to attenuate charged particle flux. I do not think that any of Nevada tests had significant EMP, most of them were underground. My understanding was that instruments were physically destroyed, through shock. I guess, thumper in the hole bought time to transmit out data. Regards Miroslav Pokorni ----- Original Message -----
From: "ghpicard" <ghpicard@...> To: <TekScopes@...> Sent: Tuesday, January 22, 2002 6:52 AM Subject: [TekScopes] Re: Digitizer on eBay --- In TekScopes@y..., "Miroslav Pokorni" <mpokorni2000@y...> wrote:I believe that those digitizers were used to measure all sorts ofparametersduring test, so a number of them was consumed for a single test. Myremember |
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Stan or Patricia Griffiths
ghpicard wrote:
--- In TekScopes@y..., "Miroslav Pokorni" <mpokorni2000@y...> wrote:I think the "damage" was more likely either the equipment was "hot" withI believe that those digitizers were used to measure all sorts ofparametersduring test, so a number of them was consumed for a single test. Myremember radiation and had to be buried with the other "hot" residue or it was actually melted down from the heat of the blast. To acquire some of this fast data, you needed to be REAL CLOSE to the source of the signals, like right right on top of it . . . Stan w7ni@... |
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