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Re: 1L20 Spectrum Analyzer
Stan or Patricia Griffiths
Hi Andrew,
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You are right about the 1L20 being used in the 555. It can also be used in any other 530/540/550 mainframe. There are a lot of places to look for manuals if your request here does not turn one up for you. You might try eBay. Another possibility is to take a look at the list of manual suppliers on my web page at: Stan w7ni@... Andrew Campbell wrote: Hi, |
Re: 475 hor.jitter
Richard Gagnon
Thank you Dean. As soon as my manual arrives I will
look into this. I thought the fan was maybe a 12vdc fan. Richg --- dhuster@... wrote: Rich, the 465, 465B, 475, 475A, 464, 466 and 468 had __________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices |
Re: 475 hor.jitter
Rich, the 465, 465B, 475, 475A, 464, 466 and 468 had identical fan
modules. And by the way, this has nothing to do with bearing noise, but if you have a fan that has a dead spot and won't always start up and you don't know whether to blame the motor or the driver chip, just put the motor on the dead spot and then pull the driver chip and reinstall it "backwards". It has a symmetrical pinout, and if one of the transistors in the driver chip is bad, you'll have moved it to a different spot in the switching sequence, the motor will no longer be on a dead spot with the reversed chip and will probably start up when power is applied. If the dead spot is still in the same place, then you can blame the motor. And Rich, the 475 has had several reliability mods over it's life, and if you have a lower serial number, it may need some of them. The -8v P/S should have a new rectifier that's much larger than the others (i.e., it's NOT a 152-0488-00) and will be laying down rather than standing up in order to clear the case. There's also a bluish 1% resistor (with the scope upside-down as you look on the main board with the front panel facing you, it's along the left edge maybe 2 or 3 inches from the front) that overheats, turns brownish and changes value, goofing up the timebases. If there's a black resistor in that spot, the mod has already been made. Otherwise, it needs replaced with a higher-power resistor. And the one mod that may concern you most is down near the hole where the horizontal deflection plate leads go down to the jug. An unmodified scope has a silver-colored, axial-lead, tantalum, 1000?F capacitor just to the front of the hole. If it's there, get rid of it, for it's underrated in voltage and will cause a jittering problem. A modified scope usually has a physically-larger, black aluminum electrolytic with a higher voltage rating installed in it's place. Dean |
475 hor.jitter
I recently picked up a 475 that has intermittent horizontal jitter and
a noisy fan. Does anyone have any ideas about the jitter? The fan looks like it could be a challenge to replace. I am shopping around for a manual and I have had the case open to clean around the hv area, though it was very clean inside. Thank you. Richg |
Re: 7A16P vs. 7704A
Stan or Patricia Griffiths
Hey, its perfectly OK to disagree with me, but in this case, you are also
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disagreeing with Tektronix since it is in the Tek microfiche where I read about the power supply problem. Yes, I suspect Tek probably assumes power hungry plugins will be used along with the 7A16P. There probably will be no overload with only two plugins installed in a 4 hole mainframe, for example. I did not know about the front panel lockout since I have never tried to power up my 7A16P in a 7K mainframe. Interesting . . . Stan w7ni@... dd@... wrote: I hate to disagree with Stan, but my experience with 7A16Ps is that if you |
Re: 7704A Repair and modules. 7B53 in faster frames
--- In TekScopes@y..., dd@a... wrote:
to the(Still.. it's fun to see the readout say, "500 pSec" on the -92s -Most of them will give a solid trigger on a 1GHz signal - a tribute power of tunnel diodes. ... but the 7B92A SN B070000&up has no tunnel diodes anymore. Jorgen dj0ud |
Tek 2230 GPIB OPT 10 or RS232 options
Hi,
Would the person that responded back to my message concerning the communication options for the TEK 2230 please respond again. I can't seem to find your message. Thank you, Vince __________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices |
Re: 7A16P vs. 7704A
I hate to disagree with Stan, but my experience with 7A16Ps is that if you
install them in a non-programmable mainframe, they power up OK, but the front panel is locked out. From looking at the schematic, it appears possible to force them to local mode, but I haven't tried that yet. I didn't see any way to reduce the +5V loading, but in my experience, that is not an issue. (Maybe if you put 2 of them in one mainframe along with some other +5V hungry plugins?) BTW, the 7A16P is used with the 7612D as well as the 7912s. |
Re: Tektronix Parts.
Phil (VA3UX)
At 12:56 AM 5/23/2001 -0400, you wrote:
At 9:00 AM +1000 2001/5/23, Michael wrote:I have the start of a Tek interest site : www.vaxxine.com/phil/ Phil Turcotte Grimsby, Ont. Michael |
Re: Tektronix Parts.
Michael Dunn
At 9:00 AM +1000 2001/5/23, Michael wrote:
It seems that it might be a nice idea if there was a list of these people or I would ask again that anyone who wishes to can place a URL link to their site in the LINKS section of the TekScopes Yahoo site. Also, people who have parts etc to sell, but DON'T have a web site, can send me a message. I will summarize all the information somewhere on the site, and clearly note where it is! Michael ----------------------------------------------------------------- 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 | ----------------------------------------------------------------- |
Re: 7704A Repair and modules.
Stan or Patricia Griffiths
Hi Bob,
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There is some possible incompatibility using the 7A16P in a normal 7K mainframe such as the 7704A. The 7A16P was specifically made to be used with the 7912AD digitizer and is programmable (that's what the "P" on 7A16P means). Anyway, I have read a note that says the additional circuitry for implementing programmability in the 7A16P may overload one or more of the 7704A's power supplies causing some unpredictable results in all the other circuits powered by them. You might try it with caution. You might get lucky and not cause any permanent damage and it might even work for you. There is probably a way to disable some of that extra circuitry in the 7A16P without damaging it as a nonprogrammable amplifier and reducing the power supply load to an acceptable level. I have not looked into that yet. Future project . . . Stan w7ni@... Bob H. wrote: Good Evening |
Re: 7704A Repair and modules.
Stan or Patricia Griffiths
As I recall, the reason Tek would not recommend a 7B53 as a timebase for a
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7704 is that it will not sweep fast enough to take full advantage of the 7704's 200 MHz bandpass. Other than that, I believe it will work just fine. An even simpler, and probably cheaper, timebase would be a 7B50 or 7B50A with does not have the delayed sweep feature. You could even use a 7B51 that is normally used with a 7B50 to provide delayed sweep but can be used as a simple timebase without a 7B50. I only suggest the 7B50, 7B50A, and 7B51 because they might be more available and cheaper than the 7B53/A alternatives. There was also an earlier version of the 7B53 called the 7B52 which would work as well . . . I really need to get on with finishing my second book . . . Stan w7ni@... dd@... wrote: I have a 7704A mainframe that is in need of repair... |
Tektronix Parts.
Michael
Hi all, :)
A couple of times recently there have been mentions of people who hold some stocks of Tek parts for sale for replacements. (e.g. pots, transistors, tubes etc). After a recent rebuild (hopefully the last) of this computer, I have unfortunately lost the message/s containing this information, and I may need some parts for a friend's 454. It seems that it might be a nice idea if there was a list of these people or organisations, either posted semi-regularly to the list, or on a web site somewhere. Does this list have a "parent" website? Or is there a list of relevant sites somewhere? I have unfortunately lost my old "bookmarks" list as well, but I know that some of the list's contributors have "Tek" sites, which I have visited... Can anyone help...? Thanks in advance for any help, and regards, :) Michael |
Tektronix 475 Oscilloscope - Position Pots
Andrew Campbell
Hi All,
I am looking for two (2) Tektronix 475 Position Pots. Tektronix Part Number 311-1411-00. Regards, Andrew Campbell Calibration and Repair Network Pty. Limited A.B.N 64 090 761 363 An ISO9001:2000 Quality Certified Company Licence No. QCC 716 Bldg. T2A, Nirimba Education Precinct Eastern Road (P.O. Box 147) Quakers Hill NSW 2763 Australia Ph: (02) 9853 3259 Fx: (02) 9853 3258 Email: service@... Web: www.candrnet.com.au |
Re: 7704A Repair and modules. 7B53 in faster frames
Seconded - before I acquired 7B87, later -92As via a package deal: aYes, that's what I was talking about... I know it's written up in one of the manuals or catalogs, but I can't seem to locate it at the moment. I guess I'm just picky :-) On the other hand, 7B8xs are pretty cheap. (Still.. it's fun to see the readout say, "500 pSec" on the -92s -Most of them will give a solid trigger on a 1GHz signal - a tribute to the power of tunnel diodes. |
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