Re: HP 8757C/D/E Service manual
On Fri, Feb 21, 2020 at 05:52 PM, Askild wrote:
I have the SM from keysight, but unfortunately it does not have any schematics...
Google ... or use the link in post ? #103263??
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Re: Replacing the fan on an HP11729C
I haven't had the time yet to test out how the new fan affects the spurs (had some personal issues to address). Hopefully, I will publish something early next week.
Dan
On Friday, February 21, 2020, 10:56:17 AM PST, pianovt via Groups.Io <pianovt@...> wrote:
I must have missed a post, but rather than read all the posts again,? ... did the spurs go away? Can you make good measurements now?
Vladan
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Hi Dan
?
Thank you for the line
?
* Blue Shift 92 and Blue Shift 93 will change some tuning constants for
the YTM tracking
?
This is a new one for me
?
Ken:
Hi...A couple of things you can try:
* Put your spec an on the AUX connector on the rear. Make sure the levels there
are as the manual suggests for the full sweep of the 7 - 13.5 GHz band. This
signal is from a splitter of the signal from the power amp inside as it is
applied to the balance of the RF stuff.
* Blue Shift 92 and Blue Shift 93 will change some tuning constants for the YTM
tracking and such. The constants are changed from the rotary knob on the plug
in. These are not saved, but you can check to see if it affects the RF.
Dan in Chandler, AZ
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Re: HP 8757C/D/E Service manual
Hi, I have the service manual with schematics for the 8757D, if you never find it. I looked quickly, I see in other that there is the CPU board, the power supply, the interface, the display board and several others... For the firmware, unfortunately I never owned 8757, on that side I will not be able to help you. ? Yves ? De?: [email protected] <[email protected]> De la part de Askild
·¡²Ô±¹´Ç²â¨¦?: 21 f¨¦vrier 2020 18:42
??: [email protected]
Objet?: [HP-Agilent-Keysight-equipment] HP 8757C/D/E Service manual ? Does anybody have the schematics for the 8757C/D/E? The Service manuals on the Keysight's site don't have the schematics.? ArtekManuals only have the A version. (Anybody knows the difference?) I was given a 8757E, and one of the log amp boards (A7) don't work. I have used the signals shown in the service manual, and traced the problem to be between TP8 and TP10. The signal is OK at TP8, but at TP10, it looks like the voltage is clipped to max voltage, and no ac signal is visible. My bord has another number than what is in the service manual, my boards has the code 08757-60087 (the sm lists 08757-60058 and 08757-60146) I have not found any firmware online, only for the A version. So I will upload my firmware to KO4BB soon. But I would like to upgrade this to the C or better D model. Anybody have the info on how to do this? If you have a D version, please share the firmware. ?Any help?would be appreciated
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Ken:
Hi...A couple of things you can try:
* Put your spec an on the AUX connector on the rear. Make sure the levels there are as the manual suggests for the full sweep of the 7 - 13.5 GHz band. This signal is from a splitter of the signal from the power amp inside as it is applied to the balance of the RF stuff.
* Blue Shift 92 and Blue Shift 93 will change some tuning constants for the YTM tracking and such. The constants are changed from the rotary knob on the plug in. These are not saved, but you can check to see if it affects the RF.
Dan in Chandler, AZ
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Re: HP 8757C/D/E Service manual
www.siliconinvestigations.com/hprep/HP8757/08757-90110-D-serv.pdf
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Re: HP 8757C/D/E Service manual
There is little difference between the C, D, and E models.? The C and E are identical except for the EEPROMs and a rear panel board that no one really needs.? Both have color CRTs. If you are in a dark room and you turn off the 8757E, you will see that the displays goes away in colors.? If you can get the C EEPROMs, it is easy to convert the E to a C...or at least it is easy for me since I know the magic incantations.?
Had you asked about 3 weeks ago, I could have gotten the service manual for you since I think they are going to just throw it away anyway.? I will be there next week for a visit and will check to see if it is still available.
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Re: HP 8757C/D/E Service manual
Hi Vladan,
Thanks for the info.
I have the SM from keysight, but unfortunately it does not have any schematics...
If nobody has schematics for this instrument, I might buy the A version from Artek.
This was a dumpster find, so getting it to work is more important than having it in spec. But I would really like to have the schematics, to make easier to pinpoint the failure.
Br, Askild
On Sat, Feb 22, 2020 at 1:32 AM pianovt via Groups.Io <pianovt= [email protected]> wrote: The service manual is PN 08757-90110. It's available for download on the web.
Almost all changes in the 8757 series were related to the change from the monochrome vector display to the Sony color (raster) display and later the LCD display. The front panel board changed too because of the transition to rubber keys.The log board has seen almost no change over the years. Unless that log board has some simple problem like a bad solder joint, you will need a special calibrator tool to get that log board in spec again. The calibrator requires a computer with a certain version of Basic and the alignment software. So, try to keep all the original parts on the board and if you do find a bad part, try to figure out if it will affect the log circuit itself. And keep each log board in its slot or the correction constants will not match. Don't adjust the power supplies either, if you do you will have the same calibration problem.
Vladan
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Re: HP 8757C/D/E Service manual
The service manual is PN 08757-90110. It's available for download on the web.
Almost all changes in the 8757 series were related to the change from the monochrome vector display to the Sony color (raster) display and later the LCD display. The front panel board changed too because of the transition to rubber keys.The log board has seen almost no change over the years. Unless that log board has some simple problem like a bad solder joint, you will need a special calibrator tool to get that log board in spec again. The calibrator requires a computer with a certain version of Basic and the alignment software. So, try to keep all the original parts on the board and if you do find a bad part, try to figure out if it will affect the log circuit itself. And keep each log board in its slot or the correction constants will not match. Don't adjust the power supplies either, if you do you will have the same calibration problem.
Vladan
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Seems like you are onto it now Ken. ??Yes, digging round in the guts of this ¡°old but good¡± gear can be darned awkward sometimes-hope you can get things sorted. ?Lets know how you get on. Cheers DaveB, NZ ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Ken Goodhew
Sent: Saturday, February 22, 2020 12:36
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] hp 83592A problem? Hi Dave ?????????????? Checked the signals and they are all exactly harmonically related, dropping the input to the spec analyzer by 9db with fixed attenuators just lowers the signals by 9db so it is not overdriving the spec analyzer Setting the generator to 600 mhz does lower the harmonics but they are then 600 mhz apart By the time I get to 1ghz the harmonics are -40 db down from the fundamental which is not too bad So whatever is causing the problem, which the service manual suggest could be low drive in to the internal mixer, is only mainly affecting the lower portion of band 0 below about 500 mhz to any great extent. Time to measure the 3.9 ghz ?signal level into the mixer which I tried to do yesterday but with the cables I had I had to use a 2m length of rg58 to get the right connectors so the attenuation at that frequency would be pretty high. Trying to find some figure was impossible so I took a wild guess at the figure and came up with about 5 db when added to the level of 5.4 db I measured means the signal is only about 10.4 db well below the 13.5 db specified. So on the way home yesterday I brought a N to SMA adaptor so I ?can put the power sensor right at the end of the hard line to measure the input into the mixer. If that signal is low then I need to chase back through the circuit to see where it is being lost. I have had to mechanically dismantle some of the case to get to the hard line SMA connectors as it is tucked in under the side rails of the chassis Hope it is not one of those modules down there in the RF section as the manual warns that they are not repairable and very expensive and by now probably unobtainium other than from a parts unit. Will advise further Ken VK2TKE Sent from for Windows 10 ? From: Dave Brown
Sent: Friday, February 21, 2020 6:14 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] hp 83592A problem ? Been away all day Ken- just back. If that? CW signal is producing multiple sigs ?on the spec an then it should be easy enuff to check if they are harmonically related to the fundamental. I see you are using 3MHZ RBW so incidental FM etc on the sweeper output shouldn¡¯t be causing any confusion. If you have multiple sigs, see if they reduce significantly with higher freq ?ones reducing the most when you drop the input to the spec an. They may not, but worth it to check. ?If they do reduce then its just? an overdriven spec an mixer causing much of the issue. ??If they are NOT harmonically related to the ?CW sig ex the sweeper then ?you probably need to dig further into the 8350/plugin. Do you get much the same result with the CW sig set much higher, say to around 600 MHz? ?Not sure all ?this addresses your original issue where the signals on the spec an were all a more or less constant 120 MHz or so apart up to 1.8 GHz- but sort this one first. ? ?DaveB, NZ ? ? ? Thanks Jim will let you know, would be probably to measure signal levels as it appears that the problem is related to harmonics in band 0 so I have to measure a few signals to see if they are correct before proceeding further. Ken. ? ? I have an 8350B and 83592B plug-in, both in perfect working order, as far as I know.? I don't mind ;) taking mine apart if there's something you want me to check vs your ailing beast.? Also 8566A spec an to check output purity etc. Sent from my Verizon, Samsung Galaxy smartphone -------- Original message -------- Date: 2/20/20 3:19 AM (GMT-08:00) Subject: Re: [HP-Agilent-Keysight-equipment] hp 83592A problem set 8350b to 15 mhz cw and did a single sweep on the spectrum analyzer and it produced a similar waveform to the previous picture, just a bit more squashed up.
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HP 8757C/D/E Service manual
Hi all,
Does anybody have the schematics for the 8757C/D/E? The Service manuals on the Keysight's site don't have the schematics.?
ArtekManuals only have the A version. (Anybody knows the difference?)
I was given a 8757E, and one of the log amp boards (A7) don't work.
I have used the signals shown in the service manual, and traced the problem to be between TP8 and TP10. The signal is OK at TP8, but at TP10, it looks like the voltage is clipped to max voltage, and no ac signal is visible.
My bord has another number than what is in the service manual, my boards has the code 08757-60087 (the sm lists 08757-60058 and 08757-60146)
I have not found any firmware online, only for the A version. So I will upload my firmware to KO4BB soon.
But I would like to upgrade this to the C or better D model. Anybody have the info on how to do this?
If you have a D version, please share the firmware.
?Any help?would be appreciated
Br, Askild
|
Hi Dave ?????????????? Checked the signals and they are all exactly harmonically related, dropping the input to the spec analyzer by 9db with fixed attenuators just lowers the signals by 9db so it is not overdriving the spec analyzer Setting the generator to 600 mhz does lower the harmonics but they are then 600 mhz apart By the time I get to 1ghz the harmonics are -40 db down from the fundamental which is not too bad So whatever is causing the problem, which the service manual suggest could be low drive in to the internal mixer, is only mainly affecting the lower portion of band 0 below about 500 mhz to any great extent. Time to measure the 3.9 ghz ?signal level into the mixer which I tried to do yesterday but with the cables I had I had to use a 2m length of rg58 to get the right connectors so the attenuation at that frequency would be pretty high. Trying to find some figure was impossible so I took a wild guess at the figure and came up with about 5 db when added to the level of 5.4 db I measured means the signal is only about 10.4 db well below the 13.5 db specified. So on the way home yesterday I brought a N to SMA adaptor so I ?can put the power sensor right at the end of the hard line to measure the input into the mixer. If that signal is low then I need to chase back through the circuit to see where it is being lost. I have had to mechanically dismantle some of the case to get to the hard line SMA connectors as it is tucked in under the side rails of the chassis Hope it is not one of those modules down there in the RF section as the manual warns that they are not repairable and very expensive and by now probably unobtainium other than from a parts unit. Will advise further Ken VK2TKE Sent from for Windows 10 ?
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From: Dave BrownSent: Friday, February 21, 2020 6:14 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] hp 83592A problem ? Been away all day Ken- just back. If that? CW signal is producing multiple sigs ?on the spec an then it should be easy enuff to check if they are harmonically related to the fundamental. I see you are using 3MHZ RBW so incidental FM etc on the sweeper output shouldn¡¯t be causing any confusion. If you have multiple sigs, see if they reduce significantly with higher freq ?ones reducing the most when you drop the input to the spec an. They may not, but worth it to check. ?If they do reduce then its just? an overdriven spec an mixer causing much of the issue. ??If they are NOT harmonically related to the ?CW sig ex the sweeper then ?you probably need to dig further into the 8350/plugin. Do you get much the same result with the CW sig set much higher, say to around 600 MHz? ?Not sure all ?this addresses your original issue where the signals on the spec an were all a more or less constant 120 MHz or so apart up to 1.8 GHz- but sort this one first. ? ?DaveB, NZ ? ? ? Thanks Jim will let you know, would be probably to measure signal levels as it appears that the problem is related to harmonics in band 0 so I have to measure a few signals to see if they are correct before proceeding further. Ken. ? ? I have an 8350B and 83592B plug-in, both in perfect working order, as far as I know.? I don't mind ;) taking mine apart if there's something you want me to check vs your ailing beast.? Also 8566A spec an to check output purity etc. Sent from my Verizon, Samsung Galaxy smartphone -------- Original message -------- Date: 2/20/20 3:19 AM (GMT-08:00) Subject: Re: [HP-Agilent-Keysight-equipment] hp 83592A problem set 8350b to 15 mhz cw and did a single sweep on the spectrum analyzer and it produced a similar waveform to the previous picture, just a bit more squashed up.
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?
Hi All.
I have recently restored an HP3460B and now I'm coming across an HP3460A needing? treatment.
But... I can't find any info about this version!
Aesthecally they look like twins but who knows inside.
Before buying, any experienced out there?
?
Thank you
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Re: Replacing the fan on an HP11729C
I must have missed a post, but rather than read all the posts again,? ... did the spurs go away? Can you make good measurements now?
Vladan
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Re: Replacing the fan on an HP11729C
Yes, that's my fault. Eyes saw the schematic. Brain said,
I don't want tea, I like pie! So fingers typed pi...
-Chuck Harris
Dan Nessett via Groups.Io wrote:
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Thanks Leo. I need to make one correction - the filter before the fan speed control is a T-filter, not a PI-filter.
Dan
On Friday, February 21, 2020, 01:37:33 AM PST, Leo Bodnar <leo@...> wrote:
Very nice summary, thanks, Dan.
Leo
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Re: Replacing the fan on an HP11729C
Thanks Leo. I need to make one correction - the filter before the fan speed control is a T-filter, not a PI-filter.
Dan
On Friday, February 21, 2020, 01:37:33 AM PST, Leo Bodnar <leo@...> wrote:
Very nice summary, thanks, Dan.
Leo
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I last corresponded with Ken in June 2019. I believe that he is well but really busy and that is why his web site does not show any updates since Aug. 29, 2015.
I can relate to that because I am just getting around to projects I began decades ago.
Cheers,
Tom
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NP.? Not that I'm the only person in this group that has that combination, mind you....
Jim
Sent from my Verizon, Samsung Galaxy smartphone
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-------- Original message -------- From: Ken Goodhew <kgoodhew@...> Date: 2/20/20 8:59 PM (GMT-08:00) Subject: Re: [HP-Agilent-Keysight-equipment] hp 83592A problem
Thanks Jim will let you know, would be probably to measure signal levels as it appears that the problem is related to harmonics in band 0 so I have to measure a few signals to see if they are correct before proceeding further. Ken. ? ? I have an 8350B and 83592B plug-in, both in perfect working order, as far as I know.? I don't mind ;) taking mine apart if there's something you want me to check vs your ailing beast.? Also 8566A spec an to check output purity etc. Sent from my Verizon, Samsung Galaxy smartphone -------- Original message -------- Date: 2/20/20 3:19 AM (GMT-08:00) Subject: Re: [HP-Agilent-Keysight-equipment] hp 83592A problem set 8350b to 15 mhz cw and did a single sweep on the spectrum analyzer and it produced a similar waveform to the previous picture, just a bit more squashed up.
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Re: 8593E Tracking generator issues
Further along... Was able to adjust offset and gain of ALC response on 5086-7906 TG per the service manual procedure. Performance is within specification, but there is a big 'hole' in the flatness at the low frequency end that varies with output level. Perhaps this is the nature of the beast, given the absolute accuracy specs that allow for ~3-4 db variation total over the operating range. Wanting to check the spectral purity, but lack a receiver / analyzer in the 100 - 500 MHz range at the moment (VNA in 'Tuned Receiver' mode tried, needs further study). It might be spurious outputs confusing the detector, as has been suggested in these threads, ?? #103226???#103124???Or, something else. Have seen some instability and oscillation in the ALC at the low frequency end from cold start. Would very much like to see a schematic of the 5086-7906..! ALC control voltage from the A10 board looks good, see stable ramps in sweep and quiet at zero span. Using 8471A detector and external ALC did not achieve leveled condition, but some response to level adjustment was seen. Have found little information on the external ALC mode for 8593E, other than with some special options it cannot be used..??
Waveforms show open loop output, 0 dBm, and -10 dBm at 0 dB step attenuator.
Thoughts..?
 
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Hi All,
The gate time pot on my 5342A had been dodgy for some time and just getting worse. No doubt I'm not the only one who has come across this issue. I found RS 790-4243 to be a good substitute for the original notwithstanding the plastic shaft and different body. It's quite a job to get the front panel out but I'm pleased with the result. Unlike the bloke in the Youtube video, I didn't need to make any other modifications to maintain functionality.
Posted in the interest of sharing .
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Paul Bicknell
Tom Phillips