Keyboard Shortcuts
Likes
- HP-Agilent-Keysight-Equipment
- Messages
Search
|
Re: HP8340B SQUEGGING
¿ªÔÆÌåÓý
It appears that you need to adjust your SRD Bias (along with the complete unleveled RF adjustment procedure) which is spelled out in the adjustment portion of the service manual.? The problem you're seeing is not all that unusual considering the age of the
unit.? I'm doing the same thing with 3 8340/41's that are sitting on my bench at the moment.? The procedure is not that difficult and the equipment required is fairly common, a decent DVM,? a power meter & sensor, a Xtal detector & a scope that is capable
of XY operation.? If the frequencies are in spec, you don't even need a counter although a spectrum analyzer would be handy for confirmation once you've finished the adjustment procedure.
Richard Parrish
From: [email protected] <[email protected]> on behalf of Gianni via groups.io <gianni.chiodo@...>
Sent: Monday, June 6, 2022 5:36 AM To: [email protected] <[email protected]> Subject: [HP-Agilent-Keysight-equipment] HP8340B SQUEGGING ?
My HP8340B , even if the level indicator say the right level end no unleveled annunciator appear , the real RF output is unstable. Sweeping at some frequencies the power out goes unleveled , it happens in the 3 High band . Only some point and small range in the first high band increasing in second high band finally large portion of band in 3rd high band. The internal power detector and all its circuit works ok ,the out voltage that goes to the error amplifier and its corresponding reference level are ok. The ALC level sims working according to the specs. At a certain point of the ALC loop A26 Board a signal is taken out SDR BIAS CONT? using an OP Amp ( way the designer have set a test point at the inverting input and not to the output is a mystery¡.but this is useful for my investigation). This signal goes to board A24 and shaped using frequency info ( 2 times ) plus an exponential generator drives the SRD in order to allow a linear operation in the power range. What happens is that to SDR is driven in non linear zone ( reverse power vs SRD voltage increase) this leads what HP manual call SQEGGING , the output power become to be modulated ,the average continue to be ok so the equipment do not detect any malfunction and no unleveled light appears . Focusing at 22.5 GHz where this problem is more evident breaking the SRD line and driving externally the correct operation can be obtained increasing the SRD voltage ?at high power output ( see PDF Misure a 22 5 GHz) . Using this info I placed a circuit offset using the test point located at the inverting input of the OP Amp located in A26 board ( a pot using -10V one side and + 5.2V other side and 1 Mohm from the cursor to the inverting input ). Inserting the offset first ?disappear the instability in high band 1 then increasing the offset the problem of high band 2 at the end setting an offset at the out of the OP amp of 0.3 V all the band are ok . This could be a work around because at the end the equipment works . Due to this need of offset ( small in first High band medium in second high band and finally 0.3 V in 3rd band ) push me to think that is not a general ?offset? the problem but a shaping problem or an offset linked with the frequency . The A24 board makes this kind of job but looks a mess al potentiometers , can someone help me because that in the past entered in similar problem? Turning pots in random mode is not what I like !!! Regards Gianni IW1EPY ? ? Da: [email protected] [mailto:[email protected]]
Per conto di Lothar baier ? It would be desirable to catalog those commands so they can be analyzed and further documented and eventually be used in creating some calibration routines that can be used by people ! Let me however render some words of caution :? Keysight/agilent has chosen the path of not to provide service software any longer for a very good reason and to put it simple its all about MONEY ! Used to service was purely auxiliary now it¡¯s a profit center , keysight wants to keep their service centers busy and they want to control end of life of their equipment , if the analyzer requires software to do adjustments and you don¡¯t have the software than you cant fix the unit period !? when it was still available the N7800A software was very expensive , If I remember correctly the framework was $7500 and then you had to pay for the different support modules separately , once you shilled out the $? you needed very specific test equipment which set you back another 100-200K depending on what you wanted to run ¡¡..? after a little while they stopped issuing licenses altogether and only made them available to big corporate self supporters ! Having said this keysight may not take kindly to the information becoming public and may undertake measures to deter the effort , therefore I strongly suggest not to use any techniques to extract the information that could be interpreted as reverse engineering or hacking ? From: [email protected] <[email protected]>
On Behalf Of Sandra Carroll via groups.io ? Hi Kalle. |
|
Re: ESA instrument adjustments - reverse engineering
¿ªÔÆÌåÓýHi regarding the EEVBLOG? although I do go on it but I find it difficult to track messages also I haven¡¯t found any storage space So I believe if it is ?HP/ Keysight? then this site should provide the best solution ? Regards Paul ? From: [email protected] [mailto:[email protected]] On Behalf Of Sandra Carroll ? Yep,? exact reason for us to do work like this. |
|
Re: The time-bomb in the HP 70700A digitizer
¿ªÔÆÌåÓýHi Ricky ? Regarding battery replacement on 70 K I am of the mind to install extra sockets so that a battery can be plugged up before you unsolder the old battery This goes for the following local oscillator? , Transition , optical , tracking gen , Synthesiser , and now the HP 70700A digitizer ? That I did not realise had a battery or battery backed up firmware / calibration so all the above and for sale might have this problem ? I am just going to sort out a supplier in the UK for the original ?TADIRON Lithium battery¡¯s? as they have a proven track record of lasting over 20 years At about ?12? each at the last enquiry ? Regards Paul ? From: [email protected] [mailto:[email protected]] On Behalf Of green ?
|
|
Re: ESA instrument adjustments - reverse engineering
Sandra Carroll
Yep,? exact reason for us to do work like this.
Several of us on a repair thread I had for the SRS PS350 High Voltage Supply ended up decoding the Roms and came up with a cal procedure as SRS gave no other way of doing it. Would it be worth starting a EEVBLOG Thread there for this,? ?I know it made work there on both the PS350 and the E4407B allot easier to collaborate? it's up to the OP of course so just a suggestion,? ?I'll gladly do what I can? |
|
Re: 53181A 3 GHz prescaler from China
I received the 3GHz prescaler board from China.? It arrived quicker than I expected.?? I installed it in my 53181A but it does not count above 1.69999 GHz.? I think this is a limitation of the counter, not the prescaler.? The board looks well made and works fine.
toggle quoted message
Show quoted text
Aside from that, I had to find the correct spacers to mount the board. The kit came with 2 but they were just the right length to interfere with the interface connector.? I put in longer spacers and that solved that problem.? The other minor issue was that the kit came with an SMA to SMA cable.?? It should be an SMA to BNC so it will mount correctly in the front panel.? Fortunately, I had an SMA to BNC cable available. Tom On 5/24/2022 6:31 PM, Jeremy B wrote:
I¡¯ve upgraded my 53181 with an eBay prescaler and oven timebase. I believe I got them from a fellow in Poland. No problems at all. For the timebase I calibrated it to a rubidium standard as described in the manual. |
|
Re: ESA instrument adjustments - reverse engineering
Sandra Carroll
Hi Robert,? Can't blame you,? I would have done the same and yeh probably not related though I do have some family in GA but most is in TN in the tri-cities area.? ?My Uncle Dave was there in GA and ran a business making Monitors used at airports.? ?My Father was also in the USAF in the 1155th Techops division based in Sacramento CA. where I grew up.? ?I do know the Carroll family had a split back in Ireland so there's now 2 clans of Carroll's.? ?mine was the one that split off as I understand it.? ?My best friend back in CA was Joe Carroll,? ?we had a blast teasing people we were related but we weren't
Sandra Carroll |
|
HP8340B SQUEGGING
¿ªÔÆÌåÓýMy HP8340B , even if the level indicator say the right level end no unleveled annunciator appear , the real RF output is unstable. Sweeping at some frequencies the power out goes unleveled , it happens in the 3 High band . Only some point and small range in the first high band increasing in second high band finally large portion of band in 3rd high band. The internal power detector and all its circuit works ok ,the out voltage that goes to the error amplifier and its corresponding reference level are ok. The ALC level sims working according to the specs. At a certain point of the ALC loop A26 Board a signal is taken out SDR BIAS CONT? using an OP Amp ( way the designer have set a test point at the inverting input and not to the output is a mystery¡.but this is useful for my investigation). This signal goes to board A24 and shaped using frequency info ( 2 times ) plus an exponential generator drives the SRD in order to allow a linear operation in the power range. What happens is that to SDR is driven in non linear zone ( reverse power vs SRD voltage increase) this leads what HP manual call SQEGGING , the output power become to be modulated ,the average continue to be ok so the equipment do not detect any malfunction and no unleveled light appears . Focusing at 22.5 GHz where this problem is more evident breaking the SRD line and driving externally the correct operation can be obtained increasing the SRD voltage ?at high power output ( see PDF Misure a 22 5 GHz) . Using this info I placed a circuit offset using the test point located at the inverting input of the OP Amp located in A26 board ( a pot using -10V one side and + 5.2V other side and 1 Mohm from the cursor to the inverting input ). Inserting the offset first ?disappear the instability in high band 1 then increasing the offset the problem of high band 2 at the end setting an offset at the out of the OP amp of 0.3 V all the band are ok . This could be a work around because at the end the equipment works . Due to this need of offset ( small in first High band medium in second high band and finally 0.3 V in 3rd band ) push me to think that is not a general ?offset? the problem but a shaping problem or an offset linked with the frequency . The A24 board makes this kind of job but looks a mess al potentiometers , can someone help me because that in the past entered in similar problem? Turning pots in random mode is not what I like !!! Regards Gianni IW1EPY ? ? Da: [email protected] [mailto:[email protected]] Per conto di Lothar baier ? It would be desirable to catalog those commands so they can be analyzed and further documented and eventually be used in creating some calibration routines that can be used by people ! Let me however render some words of caution :? Keysight/agilent has chosen the path of not to provide service software any longer for a very good reason and to put it simple its all about MONEY ! Used to service was purely auxiliary now it¡¯s a profit center , keysight wants to keep their service centers busy and they want to control end of life of their equipment , if the analyzer requires software to do adjustments and you don¡¯t have the software than you cant fix the unit period !? when it was still available the N7800A software was very expensive , If I remember correctly the framework was $7500 and then you had to pay for the different support modules separately , once you shilled out the $? you needed very specific test equipment which set you back another 100-200K depending on what you wanted to run ¡¡..? after a little while they stopped issuing licenses altogether and only made them available to big corporate self supporters ! Having said this keysight may not take kindly to the information becoming public and may undertake measures to deter the effort , therefore I strongly suggest not to use any techniques to extract the information that could be interpreted as reverse engineering or hacking ? From: [email protected] <[email protected]> On Behalf Of Sandra Carroll via groups.io
Sent: Sunday, June 5, 2022 8:37 PM To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] ESA instrument adjustments - reverse engineering ? Hi Kalle. |
|
Re: HP8563E-Damaged red coax from A4 PCB-Is it easy to replace?
This red cable is approx 80cm long and travels between the A3 and A4 PCB's (located on the top stack of boards or folded out to the right). I have checked the continuity of the cable and it is OK.
I checked it by tack soldering four wires onto a couple of SMB connectors on one of the boards. I then plugged the cable into the sockets at both ends and used the continuity test on my multimeter to test the cable whilst I moved it around. There is NO sign of any breaks. So now I can proceed with reassembly. Thanks everyone for your help. |
|
Re: ESA instrument adjustments - reverse engineering
Lothar baier
¿ªÔÆÌåÓýIt would be desirable to catalog those commands so they can be analyzed and further documented and eventually be used in creating some calibration routines that can be used by people ! Let me however render some words of caution :? Keysight/agilent has chosen the path of not to provide service software any longer for a very good reason and to put it simple its all about MONEY ! Used to service was purely auxiliary now it¡¯s a profit center , keysight wants to keep their service centers busy and they want to control end of life of their equipment , if the analyzer requires software to do adjustments and you don¡¯t have the software than you cant fix the unit period !? when it was still available the N7800A software was very expensive , If I remember correctly the framework was $7500 and then you had to pay for the different support modules separately , once you shilled out the $? you needed very specific test equipment which set you back another 100-200K depending on what you wanted to run ¡¡..? after a little while they stopped issuing licenses altogether and only made them available to big corporate self supporters ! Having said this keysight may not take kindly to the information becoming public and may undertake measures to deter the effort , therefore I strongly suggest not to use any techniques to extract the information that could be interpreted as reverse engineering or hacking ? From: [email protected] <[email protected]>
On Behalf Of Sandra Carroll via groups.io
Sent: Sunday, June 5, 2022 8:37 PM To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] ESA instrument adjustments - reverse engineering ? Hi Kalle. |
|
Re: ESA instrument adjustments - reverse engineering
Robert Carroll
¿ªÔÆÌåÓýHi Sandra I couldn't resist? though I'm pretty sure you are not related to me.? I am Robert Carroll and was raised starting in 1945 in East Point, GA.? I went to Georgia Tech through my Masters and thanks to the draft was inducted into the USAF and was assigned to intelligence work and development of false target repeaters to protect the B-52 bombers.? ?And there I was frequently using HP equipment at Wright Patterson Air Force Base. And though now an ancient one, I still use HP equipment in connection with my Ham Radio. Robert Carroll (w2wg now in Cobb County, GA.) Sent from my Verizon, Samsung Galaxy smartphone -------- Original message -------- From: Sandra Carroll <smgvbest@...> Date: 6/5/22 9:36 PM (GMT-05:00) Subject: Re: [HP-Agilent-Keysight-equipment] ESA instrument adjustments - reverse engineering This is fantastic work.? ? When I was working on hacking the E4407B one thing I was looking for was the SCPI commands but could never find them. Did you find these on the E4407B or did you find them in the looking at N7800?files? I really hope we can find a way to be able to do a cal.? personally I'd like to cal my TG as I think that it needs it? If I can help on this I'm more than will. Sandra |
|
Re: ESA instrument adjustments - reverse engineering
Sandra Carroll
Hi Kalle.
This is fantastic work.? ? When I was working on hacking the E4407B one thing I was looking for was the SCPI commands but could never find them. Did you find these on the E4407B or did you find them in the looking at N7800?files? I really hope we can find a way to be able to do a cal.? personally I'd like to cal my TG as I think that it needs it? If I can help on this I'm more than will. Sandra |
|
Re: The time-bomb in the HP 70700A digitizer
Has anyone replaced the battery in the hp 70700a and ? know: a) the battery specifications,? shape/size; ? &? the R&R installation procedure ? { without loosing the existing Pgm in Ram: obviously parallel install, but did HP have a defined procedure ? } & b) the replacement battery part #,? from Mouser or Digikey ? There is no reference to the word "battery" to be found in either of the Install, Op Man, Service Man, nor Pgm Man. ( HP Man #'s? 70700-90001, -90003, -90005, -90021 ) thank you, rick |
|
Re: HP 8970B System Check
"Lothar baier" <Lothar@...> writes:
ok first of the gain of this unit is not a hard specs but quantified as >xx , keep in mind that this is a noise figure testset that is used as part of a system and is calibrated out before measurements are performed ,? the 8971C has a wideband preamp in the signal path that is present for all measurement modes , the main purpose of this amp is to lower the system NF,? the amp has a spec of >20.5dB over the 10MHz-26GHz but since this a extremely wideband amplifer gain can vary quite a bit over the entire range , for SSB mode no additional parts are switched in so if you measure higher gain than anticipated than either somebody has messed with the unit and replaced either the amplifier with a replacement that has more gain or the attenuator is bad but i have seen very few attenuators that are showing lower attenuation than published usually attenuation goes higher ...Thanks so much Lothar, this is all immensely helpful. I performed the coarse calibration after setting the upper frequency limit to 18 GHz and the LO input power to 1 dBm since I have option 001. The calibration passed and I now see about 24 dB of gain in SSB3. That's a bit high but from your statement about the gain only being specified as a lower limit and varying, it sounds like this isn't an issue. I still see around 6 dB NF instead of 8-12 dB when performing the system check (step 16). I'm not entirely clear what noise figure it's measuring here; is this the combined test set + 8970B receiver NF? If so, maybe because the preamp gain is on the high side, the system noise figure is lower than expected. For SSB2 the signal is amplified 20dB then goes through a bandpass filter and a attenuator that improves matching before entering the mixer and then the IF amplifier ,This is missing the contribution from AT3 right? That would move the gain 6 dB lower. For SSB3 the equation looks similar but the filter loss is 3dB and the attenuator is 3dB instead of 7dB so you have 6dB instead of 7.5dB meaning your gain increases to 25.5dB !It does, thank you. Matt |
|
16700A won't start graphical display
Hi, After several years and a recent cross country move I need a logic analyzer again.? I tried my 16702B and it is DOA; the power supply is getting AC but won't start. I then tried my 16700A.? The VGA display eventually came up with a screen with 8 yellow boxes on the bottom of which 3 had some text in them like "REMOTE", etc.? It looked like just a text display. I then hooked up my laptop to the serial port and rebooted.? I got this (copyright stuff at the beginning deleted): ? ?# ? # # ? ? #### ? ? ?# ? ?# ? ? ? ###### ?# ? ?# ? ##### ?# ? # ? # ? ?# ? ? # ? ?# ? ? ? # ? ? ? ## ? # ? ? # # ? ? # ?# ? ? ? ? ?# ? ?# ? ? ? ##### ? # # ?# ? ? # ####### ?# ?### ? ? # ? ?# ? ? ? # ? ? ? # ?# # ? ? # # ? ? # ?# ? ?# ? ? # ? ?# ? ? ? # ? ? ? # ? ## ? ? # # ? ? # ? #### ? ? ?# ? ?###### ?###### ?# ? ?# ? ? # ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?Logic Analysis System httpd.conf file installed /sbin/bcheckrc: Checking for LVM volume groups and Activating (if any exist) Volume group "/dev/vg00" has been successfully changed. vxfs fsck: sanity check: root file system OK (mounted read/write) /sbin/itemap: WARNING: An attempt to write keyboard mapping entries past /sbin/itemap: the end of the buffer.? Further writes will be ignored. Checking hfs file systems /sbin/fsclean: /dev/vg00/lvol1 (mounted) ok HFS file systems are OK, not running fsck Checking vxfs file systems /dev/vg00/lvol4 : vxfs fsck: sanity check: root file system OK (mounted read/write) /dev/vg00/lvol5 : vxfs fsck: sanity check: /dev/vg00/lvol5 needs checking log replay in progress replay complete - marking super-block as CLEAN /dev/vg00/lvol6 : vxfs fsck: sanity check: /dev/vg00/lvol6 needs checking log replay in progress replay complete - marking super-block as CLEAN Jul 07 01:07:11 auto_parms >> Checking network status. Jul 07 01:07:11 auto_parms >> Network was disabled by boot scripts on previous boot.? Re-activating the network. 8/16/6 ? 0x001083B89AE4 0 ? UP ? ? ? lan0 ? ? DOWN ? 4 ? ETHER ? ? ?Yes ? ? 52 Jul 07 01:07:12 auto_parms >> /sbin/auto_parms, checking network for DHCP server (see /etc/auto_parms.log) Jul 07 01:07:25 auto_parms >> DHCP Client Status: NO_REPLY_RECEIVED ? ? ?HP-UX Start-up in progress ? ? ?__________________________ ? ? ?Mount file systems ................................ OK ? ? ?Setting hostname .................................. OK ? ? ?Enable auxiliary swap space ....................... OK ? ? ?Start syncer daemon ............................... OK ? ? ?Configure LAN interfaces .......................... OK ? ? ?Check LAN Status .................................. N/A ? ? ?Start Software Distributor agent daemon ........... OK ? ? ?Configuring all unconfigured software filesets .... OK ? ? ?List and/or clear temporary files ................. OK ? ? ?Clean up old log files ............................ OK ? ? ?Start system message logging daemon ............... OK ? ? ?Configure HP Ethernet interfaces .................. OK ? ? ?Configure HP 100BT interfaces ..................... N/A ? ? ?Configure LAN interfaces .......................... OK ? ? ?Start NFS core subsystem .......................... OK ? ? ?Start NFS client subsystem ........................ OK ? ? ?Start Internet services daemon .................... OK ? ? ?Cleaning up NIS client subsystem .................. OK ? ? ?Start NIS client subsystem ........................ OK ? ? ?Verifying NIS client subsystem .................... OK ? ? ?Starting kks daemon ............................... OK ? ? ?Start time synchronization ........................ N/A ? ? ?Start print spooler ............................... OK ? ? ?Start clock daemon ................................ OK ? ? ?Set X11 Device Configuration ...................... OK ? ? ?Start 16610A Processor Run Control daemon ......... OK ? ? ?Start httpd (Web Server) .......................... N/A ? ? ?Start NFS server subsystem ........................ OK ? ? ?Start Lmgrd daemon ................................ OK The system is ready. Starting Logic Analysis System ... Shutting down Logic Analyzer ... Starting Logic Analysis System ... Shutting down Logic Analyzer ... Starting Logic Analysis System ... Shutting down Logic Analyzer ... Starting Logic Analysis System ... Shutting down Logic Analyzer ... Starting Logic Analysis System ... Shutting down Logic Analyzer ... Starting Logic Analysis System ... Shutting down Logic Analyzer ... Starting Logic Analysis System ... TERM = (hp) Shutting down Logic Analyzer ... Starting Logic Analysis System ... Shutting down Logic Analyzer ... Starting Logic Analysis System ... Any ideas on how to get out of this mode? Thanks, Marc |
|
Re: HP 8970B System Check
Lothar baier
ok first of the gain of this unit is not a hard specs but quantified as >xx , keep in mind that this is a noise figure testset that is used as part of a system and is calibrated out before measurements are performed ,? the 8971C has a wideband preamp in the signal path that is present for all measurement modes , the main purpose of this amp is to lower the system NF,? the amp has a spec of >20.5dB over the 10MHz-26GHz but since this a extremely wideband amplifer gain can vary quite a bit over the entire range , for SSB mode no additional parts are switched in so if you measure higher gain than anticipated than either somebody has messed with the unit and replaced either the amplifier with a replacement that has more gain or the attenuator is bad but i have seen very few attenuators that are showing lower attenuation than published usually attenuation goes higher ...
For SSB2 the signal is amplified 20dB then goes through a bandpass filter and a attenuator that improves matching before entering the mixer and then the IF amplifier , the lineup looks like this :? 20dB (RF Amp)-0.5dB (filter )-7dB (attenuator)-10dB(Mixer)+22dB (IF amplifier) = 24.5dB so your 24dB measurement is in line with what you should see ! For SSB3 the equation looks similar but the filter loss is 3dB and the attenuator is 3dB instead of 7dB so you have 6dB instead of 7.5dB meaning your gain increases to 25.5dB ! Now a few caveats :? SSB2 and SSB3 use a mixer and the conversion loss of a mixer generally depends on the LO power ,? if you have a unit with LO amp than the typical LO power you should feed in the unit is 1dBm which after beein amplified by 10dB and then passed through some cables gives you about 10dBm LO power ,? if you apply a higher LO power the amplifier Pout increases until the amplifier starts compressing, this means that your conversion loss slightly improves at the risk that the power exceeds eventually damage level and the mixer sustains damage , if not then the amplifier will go into compression reducing the gain and Pout of the amplifier so the conversion gain of the mixer will increase as the lo power coming from the buffer amp starts dropping .......? so if your unit has the LO amplifier (option 001 or 001/002) make sure you keep your LO at or below 1dBm ,? if the unit does not have LO buffer amp than your LO should be typically around 7-10dB ! Last but not least keep in mind that the YIG filter has a bandwidth of only 10-30MHz , your 8970B has a fixed IF BW of 4MHz so if your filter does not track correctly you will be tuned on the flanks of the filter and your loss will increase significantly above the 3dB in the center of the passband , the fact that your gain increases when you tune your signal source shows this is what is happening here . This is why you normally when you put together a system you perform the coarse and fine peaking procedure outlined in the manual and repeat it every now and then i hope this helps? |
|
Re: HP 8970B System Check
Another thing you could do to check the filters is sweep the input signal and look at the filter profile (constant LO) on a spectrum analyzer.
toggle quoted message
Show quoted text
Cheers! Bruce Quoting bruce@...: Based on your reported measurements, I'm wondering if the appropriate filter set for the selected measurement is actually happening. Unfortunately, this can only be confirmed by opening and measuring. |
|
Re: HP 8970B System Check
Based on your reported measurements, I'm wondering if the appropriate filter set for the selected measurement is actually happening. Unfortunately, this can only be confirmed by opening and measuring.
toggle quoted message
Show quoted text
Another possible approach would be to measure the relative noise power (no signal in or a known noise source in) would give an approximation of the actual bandwidth provided by the selected filters. Cheers! Bruce Quoting Matt Huszagh <huszaghmatt@...>: "Lothar baier" <Lothar@...> writes:It sounds to me like your YIG filter is not peaked, you might need to run the adjustments for the yig driver !Thanks for the input Lothar. |
|
Re: HP 8970B System Check
"Lothar baier" <Lothar@...> writes:
It sounds to me like your YIG filter is not peaked, you might need to run the adjustments for the yig driver !Thanks for the input Lothar. The only adjustments actually described in the HP 8971C manual are power supply adjustments. The troubleshooting section for the YIG filter driver basically has the technician check a number of voltages and replace components when the voltages are out of spec. Is the power supply adjustments what you're referring to? The +20V supply is used to power the YIG driver and is one of the supplies that can be adjusted. However, the acceptable range isn't that narrow: +-0.1V. Thanks Matt |
Paul Bicknell