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I have a dead YIG (5086-7473) in the source of an HP8753C that I am replacing.
The manual says to do the procedure for setting the 'source pretune constants correction'.?
The section on setting the 'source default correction constants' says that this must be done before the source pretune; however, this will require me to set the 'RF Output Power Correction Constants' and I do not have the equipment for this step (HPIB power meter).
Since I'm just changing the YIG and not the whole source block, do I really need to reset all the souce default CCs? Can I just do the?'source pretune constants correction'?
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Are you sure the YIG is dead? How do you know? I suggest you don't adjust anything until you know what the problem is. My method of troubleshooting is to go through the adjustments procedure but WITHOUT ADJUSTING ANYTHING. Anything way off indicates the?problem area. Often a failure in a closed loop. Finding a failure in a closed loop can be tricky and requires a knowledge?of the?circuit function.? When you have repaired the problem then you can do the adjustments. Making adjustments without repairing the problem just makes new problems and it will be much more difficult to identify the fault. Many HP problems are due to power supply failure.
I have a dead YIG (5086-7473) in the source of an HP8753C that I am replacing.
The manual says to do the procedure for setting the 'source pretune constants correction'.?
The section on setting the 'source default correction constants' says that this must be done before the source pretune; however, this will require me to set the 'RF Output Power Correction Constants' and I do not have the equipment for this step (HPIB power meter).
Since I'm just changing the YIG and not the whole source block, do I really need to reset all the souce default CCs? Can I just do the?'source pretune constants correction'?
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Does replacing the YIG without adjusting anything bring the VNA back to life? If not it possibly isn't a bad YIG.
Are you sure the YIG is dead? How do you know? I suggest you don't adjust anything until you know what the problem is. My method of troubleshooting is to go through the adjustments procedure but WITHOUT ADJUSTING ANYTHING. Anything way off indicates the?problem area. Often a failure in a closed loop. Finding a failure in a closed loop can be tricky and requires a knowledge?of the?circuit function.? When you have repaired the problem then you can do the adjustments. Making adjustments without repairing the problem just makes new problems and it will be much more difficult to identify the fault. Many HP problems are due to power supply failure.
I have a dead YIG (5086-7473) in the source of an HP8753C that I am replacing.
The manual says to do the procedure for setting the 'source pretune constants correction'.?
The section on setting the 'source default correction constants' says that this must be done before the source pretune; however, this will require me to set the 'RF Output Power Correction Constants' and I do not have the equipment for this step (HPIB power meter).
Since I'm just changing the YIG and not the whole source block, do I really need to reset all the souce default CCs? Can I just do the?'source pretune constants correction'?
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I generally try not to kibitz, but your comment about going through the adjustment procedure WITHOUT touching ANYTHING is ABSOLUTELY SPOT ON !!
Quoting peter bunge <bunge.pjp@...>:
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Show quoted text
Are you sure the YIG is dead? How do you know? I suggest you don't adjust
anything until you know what the problem is.
My method of troubleshooting is to go through the adjustments procedure but
WITHOUT ADJUSTING ANYTHING. Anything way off indicates the problem area.
Often a failure in a closed loop.
Finding a failure in a closed loop can be tricky and requires a
knowledge of the circuit function.
When you have repaired the problem then you can do the adjustments.
Making adjustments without repairing the problem just makes new problems
and it will be much more difficult to identify the fault.
Many HP problems are due to power supply failure.
On Tue, Feb 1, 2022 at 11:24 AM vk2bea via groups.io <vk2bea=
[email protected]> wrote:
I have a dead YIG (5086-7473) in the source of an HP8753C that I am
replacing.
The manual says to do the procedure for setting the 'source pretune
constants correction'.
The section on setting the 'source default correction constants' says that
this must be done before the source pretune; however, this will require me
to set the 'RF Output Power Correction Constants' and I do not have the
equipment for this step (HPIB power meter).
Since I'm just changing the YIG and not the whole source block, do I
really need to reset all the souce default CCs? Can I just do the 'source
pretune constants correction'?
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On Tue, Feb 1, 2022 at 05:40 PM, peter bunge wrote:
Are you sure the YIG is dead? How do you know? I suggest you don't adjust anything until you know what the problem is.
My method of troubleshooting is to go through the adjustments procedure but WITHOUT ADJUSTING ANYTHING. Anything way off indicates the?problem area. Often a failure in a closed loop.
?
The voltages are OK but there is NO outut from the YIG. I see the 3.8 GHz signal (+10dbm) from the cavity oscillator but absolutely nothing from the YTO.? If it's no the YTO what else could it be?
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yig is dead. The Yig in the 8753 part of the dreaded HP yigs that tend to fail. Find a new 5086-7934. Repair is only possible with a part that is not easy to source and you need a wirebonder
best regards Peter
On Tue, Feb 1, 2022 at 05:40 PM, peter bunge wrote:
Are you sure the YIG is dead? How do you know? I suggest you don't adjust anything until you know what the problem is.
My method of troubleshooting is to go through the adjustments procedure but WITHOUT ADJUSTING ANYTHING. Anything way off indicates the?problem area. Often a failure in a closed loop.
?
The voltages are OK but there is NO outut from the YIG. I see the 3.8 GHz signal (+10dbm) from the cavity oscillator but absolutely nothing from the YTO.? If it's no the YTO what else could it be?
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On Wed, Feb 2, 2022 at 07:40 AM, Peter Hansen wrote:
yig is dead. The Yig in the 8753 part of the dreaded HP yigs that tend to fail. Find a new 5086-7934. Repair is only possible with a part that is not easy to source and you need a wirebonder
best regards Peter
Yes, my conclusion also (unfortuantely). I did find a replacement YIG (not cheap) but I still have the original question regarding the pretune constants setup when I replace it.
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It is hard to guess a person's?level of expertise but since you can measure?the 3.8GHz I think you know what you are doing. How and where are you measuring?the YIG output? Have you checked ALL the self tests.?The higher level ones have to be specifically called up and are not included in the normal boot up self test. Is the analog bus working? Does the tune voltage look normal? These are a few things that can make a YIG appear dead. I will send you some repair logs privately that might help.
On Tue, Feb 1, 2022 at 05:40 PM, peter bunge wrote:
Are you sure the YIG is dead? How do you know? I suggest you don't adjust anything until you know what the problem is.
My method of troubleshooting is to go through the adjustments procedure but WITHOUT ADJUSTING ANYTHING. Anything way off indicates the?problem area. Often a failure in a closed loop.
?
The voltages are OK but there is NO outut from the YIG. I see the 3.8 GHz signal (+10dbm) from the cavity oscillator but absolutely nothing from the YTO.? If it's no the YTO what else could it be?
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I am not sure why the 8753C manual says that all defaults must be preloaded before setting the pretune constants. I do know that this is not the case for the 8753E. I doubt that you have access to a 9122C external floppy drive (it's easier to find a GPIB power meter), but if you do, I think you may be able to back up the original eeprom. If you do that, you can always restore the settings.
The early 8753D versions (with the old processor bord) are more similar to the 8753C than the 8753E. If you can find an adjustment manual for the "D", see what it says there.
What happens if you just install the new YTO and turn the analyzer on without the pretune adjustment?
Vladan
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Could he use HPDidk for the backup ??? Cheers! Bruce Quoting "pianovt via groups.io" <pianovt@...>:
I am not sure why the 8753C manual says that all defaults must be preloaded before setting the pretune constants. I do know that this is not the case for the 8753E. I doubt that you have access to a 9122C external floppy drive (it's easier to find a GPIB power meter), but if you do, I think you may be able to back up the original eeprom. If you do that, you can always restore the settings.
The early 8753D versions (with the old processor bord) are more similar to the 8753C than the 8753E. If you can find an adjustment manual for the "D", see what it says there.
What happens if you just install the new YTO and turn the analyzer on without the pretune adjustment?
Vladan
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On Wed, Feb 2, 2022 at 01:31 PM, pianovt wrote:
I am not sure why the 8753C manual says that all defaults must be preloaded before setting the pretune constants. I do know that this is not the case for the 8753E. I doubt that you have access to a 9122C external floppy drive (it's easier to find a GPIB power meter), but if you do, I think you may be able to back up the original eeprom. If you do that, you can always restore the settings.
Maybe because the expect the whole source module to be replaced rather than just the YIG. The output level would be a function? of the ALC which doesn't change if just the YIG is replaced.??
What happens if you just install the new YTO and turn the analyzer on without the pretune adjustment?
I'll let you know when it goes in. The replacement unit I got must be a later version ... it has metric hardware (the original is imperial). I've got to get some 3mm harware before I can put it in 8-( No, I don't have the disk so I can't do the backup. Even if I did back up, wouldn't the new pretune constants then be overwritten when I restore?? BTW I see there is a disk emulation project that simulates the HPIB floppy with an SD card. Has anyone tried this on the 8753? Michael
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On Wed, Feb 2, 2022 at 08:54 AM, peter bunge wrote:
It is hard to guess a person's?level of expertise but since you can measure?the 3.8GHz I think you know what you are doing.
No worries.?
How and where are you measuring?the YIG output??
I'm using a spectrum analyzer to look at the output directly from the YIG. (remove the semirigid cable and connect to the spectrum analyzer)
Have you checked ALL the self tests.?The higher level ones have to be specifically called up and are not included in the normal boot up self test.
Is the analog bus working? Does the tune voltage look normal? These are a few things that can make a YIG appear dead.
I got the replacement YIG today and it works (I can see output on the spectrum analyzer) but the mounting harware went from imperial to metric. When I get some 3mm bolts tomorrow I'll mount it properly and see what needs alignment.
I will send you some repair logs privately that might help.
thanks! Michael
?
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Yes, the new constants would be replaced by the old ones, but you would not run the risk of doing anything irreversible. My thought was that you could try to set the YTO pretune constants without wiping out any of the other adjustments. If it doesn't work, you could go back to what you had before the experiment. I don't know this for a fact, but I would guess that you can adjust the YTO pretune constants without loading all the other defaults.
Vladan
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On Wed, Feb 2, 2022 at 04:22 PM, vk2bea wrote:
No, I don't have the disk so I can't do the backup. Even if I did back up, wouldn't the new pretune constants then be overwritten when I restore??
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On Wed, Feb 2, 2022 at 04:46 PM, pianovt wrote:
I don't know this for a fact, but I would guess that you can adjust the YTO pretune constants without loading all the other defaults.
OK, thanks. I think I'll try this. The worst thing that could happen is that it doesn't work and I have to do the whole procedure (assuming I can borrow an an HP power meter) but I'm no worse off.?
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Michael wrote: BTW I see there is a disk emulation project that simulates the HPIB floppy with an SD card. Has anyone tried this on the 8753?
I've successfully used http://www.dalton.ax/hpdisk on a 8720C.
Br
Marcus
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From a private discussion I had on EEVblog back in 2018 about using the hpdisk?project with an 8753C.? I'll include the entire message for those interested in building the project.? I italicized the parts that are more or less specific?to the 8753C (Willem is referring to a PIC programmer):
From my emails back and forth with Anders...
I programmed my PIC using the in-circuit serial programming connector and a PICkit 2 from MPLABx on a MAC mini.? (The MPLABx programming UI left a lot to be desired and I went back to the old tools on a PC to check that the PIC was in fact programmed.)? If the Willem is using the in-circuit protocol, it would just be a matter of connecting the ICSP connector to the right pins on the DIP socket.
There were a few gotchas.
Getting the right GPIB connector soldered on the correct side of the board... a male connector goes on the bottom side of the board, a female connector on the top.? The originally specified connector was obsolete, but a male connector with right angle PCB pins fit fine.? Normally, a device would have a female connector, but using a male connector allows it to be plugged directly into the instrument.
The board must be powered up before turning on the 8753x or it doesn't work (I think it gets insufficiently powered through its protection diodes and brownout reset wasn't enabled in the firmware).
The board I got from Anders didn't have the SD card metal case connected to ground, resulting in the SD card being write protected.? I added a jumper to fix that.
I used hpdir to make a 9134D?disk?image.? As far as I can tell, I used a 1GB partition on a 16GB SD card.? The board is at work, so I can't check it until Monday.
The 8753C does strange things to LIF formatted disks when you delete a file.? The only app that worked for me was lifutils running on a MAC mini.??HP's lifutil doesn't see any files after a deleted file.? hpdir doesn't like the zero start block in a deleted file and complains every time you do anything.
The files saved by the 8753C are in a record based ascii format.? The lifext utility will convert to a human readable format.
Hope that helps, Orin.
On Thu, Feb 3, 2022 at 12:26 AM Marcus Gustafsson < mankan@...> wrote: Michael wrote: BTW I see there is a disk emulation project that simulates the HPIB floppy with an SD card. Has anyone tried this on the 8753?
I've successfully used on a 8720C.
Br
Marcus
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On Thu, Feb 3, 2022 at 12:26 AM, Marcus Gustafsson wrote:
http://www.dalton.ax/hpdisk
Yes thats the one I was looking at. Great I might give this a try on the 8753.
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vk2bea