help needed to repair HP spectrum analyser

[kenramesh]

I have two preliminar service manuals for 8594A and 8595A, both are referenced to 8593A service manual as similar.

8594A:
https://www.dropbox.com/s/tcbbsknii8df9n3/8594A_Preliminary%20Service%20Manual.pdf?dl=0

8595A:
https://www.dropbox.com/s/e3gdwtknw44ndej/8595A_Preliminary%20Service%20Manual.pdf?dl=0

I'm unable to find a manual for 8593A, but found a complete manual for 8595A:
http://www.ko4bb.com/getsimple/index.php?id=download&file=HP_Agilent/HP_8595A_Service_Manual.pdf

Page 421 describes possible SW/HW causes of "FREQ UNCAL" message.

Starting here you find CLIP schematics:
http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=HP_Agilent/HP_8590_Spectrum_Analyzer/HP_8590_Clip

I ll go through the manual links u provided & get back to u

thanks a lot

[kenramesh]

You have run the internal self-test?

Just a shot in the dark: Was the SRAM-Battery / The Chip with the Calibration-Data ever changed? If the instrument loses these information, it may very well be that the coarse DAC for the YTO is putting out the wrong values so the PLL cannot lock anymore.

Internal self test  ?   Tried calibration , adjustments, diag  , troubleshooting related tests bu t dint come across internal self tests in instrument menu or in the manual. 

Checked the battery its fine , I even tried replacing a new battery .

[kenramesh]

That something connected to the YIG is getting warm is normal. That thing requires quite a bit of current to generate the magnetig fields.

YIG's normally have a heater.
Here is some info on driving one from a power supply, although not much use unless you have another way of measuring the output.

http://www.rollanet.org/~joeh/projects/Connecting_the_HP_5086-7023_YTO.pdf

I tried but couldn't perform this task.

thankyou

[kenramesh]

I have two preliminar service manuals for 8594A and 8595A, both are referenced to 8593A service manual as similar.

8594A:
https://www.dropbox.com/s/tcbbsknii8df9n3/8594A_Preliminary%20Service%20Manual.pdf?dl=0

8595A:
https://www.dropbox.com/s/e3gdwtknw44ndej/8595A_Preliminary%20Service%20Manual.pdf?dl=0

I'm unable to find a manual for 8593A, but found a complete manual for 8595A:
http://www.ko4bb.com/getsimple/index.php?id=download&file=HP_Agilent/HP_8595A_Service_Manual.pdf

Page 421 describes possible SW/HW causes of "FREQ UNCAL" message.

Starting here you find CLIP schematics:
http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=HP_Agilent/HP_8590_Spectrum_Analyzer/HP_8590_Clip

Read the manuals .

Helpful schematics .

As spare parts not available got stuck .

Analog Interface, YTO, Counterlock one of the part might be the culprit.

Thank you for the info provided.

[kenramesh]

I measured 10 pin connector on  YTO (5086-7833) oscillator with digitalmultimeter after the analyser was switched -on.

pin nos.    standardsignal    obtained

Pin1     =  minus 15v    =   minus 15.02v

pin2     =  a gnd           =          -

pin3     =  a gnd           =          -

pin4     =  +5v             =  +5v

pin5     = maincoil+     =  +14.81v

pin6     = maincoil-      =  +9.63v

pin7     =   a gnd         =      -

pin8     =  +15v          =  +14.83v

pin9     = FM-signal     =   0.041v

pin10   = FM+signal    =   0.041v


Are these obtained values at pin 5,6, 9, 10 right or wrong.

[GrifTech]

Hi! Had the same issue, it's most likely the yid ocillator. Measure its output. Should be between 15, and 20dB.
Hope you have fixed the issue.

[C.Mueller]

...well, because this sounds familiar I didn't start a new topic (sorry Kenramesh). I also have trouble with our company's HP8595A spectrum analyzer
after replacing the internal 3.7V battery (which was from 1991!)

Yes, I know there is another guy with HP8595E but he has the luck that his analyzer still responds while
mine here shows these things after startup:

FAIL: 0030 0000000000   FREQ UNCAL

I tried to do the internal calibration (lead to this):

CAL Signal not found (I also tried an external signal generator set to 300MHz -20dBm)

Last but not least I tried internal diagnosis
(after a while the analyzer doesn't respond anymore to pushing buttons)


Pushing the "Preset" button leads to a bootloop (restart also, I have to unsolder the battery and discharge the 0.22F capacitor
in order to get the analyzer started).

It seems that there are more bugs to fix.
I don't have to repair it on my own, I'm absolutely happy if you could name me a capable service provider (in europe) who is
specialized in repairing (and calibrating) of old spectrum analyzers.
Thanks

[lugaw]

Meanings of the SRQ message:

SRQ 110 is Hardware Broken

[Samukas]

Hello, my name is Samuel, I would like to know if it is possible to send the firmware for the HP 8594A spectrum analyzer, I can't find it anywhere, thank you to anyone who can help.  It could be any revision from the year 92.