Re: DIY: Repair of HP Step Attenuators
Which size should I select on that page?
I have stuck attenuator sections in three different instruments, seems to be a common problem.
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Marko Cebokli
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Re: DIY: Repair of HP Step Attenuators
HiI just disassembled my hp8648 attenuator 33322-60011.
I found the little rubber orings have broke.
I need to know exactly how to disconnect the rods that the orings are on from the contact, without breaking anything.
Thank you to ? Microwaveengineer1968??? for an excellent write up.
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I found this link to the orings ? ?
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Thank you
Bob
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Re: 89605 / 89606 cal file
Awesome and thank you!
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I bricked two E1439C digitizers from a bad firmware update and developed a procedure to fix those.
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I need to write a small program to reset the serial number.?
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The A1 (main board) cal date is also lost. The A3 cal date is retained (on a 23C02 I2C EEPROM).
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I wonder if the A3 board has attenuation data.
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On the A1 board, I don’t see much for adjustments. Being an ADC, if the voltages for references are correct they don’t require adjustment. If they’re wrong then that’d be a repair. I recall seeing a counter le markings for capacitors. I’d guess in the same way as an (Tektronix) oscilloscope having a lug to clip a probe onto and the probe having a couple of trimmers to adjust for minimum under/overshoot, perhaps the only necessary adjustment is the input termination to achieve minimum harmonic distortion of a sine wave, and with a square wave input, a specific ratio of relative power levels.
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The VISA API has no documented call that I’ve seen for updating cal dates.
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i don’t suppose anyone has seen a calibration procedure for the E1438/E1439, but it’d be great if someone could confirm any of my suspicions.
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I plan on sharing some cliffs notes and raw flash images extracted from an E1439A and the image I put on the E1439C to unbrick it.
what worked for me to not brick after putting the image on there was to have edited the model number and serial information before resoldering the chip, and then upgrade to B.01.02 firmware and then B.02.01 firmware (the versions might be different depending on serial range).
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I don’t know what all the differences are between the E1439C and E1439A, but I did notice a 1.2V SOT-23 reference attached to two pins of a CPLD and the third lead had a short wire attached to a third pin on the same.
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Re: HP3325A Trouble, Calibration FAIL 2 & 3
I changed Q219 and its complementary transistor. Now I can adjust the 7.5Volts on F3. The amp is now fixed, but the A-CAL Fail error for square and triangle is still present.
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The output is correct, sync out as well, amplitude into a 50 Ohm load is ok, on sine, square and triangle & ramp
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When switching to ramp function something curious follows: The display goes off, the ramp function is visible on the scope, but it 'sweeps'.
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Picture 1: relay board, relays are clickking, are these types they reliable? The yellow relays are often mentioned to be cleaned, my could not be opened.
Picture 2: sinus 1kHz, lokks as expected.
Picture 3: ramp moving with about 0.5Hz.
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here is a video: shows the moving of the ramp and then flips to the correct curve? for a second.
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Outputs at the analog switches are as expected, all voltages as well.
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The self test works except the AC fail, FAIL 2, FAIL 3
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The manual says this is 60% of the controller.?
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Any advices waht to test now? ROM/RAM?
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Or has anyone spare? boards for the 3325A to exchange and for testing ?
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Re: Intermittent REF UNLOCK error message on 8591A Spectrum Analyzer
Hi Anders
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Just go to the Files section i have been uploaded the Clip to 8590/91A
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Br
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Johnny
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Re: E4402B SA power problem - need DC socket connections
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Re: microscope / high magnification camera options for soldering, faults, and other examinations/inspections
I later suspected that 15x would be too much. I'll have a look for AO570/145.
Thanks.
Renaud
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Re: How to I disassemble the HP/Agilent 8495B attenuator ?
sorry, mine has N-type connectors and looks exactly as this one
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Re: How to I disassemble the HP/Agilent 8495B attenuator ?
Thanks, I have the manual, mine has no screws on each end, for? a? picture please see
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Re: microscope / high magnification camera options for soldering, faults, and other examinations/inspections
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Hi Steve, Thanks for that advice. Why are 145 eyepieces better please? It seems 147 are very common. Best regards, Renaud
The 145 eyepiece is 10x. The 147 is 15x. The AO570 body has magnifications from .7x to 4.2x, so the effective magnification with the 10x eyepiece is 7x to 42x. With the 15x the range of magnification is 10.5x to 63x. ?The 42x magnification is plenty and the 7x is a very useful wider field of view.?
The AO catalogs actually call for the AO 184 eyepiece if you want a 15x eyepiece for the AO 569 or AO 570. The AO147 eyepiece was for the American Optical Cycloptic stereo microscope. Since the AO engineers spec’d the 145 and 184 for the AO 570 I suspect there are differences appropriate for those microscopes. | |
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Re: How to I disassemble the HP/Agilent 8495B attenuator ?
Do you have a manual attenuator or the electronically switched one?
There are 4 screws on each end of the attenuator, if you have SMA/3.5mm connectors, then remove the nuts on those connectors, the cover plate between the connectors, and that will expose the 12-16 screws that hold the top cover with the attenuator pads on it. You will need to loosen at least one end plate to take the
top cover plate/attenuator plate off.
A lot of this information is in the HP/Agilent/Keysight Microwave Accessory catalog and in the HP 8495B Operating and Service manual, yes it does contain theory of operation, schematics, parts breakdown, and parts listing. A .pdf of the manual is attached.
Don Bitters
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Forgot to attach, sorry, Gary WA2OMY ?
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From: Gary Hitchner <talgarth@...>
Sent: Monday, March 24, 2025 3:43 PM
To: '[email protected]' <[email protected]>
Subject: FS 8660 plug in's? List,? FS - Three plug in’s ?used in 8660’s. 2)- 86603A ?one has phase modulation capability.? These are the high frequency units that go to 2600 MHz. 1)- 86633B, ?Modulation plug in.? These plug in’s were all in use and working about a year ago when the 8660;s were retired, maybe one has a bad attenuator step. Sold as is, but as pictured and complete,?? $150.00 for all three shipped to your door, US only, L48. Gary WA2OMY
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Anyone have the 17090C Measurement Graphics Software for the 7090A Plotter
Hey All,
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I asked over on VinHPcom but apart for a pointer to the 17090B Software up on HPMuseum I didn't hear much back, so I thought I'd ask here as well.
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The C version of the software apparently works with Series 300 machines so I'm interested in trying to see if it works with my Viper machine.
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So if anyone has a copy I'd appreciate it if I could snag one from you.
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Thanks,
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TonyG
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Do you have pictures?
Glenn
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Show quoted text
On 3/24/2025 3:43 PM, Gary Hitchner via groups.io wrote: List,? FS -
Three plug in’s ?used in 8660’s.
2)- 86603A ?one has phase modulation capability.? These are the high frequency units that go to 2600 MHz.
1)- 86633B, ?Modulation plug in.
These plug in’s were all in use and working about a year ago when the 8660;s were retired, maybe one has a bad attenuator step.
Sold as is, but as pictured and complete,?? $150.00 for all three shipped to your door, US only, L48.
Gary
WA2OMY
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
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List,? FS - Three plug in’s ?used in 8660’s. 2)- 86603A ?one has phase modulation capability.? These are the high frequency units that go to 2600 MHz. 1)- 86633B, ?Modulation plug in.? These plug in’s were all in use and working about a year ago when the 8660;s were retired, maybe one has a bad attenuator step. Sold as is, but as pictured and complete,?? $150.00 for all three shipped to your door, US only, L48. Gary WA2OMY
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Re: E4402B SA power problem - need DC socket connections
The other area of the PSU to look at is standby power and startup circuit. In the older 859x series there is a Schottky diode HSMS-2800 that goes leaky. It's function is to rectify the output from a low current oscillator to generate a pull up voltage for the turn on signal. If it drops too low, the PSU shuts down. Higher temperatures increase leakage, which could cause these symptoms.
I don't know how relevant they are, but I posted traced schematics of the 8591E PSU to the files section a few weeks ago.
Chris G4MWQ
Well, well, well!? I put 12V on the DC connector and removed the mains and the SA fired up.? about 12V at the plug at 7A when running, from a commercial switchmode 13.8V psu.
And it stayed fired up for 3 hours until I got bored and turned it off.? The display was perfect, no error messages, doing exactly what I expected, which was nice.
This means that the fault must lie in the very first stage of the PSU, where the ac is rectified and down-converted to 15V or so.
Maybe dried-out main reservoir caps giving excessive ripple. or rectifier(s).
I've got other things to attend to now but will get back to this in a week and get the PSU out and some caps changed.
I also used the EEVBlog mechanism to install a narrow bandwidth option "upgrade" and it works beautifully!
Good result all round for now.?
Thanks for the help.
-Jeremy
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Re: E4402B SA power problem - need DC socket connections
That's good news.
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Robert.
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Re: E4402B SA power problem - need DC socket connections
Well, well, well!? I put 12V on the DC connector and removed the mains and the SA fired up.? about 12V at the plug at 7A when running, from a commercial switchmode 13.8V psu.
And it stayed fired up for 3 hours until I got bored and turned it off.? The display was perfect, no error messages, doing exactly what I expected, which was nice.
This means that the fault must lie in the very first stage of the PSU, where the ac is rectified and down-converted to 15V or so.
Maybe dried-out main reservoir caps giving excessive ripple. or rectifier(s).
I've got other things to attend to now but will get back to this in a week and get the PSU out and some caps changed.
I also used the EEVBlog mechanism to install a narrow bandwidth option "upgrade" and it works beautifully!
Good result all round for now.?
Thanks for the help.
-Jeremy
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Re: 89605 / 89606 cal file
Hi Ed,
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Here are 3 text files from separate serial number 89605A/B units.? I don't think I have any 606 cal files.? Would be happy to collaborate to set up a test procedure to build cal files for these, as I have several.
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Adam
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Intermittent REF UNLOCK error message on 8591A Spectrum Analyzer
I have just bought an 8591A that has an intermittent REF UNLOCK error message when I use the internal 10 MHz reference. The error comes every 0,5 to 10 second.
The internal reference is 10,000 MHz and the amplitude is around 350 mV peak to peak. The waveform is a bit distorted - not a clean sinus wave.?
The error REF UNLOCK disappears if I connect an external 10 MHz reference - If the amplitude is exactly 130 mV peak to peak.
If the amplitude is higher than 140 mV peak to peak, the intermittent error REF UNLOCK comes back.
Also if the external reference is adjusted lower than 9,98 MHz or higher than 10,02 MHz the error REF UNLOCK disappears even if the amplitude is higher than 140 mV peak to peak.
My 8591A has serial number 3122U01724 and software revision 7.5.91.
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I have checked the Service Manual but it does unfortunately not contain any drawings of the A25 Counter Lock Assembly.
I am very grateful if anybody has any suggestions!
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Ralf Rosche
Steve Holland
