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Who added "HP Innards of the frequency doubler." ?
There's a directory in the files area called "HP Innards of the frequency doubler." Unfortunately, there's no clue as to what instrument this is related to. I can't see who created the directory. If you know anything about this, please let me know and I will create an appropriate directory for it. -- Dr David Kirkby Ph.D Kirkby Microwave Ltd Email: drkirkby@... Web: Telephone 07910 441670 (UK) or +44 7910 441670 (international) Registered in England and Wales, company number 08914892.? Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT |
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Re: HP 8557A Start-Up Calibration & Linear Mode - Errors in Manual?
Hi Don, ? Thank you so much for your detailed reply.? I didn¡¯t realize anyone responded to my message.? But I¡¯m still working on this project off and on.? The most recent issue was with the 182T supply which I was able to resolve.? Also replaced those leaky series regulator transistors in the low voltage power supply. ? So here is where I am at with 8557A.? Everything looks great on the operator¡¯s check up until step 26.? At this point the manual asks to bring the 250MHz cal signal up to the top graticule line using the ref level fine control and the vertical gain pot.? Even with the vertical gain to max, I cannot get the peak to the top graticule line in both modes.? Set to 10dB/div, the signal is about one div shy of the top graticule line (with ref fine set to max as well; coarse ref level is set to -20dB.? this makes for a total of -32dB).? Also, the baseline of the signal is elevated to ~3 divisions above the bottom graticule line ¨C not sure if that is normal or not.? I can take pictures of these traces for reference.? Then, for linear mode, the cal signal peak is no greater than 1 div above the bottom graticule line.? So there is no way I can adjust both of them to the top graticule line.? Baseline in linear mode is at the bottom graticule line.?? ? Now I¡¯ve run through some of the performance tests.? Tests such as Resolution Bandwidth accuracy, Resolution Bandwidth selectivity, Average Noise level, Amplitude Accuracy between Bandwidths, and Input Attenuator Accuracy tests all look normal and are either within spec or close enough.? Things start to go south when I look at the Reference Level Accuracy test.? There is significant inaccuracy when switching between 0 and -10dB.? After that, the change in amplitude remains in spec from -20dB to about -60dB (while adjusting an external 10dB step attenuator).? From -70dB to -90dB things start to fall out of spec again. ?Also, the Log amplitude display test results are wonky as well.? ? At this point I¡¯m struggling to determine if this is an issue with Step Gain board, Log amplifier board, or vertical driver board.? This unit was in much worse shape when I got it.? I already performed a repair of the front end (the infamous finger contacts and a bad coarse tuning knob).? Perhaps I¡¯m missing something mechanically on the front end? Also, I picked up a 1st converter assembly board (which contains the first mixer) since I had heard that the mixers on these are easily damaged.? Swapping them made no difference.? The seller claimed this board was from a working unit, but who knows.?? ? Anyways, that is where I am at with it.? Will continue to keep working on it.? But greatly appreciate anyone¡¯s input. ? Thanks again! ? -Frank |
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Re: HP 4192A LF Impedance Analyzer Repair Assistance Needed
¿ªÔÆÌåÓýoops, I highlighted the wrong section in red, ?the voltage at pin 6 should be around -15V instead of -4.89V ? ???? ?Relay OFF ||| Relay ON ? Broche 3 +3,414 ||| +4,85 Broche 4 +4,866 ||| +4.86 Broche 5 -15.81 |||-16.06 Broche 6 -4.89 ?||| +0.65 ? ? De?: yves_tardif@... <yves_tardif@...> ? Hi, The schematics I have are barely readable, if you have a better copy it would be easier. ? But when the optocoupler is not working, the driver transistor conducts it thanks to the base resistor going to +15V. To depolarize this transistor, it is therefore necessary that the optocoupler conducts, and that the voltage at the base of the output transistor is very close to -15V. To simulate the effect of the optocoupler, a short circuit of the base to -15V for the driver transistor should deactivate the relay (on the image, red jumper). ? According to your information, there is a voltage of 1.452V at the terminals of the optocoupler LED when it conducts, without knowing the specifications of the optocoupler the voltage could be normal. But the voltage at pin 6 of the optocoupler (or base of the output transistor), is not at -15V. So I would say that U2 is failing. ? I have a 4192A and a 4274A/75A. If I have some free time I will try to read the voltages surrounding this circuit. ? Broche 3 3,414 ||| 4,85 Broche 4 4,866 ||| 4.86 Broche 5 -15.81 ||| -16.06 Broche 6 -4.89 ||| 0.65 ? ? ? De?: [email protected] <[email protected]> De la part de pac1085 ? Hi, First a disclaimer, I'm just a hobbyist with an only a couple of years of electronics experience under my belt. ?So it's possible I'm missing something very simple due to lack of basic understanding. ?I've had some good success repairing broken test equipment and could use some help with this HP 4192A I recently acquired. ? When I received the unit, it would pass zero'ing Open, but it would fail when you tried to Zero short with error E-07. ? I went thru and executed the performance tests per the manual. Paragraph 4-9 "Measurement Signal Frequency Accuracy Test" - Good Paragraph 4-11 "Measurement Signal Level Accuracy Test" - Good Skipped the rest since I hit a brick wall when I couldn't set it up for impedance measurements because I couldn't zero short. I also performed 4-21 "Amplitude Accuracy Test", which it passed, after reading 8-113 "Isolation of the VRD Section"? ? After many hours spent in the service manual, I found something in section 8-111, "Isolation of the Range control circuit" ? In particular, the section that talks about a failure in the source resistor circuit. With a short across the unknown terminals, the test currents were way out of range vs what the manual specified. ? This led me to the flow diagram on page 8-86. ?In the 5th column there is a section where you manually set the ZY range and you should see the amplitude of the signal drop from the HCUR terminal. ?It did not drop when in the 10k or 100k range. The actions suggested checking A1K2, K3, Q19, Q26, U5 and U6 (under the HCUR AMP cover on the A1 board). ?I tested the relays and could see that the circuit was working correctly when manipulating the range setting on the front panel. ? During that process, I noticed relay K1 is always on. ?K1 is only supposed to be on in when the instrument is in amplitude-phase measurement mode. (according to the text on page 8-87) ? I removed K1 and the relay itself tests OK. ? With the relay left out, I installed a jumper on the PCB between relay pins 1 and 4, manually bringing the source resistors into play, so the unit should function correctly in impedance measurement mode now. ? It fixed the problem. I can now zero open, zero short, and make impedance, capacitance, etc measurements with no issues (and they are roughly the same readings im getting on my 4274A) ? Now I need to figure out why K1 is always stuck on. ?It is a normally open relay. ?This is where I need some help. ? The manual says to check the relay K1, its driver transistor, a 2n3904 (Q8) and the optoisolator U2. ?The relay test OK, the transistor tests ok on the curve tracer, I tried another one just in case. ?I have no experience with optoisolators and I'm not really sure what I'm looking for. ? I installed an LED in place of the relay coil, ?and it does appear the commands from the front panel are making It thru the optoisolator and firing the driver transistor. ?The intensity of the LED changes but it never shuts off completely.? ? Here are the voltages from the bottom half of U2 (pins 3,4,5,6), which is the section used to drive Q8. Impedance Mode (K1 should be off) ||| Amplitude-Phase Mode (K1 should be on) Pin 3 3.414 ||| 4.85 Pin 4 4.866 ||| 4.86 Pin 5 -15.81 ||| -16.06 Pin 6 -4.89 ||| 0.65 ? It appears that the relay coil pins are still getting 9-10v even when it's supposed to be off. ? What else should I check with regards to this optoisolator? ?It's HP P/N 01990-0577. ?I spent a while doing a parametric search on digikey and can't find any modern comparable transistor output parts. ?Mostly because the anode/cathode is in a different orientation, but I notice there are a few resistors in the HP opto that I don't see in the modern ones. ?Not sure what other specs to look for other than 50mA (which is what the description of the part says in the HP manual). I'm not sure what type of signal is supposed to be going into the opto on pin 3, is it possible that the front panel isn't supplying enough signal to fire it fully? ? Any help greatly appreciated. Thanks! Phil ? |
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Re: HP 4192A LF Impedance Analyzer Repair Assistance Needed
Shorting pin 5 to 6 does cause the relay to shut off, so that's good. ?I also checked some voltages on the other half of the opto which controls relay K6 (engaged when oscillator level is <70mV) and it works correctly. ?-15v on pin 7 as expected. I'm also seeing similar voltages on pins 2 and 3 so it looks like both half of the opto are getting good control signal.
?
Here's a slightly better pic of that section of the schematic. ?I have an original copy of the service manual binder but the resolution in that is poor as well.
?
Now the question is, what do I replace this optoisolator with.
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It looks like Sphere may have one in stock, if their website is accurate, but I'm hoping I can find a modern replacement incase another one goes in the future.
?
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Re: Boonton 92BD Troubleshooting
I currently have very poor vision, so I missed tat part. I've had eye problems my whole life, but I now have cataracts and hav? been unable to have the surgery. These units have fa outlived their design life and the chopper is always suspect because the lamps weren't rated for a very long useful life. I would add a sub board with the modern circuit, rather than mess with reusig badlt aged lamps., but that choice is yours. I repaired equipment for? daily use in production, along with my opersoal shop.? so the equipment had to meet all specifications at outr in house Metrology lab. I prefer to repair a fault, just once. My work centered on testing and calibrating boards made in house for our products, but I ofteny worked with the lab to find was to repair equipment that there were few or no spare parts. On Sat, Oct 5, 2024 at 3:30?PM Bill Berzinskas via <bberzinskas=[email protected]> wrote:
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Re: HP 4192A LF Impedance Analyzer Repair Assistance Needed
¿ªÔÆÌåÓýHi, The schematics I have are barely readable, if you have a better copy it would be easier. ? But when the optocoupler is not working, the driver transistor conducts it thanks to the base resistor going to +15V. To depolarize this transistor, it is therefore necessary that the optocoupler conducts, and that the voltage at the base of the output transistor is very close to -15V. To simulate the effect of the optocoupler, a short circuit of the base to -15V for the driver transistor should deactivate the relay (on the image, red jumper). ? According to your information, there is a voltage of 1.452V at the terminals of the optocoupler LED when it conducts, without knowing the specifications of the optocoupler the voltage could be normal. But the voltage at pin 6 of the optocoupler (or base of the output transistor), is not at -15V. So I would say that U2 is failing. ? I have a 4192A and a 4274A/75A. If I have some free time I will try to read the voltages surrounding this circuit. ? Broche 3 3,414 ||| 4,85 Broche 4 4,866 ||| 4.86 Broche 5 -15.81 ||| -16.06 Broche 6 -4.89 ||| 0.65 ? ? ? De?: [email protected] <[email protected]> De la part de pac1085 ? Hi, First a disclaimer, I'm just a hobbyist with an only a couple of years of electronics experience under my belt. ?So it's possible I'm missing something very simple due to lack of basic understanding. ?I've had some good success repairing broken test equipment and could use some help with this HP 4192A I recently acquired. ? When I received the unit, it would pass zero'ing Open, but it would fail when you tried to Zero short with error E-07. ? I went thru and executed the performance tests per the manual. Paragraph 4-9 "Measurement Signal Frequency Accuracy Test" - Good Paragraph 4-11 "Measurement Signal Level Accuracy Test" - Good Skipped the rest since I hit a brick wall when I couldn't set it up for impedance measurements because I couldn't zero short. I also performed 4-21 "Amplitude Accuracy Test", which it passed, after reading 8-113 "Isolation of the VRD Section"? ? After many hours spent in the service manual, I found something in section 8-111, "Isolation of the Range control circuit" ? In particular, the section that talks about a failure in the source resistor circuit. With a short across the unknown terminals, the test currents were way out of range vs what the manual specified. ? This led me to the flow diagram on page 8-86. ?In the 5th column there is a section where you manually set the ZY range and you should see the amplitude of the signal drop from the HCUR terminal. ?It did not drop when in the 10k or 100k range. The actions suggested checking A1K2, K3, Q19, Q26, U5 and U6 (under the HCUR AMP cover on the A1 board). ?I tested the relays and could see that the circuit was working correctly when manipulating the range setting on the front panel. ? During that process, I noticed relay K1 is always on. ?K1 is only supposed to be on in when the instrument is in amplitude-phase measurement mode. (according to the text on page 8-87) ? I removed K1 and the relay itself tests OK. ? With the relay left out, I installed a jumper on the PCB between relay pins 1 and 4, manually bringing the source resistors into play, so the unit should function correctly in impedance measurement mode now. ? It fixed the problem. I can now zero open, zero short, and make impedance, capacitance, etc measurements with no issues (and they are roughly the same readings im getting on my 4274A) ? Now I need to figure out why K1 is always stuck on. ?It is a normally open relay. ?This is where I need some help. ? The manual says to check the relay K1, its driver transistor, a 2n3904 (Q8) and the optoisolator U2. ?The relay test OK, the transistor tests ok on the curve tracer, I tried another one just in case. ?I have no experience with optoisolators and I'm not really sure what I'm looking for. ? I installed an LED in place of the relay coil, ?and it does appear the commands from the front panel are making It thru the optoisolator and firing the driver transistor. ?The intensity of the LED changes but it never shuts off completely.? ? Here are the voltages from the bottom half of U2 (pins 3,4,5,6), which is the section used to drive Q8. Impedance Mode (K1 should be off) ||| Amplitude-Phase Mode (K1 should be on) Pin 3 3.414 ||| 4.85 Pin 4 4.866 ||| 4.86 Pin 5 -15.81 ||| -16.06 Pin 6 -4.89 ||| 0.65 ? It appears that the relay coil pins are still getting 9-10v even when it's supposed to be off. ? What else should I check with regards to this optoisolator? ?It's HP P/N 01990-0577. ?I spent a while doing a parametric search on digikey and can't find any modern comparable transistor output parts. ?Mostly because the anode/cathode is in a different orientation, but I notice there are a few resistors in the HP opto that I don't see in the modern ones. ?Not sure what other specs to look for other than 50mA (which is what the description of the part says in the HP manual). I'm not sure what type of signal is supposed to be going into the opto on pin 3, is it possible that the front panel isn't supplying enough signal to fire it fully? ? Any help greatly appreciated. Thanks! Phil ? |
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Re: E4407B ESA spectrum analyzer starting up as wrong type
¿ªÔÆÌåÓýYes, it should appear automatically. ? Yves De?: [email protected] <[email protected]> De la part de Peter Hansen ? Hello The board with the BNC on the back is seated but could be faulty. Should it show up in the Hardware list ? best regards Peter Fra: [email protected] <[email protected]> p? vegne af Yves Tardif <yves_tardif@...> ? Hi, Does your E4407B detect the hardware FREQUENCY EXTENSION? System More Show Hdrwr ? Yves ? De?: [email protected] <[email protected]> De la part de Peter Hansen ? Hi all I got the E4407B to boot and it is a E4407B with the needed hardware. But it boots as a 3GHz model. So where is it stored what type it is supposed to be. It does not sweep even as the 3GHz version.? Anyone know how get it back to E4407B. the Start screen says it is an E4407B but the highest frequency possible 3GHz best regards Peter OZ1LPR |
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Re: E4407B ESA spectrum analyzer starting up as wrong type
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Show quoted text
From:[email protected] <[email protected]> on behalf of Peter Hansen <oz1lpr@...>
Sent:?Saturday, October 5, 2024 1:34 PM To:[email protected] <[email protected]> Subject:?Re: [HP-Agilent-Keysight-equipment] E4407B ESA spectrum analyzer starting up as wrong type ?
Hello The board with the BNC on the back is seated but could be faulty. Should it show up in the Hardware list ?
best regards Peter
Fra:[email protected] <[email protected]> p? vegne af Yves Tardif <yves_tardif@...>
Sendt:?5. oktober 2024 22:16 Til:[email protected] <[email protected]> Emne:?Re: [HP-Agilent-Keysight-equipment] E4407B ESA spectrum analyzer starting up as wrong type ?
Hi, Does your E4407B detect the hardware FREQUENCY EXTENSION? System More Show Hdrwr ? Yves ?
De?:[email protected] <[email protected]>
De la part de?Peter Hansen ? Hi all I got the E4407B to boot and it is a E4407B with the needed hardware. But it boots as a 3GHz model. So where is it stored what type it is supposed to be. It does not sweep even as the 3GHz version.? Anyone know how get it back to E4407B. the Start screen says it is an E4407B but the highest frequency possible 3GHz best regards Peter OZ1LPR |
Dr. David Kirkby, Kirkby Microwave Ltd
Frank Mashockie
Michael A. Terrell
