Well-done! And thanks a million. I've seen this photoresistor calibration described in forum posts, but never seen it done. Fiddly, but not nearly as bad as I'd feared, should I ever need to work through it. My 334A works fantastically with auto-nulling, but the main dial doesn't read out/ "see" the correct frequency, and slipping the dial won't correct for the discrepancy. Not a huge problem, as one can always use a frequency counter (and most of the time, the input frequency being used is known anyway).
Thanks for the comment! The 334A is a very capable unit. Even though it lacks auto set level, once you get the knack of making a measurement it isn’t so bad. Not being able to read dB and % distortion at the same time is inconvenient sometimes for me.
Hello, i have the same one in my shop, mine was acting up and i found out that one those 10uf caps shorted out! so i replaced all electrolytics. Works like a charm now, thanks for the video!
In my recollection, another big difference between the 334A and the 333A was the auto-null. It is selected by the prominent switch to the right of the meter. You could start with Manual tuning and then turn to Auto for the final null finding. For years, I was drooling for this 334A. In our Ham & HiFi club, we had two Heathkit analyzers for our audio endeavors, one was harmonic distortion analyzer and the second one for intermodulation (2-frequency) analyzer. This HP 334A (and the 333A for that matter) was way more expensive than both the Heathkits, and still missing the intermodulation feature. So, keep drooling, guys!
Yes the auto tune is definitely a nice feature. Manual tuning on the 334A is very finicky. Since this video I’ve acquired an HP339A which has a much lower measurement floor and low distortion source. I’m also in the final stages of building my own measurement set via Robert Cordell’s very capable design in Audio Magazine. I’ll be doing a series on this build hopefully soon. Thanks for the comment.
Nice analysis and repair. My first thought when you mentioned replacing the photoresistors was, why not replace the lamp instead? You did get it fixed and working in tolerance though. Either way it's working well again. Thanks for the video.
I actually have replacement lamps as well but they appear to not be needed. Per the manual the bulb type is 1869D, 14V at 10mA. Thanks for the comment.
Can you be more specific with your question? The math was a summation of the two readings: the DA meter reading plus the change of the spectrum analyzer reading.
@@FreeElectron Why the summa of 2 different readings: one the internal measure -61dBm, and then the Output level? The output level is 0,1RMS with full scale instrument deflection (page 1-2 of the SM from Keysight), it's a relative level, not absolute level.
@@cbiz8 Going off the procedure from section 5-9. This is the fundamental rejection test. The note states "...total fundamental rejection is the sum of the 333A/334A Meter Range setting and the wave analyzer reading." I'm assuming a wave analyzer is a spectrum analyzer. The specification is looking for a rejection of the fundamental with a rejection value of at least 80 dB. The meter indication alone only goes to 75 dB (assuming on the 60 dB scale and full calibrated range is 75dB). By starting the test from a reference of 0 dB one would be unable to see a rejection of greater than 80 dB from the meter indication alone, which is why some additional measurement is required. This is my interpretation of the method for performing this test. If I am incorrect in this line of thought please inform me. Some of this information is covered in more detail in the second part of this series but that portion is still in the works. Thank you for the comment.
@@FreeElectron I havn't red the procedure before. Sorry. The HP 310A seems to be a sort of Selective Level Meter. Thank you for your detailed answer. Best regards.
Well-done! And thanks a million. I've seen this photoresistor calibration described in forum posts, but never seen it done. Fiddly, but not nearly as bad as I'd feared, should I ever need to work through it. My 334A works fantastically with auto-nulling, but the main dial doesn't read out/ "see" the correct frequency, and slipping the dial won't correct for the discrepancy. Not a huge problem, as one can always use a frequency counter (and most of the time, the input frequency being used is known anyway).
Thanks for the comment! The 334A is a very capable unit. Even though it lacks auto set level, once you get the knack of making a measurement it isn’t so bad. Not being able to read dB and % distortion at the same time is inconvenient sometimes for me.
Hello, i have the same one in my shop, mine was acting up and i found out that one those 10uf caps shorted out! so i replaced all electrolytics. Works like a charm now, thanks for the video!
In my recollection, another big difference between the 334A and the 333A was the auto-null. It is selected by the prominent switch to the right of the meter. You could start with Manual tuning and then turn to Auto for the final null finding. For years, I was drooling for this 334A. In our Ham & HiFi club, we had two Heathkit analyzers for our audio endeavors, one was harmonic distortion analyzer and the second one for intermodulation (2-frequency) analyzer. This HP 334A (and the 333A for that matter) was way more expensive than both the Heathkits, and still missing the intermodulation feature. So, keep drooling, guys!
Yes the auto tune is definitely a nice feature. Manual tuning on the 334A is very finicky. Since this video I’ve acquired an HP339A which has a much lower measurement floor and low distortion source. I’m also in the final stages of building my own measurement set via Robert Cordell’s very capable design in Audio Magazine. I’ll be doing a series on this build hopefully soon. Thanks for the comment.
Nice analysis and repair. My first thought when you mentioned replacing the photoresistors was, why not replace the lamp instead? You did get it fixed and working in tolerance though. Either way it's working well again. Thanks for the video.
I actually have replacement lamps as well but they appear to not be needed. Per the manual the bulb type is 1869D, 14V at 10mA. Thanks for the comment.
I want to purchase a complete mantenance manual, how mutch is the cost ?
Nice work & vid.
can I print all the squematic circuits?
I have given away my share of those.
incandescent bulbs produce less light as they age. shoulda replaced them first...
I don't understand your Math at 53:30 ....
Can you be more specific with your question? The math was a summation of the two readings: the DA meter reading plus the change of the spectrum analyzer reading.
@@FreeElectron Why the summa of 2 different readings: one the internal measure -61dBm, and then the Output level? The output level is 0,1RMS with full scale instrument deflection (page 1-2 of the SM from Keysight), it's a relative level, not absolute level.
@@cbiz8 Going off the procedure from section 5-9. This is the fundamental rejection test. The note states "...total fundamental rejection is the sum of the 333A/334A Meter Range setting and the wave analyzer reading." I'm assuming a wave analyzer is a spectrum analyzer. The specification is looking for a rejection of the fundamental with a rejection value of at least 80 dB. The meter indication alone only goes to 75 dB (assuming on the 60 dB scale and full calibrated range is 75dB). By starting the test from a reference of 0 dB one would be unable to see a rejection of greater than 80 dB from the meter indication alone, which is why some additional measurement is required. This is my interpretation of the method for performing this test. If I am incorrect in this line of thought please inform me. Some of this information is covered in more detail in the second part of this series but that portion is still in the works. Thank you for the comment.
@@FreeElectron I havn't red the procedure before. Sorry. The HP 310A seems to be a sort of Selective Level Meter. Thank you for your detailed answer. Best regards.