开云体育

HP 8970B with 346B Noise source - Error 13

Razvan Popescu All Messages By This Member #144867 Hello, Since the thread about cheap noise source on the other list got very interesting and I was doing some repairs on my HP 8970A and 8970B I would like to ask some questions which I am not sure how to approach. I bought a 346B some years back and used it with my 8970A and all was OK, recently I got an 8970B with E70 error. I found the 1st EPROM broken and replaced it with the firmware found on KO4BB site. Since I was inside the unit also replaced the battery. And here the problem started... After battery replacement I had E80 so I proceeded with the calibration 33 SP and the 346B source. Problem is that it fails in around 1-2 seconds with E13. E13 is saying that it is practically not enough ENR coming from the source?! Correct me if I'm wrong. So I powered on the 8970A and tested the source there. All OK and 33.1 SP works fine and shows around +4.x dBm uncorrected value after it finishes. From my readings on the HP lists I saw some people reported that the value should be +6 to +8 dB uncorrected. WHy I only see +4 dB? So I am not sure now if my 346B is broken or the 8970B is broken since everything works on 8970A. Another possibility would be that the 5dB attenuator pad in the 8970B is broken. Can someone tell me what is the uncorrected value for the 346B and 8970A after calibration? Is there any difference in reported uncalibrated value between 8970A and 8970B? Best regards, Razvan
DF6NA Rainer All Messages By This Member #144868 E 13 =>? ENR must be 11dB minimum at 30MHz - the HP346b has 5dB ! ! ! Am 14.06.2024 um 10:49 schrieb Razvan Popescu via groups.io: toggle quoted message Show quoted text Hello, Since the thread about cheap noise source on the other list got very interesting and I was doing some repairs on my HP 8970A and 8970B I would like to ask some questions which I am not sure how to approach. I bought a 346B some years back and used it with my 8970A and all was OK, recently I got an 8970B with E70 error. I found the 1st EPROM broken and replaced it with the firmware found on KO4BB site. Since I was inside the unit also replaced the battery. And here the problem started... After battery replacement I had E80 so I proceeded with the calibration 33 SP and the 346B source. Problem is that it fails in around 1-2 seconds with E13. E13 is saying that it is practically not enough ENR coming from the source?! Correct me if I'm wrong. So I powered on the 8970A and tested the source there. All OK and 33.1 SP works fine and shows around +4.x dBm uncorrected value after it finishes. From my readings on the HP lists I saw some people reported that the value should be +6 to +8 dB uncorrected. WHy I only see +4 dB? So I am not sure now if my 346B is broken or the 8970B is broken since everything works on 8970A. Another possibility would be that the 5dB attenuator pad in the 8970B is broken. Can someone tell me what is the uncorrected value for the 346B and 8970A after calibration? Is there any difference in reported uncalibrated value between 8970A and 8970B? Best regards, Razvan
DF6NA Rainer All Messages By This Member #144869 Am 14.06.2024 um 10:59 schrieb DF6NA Rainer: E 13 =>? ENR must be 11dB minimum at 30MHz - the HP346b has 5dB ! ! ! SRI it's the 346A?? ! ! ! Am 14.06.2024 um 10:49 schrieb Razvan Popescu via groups.io: Hello, Since the thread about cheap noise source on the other list got very interesting and I was doing some repairs on my HP 8970A and 8970B I would like to ask some questions which I am not sure how to approach. I bought a 346B some years back and used it with my 8970A and all was OK, recently I got an 8970B with E70 error. I found the 1st EPROM broken and replaced it with the firmware found on KO4BB site. Since I was inside the unit also replaced the battery. And here the problem started... After battery replacement I had E80 so I proceeded with the calibration 33 SP and the 346B source. Problem is that it fails in around 1-2 seconds with E13. E13 is saying that it is practically not enough ENR coming from the source?! Correct me if I'm wrong. So I powered on the 8970A and tested the source there. All OK and 33.1 SP works fine and shows around +4.x dBm uncorrected value after it finishes. From my readings on the HP lists I saw some people reported that the value should be +6 to +8 dB uncorrected. WHy I only see +4 dB? So I am not sure now if my 346B is broken or the 8970B is broken since everything works on 8970A. Another possibility would be that the 5dB attenuator pad in the 8970B is broken. Can someone tell me what is the uncorrected value for the 346B and 8970A after calibration? Is there any difference in reported uncalibrated value between 8970A and 8970B? Best regards, Razvan
Razvan Popescu All Messages By This Member #144870 It works on the 8970A and reports +4dB after calibration. It doesn't work on 8970B. Do you have a 8970A and 346B to check the uncorrected value reported? toggle quoted message Show quoted text On 14/06/2024 13:01, DF6NA Rainer via groups.io wrote: Am 14.06.2024 um 10:59 schrieb DF6NA Rainer: E 13 =>? ENR must be 11dB minimum at 30MHz - the HP346b has 5dB ! ! ! SRI it's the 346A?? ! ! !
Ulf Kylenfall Member Profile All Messages By This Member #144871 Apart from suspecting the 5dB pad in the 8970B... I will hint at a solution to this problem may be the supply voltages out of tolerance. Check all DC voltage levels on the various boards and modules. NOT by measuring at the PSU test pins. I once had a similar problem in an 8970A. That instrument repeatedly failed self calibration with various error messages. All voltages checked out OK on the PSU but on the (large) CPU board, the TTL 5V was somewhere like 4.3 to 4.4V and fluctuating. There are several axial inductors that decouple the DC voltages, one of which had a too large DC resistance. Once replaced, the instrument returned to fully functional. Cheers Ulf / SM6GXV
paulswed All Messages By This Member #145078 Razvan I don't have your answer but face a similar issue on my 8970a. Though I do not have any official HP noise source. I do have noise sources and amplifiers so have tried various levels all with the same result. Fail after 2 seconds. I can easily go to?+6 dbm on a spectrum analyzer as an example. I set the unit aside for the moment. Its for Ham Radio use and no rush. Regards Paul WB8TSL
Razvan Popescu All Messages By This Member #145081 Hello Paul, I also use my units for Ham Radio and at least I have the 8970A working. I didn't have time to look at the voltages in the B model. I have the original HP noise source but as I said I am not sure if it is OK or not. From what I understood the signal should be +11dBm to calibrate it. I have a feeling that my B unit has the 5dB pad broken based on some tests I did from the service manual. I will need to have a look at it later this year... let me know if you find something related to Error 13 in your unit. 73! Razvan toggle quoted message Show quoted text On 26/06/2024 17:44, paulswed via groups.io wrote: Razvan I don't have your answer but face a similar issue on my 8970a. Though I do not have any official HP noise source. I do have noise sources and amplifiers so have tried various levels all with the same result. Fail after 2 seconds. I can easily go to?+6 dbm on a spectrum analyzer as an example. I set the unit aside for the moment. Its for Ham Radio use and no rush. Regards Paul WB8TSL _._,_._,_
paulswed All Messages By This Member #145083 Razvan I appreciate your reply. Well thats a surprise. 11dbm as measured on a power meter like a HP436, or a spectrum analyzer? Thats 100 mw. I never would have thought to go that high for a input. I looked at the various online information and never really felt that I understood what was required. I recall there was a test procedure for the HP noise source. It wasn't that high of a power level. But its been about 6 months and many projects in between. Thanks for you comments. Paul WB8TSL?
Razvan Popescu All Messages By This Member #145084 Hello Paul, The manual says to use the 346B/C for the calibration which are 15dB ENR sources. It also says you can use the 346A but you need to add +10dB of gain. So a minimum of +11dB sounds normal I would say. I didn't check my sources yet on a spectrum analyzer or with a power meter, I don't have too much free time for hobbies... 73! Razvan toggle quoted message Show quoted text On 27/06/2024 15:11, paulswed via groups.io wrote: Razvan I appreciate your reply. Well thats a surprise. 11dbm as measured on a power meter like a HP436, or a spectrum analyzer? Thats 100 mw. I never would have thought to go that high for a input. I looked at the various online information and never really felt that I understood what was required. I recall there was a test procedure for the HP noise source. It wasn't that high of a power level. But its been about 6 months and many projects in between. Thanks for you comments. Paul WB8TSL _._,_._,_
DF6NA Rainer All Messages By This Member #145085 开云体育 Am 27.06.2024 um 13:11 schrieb paulswed: I appreciate your reply. Well thats a surprise. 11dbm as measured on a power meter like a HP436, or a spectrum analyzer? Thats 100 mw. I never would have thought to go that high for a input.???? => go back to school ! And 11dB ENR is not the same as 11dBm !
Dr. David Kirkby, Kirkby Microwave Ltd Member Profile All Messages By This Member #145086 On Thu, 27 Jun 2024 at 14:11, paulswed via <paulswedb=[email protected]> wrote: Razvan I appreciate your reply. Well thats a surprise. 11dbm as measured on a power meter like a HP436, or a spectrum analyzer? Thats 100 mw. I never would have thought to go that high for a input. The excess noise ratio (ENR) is reference to thermal noise at 290 K - not to 1 mW. 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

Previous Topic Next Topic