Re: [time-nuts] HP Z3805A GPSDO Oven Heater Voltages
Jarl, Thank you for your help on this. It appears that either; the CPU has a bad output pin, some unknown command has turned the heater off, or the firmware is programmed that way. The 10 MHz frequency had always been very 'stable', and I didn't know there was a problem until I bought a 2nd HP Z3805A and felt how warm the (50C) insulated double oven should feel. I am trying to communicate with the seller in Hong Kong. So far he hasn't acknowledged that the CPU output pin can turn-off the heater. By the way, your projects onhttp://risums.net/hjem/oz9mo/index.html http://risums.net/hjem/oz9mo/index.html are very interesting and described very clearly. Nice work! John, KM6QX _ From: Jarl Risum [mailto:jarl.ri...@gmail.com] Sent: Thursday, April 24, 2014 5:23 AM To: John Stuart Subject: Re: HP Z3805A GPSDO Oven Heater Voltages John, Thanks for the feedback and congratulations with your result so far. Unfortunately I have no further information regarding the function of the outer oven control signal from the processor board. You are probably right in assuming that the signal might be used to prevent the outer oven from overheating in case the thermistor went open, since the processor on the main board do monitor the outer oven heater voltage through P2/9. Speculating further: It might also be used by manufacturers to switch off the outer oven heater circuit permanently in HP Z3805's using the 5 MHz MTI OCXO if a suitable RS-232 command exist for this purpose. Cheers from OZ9MO / Jarl in Denmark Some of my Time-Nuttery: http://risums.net/hjem/oz9mo/index.html 2014-04-24 3:13 GMT+02:00 John Stuart j.w.stu...@comcast.net: Jarl, OZ9MO Thank you for those two links! They have the information I needed, and are very well 'hidden' on the internet. I have had partial success. Per the work-around on www.realhamradio.com, I pulled P2-8 on the power board up to +5V, and the outer heater came on and is now being controlled by temperature controller on the power board; TP104 is modulating around 15.75 V. However the heater on/off control signal from the main circuit board (normally connected to P2-8) is still OFF at 0.0 V. For some reason (maybe firmware) the units CPU is not turning on this signal. I am thinking about permanently wiring +5V to P2-8 to keep the heater enabled. Why would the outer oven ever be turned OFF ?? Maybe to prevent over-temperature damage if the NTC sensor fails? When I bought this HP Z3805A from the Hong Kong seller a couple of years ago, it was advertised as having been upgraded to the features (firmware?) of the HP(Symmetricam) 58503A. Does anyone else have this 'model' and does the Double Oven XO keep the unit's top very warm, like it should? John Stuart, KM6QX Lafayette, CA _ From: Jarl Risum [mailto:jarl.ri...@gmail.com] Sent: Wednesday, April 23, 2014 2:22 AM To: j.w.stu...@comcast.net Subject: HP Z3805A GPSDO Oven Heater Voltages Hi John You will find a comprehensive description of the outer oven heater circuit here: http://www.ko4bb.com/Manuals/05%29_GPS_Timing/Z3801/Z3801A_Outer_Oven/Web_Pa ge/Z3801A%20Outer%20Oven%20Controller.htm In my HP Z3805A the outer oven circuit is identical to the circuit in HP Z3801. A description of a Z3801A outer oven fault similar to the one you have can be found here: http://www.realhamradio.com/oven-confusion.htm You will also find a suggestion for a simple remedy. Good luck. Cheers from OZ9MO / Jarl in Denmark ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP Z3805A GPSDO Oven Heater Voltages
John, I have a similar unit (probably from the same seller), advertised as an Z3805A upgraded to the features of 58503A, whatever that is supposed to mean. Mine also does not get warm on top, though it appears to be providing a decent 10 MHz output and indicates GPS lock. This is the best reference in the lab at the moment so I can't truly speak to the stability of the output. Thanks for the heads-up that the outer oven is not being turned on by the CPU. I haven't opened up the case yet but will do so as soon as my order of round tuits arrives :) Henry On Thu, Apr 24, 2014 at 10:15 AM, John Stuart j.w.stu...@comcast.net wrote: Jarl, Thank you for your help on this. It appears that either; the CPU has a bad output pin, some unknown command has turned the heater off, or the firmware is programmed that way. The 10 MHz frequency had always been very 'stable', and I didn't know there was a problem until I bought a 2nd HP Z3805A and felt how warm the (50C) insulated double oven should feel. I am trying to communicate with the seller in Hong Kong. So far he hasn't acknowledged that the CPU output pin can turn-off the heater. By the way, your projects onhttp://risums.net/hjem/oz9mo/index.html http://risums.net/hjem/oz9mo/index.html are very interesting and described very clearly. Nice work! John, KM6QX _ From: Jarl Risum [mailto:jarl.ri...@gmail.com] Sent: Thursday, April 24, 2014 5:23 AM To: John Stuart Subject: Re: HP Z3805A GPSDO Oven Heater Voltages John, Thanks for the feedback and congratulations with your result so far. Unfortunately I have no further information regarding the function of the outer oven control signal from the processor board. You are probably right in assuming that the signal might be used to prevent the outer oven from overheating in case the thermistor went open, since the processor on the main board do monitor the outer oven heater voltage through P2/9. Speculating further: It might also be used by manufacturers to switch off the outer oven heater circuit permanently in HP Z3805's using the 5 MHz MTI OCXO if a suitable RS-232 command exist for this purpose. Cheers from OZ9MO / Jarl in Denmark Some of my Time-Nuttery: http://risums.net/hjem/oz9mo/index.html 2014-04-24 3:13 GMT+02:00 John Stuart j.w.stu...@comcast.net: Jarl, OZ9MO Thank you for those two links! They have the information I needed, and are very well 'hidden' on the internet. I have had partial success. Per the work-around on www.realhamradio.com, I pulled P2-8 on the power board up to +5V, and the outer heater came on and is now being controlled by temperature controller on the power board; TP104 is modulating around 15.75 V. However the heater on/off control signal from the main circuit board (normally connected to P2-8) is still OFF at 0.0 V. For some reason (maybe firmware) the units CPU is not turning on this signal. I am thinking about permanently wiring +5V to P2-8 to keep the heater enabled. Why would the outer oven ever be turned OFF ?? Maybe to prevent over-temperature damage if the NTC sensor fails? When I bought this HP Z3805A from the Hong Kong seller a couple of years ago, it was advertised as having been upgraded to the features (firmware?) of the HP(Symmetricam) 58503A. Does anyone else have this 'model' and does the Double Oven XO keep the unit's top very warm, like it should? John Stuart, KM6QX Lafayette, CA _ From: Jarl Risum [mailto:jarl.ri...@gmail.com] Sent: Wednesday, April 23, 2014 2:22 AM To: j.w.stu...@comcast.net Subject: HP Z3805A GPSDO Oven Heater Voltages Hi John You will find a comprehensive description of the outer oven heater circuit here: http://www.ko4bb.com/Manuals/05%29_GPS_Timing/Z3801/Z3801A_Outer_Oven/Web_Pa ge/Z3801A%20Outer%20Oven%20Controller.htm In my HP Z3805A the outer oven circuit is identical to the circuit in HP Z3801. A description of a Z3801A outer oven fault similar to the one you have can be found here: http://www.realhamradio.com/oven-confusion.htm You will also find a suggestion for a simple remedy. Good luck. Cheers from OZ9MO / Jarl in Denmark ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP Z3805A GPSDO Oven Heater Voltages
Jarl, OZ9MO Thank you for those two links! They have the information I needed, and are very well 'hidden' on the internet. I have had partial success. Per the work-around on www.realhamradio.com, I pulled P2-8 on the power board up to +5V, and the outer heater came on and is now being controlled by temperature controller on the power board; TP104 is modulating around 15.75 V. However the heater on/off control signal from the main circuit board (normally connected to P2-8) is still OFF at 0.0 V. For some reason (maybe firmware) the units CPU is not turning on this signal. I am thinking about permanently wiring +5V to P2-8 to keep the heater enabled. Why would the outer oven ever be turned OFF ?? Maybe to prevent over-temperature damage if the NTC sensor fails? When I bought this HP Z3805A from the Hong Kong seller a couple of years ago, it was advertised as having been upgraded to the features (firmware?) of the HP(Symmetricam) 58503A. Does anyone else have this 'model' and does the Double Oven XO keep the unit's top very warm, like it should? John Stuart, KM6QX Lafayette, CA _ From: Jarl Risum [mailto:jarl.ri...@gmail.com] Sent: Wednesday, April 23, 2014 2:22 AM To: j.w.stu...@comcast.net Subject: HP Z3805A GPSDO Oven Heater Voltages Hi John You will find a comprehensive description of the outer oven heater circuit here: http://www.ko4bb.com/Manuals/05%29_GPS_Timing/Z3801/Z3801A_Outer_Oven/Web_Pa ge/Z3801A%20Outer%20Oven%20Controller.htm In my HP Z3805A the outer oven circuit is identical to the circuit in HP Z3801. A description of a Z3801A outer oven fault similar to the one you have can be found here: http://www.realhamradio.com/oven-confusion.htm You will also find a suggestion for a simple remedy. Good luck. Cheers from OZ9MO / Jarl in Denmark ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] HP Z3805A GPSDO Oven Heater Voltages
I have a HP Z3805A / 58503A with a cold outer oven. I have installed another HP 10811-60165 DOXO, and then another power board. Still, the outer oven is not heating. Heater resistance is ok at 19 ohm, but voltage on red wires to heater are both at 5.0 VDC. On another (good warm) HP Z3805A, the red wire voltage on P3-3 is at 15.27 V, so there is current flow through the heater and the DOXO is nice and warm. I found two other voltage differences on the power board terminals: P2-8 Violet = 0.00 V vs. 4.5 on the good unit P2-9 Green = 8.14 V vs. 1.95 V on the good unit So, can someone tell me what the green and violet wires do that connect to the main circuit board? Any suggestions on how / what to troubleshoot next? John Stuart, KM6QX Lafayette, CA ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
