[time-nuts] PRS10 case temperature

Shaun Merrigan shaun_merrigan at outlook.com
Fri Nov 16 22:02:02 UTC 2018


Scott:

Here are the analog output values I am seeing:

ad0 0.005 Spare
ad1 2.316 +24 Volt Heater Supply
ad2 2.327 +24 Volt Electronics Supply
ad3 0.491 Lamp Drain Voltage
ad4 0.343 Lamp Gate Voltage
ad5 2.402 Crystal Heater Control
ad6 2.358 Cell Heater Control
ad7 1.557 Lamp Heater Control
ad8 2.413 AC Photosignal
ad9 2.491 Photocell I/V Voltage
ad10 0.657 Case Temperature
ad11 0.950 Crystal Thermistors
ad12 0.958 Cell Thermistors
ad13 0.957 Lamp Thermistors
ad14 2.503 Frequency Pot Voltage
ad15 0.005 Analog Ground
ad16 2.520 22.48MHz Varactor Voltage
ad17 3.190 360MHz Varactor Voltage
ad18 1.910 Gain Control Voltage
ad19 4.740 RF Synthesizer Lock Indicator

This unit has a large passive heatsink and the values are from RbMon.

Shaun Merrigan

-----Original Message-----
From: time-nuts <time-nuts-bounces at lists.febo.com> On Behalf Of Scott Mace via time-nuts
Sent: Friday, November 16, 2018 1:37 PM
To: time-nuts at lists.febo.com
Cc: Scott Mace <smace at intt.net>
Subject: [time-nuts] PRS10 case temperature

I have been experimenting with a PRS10 and using Lady Heather to collect data.  This unit had several failed components in the lamp assembly, which I replaced and the unit locks well now.  One thing I noticed is that on cold startup, the unit seems to think it's already at 40-50C, when in reality it's only slightly above room temperature.  The sensor settles around 79-82C.  I've measured the baseplate and it is around 50C.  I believe that all of the ovens are running slightly low as a result (if I understand the circuit correctly).  I'm thinking that the case temp sensor, a LM45C, on the power supply board is bad.  Anyone else running a PRS10 with reasonably correct baseplate temperatures?

Here are some of the numbers I'm seeing:

AD1 - Heater supply : 24.360V
AD2 - +24V supply: 24.370V
AD3 - Lamp FET drain: 4.910V
AD4 - Lamp FET gate: 4.080V
AD5 - OCXO heater: 1.811V
AD6 - Cell heater: 2.101V
AD7 - Lamp heater: 1.513V
AD8 - Photo signal: 3.831
AD9 - I/V converter: 4.804V
AD10 - Case temperature: 80.80 C
                          ^^^^
AD11 - XTAL thermistors: 0.961
AD12 - Cell thermistors: 0.971
AD13 - Lamp thermistors: 0.972
AD14 - Freq cal pot: 2.337
AD15 - Analog ground: 0.005V
AD16 - TXCO varactor: 7.240V
AD17 - VCO varactor: 11.520V
AD18 - Multiplier gain: 11.520V
AD19 - RF synth lock: 4.900V



	Scott



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