My unit's Lamp Voltage does swing up and down until it locks. It just takes longer than the 3.5 - 4 minutes the manual says.
I checked the Lamp Voltage when Locked and it is 9.4 vdc. 73, Dick, W1KSZ -----Original Message----- >From: Don Key <[email protected]> >Sent: Jul 28, 2009 8:22 AM >To: Discussion of precise time and frequency measurement <[email protected]> >Subject: Re: [time-nuts] LPRO-101 Status > > >----- Original Message ----- >From: <[email protected]> >To: "time-nuts" <[email protected]> >Sent: Tuesday, July 28, 2009 9:25 AM >Subject: Re: [time-nuts] LPRO-101 Status > > >On July 25, 2009 don.key at ntlworld.com wrote > >>The second one would not lock within 15 minutes, so I returned it (to >>China) >>for a replacement. As I didn\'t have a heatsink, I didn\'t want to leave it >>any longer. Besides, if it doesn\'t lock within 5 minutes, then I assume it >>is faulty. Instead of the frequency sweeping up & down, the Xtal volts >>started at around 6V2, then swept down to 0V & stayed there, leaving the >>frequency about 180Hz low, as seen on a HP 8591E analyzer. > >>Out of interest, did your unit sweep up & down, or was it similar to mine? > >I had exactly the same problem with one of my units, but fixed it. >In LPRO the voltage starts sweeping around 6.2V and goes up and down between >two preset limits (about 0.5V and 12.5V) until lock occurs. >Comparator circuits do sense the crossing of voltage limits and >invert sweeping. Depending on what comparator fails, the unit remains >in deadlock around 0V or 14.3V. >I have had both cased with two units. >In the case of 0V the faulty component was resistor R230 (100K, bottom of >pcb). >It reads onboard about 23K when faulty and about 18K when good. Replaced >R230, >the unit now works. >In the case of 14.3V the faulty component was R215 (100K, bottom of pcb). >It reads onboard >1Mohm when faulty. Replaced it, and the unit works. > >I have several LPRO, and all of them do lock in about 3.5 mins at ambient >temperature of 20 °C or so. I use heatsinks. > >Bye, >Antonio I8IOV > > >I was tempted to open up the faulty unit, but thought it was best to return >it ASAP for a replacement (even though it cost me £6.51 postage). >If it happens again, I will know where to look first! >Cheers > >...Jim > > >_______________________________________________ >time-nuts mailing list -- [email protected] >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
