Re: [time-nuts] HPZ3801 Failure

2016-02-04 Thread paul swed
Daves absolutely correct about working around bad supplies. The reason for the preregulator is that it would allow the 3801 to meet European ETSI dc voltage standards that goes up to 75VDC on the telco battery bus. US can reach 56 VDC. Anyhow if thats your only problem then you can solve the

Re: [time-nuts] HPZ3801 Failure

2016-02-04 Thread Joseph Gray
It seems that there has been a rash of Z3801A failures lately. Mine has been out of lock for a couple of months, but I haven't had time to look into it. Comparing it against my other GPSDO, it seems that the OCXO is not the problem, as after all this time, it is only 2 Hz off. I'm guessing the GPS

Re: [time-nuts] HPZ3801 Failure

2016-02-04 Thread Joseph Gray
Wes, I just checked and KO4BB already has the power supply info. http://www.ko4bb.com/manuals/index.php?dir=02_GPS_Timing/Z3801 Joe Gray W5JG On Thu, Feb 4, 2016 at 5:21 PM, paul swed wrote: > Daves absolutely correct about working around bad supplies. > The reason for

Re: [time-nuts] HPZ3801 Failure

2016-02-04 Thread Artek Manuals
Wes Some one reversed engineered the supply about 10 years ago and they posted the schematic on the WEBThe web link I have no longer works so I will email you the schematics of the supply direct. I will check to see if the files are not already up on KO4BB and if not I will post them up

[time-nuts] HPZ3801 Failure

2016-02-04 Thread Wes Atchison
My HPZ3801 has died. It appears the internal DC to DC converters have died. The fuses (4) I have found on the boards check good with an ohmmeter. I have checked voltage on test points where labeled as a supply. No voltages present. Is there a schematic available somewhere? Has anyone repaired