[time-nuts] 5065A - Looking for AC XFMR PAECO 9100-2742 specification
ulf_r_k at yahoo.com
Thu Jul 27 13:24:17 EDT 2017
Trying to repair an old 5065A.
After a lot of problems with the Rubidium cavity restoration, it was time to startthe unit.
Lucklily, I did not have the Rubidium temperature controller PCB mounted,but the Power supply regulator malfunctioned and blew the AC mains fuse (0.5A).
Removing that board I discovered that the "24-32V" raw DC was some 40 Volts.
Yes - The unit was correctly configured for 230VAC. Even withsome load, the DC was still ~40V
Unable to find out why, I had to remove the original transformer and replace itwith a 22V unit after which the rectified DC was back to some 32 Volts.
(In Europe, there are seldom primarys with two windings 115/230 which madethe search extra tedious).
The 5065 was originally wired with internal battery backup as well asa mechanical clock. These options was removed since the batterieswere deceased and the clock driver flip-flop unobtanium.
After PSU board repair, all supply voltages are normal, the Rubidiumcavity warms up and the crystal oscillator and syntesizer seems to work.
Have not gotten further, just want to know what the h**k was going onwith the transformer...
Ulf - SM6GXV
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