[time-nuts] Z3801A Internal A/C Supply ??
OK if you followed the previous thread on this unit you will remember that the front half of my supply the reverse polarity and under/ over voltage switch is bad but the DC-DC converter half of the supply is good. I initially cut a trace and rerouted the power input to bypass the voltage protection circuit and I am feeding the DC-DC section with one of my LAB supplies (Tektronix PS503A) . Long term I needed to free up the lab supply for other tasks so I set about looking for a permanent supply to run the Z3801A. since the 0-60V supply I was using to feed the Z3801 48V either killed the Z3801 supply when it died or vice versa.. the 0-60V supply was kind of big and clunky anyway, Scrounging around in the junk box I came up with a pair of 19.5V/3amp HP laptop supplies which were identical I hooked the outputs of these two in series (39V under load at 500ma) which seemed perfect. I have now been running the Z3801A off these two for a couple of days now and the supplies work fine and are hardly warm to the touch. So here is my question These two supplies will fit quite nicely inside the Z3801A case. Making the the Z3801A "plug in the wall" AC compatible no external supply. Should I be concerned about. 1) Noise from the supply or the A/C lines now inside the box 2) Heat from the supplies, as I said they are hardly warm to the touch after running for two day . I could / probably should measure the case temperatures but I suspect they are less than 35C Thoughts... suggestions. opinions Dave NR1DX -- Dave manu...@artekmanuals.com www.ArtekManuals.com --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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] Z3801A Internal A/C Supply ??
Dave wrote: Should I be concerned about. 1) Noise from the supply or the A/C lines now inside the box Yes, you should always be concerned about both radiated and conducted noise generated by switching supplies, inside or outside the enclosure. Personally, I would never run the output of a switcher directly into (or inside) any electronic equipment that receives, processes, or generates precision signals. At the very least, I would package the switcher in a separate metal enclosure with a linear cleanup regulator and appropriate RF filtering, and feed the cleaned-up DC through a shielded cable to the instrument (allowing the supply to be located a meter or more away from the instrument). NB: the shield should NOT be the power supply common conductor. It should be connected directly to chassis at the instrument, and either floating or bypassed (0.1uF) to the chassis of the power supply. I like the Philmore "multi-pin mobile connectors" for this (see below). I hard-wire the cable at the power supply end, and use a male chassis socket on the instrument and an in-line female plug on the instrument end of the cable. The power supply "hot" and common should be bypassed (0.1uF) to the instrument chassis right at the socket, then they should pass through a common-mode filter, before being fed to internal circuitry. 2) Heat from the supplies, as I said they are hardly warm to the touch after running for two day. I doubt you need to worry about this, if they are cooler to the touch than the OCXO. Best regards, Charles ___ 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.
