The power supply that I need is the 48v (sorry for calling it 50v I was an Airline Pilot, not an engine) supply that bolts to the motherboard with Torx T-15 bolts just above Motorola Oncore GPS receiver board. I will certainly take a 24v model, if I have to, but prefer the 48v model because this particular Z3801A chassis already has a 48v power supply built inside there rear of the chassis to power the original, bolt down, Z3801A 48v power supply.
This may sound confusing. Some explanation is in order. About 20 years ago I bought 25 Z3801A's from a surplus dealer in Dallas. These units were just as they came out of the early cell towers, basically useless to Hams. These units all required 48v to run them, had no display, other than some LED's, and were good for nothing except an excellent time base without being hooked to a computer. I did a little machining to the chassis and added a transformer and a few parts to supply the 48v these Z3801A required. Also added a 3 wire AC line plug. Also added Dave Robinson G4FRE / WW2R clock with a nice bezel from Digikey. The clock made the unit desirable and they sold like "Hot Cakes". Unfortunately, when I went back to the dealer in Dallas for more Z3801A's, the price had gone up about 4 times from what I had originally paid. It seems that Hams all over the country had about the same idea that I had. That ended the project for me. Through the years I got a few of these units back for service for various reasons. Mostly it was just for lack of understanding. Now, twenty years later, rather than just throwing the parts units out, I decided to see what I can make out of them. If I can find the 48v power supplies I can easily put one complete unit together, and possibly two. Thus my post. 73 de Lon, K5JV K5jv@ kingwoodcable.com 281-795-1335 . On Fri, May 6, 2022 at 3:31 PM Lon Cottingham <lonk...@gmail.com> wrote: > > On Fri, May 6, 2022 at 3:22 PM ed breya <e...@telight.com> wrote: > > > > I'm a little confused now about what power supply is at issue. The > > normal PS board in the Z3801A mounts on top of the main board, and > > provides +/- 15V and +5V to it, to run everything. The PS board also > > includes the outer oven control, run from a separate 5V DC-DC converter. > > The two DC-DC converters and a bunch of support circuitry are rigged to > > run around 24V or 48V nominal, depending on the sub-model. > > > > Is this the board that's missing? If so, now I understand why you're > > looking for a whole new one. I was picturing fixing one that's crapped out. > > > > I wouldn't be too picky about getting a 48V one versus 24V one - it's > > better than nothing, and it's quite easy to change the external PS to > > 24V. Go with whichever one you can find. > > > > If you can't find anything at all, and build an alternate system, you'll > > need to replicate the outer oven control, besides supplying the main > > board power. > > > > Ed > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > > an email to time-nuts-le...@lists.febo.com > > To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.