To All, An update to my Z3801A saga.
Summary: As you know, I purchased this Z3801A at the Dayton Hamfest. The person who sold it to me said it was modified for RS-232. I powered the unit up and the only thing it ever did was go into the holdover mode. Tried hooking RS-232, but got no response. Did some reading and found the little green blinking light was a good thing, all the others indicated a failure in ram, rom, etc. Boot was good if all the front panel lights went on in sequence. Update: Took the unit apart to do some serious trouble shooting. Found the signals (logic side) on the RS-232 did not go all the way to ground. Subbed in another RS-232 transceiver, still no luck. Found another note on the internet about removing the 5 little zero ohm resistors on the bottom to do the RS-232 conversion. Looked on the bottom and they were still there!!! I removed them and the signals now went all the way to ground and appeared to be normal. Tried various programs to link up (GPS.EXE, SatStat, RS-232 comm). Saw the commands going in, and I did see a response from the Z3801A, but the computer could not read the response. Since I did see a response from the Z3801A on the scope, I figured it was receiving commands. I hooked up an antenna and sent a survey command. Apparently if the GPS is moved (I don't know how much) the Z3801A needs to do a survey otherwise it won't lock. I went shopping, and came back about 2 hours later, and low and behold, a GPS LOCK!!! Still to go: The RS-232 signals look fine going into the cable, +/-5V, any ideas why the computer won't read it? Am I missing something? I tried two different ports in case I screwed one up one of the ports, but no luck. Bob AC2AZ _______________________________________________ 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.