Pete Joe sure gave you the answer. So you have fallen prey to the time-nuttery CS drug. I would never have thought you would have. So Not that I can out do what Joe told you. But on my sad frankenstein of a 5061running on fumes of CS the beam current is so low that I have to use a magnifying glass to watch the peaks! we are talking approx 3-4 on the meter and thats with the pot all the way up. I am amazed that it all locks consistently actually. Its tough so as Joe says use a solid reference to align the OCXO first. He also hit all of the singing dc to dc convereters. Its normal. Thats what earplugs are for. ;-) Sounds like you are in far better shape. Regards Paul WB8TSL
On Tue, Dec 11, 2012 at 8:46 AM, J. L. Trantham <jlt...@att.net> wrote: > Pete, > > There are two HV power supplies, +3500 (A18) and -2500 (A19), both of which > can 'sing'. A18 comes on when power is applied and in CS OFF mode. A19 > comes on when you move to any mode other than CS OFF. There is also a > battery back up option, Option 002, that has a battery charger board (A2), > that can sing when trying to charge 'dead' NiCd's. It comes on when power > is applied and in CS OFF mode as well. A2 can be removed with no effect on > the rest of the unit to test that theory. When does your unit start > singing? > > The BEAM I indication can be adjusted by the BEAM I METER pot on the > control > panel. It only adjusts the meter indication, not the beam current. The > beam current can be affected/changed by the C FIELD adjustment and by > following the instructions in the manual to align the oven controller (A11) > and the Electron Multiplier on the Power Regulator board (A15). Once > aligned, adjust the BEAM I METER pot for an 'on scale' indication. This is > different on the 5061B where BEAM I METER on the control panel is replaced > by BEAM I and is, in fact, the Electron Multiplier adjustment. There are > different versions of the A15 board, some of which have a pot to adjust the > electron multiplier and others with fixed resistors. > > The change in BEAM I indication as you adjust the COARSE freq can be very > small. The larger the beam current, the greater the fluctuation, but it > can > still be very small, a division or two. The figures in the manual are > quite > 'magnified' in my experience. However, I have never played with a 'new' CS > tube. > > The change in BEAM I indication as you adjust the COARSE freq is also very > easy to miss and it takes only a very small adjustment of COARSE to go > through the entire range. My usual procedure is to let the 5061A warm up > for several hours, in the CS OFF mode, make sure the OCXO is stable, then > compare it's frequency to that of a GPSDO, then adjust the COARSE freq > (with > FINE set to 250) to precisely match the GPSDO. I have a TBolt that I use > it's 10 MHz to trigger the horizontal of a scope and put the 5 MHz of the > 5061A to the vertical. That done, I then select LOOP OPEN, let the CS oven > warm up, the BEAM I come up, the 2nd HARMONIC come up, then select CONT > OPER > and hit the RESET button. If the OCXO is 'on frequency', CONTROL should > indicate zero and you should be on the top of the center peak. Adjustment > of the COARSE should then be able to demonstrate the 'peaks' to prove you > are on the top of the center peak. > > I don't recall any 'false' modes that will give an erroneous indication. > However, I have had failures in the LOGIC board (A14) that have caused > indication problems. > > These units are fun to play with and work on. They make great 'house > standards'. I leave them in CS OFF all the time, which lets the OCXO and > ion pump run continuously. > > Hope this helps. > > Joe > > > > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Pete Lancashire > Sent: Monday, December 10, 2012 10:59 PM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] 5061A Beam Current question > > > I've got a couple questions on a early S/N 5061A I got a few days ago. > > It took a couple days but the Ion Pump current is now down to "zero" or at > least less then one division on the meter. > > I'm able to get the unit to go into continuous operation mode by following > the TURN-ON PROCEDURES but have a few qestions > > 1. The unit 'sings' I'm tone deaf but its a high pitch. It could take some > doing to isolate where it is coming from. Any ideas ? > > 2. How much should the beam current change when turning the OSC FREQUENCY > COARSE adjustment ? > > On time about 45 to 60 minutes > > The current scribbled on the door is 19, I'm running pretty much 30. When > making the adjustment the difference between the peak and any other > position > is only plus/minus a max of 2 or 3. > > 3 And i guess for last, are there any false modes that will turn off the > ALARM and turn on the Con't Operation light ? > > Thanks > > -pete > > PS Anyone have a side panel without the front handle broken ? > > _______________________________________________ > 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. > > > _______________________________________________ > 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. > _______________________________________________ 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.