Hi I didn't leave it on for very long. IIt would not surprise me if there's some drift that's occurred. It was last calibrated in 2006.
Bob On Mar 9, 2010, at 8:48 PM, paul swed wrote: > Bob how long has it been on > I think it needs to be stable like about 30 minutes > > On Tue, Mar 9, 2010 at 8:37 PM, Bob Camp <li...@rtty.us> wrote: > >> Hi >> >> Ok, the trigger level pots are bent but functional. The one that was stuck >> works after a bit of readjustment of the knob. >> >> All three inputs (ext arm, and the two channels) blink when I put the 10 >> MHz into them. The two with the working pots behave as expected as the pot >> is turned (trigger in the middle, no trigger on both ends). >> >> For what ever reason it seems to think that the period of it's 10 MHz >> standard is 99.5 ns. In frequency mode it thinks the standard is at 9.998xxx >> MHz. Obviously it's a little confused .... >> >> Sounds like it's worth working on, unless the 99.5 ns thing indicates some >> sort of massive failure. >> >> Bob >> >> >> On Mar 9, 2010, at 7:03 PM, Mark Sims wrote: >> >>> >>> I've had the "pleasure" of fixing way too many 5370A and 5370B front >> panels. It's been a while so these musings may be clouded... also beware >> of the two or three different front panel designs. Also there are "hybrid" >> 5370A's out there with 5370B front ends. >>> >>> There are 4 pots on the front panel: the 470K display update rate, a >> 10K or 200 ohm arming level (200 ohm on 5370B and later 5370A's), and two >> 5K trigger level. All are linear taper, all have switches, all are small >> pots with (1/4"? bushings). Finding pots with proper switches ain't easy. >>> >>> I have never had to do the trigger level pots. They have metal shafts >> and seldom break. Their switches are what you would expect (closed when the >> pot is turned clockwise). In the far CCW direction the switch is open and >> selects the 0V trigger level. >>> >>> The other two pots are an exceedingly crappy hp design. They have >> fragile plastic shafts and really poor quality switches. The switches need >> to be closed when the switch is counterclockwise. HP's pots have both >> normally open and normally closed contacts. Frankly these pots are seldom >> used and you can use a switchless pot and just hardwire those pads. >>> >>> The display rate pots is particularly useless. You can just hardwire it >> to max. >>> >>> The biggest bugaboo in buying a 5370 is the state of the HP custom input >> amplifier chips. They can be damaged by overloading the input. Blow one >> and you are screwed. Buy a 5370 with a blown input amp and you are screwed. >> The 5370A and 5370B used different chips. The 5345A counter is a source >> of input amp chips. >>> >>> It would be VERY nice if some clever person built drop in replacement >> "chips" built of modern SMD parts on a DIP header. Those input amp chips >> are socketed. They are little more than a comparator. >>> >>> Quick check of the 5370A inputs is to set the unit to "SEParate" inputs >> and connect the back panel 10 MHz ref signal to each of the inputs. The >> signal level LED should flash. A steady LED means that input is toast (or >> the input PCB slide switches are full of navel lint and need cleaning). >>> _________________________________________________________________ >>> Hotmail: Free, trusted and rich email service. >>> http://clk.atdmt.com/GBL/go/201469228/direct/01/ >>> _______________________________________________ >>> 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. > _______________________________________________ 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.
