I think it has to warm up for about 30 minutes Seem to recall interpolators maybe not just seems like that
On Tue, Mar 9, 2010 at 8:37 PM, Bob Camp <[email protected]> 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 -- [email protected] > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
