John, Thanks for the good advice. I definitely need to pull the front panel to replace the flakey BNC. After that, I'll do what I can with the A3/A4 adjustments. I just took another look at what I was doing last night and the two input channels do need adjusting. The B channel is worse.
I have a few other things that need to get done this weekend, so the 5370A will be on the bench for a little while. I'll get back to you after I get the inputs adjusted. Joe Gray KA5ZEC On Sat, Oct 10, 2009 at 6:07 PM, John Miles <jmi...@pop.net> wrote: > >> I plan on doing the A3/A4 adjustments. I just don't know where I'm >> going to get a pulse generator or the fancy scope with the 1GHz >> sampling plugin. Not the type of equipment on your average test bench. > > You won't need any exotic gear for the DAC voltage adjustments or the A3/A4 > input assembly adjustments, which is what comes first in the manual. As I > recall the scope is only used for symmetry adjustments in that section of > the manual, so the risetime is not all that important as long as it will > give you a stable trigger. > > You can skip the pulse-response adjustment unless you have reason to suspect > a specific problem. Watch for the pots that this step calls for, and don't > center them at the beginning of the alignment process when the manual tells > you to. As I recall there are various typos in the manual, so watch out for > that too. :) In general, the 5370 alignment instructions are crap by HP's > usual standards, so *be careful*. Read and understand everything before > doing anything. > > The A18 DAC adjustments should actually be done first IMHO. Don't worry if > the test limit voltages are not achievable -- they aren't, on any 'B' model > I've ever aligned -- as long as they are symmetrical. For example, +/- 1.9 > volts is OK, instead of the +/- 2.2 volts called for in some versions of the > manual. > > If you don't have an 8082A pulse generator and a fast scope, you will want > to stop there, and not mess with A19/A20. Likewise you probably do not need > to align the A21 multiplier (which is the only step that requires a spectrum > analyzer) if you don't have reason to suspect a problem with it. I believe > some people have found that the standard-deviation floor can be improved by > realigning A21 but I haven't done that myself. > > The instructions that call for a 1 GHz sampling scope don't actually need a > sampling scope; they can be followed with a Tek 2467-class scope as well. > But again, the front-end work should be doable with a good 100 MHz+ model, > and the rest should not be attempted without an 8082A pulse generator. > > The nasty thing about aligning a 5370 is the fact that the steps generally > begin with setting all the pots and trimmers to a fixed position, usually > midpoint. Ordinarily it's best not to disturb the alignment of a stage > that's already in tolerance, but they don't give you that option with the > 5370, and you may get pretty far before you discover that your test > equipment such as the pulse generator is not up to the task. When they call > for an 8082A in the A19/A20 section, they *mean* an 8082A, and you don't > want to get halfway into that procedure before you realize that. > > -- john, KE5FX > > > > > _______________________________________________ > 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.