开云体育

Re: 8516A cable question

Lothar baier #123184 开云体育 There is no schematic for the 8516 only a few block diagrams , the switching isn’t done by relays but rather with pin diodes inside the brick , the doubler control board is buttoned up on the Doubler , the only information to be gathered from the service manual is that there are 4 control lines that go to a PAL that acts as adress decoder , from there are 5 lines one goes to the doubler to switch it in and out the other 4 lines go to a block labeled filter control which outputs 5 lines that go to the actual doubler block so there is quite a bit of switching going on but there is no info on the switch points or details on the filters . Having a crossover cable definatly might be a concern but he also mentioned that it used to work “intermittent”? so that’s also something to think about ? ? Sent from for Windows ? toggle quoted message Show quoted text From: Bruce via groups.io Sent: Wednesday, March 2, 2022 6:48 PM To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question ? Sure but it is comparatively slow - Normal 8510C sweep is relatively? slow, and the problem can be avoided by only weeping 50-20 and say? 25-40GHz. I think the best first step is to look at the doubler switching module? to see if the relay is actually switching the doubler in.? I don't? seem to have a schematic diagram for the 8516, but hopefully, HP? included a LED on the module? In any case need to check the cable connections and determine whether? the doubler is being energized - actually, maybe just watching the +? supply to the doubler itself might work. Cheers! Bruce Quoting Lothar baier <Lothar@...>: > Disagree with you on this, dont forget that the synthesizer is swept? > so if you do a 45MHz to 40GHz sweep the doubler is switched in and? > out constantly so your DC now becomes a squarewave , also the? > control signal not only switches the doubler but also switches in? > and out filters to clean up the signal so there is some activity? > going on those control lines ! > One way to find out would be to tack a scope probe on the control? > lines and look at the shape of the control signals >> On Mar 2, 2022, at 18:30, Bruce via groups.io? >> <bruce@...> wrote: >> >> ?Missed that - the 20 ft cable seems NOT likely to be a problem -? >> these ar DC control signals.? I recall some discussion that it is a? >> straight through cable without cross over based on looking at 8341? >> and 8516 schematic diagrams - I think that I'd focus on? >> investigating the wiring of the cable. >> >> 1) Determine which conductors are used and be certain that the? >> cable has those conductors 1-1 without cross over. >> >> Cheers! >> >> Bruce >> >> Quoting Lothar baier <Lothar@...>: >> >>> He mentioned earlier in this thread that its only 20-40GHz but he? >>> also mentioned using a 20ft cable ? which could be the problem, I? >>> am not sure what the control interface is , the part number of the? >>> control cable says RS232 and there are 4 lines connected in the? >>> testset BUT the doubler control uses a PAL as a decoder so I think? >>> it’s a parallel interface and having a 20ft cable could be a bit? >>> much >>> >>> Sent from Mail<> for Windows >>> >>> From: Bruce via groups.io<mailto:bruce@...> >>> Sent: Wednesday, March 2, 2022 6:21 PM >>> To:? >>> [email protected]<mailto:[email protected]> >>> Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question >>> >>> Does the IF error occur below 20 GHz ??? If not, the doubler is >>> suspect - if so, look at the switching or the test set. >>> Nexg step would be to try and look at the test set VTO.? It is >>> difficult because they pipe it directly into the samplers. >>> >>> Cheers! >>> >>> Bruce >>> >>> Quoting ratn9ne@...: >>> >>>> Wow you guys are fast to help! >>>> Here is some more info: error is only from 20-40GHz, so it has >>>> something to do with the doubler I assume. Any span or frequency in >>>> this range has this error. I have seen >20GHz work for a little >>>> while but only randomly. My next idea is a shorter DB25 cable as >>>> mine is about 20 feet long. Tried turning up the LO power coming in >>>> on the sweeper with no luck. I can't find a replacement doubler on >>>> ebay to test with. These must be very rare. Can they be serviced? >>>> This display/sweeper/control box setup has been tested with an 8515 >>>> and no errors at all. >>>> >>>> >>>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >> >> >> >> >> >> >> >> > > > ?

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#123184

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