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Re: Analog vs Digital Oscilloscopes
¿ªÔÆÌåÓýPerhaps that may be due to the lack of reasonable international cost shipping options and the relative fragility of the instruments.? Peter On Jul 21, 2017, at 10:23 AM, 'Craig Sawyers' c.sawyers@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:
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Re: Help needed with HP Pin diode.
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Hi Henrik if you want a simple single wire ended
pin diode you might find something like the older 5082-3001 or 3002 might work
in that application. They are only specc'd down to 10MHz in my very old HP book
(Aug 1967 !!) but should work as a modulator down to 1MHz because you can use
normal HS diodes for that. The pins will be better at the high frequency
end.
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Alan
G3NYK
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Re: Analog vs Digital Oscilloscopes
¿ªÔÆÌåÓý7103/4's aren't that rare, see them all the time at fleas for $100-300 and usually with plugins.? I only have the R7103 as I wanted that form factor.? Peter On Jul 21, 2017, at 8:45 AM, Chuck Harris cfharris@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:
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Re: Analog vs Digital Oscilloscopes
Indeed, and that is the slow set of plates. Think
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vertical for the real speed. -Chuck Harris David DiGiacomo telists@... [hp_agilent_equipment] wrote: On Thu, Jul 20, 2017 at 6:17 PM, Daniel Koller kaboomdk@... |
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Re: Analog vs Digital Oscilloscopes
Hi Dan,
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I think there is a math error, but its only physics, so close is pretty good. That is why I said "The 7104... operates in this region". Imagine what would have come next if tektronix had made the next generation leap with the MCP. The horizontal sweep is not even close to the fastest thing the 7104 does with its beam... sweep is a pretty slow function for any scope... For example, the 7104 travels the beam about 8 divisions in 300ps in the vertical direction, while sweeping 200ps/division in the horizontal direction... the diagonal speed is pretty spritely. And, there is an OEM version of the 7104 that is 3x that fast. All these speeds are limited by the amplifiers, not the CRT... The CRT is about another 2x that fast. Additionally, just because an electron in the beam is launched, doesn't mean it gets multiplied in the MCP...its only those that happen to hit an active spot on the MCP's walls at just the right angle that get multiplied. Interesting to think about... don't you think? As to the question about speckle, yep, there is a grainy character to all of the cells that show on the screen. If you adjust the internal "MCP Output" pot, you can make the screen scintillate quite nicely. Go the other direction, and you can make the beam only show the very hottest electrons that went down the pipe, making the trace very grainy. If the 7104 wasn't so rare, it would make quite a nice little physics experiment. -Chuck Harris Daniel Koller kaboomdk@... [hp_agilent_equipment] wrote: Hi Chuck, Almost, but not quite. I don't know what the electron beam current of a |
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Re: LO port on HP 8591A
Hi Gerry
Option 010 is the tracking generator and the LO port is part of it. 8591A's with option 010 do appear from time to time, albeit at a price. A quick way of determining of option 010 is fitted is to look for the second N connector under the display. 73 George G6HIG ________________________________________ From: hp_agilent_equipment@... <hp_agilent_equipment@...> on behalf of gerrykav@... [hp_agilent_equipment] <hp_agilent_equipment@...> Sent: 21 July 2017 09:04 To: hp_agilent_equipment@... Subject: [hp_agilent_equipment] LO port on HP 8591A I am about to buy a HP 8591A SA for what seems like a good price, given availability of these units in Ireland (€400). However, it does not have the TG fitted, and when I look at the back, the LO port is blanked off. Is it usual that there is no LO port? There is no option listing this as a feature. I was planning to either build a TG myself or get a generic one, at least in the short-term. Can anyone illuminate? Thanks Gerry |
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Help needed with HP Pin diode.
?I have a Schlumberger 4002 signal generator, I need help with a pin diode in this unit. The pin diode is QPND 4709?(HP manuafacture), I can't find it anywhere, I am looking for this or a replacement for it, would like a non smd, since layout is for leaded axial type. I have no experience with pin diodes and need help. The pin diodes is used for AM modulation and level adjustment of the carrier, please see the schematic I attached.? Thank you. Rgds Henrik ? |
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LO port on HP 8591A
I am about to buy a HP 8591A SA for what seems like a good price, given availability of these units in Ireland (€400). However, it does not have the TG fitted, and when I look at the back, the LO port is blanked off. Is it usual that there is no LO port? There is no option listing this as a feature. I was planning to either build a TG myself or get a generic one, at least in the short-term.? Can anyone illuminate? Thanks Gerry |
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Re: 141T reference replacement..a cure??
Examination of the 8552A schematics suggests that the blown fuse is connected with +100V only indirectly, because it is the reference controlling the -12.6V regulator.? The +20V rail won't?go above nominal on +100 overvoltage, but there is a 24V/14V crowbar on the -12.6V rail.? The fact that this crowbar is explicitly designed to pass a -24V spike for a few milliseconds after power-on indicates that HP was aware of the gas tube ignition problem.? But if the spike goes on too long, the crowbar setpoint drops to -14V, and poof. |
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HP 3325a GPIB Stops Talking after 3 Minutes
My 3325a works perfectly from the front panel. However, when I attempt to control the instrument from gpib it will communicate for only 1-3 minutes and then fails, bringing down the gpib bus and jamming other instruments in the chain. HP service info admits 3325a gpib optos are a high failure rate item. I'm thinking of just gang replacing all of them. ? If not the optos, and I want to try out my never used HP Signature Analyzer, I need to know the firmware version of my unit. Where is that?? I downloaded May 84 pdf from Agilent. Signature analysis will be worthless if the signature diagrams in the May 84 manual are obsolete for my unit. Anyone in this group have a set of signature diagrams for various firmware versions of this instrument? Stan |
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Re: HP-3586B PS problem - connector J2 overheating
¿ªÔÆÌåÓýHi Guys, My recommendation is to sacrifice serviceability a little bit. Scrap the Molex females and solder wires directly to the pins. If two adjacent pins are being used to ¡°split¡± ?the same current then put a Wire Link between them? also. Molex connectors of that type are useless for carrying Power Supply current. I been through this problem in HP manufacturing years ago and would not allow that type of connectorization on the products I was responsible for. ? Regarding the comment about Knobs falling apart, The damage to the Knobs may have happened when they were New. We had this problem in the mid seventies. It was baffling at first but we found the problem. Around that time we started using a Rapid Expansion foam for packing the Instruments in their Cartons. That foam gave of some gases. I don¡¯t know what in particular. After the instruments had been in transit for maybe two weeks, the damage was done and the customer would complain the Knobs would fall apart as soon as they were turned. The cure was to pre-pack the Instruments in a metallic sealed bag which was impervious to the gas, before putting them in their cartons. Problem went away. And Yes I worked in a Microwave and Telecommunications Division. However, thirty years later, who knows what environment the instruments may have been exposed to. ? Good Luck ¨C Bill Lauchlan ? From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...]
Sent: Thursday, July 20, 2017 9:54 PM To: hp_agilent_equipment@... Subject: Re: [hp_agilent_equipment] HP-3586B PS problem - connector J2 overheating ? ? Glad to be able to help. |
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Re: HP-3586B PS problem - connector J2 overheating
Glad to be able to help.
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These units are complicated but quite repairable so I expect you could get both running. Peter On 7/20/2017 9:41 PM, jim@... [hp_agilent_equipment] wrote:
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Re: HP-3586B PS problem - connector J2 overheating
Thanks Peter,?
I am glad to hear that I'm not alone with regard to the connector overheating failure on the 3586s. When I first saw that both had overheated at roughly the same time and in the same place I suspected that it was probably the connector itself, but then thought that nothing could be that simple. Thanks for the repair suggestion. I will follow through with it. ?Reminded me of a batch of 80s ?HP microwave testing equipment I picked up as a lot for the parts. Practically all the knobs had crumbled and fallen off the units. How could the HP engineers know what would happen to certain components after 30 years.? I had no idea that the pins were spring loaded and would fail under excess heat. Replacement of the connector should not be too much of a problem.? Many thanks for the answer to my query. I was going to use the second one for parts, but now I see that there is a chance to get both running again.? Jim? |
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Re: HP-3586B PS problem - connector J2 overheating
Thanks George,?
That's a sensible recommendation and I will follow through with it. I received another reply suggesting the same thing from another group member who also had this problem with his 3586B. I did think about the possibility last year when I saw that both units were experiencing overheating on J2, but then thought nothing could be that simple. Hi.? How would HP know that their connectors would fail on this line of equipment 30 years later from ?overheating. It reminds me of the broken knobs on some HP microwave testers from the 80s that I acquired.. All those knobs seemed to just crumble and fall off after so many years. Nothing lives forever.? Thanks for the reply and suggestion.? Jim? |
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Re: 141T reference replacement..a cure??
My experiments scoping NE-2 ignition show that Dark-effect-reduced tubes like the ZZ1000 contain Krypton-85 to supply free electrons which facilitate firing in total darkness. These tubes age three ways.? First, the Kr-85 decays, with a half-life of about ten years.? Without it, the tube takes longer to fire when it's in the dark.? This lengthens the turn-on spike, and since it's rising all that time, it This effect can be counteracted by illuminating the tube.? Illumination which comes on when the supply is energized reduces the delay to a certain value which is still fairly large.? I don't know if it's enough. Full-time illumination reduces the delay to a small value.? This is inconvenient, because it requires wiring from the mains side of the power switch. That covers tubes that have failed only due to Kr-85 decay. The second aging symptom is a rise in firing voltage.? The mechanism is a change in gas composition and pressure as electrode evaporation traps gas.? It progresses whenever the tube is running.? Since delay increases fast as headroom shrinks, even an illuminated tube will eventually fail. The third aging symptom is a rise in operating voltage.? Someday it will go beyond adjustment range, but I believe that the firing voltage will become unacceptably high first. You can measure the firing voltage in-circuit with a scope.? If it's out of spec - above 115V - then shining light is a stopgap even if it initially works.? Just put in a TL431. |
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Re: HP-3586B PS problem - connector J2 overheating
I had this same problem.
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I ended up replacing the PCB connector first, just because I was worried about carbonization. When the cable connector pins overheat the springs inside lose temper and get worse. They will also need replacement as they will never work properly again. If you look carefully you can see how they can be removed from the housing. Only remove the good contacts, don't bother with the overheated ones, they need to be replaced. You can get all the parts from Digikey or Mouser. I paid a little extra and got gold plated pins, just to give me more confidence of a longer term fix. Peter On 7/20/2017 8:23 PM, jim@... [hp_agilent_equipment] wrote:
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Re: HP-3586B PS problem - connector J2 overheating
Hi Jim
These look like standard Molex connectors, whether .1" or .156" pitch I cannot tell from the images. These connectors rely on a single wiping face under spring pressure from themselves, when they get warm they fail, this appears to be what has occurred here, simply replace them. These connectors can be had on fleabay or via your favourite supplier. The really stupid thing is that the pins are frequently used in parallel to obtain a higher current ratting, this does not work long term as one pin invariably has a lower resistance and takes the lions share of the current and overheats. 73 George G6HIG ________________________________________ From: hp_agilent_equipment@... <hp_agilent_equipment@...> on behalf of jim@... [hp_agilent_equipment] <hp_agilent_equipment@...> Sent: 21 July 2017 00:23 To: hp_agilent_equipment@... Subject: [hp_agilent_equipment] HP-3586B PS problem - connector J2 overheating Gentlemen, I two HP-3586Bs that have gone down with essentially the same problem. One failed last year and the other one just yesterday. I attempted a year ago to clean both power supply boards of battery leakage as suggested by the group. One was worse than the other, but after using DeOxit with swabs, both boards looked OK. I could not visually find any actual damage to components or connections. Both evidenced severe connector heating on J2, pins 1.2.3 and 9,10. I am assuming this secondary cause brought them both down. You can view three of the connectors at: I've looked at the recommendations for troubleshooting in Service Group J, but this appears to go beyond those. It would appear that my cleaning job on the PS boards did not solve the problem. So where should I looks next before I investigate further. I most sincerely appreciate as usual the great expert assistance I always receive from this group when something HP is over my head. Many thanks, Jim W3BH |