Re: HP 6643A Mains Fuse Specs
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On Mon, Nov 13, 2023, 3:48 PM ±õ²õ³Ù±¹¨¢²Ô < erretrete@...> wrote:
Hello Michael,
looks to me it is "M" medium acting
fuse...
for the 200W model (654xA and 664xA) 5A
for the 500W model 12A...
- You need 5A Medium acting fuse
(without marking; there should be no
"F" or "T")
Istvan
2023. 11. 13. 22:31 keltez¨¦ssel,
Michael Yellin ¨ªrta:
Hello All,
I recently obtained two HP 6643A units, one working, and the other
not working.? I started to troubleshoot the broken one, my first
step was checking the Mains fuse, in the service manual known as
F450.? When I check the specs in the manual, it conflicts in some
places, as well as not providing all the needed information.
First, in two places, it states that the fuse should be a 12amp
fuse for 120 Volt operation, while in another place, it indicates
a 5amp fuse for 120 volt operation. (See below) The popped fuse I
removed was a 5amp fuse.? I then checked the working unit, and it
also had a 5 amp fuse.? Last, no where does it mention the
physical size of the fuse (I measured it at 32mm by 12mm or 1.25
in by .25 in.) nor does it mention whether it should be fast or
slow acting,
Can anyone provide any guidence?
TIA
Michael
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Re: HP 6643A Mains Fuse Specs
Hello Michael,
looks to me it is "M" medium acting
fuse...
for the 200W model (654xA and 664xA) 5A
for the 500W model 12A...
- You need 5A Medium acting fuse
(without marking; there should be no
"F" or "T")
Istvan
2023. 11. 13. 22:31 keltez¨¦ssel,
Michael Yellin ¨ªrta:
toggle quoted message
Show quoted text
Hello All,
I recently obtained two HP 6643A units, one working, and the other
not working.? I started to troubleshoot the broken one, my first
step was checking the Mains fuse, in the service manual known as
F450.? When I check the specs in the manual, it conflicts in some
places, as well as not providing all the needed information.
First, in two places, it states that the fuse should be a 12amp
fuse for 120 Volt operation, while in another place, it indicates
a 5amp fuse for 120 volt operation. (See below) The popped fuse I
removed was a 5amp fuse.? I then checked the working unit, and it
also had a 5 amp fuse.? Last, no where does it mention the
physical size of the fuse (I measured it at 32mm by 12mm or 1.25
in by .25 in.) nor does it mention whether it should be fast or
slow acting,
Can anyone provide any guidence?
TIA
Michael
  
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Reg, Very interesting. As I believe I was the ringleader of that debate, you may have also seen on EEVBlog I just?crossed on the (dark side!) of automated data logging. I'm using "xyphro"s?GPIBUSB?controller, and wrote a Python program to log this stuff into a file. It works great! I'm using my 8 1/2 digit Prema 6048 to harvest the readings, and the GPIB interface works with it without any trace of a hiccup.?
I've just executed 11 hrs of logs (overnight), amounting to 2000 data points?(each being a 20s integration of the Prema in VDC measurements, such that all those bunch of digits would be collected). Obviously, any aging study would need a completely different time scale than this.?
Pretty cool stuff, being able to do this. I've just got this working after months (arguably years!) of trying without much success.? Radu.?
On Mon, Nov 13, 2023 at 2:20?PM Reginald Beardsley via <pulaskite= [email protected]> wrote: This will be *very* interesting.? Grab your popcorn!
As it happens, I bought the 3458A specifically because of an EEVblog argument of many years standing about whether one could predict the aging rate of an individual device.? ?All I ever wanted was was ASCII digits I could analyze myself that were used to generate the plots.
So now I am building a 100 channel multiplexer for a 3458A to collect my own data.
Have Fun!
Reg
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This will be *very* interesting. Grab your popcorn!
As it happens, I bought the 3458A specifically because of an EEVblog argument of many years standing about whether one could predict the aging rate of an individual device. All I ever wanted was was ASCII digits I could analyze myself that were used to generate the plots.
So now I am building a 100 channel multiplexer for a 3458A to collect my own data.
Have Fun!
Reg
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HP 6643A Mains Fuse Specs
Hello All, I recently obtained two HP 6643A units, one working, and the other not working.? I started to troubleshoot the broken one, my first step was checking the Mains fuse, in the service manual known as F450.? When I check the specs in the manual, it conflicts in some places, as well as not providing all the needed information. First, in two places, it states that the fuse should be a 12amp fuse for 120 Volt operation, while in another place, it indicates a 5amp fuse for 120 volt operation. (See below) The popped fuse I removed was a 5amp fuse.? I then checked the working unit, and it also had a 5 amp fuse.? Last, no where does it mention the physical size of the fuse (I measured it at 32mm by 12mm or 1.25 in by .25 in.) nor does it mention whether it should be fast or slow acting, Can anyone provide any guidence? TIA Michael   
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Re: DIY 11667A Power Splitter, resistor placement?
On Sun, Nov 12, 2023 at 08:22 AM, Jared Cabot wrote:
it can't be that difficult' then soon realising I'm staring into the bottomless pit.
... and so this Iron Man isn't Tony Stark after all!? I knew YouTube and the Internet could deceive... I'm so disillusioned.?
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Re: Looking for HP alphanumeric display module 3 digits: 5082-7100 or 1990-0476
On Mon, Nov 13, 2023 at 06:53 PM, Stephen Hanselman wrote:
I think I have one of the 3 digit displays, I¡¯ll have to check
Thanks, Stephen. ATM, it seems RobertG8RPI has one available and he's in Europe, as I am, so I may be set. Raymond
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Congratuarions.
I may be having an off day, but I can't figure out what "acal" means.
DaveD
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On Nov 13, 2023, at 13:50, Reginald Beardsley via groups.io <pulaskite@...> wrote:
?In a fit of TEA syndrome I bought a "parts/repair" unit on ebay which does not acal. I know very little about the instrument and am having trouble getting a copy of the relevant manuals as Keysight's PDF downloads seem not to work.
A search for "acal 3458a" produced nothing useful.
Does anyone know of any repair logs covering the problem or alternate sources for the documentation?
I'm also in search of a bezel for the display.
Thanks,
Reg?
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The other good source of info on this is the EEVBlog community (Forums - Metrology in particular).? I believe there's a great deal of threads and posts on this?unit in particular - being such a ubiquitous and famous unit in the metrology world.? Radu.?
On Mon, Nov 13, 2023 at 10:55?AM Radu Bogdan Dicher via <vondicher= [email protected]> wrote: Reg, There's quite a lot of work, excellently documented, on xDevs:?. I'd probably start from there to familiarize with the instrument.? I think there's also a good number of documents for download on there related to it.? Hope this helps. Radu.?
On Mon, Nov 13, 2023 at 10:50?AM Reginald Beardsley via <pulaskite= [email protected]> wrote: In a fit of TEA syndrome I bought a "parts/repair" unit on ebay which does not acal.? I know very little about the instrument and am having trouble getting a copy of the relevant manuals as Keysight's PDF downloads seem not to work.
A search for "acal 3458a"? produced nothing useful.
Does anyone know of any repair logs covering the problem or alternate sources for the documentation?
I'm also in search of a? bezel for the display.
Thanks,
Reg?
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Reg, There's quite a lot of work, excellently documented, on xDevs:?. I'd probably start from there to familiarize with the instrument.? I think there's also a good number of documents for download on there related to it.? Hope this helps. Radu.?
On Mon, Nov 13, 2023 at 10:50?AM Reginald Beardsley via <pulaskite= [email protected]> wrote: In a fit of TEA syndrome I bought a "parts/repair" unit on ebay which does not acal.? I know very little about the instrument and am having trouble getting a copy of the relevant manuals as Keysight's PDF downloads seem not to work.
A search for "acal 3458a"? produced nothing useful.
Does anyone know of any repair logs covering the problem or alternate sources for the documentation?
I'm also in search of a? bezel for the display.
Thanks,
Reg?
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In a fit of TEA syndrome I bought a "parts/repair" unit on ebay which does not acal. I know very little about the instrument and am having trouble getting a copy of the relevant manuals as Keysight's PDF downloads seem not to work.
A search for "acal 3458a" produced nothing useful.
Does anyone know of any repair logs covering the problem or alternate sources for the documentation?
I'm also in search of a bezel for the display.
Thanks,
Reg?
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Re: Looking for HP alphanumeric display module 3 digits: 5082-7100 or 1990-0476
It was me, Robert, trying to contact you directly.
Raymond
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Re: Looking for HP alphanumeric display module 3 digits: 5082-7100 or 1990-0476
Robert,
?when I saw your picture I had to run to my shop to make sure I still had my collection. Your box is the same way I have mine down to the color and sections. Also the selection of LEDs.?
I think I have one of the 3 digit displays, I¡¯ll have to check
steve
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Re: Looking for HP alphanumeric display module 3 digits: 5082-7100 or 1990-0476
On Mon, Nov 13, 2023 at 05:43 PM, Robert G8RPI wrote:
Yes, I have quite a collection of displays :-). While not shown I have a second of the 3 digit displays. The are ex equipment but were socketed.
BTW, that *is* a nice bunch of led displays! I have one like the string with black bars above and below the leds. I really like these dot-displays and thought it was time to build something using them. Do you know in what equipment the 3-digit displays were used? The HP 9820A programmable desktop calculator seems to be a candidate. Raymond
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Re: Looking for HP alphanumeric display module 3 digits: 5082-7100 or 1990-0476
On Mon, Nov 13, 2023 at 05:43 PM, Robert G8RPI wrote:
Got it out and the good news is it is red and rows are common anode. So Positive to select row and 0V to select column.
Can't go wrong there, it seems! Just curious what the different model number is about. BTW, my HP 5300A Measuring System display unit employs a display like the 6-digit one in the top of your picture. So, how do we go about? I'd really like to have (at least!) one of the 3-digit modules, if you know they (all leds) are OK. How to proceed? Raymond
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Re: DIY 11667A Power Splitter, resistor placement?
I indicated in message #140182 the KISS and the desire to minimize the unavoidable and fun to deal?
with discontinuities that can result. I would construct this with 3.5 mm connectors and see how this
plays. The launch is void of most of the serious discontinuity and if the connectors are prepared by?
filing the pin down to the coax launch, should be a reasonable start. The construct of this assembly?
should take about 30 minutes if hardware is in hand.?
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Re: Looking for HP alphanumeric display module 3 digits: 5082-7100 or 1990-0476
On Mon, Nov 13, 2023 at 04:54 PM, Harvey White wrote:
If you want a 32 bit processor, you might want to check the ST Micro Nucleo boards.
Hi Harvey, For this not-so-ambitious project, two of my nanos (I have a box full of them) in concert works very nicely. In other, more ambitious projects I certainly will consider more powerful processors. Raymond
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Re: Looking for HP alphanumeric display module 3 digits: 5082-7100 or 1990-0476
On Mon, Nov 13, 2023 at 02:32 PM, Ed Marciniak wrote:
While some of the earlier and slower arduino boards had 5V TTL, it¡¯s worth looking at some of the newer boards that have hardware serial ports¡
Hi Ed, Thanks for the suggestion. I have a box full of nanos, costing only a few euros each and I like their simplicity. It works nicely with old 5V devices and the number of I/O's usually is quite sufficient. My vintage-led clock will not only be GPS-controlled but a multiprocessor system as well! I will really consider the newer models for more ambitious projects! Raymond
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