OK Tom,

I'll work up a little word document today and post it with some photos.

Dave W6TE

-----Original Message-----
From: [email protected]
<[email protected]> On Behalf Of Tom B
Sent: Tuesday, July 30, 2019 9:40 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Need help with HP 441A
Power Meter not turning off (or sometimes not turning on)

Hi Dave,

If there is an easy way to take the front panel apart I would like hear about it. I have found it to be a real pain. Please send me your instructions.

Tom Bryan

Yes, Dave, Please provide that info, it would be of great interest!

Tom, I guess the fact that you were able to find a replacement panel means that you never found the actual cause of the switch failure, am I right? If they are metal contacts, I wonder how/why the voltage is coming back to the schmitt trigger but at a level which is just below the threshold voltage to toggle it...What would reduce that voltage, I wonder?

_._,_._,_

OK Tom,

I'll work up a little word document today and post it with some photos.

Dave W6TE

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Tom B
Sent: Tuesday, July 30, 2019 9:40 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Need help with HP 441A Power Meter not turning off (or sometimes not turning on)

Hi Dave,

If there is an easy way to take the front panel apart I would like hear about it. I have found it to be a real pain. Please send me your instructions.

Tom Bryan

Victor,

The front panel?€?s on those meters are very easy to take apart and
re-assemble. It only takes a few minutes. I do it almost every day as
I work on these meters. If you need a step by step directions let me
know and I would be happy to advise.

Dave W6TE

From: [email protected]
<[email protected]> On Behalf Of victor smith
Sent: Tuesday, July 30, 2019 9:30 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Need help with HP 441A
Power Meter not turning off (or sometimes not turning on)

Victor,

The front panel?€?s on those meters are very easy to take apart and
re-assemble. It only takes a few minutes. I do it almost every day as I
work on these meters. If you need a step by step directions let me know
and I would be happy to advise.

Dave W6TE

From: [email protected]
<[email protected]> On Behalf Of victor smith
Sent: Tuesday, July 30, 2019 9:30 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Need help with HP 441A Power
Meter not turning off (or sometimes not turning on)

?

Tom,

Thank you so much. You have confirmed what my own investigation led me to suspect. Long Story Short: I did take off the front panel (always fraught with ways that things can go wrong, I always think something is going to crack) and then managed to carefully remove the LCD Display subassembly, revealing a really hard to disassemble metal shield covering the switches. At that point I decided that rather than break a good power meter trying to repair the front panel, the better part of valor would be to put everything back together and start looking for a replacement front panel!

The good news is that I did manage to reassemble everything without damaging the delicate ribbon connectors, etc.

And now you have confirmed with your experience, thanks telling me about the irreparable switches! Now I don't feel so bad!

As far as that manual, (the E4418) The ones I see on the Keysight site do not have sub-assembly parts lists or schematics, just the final assembly parts. Is there a manual somewhere else with schematics?

I am now in the market for a 441A front panel, (or a 4418 panel), if any group members know of one!

In the meanwhile, I have a nice power meter that needs to be unplugged after use!

The battery seems to be fine, over three volts. And besides:

I made some progress on this thing. Knowing that I was looking for a logic
shift whenever the power button was pushed, I found the line on the front
panel connector that showed a state change whenever the button was pushed,
and after several minutes of probing around, discovered the Schmitt
Trigger IC on the main board that was toggled by that line. I am lucky,
because I have a second, working power meter of the same type. So I was
able to determine that the problem was that the "bad" unit is only
shifting the Schmitt input between 0 and 1.6-1.7 volts. A good unit shifts
between 0 and 4 volts. I can turn the unit on and off at will with a 1k
pull-up resistor applied to the Schmitt input pin. That tells me the main
board part is probably ok. So it looks like I will probably need to pull
the front panel off to investigate why the level coming back to the main
board is so low. Resistances all seem the same comparing good and bad
units, which is puzzling. But since I really am working blind, and there
are more than one power circuits (with separate ground/return paths), I
may just not be measuring at the right places. With the panel off, I can
try to trace the paths for that button and figure out if it's a bad
contact (I assume carbon rubber pad to circuit trace type, just based on
the feel of it) or some other issue. The cable and connector look OK.

Wish I had a schematic.....

Vic

I tried setting up a test for the diode using approximately a 3VDC source (a very weak 9V battery I happened to have on hand) with a 3.3K resistor in series between the anode and cathode (naturally, with the heater connected and sufficiently warmed up). I could not measure any voltage across the resister regardless of the polarity of the source voltage. I also tried it with the DVM in series with the resistor/voltage source and still could not detect anything even close to 1ma.
Thinking that was more-or-less conclusive of a bad tube, I tried this with a NIB EA53 (adjusting the heater voltage accordingly) and still could not see any significant current flow regardless of the polarity of the source voltage.
Unless _both_ tubes are bad (unlikely but I can test the EA53 in the working probe to verify that one), then I think this test setup is somehow invalid (although I don't see how with such a simple setup).
I'm not where I can get to my workshop for a while so can't report more findings until I get back there but thought I'd pass this along.
Thanks,
Barry - N4BUQ
----- Original Message -----

From: "Barry" <n4buq@...>
To: [email protected]
Sent: Saturday, July 27, 2019 8:15:28 PM
Subject: Re: [HP-Agilent-Keysight-equipment] Testing a 2-01C Diode

I plan to test it per the suggestions. It is possible, though, that I might
have damaged it feeding the 50-ohm terminated output of the 3310B directly
to the tube tip as I expect that would have produced more than 1mA unbridled
current from the generator. I did that before I read about the 1mA rating.

This poor probe, though, had multiple problems so the tube might have been
bad when I got it. I mentioned that the spring connector was falling out of
its slotted socket, but I also discovered that the cable's braid was not
connected to the sleeve of the plug so the heater couldn't work. I can't
tell if it was that way from the factory or whether someone did that
intentionally (and I can't figure why anyone would want to do that).
Connecting that let the heater start working but have not successfully
gotten a signal through the tube.

If the tube still checks bad, then I'll be looking for a replacement tube.

Thanks again,
Barry - N4BUQ

----- Original Message -----

From: "Chuck Harris" <cfharris@...>
To: [email protected]
Sent: Saturday, July 27, 2019 5:34:44 PM
Subject: Re: [HP-Agilent-Keysight-equipment] Testing a 2-01C Diode

Well, it is a detector, not a rectifier. A very special
detector in that it works from about a milivolt through
a kilovolt.

-Chuck Harris

n4buq wrote:

That's the way I thought of it. It's just a diode and should act like
one
if it's good. What gets me is the relatively tiny forward DC current
rating. For tube construction, that just seems odd - especially
considering it's rated at 1000V.

Thanks,
Barry - N4BUQ

Ditto for me regarding the 83712B sig gen.?Will check into the cal kit items, though.Jim Ford?Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: ¸é±ð²Ô¨¦±ð <k6fsb.1@...> Date: 7/28/19 6:09 PM (GMT-08:00) To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] [test-equip-trader] more TE purging
I would love a 4284a but out of my price range......I will continue
with my kluges.....
¸é±ð²Ô¨¦±ð

On 2019-07-28 10:24 a.m., Pete Manfre
wrote:











Not even any
offers¡­? not many builders/experimenters remaining
out there I guess.?








>
>
> Still have the following available¡­
all tested and working properly.? Pics on
request.
>
>
>? ? ?4284a? lcr(z) $1650.
Into storage trailer this week
>
>? ? ?4285a? lcr(z) $1650.
Into storage trailer this week
>
>? ? ?83712b. 20GHz sig. gen, $1800¡­
offers??
>
>? ? ?sold
>
>
>? ? ?sold
>
>? ? ?8720d 20GHz VNA. $6150¡­
offers ?
>
>? ? ?8562a 22GHz spec an, $1250¡­
into trailer this week
>
>? ? ?All tested and working fine. Once
into trailer¡­ next of kins' problem















>
>? ? ?Thanks for looking,
>? ? ?Pete wa2odo

Too bad! ?I wonder if there is a hidden menu or only settable over GPIB. Seems more likely a fault of some sort though.?

I have one of these so if it gets to the point of internal measurements I can help.?

Peter

On Jul 29, 2019, at 8:56 PM, victor smith <vcs3@...> wrote:

Peter, good idea! But no, I looked and don't see any mention of power on options in the configuration menus. That is how it acts, though, and these were used in an untended system rack type of situation, from what I have been told. But I just dont see any settings for anything involving turn-on or standby.

_._,_._,_

Peter, good idea! But no, I looked and don't see any mention of power on options in the configuration menus. That is how it acts, though, and these were used in an untended system rack type of situation, from what I have been told. But I just dont see any settings for anything involving turn-on or standby.