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Date
Re: PCB mounting tabs for 5300/34740 series

 

Ah, TPU is an excellent suggestion. I was thinking "rigid but flexible", which doesn't put me in mind of TPU, but I would definitely try that.

-Dave

On 11/22/24 11:45, David Holland via groups.io wrote:
TPU may work as well.??? Either will need attention paid to the layer lines...
Sent via mobile annoyance thingy, please pardon any typos.
On Fri, Nov 22, 2024, 11:22?AM Dave McGuire via groups.io <> <mcguire@... <mailto:[email protected]>> wrote:
On 11/22/24 04:20, Joel Setton via groups.io <> wrote:
> I am refurbishing a few units in the 34740 DVM series, and I need to
> replace several PCB mounting tabs (pic attached). These were
damaged in
> shipment, and since they have to be flexible when mounting the
PCB, I
> think 3D-printed parts would break immediately. The part number is
> 05300-40003.
> Would anyone have a few spares ?
? ?Actually I believe with proper filament selection these might work
when 3D printed.? Try PETG; it may have sufficient flexibility.
? ? ? ? ? ? ?-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
--
Dave McGuire, AK4HZ
New Kensington, PA
Re: PCB mounting tabs for 5300/34740 series

 

TPU may work as well.??? Either will need attention paid to the layer lines...

Sent via mobile annoyance thingy, please pardon any typos.


On Fri, Nov 22, 2024, 11:22?AM Dave McGuire via <mcguire=[email protected]> wrote:
On 11/22/24 04:20, Joel Setton via wrote:
> I am refurbishing a few units in the 34740 DVM series, and I need to
> replace several PCB mounting tabs (pic attached). These were damaged in
> shipment, and since they have to be flexible when mounting the PCB, I
> think 3D-printed parts would break immediately. The part number is
> 05300-40003.
> Would anyone have a few spares ?

? ?Actually I believe with proper filament selection these might work
when 3D printed.? Try PETG; it may have sufficient flexibility.

? ? ? ? ? ? ?-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA
Re: PCB mounting tabs for 5300/34740 series

 

On 11/22/24 04:20, Joel Setton via groups.io wrote:
I am refurbishing a few units in the 34740 DVM series, and I need to replace several PCB mounting tabs (pic attached). These were damaged in shipment, and since they have to be flexible when mounting the PCB, I think 3D-printed parts would break immediately. The part number is 05300-40003.
Would anyone have a few spares ?
Actually I believe with proper filament selection these might work when 3D printed. Try PETG; it may have sufficient flexibility.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA
Re: Troubleshooting a 8591e with opt 130

 

Yves,
?
I had some spare time so started with some measurements myself.?
Checked the testpoints on top of the Log amplifier, TP1, TP3 and TP4.

TP1: Log mode: -6.22V / LIN mode : 14.25V

TP3: -9.315V

Tp4: -8.542V

?

The -9.3 on Tp3 seems on par with the schematics. The -8.5 on TP4 is supposed to be a temperature dependent voltage, could be ok, would say I expected it a bit lower.?

Tp1 is switched in the Lin/Log mode. Since it's depending on 3 Potentiometers i'm not too sure what's to be expected there.

?

Apart from that I did some more RF measurements/checks. I figured that the 300MHz -20dBm cal signal wasn't exactly -20dBm as i measured before. I wondered if any deviation would be observable when changing the cal signal level.?

I started in Factory default calibration.

Using the cal signal in, Measured: 300MHz-16.7dBm in log mode, -30.8dBm in Lin mode.

Did a full self cal.

Using the cal signal in, Measured: 300MHz -5.2dBm in log mode, -20.2 dBm in Lin mode, so both roughly 11dB increased, Lin at expected level.

?

300MHz cal signal measured to be -22.1 dBm with TinySA, used R19 on third converter to adjust to -19.8/-20.5dBm on TinySa. Roughly +2dB

Connected to 8591E measured as:

Using the cal signal in, Measured: 300MHz -3.3 dBm in log mode, -17.8 dBm in Lin mode, roughly 2 db gain as expected

Back to factory Cal:

Using the cal signal in, Measured: 300MHz -14.3dBm in log mode, -28.5 dBm in Lin mode, 2dB increase present again

Did a full self cal again:

Using the cal signal in, Measured: 300MHz -5.2dBm in log mode, -20.2dBm in Lin mode. Both roughly 9dB increased, Lin at expected level.?

So with a higher level Cal signal in the measured levels after cal are still the same.?

I was hoping to be able to draw some form of a conclusion whether it's too much gain in Log path or too little gain in Lin path that's being overcompensated during selfcal but i'm not sure I can.?

?

Marco
Re: HP8753E and HP8753ES display information FYI

 

Very interesting and useful. TNX.
F1EKU.
PCB mounting tabs for 5300/34740 series

 

Hello everyone,
?
I am refurbishing a few units in the 34740 DVM series, and I need to replace several PCB mounting tabs (pic attached). These were damaged in shipment, and since they have to be flexible when mounting the PCB, I think 3D-printed parts would break immediately. The part number is 05300-40003.
Would anyone have a few spares ?
?
Thanks !
Joel Setton

05300-40003.jpg

HP8753E and HP8753ES display information FYI

 

Hello All,
Just a short summary of information should anyone be interested:
?
1)? The HP8753E uses HP display part number 08720-60160 (meaning that the display was first used in the 8720D in my guess). The display is the Sharp LQ9D340.? It is nominally about 7.5 mm thick.? [8753E Display hold down is HP part number 08720-40012]
3)? The 8753ES display is HP part number 08753-60937. This display is the Sharp LQ084V1DG41.? It is nominally about 12 mm thick. ?[8753ES Display hold down is HP part number 08753-00150]
?
The displays have identical X,Y dimensions and the same electrical interface.? The advantages of the ES display include better contrast and a much easier to change backlighting tube (CCFL).? It is also about $20ish cheaper on the used display market. The backlight tubes are as follows:
1)? 8753E:? Straight tube - 140 mm x 2.2 mm diameter
2)? 8753ES:? L shaped tube.? Available here, on ebay, and probably elsewhere:? https://www.ccflwarehouse.com/185x140x2lcc.html
?
If you want to put the ES display into the E then you have to modify the display hold down to give yourself about 4 mm more thickness.? I did this by creating some new hooks on the display holder (out of aluminum bent to the correct shape) and physically removed the old hooks.? You also need longer screws for the opposite side.? If on the other hand you want to fit an E display into an ES, you simply need to put a spacer behind the LCD (again - roughly 4 mm).
?
Note:? The ES display is common to other instruments including (apparently) the R&S CMU 200.
?
For detailed specifications on the displays see:
??
?
?
My 2 cents on the dim display issues that many experience with these units:
1)? The LED conversion works, but is generally not required.
2)? In many cases, the mylar film gets hot and blackens and/or wraps around the CCLF lamp which decreases the brightness significantly.? On the ES display, it is pretty trivial to remove the lamp, remove the mylar, and replace this with some aluminum foil for your reflector.? Add some paper thin foam spacers if needed selectively to hold the aluminum foil in place around the lamp.? In many cases this is all it takes to go from poor brightness to good visibility.
?
As for the inverted display issue, it tends to always be the white display connector (PCB to display).? If you disassemble and reassemble this 2-3 times, it will wear off the corrosion and you should be good for at least 12 months.
?
Re: Troubleshooting a 8591e with opt 130

 

¿ªÔÆÌåÓý

Marco,

?

Indeed, removing option 130 removes a variable.

You will have to put jumper A14W1 back if you do this. But I don't know if it will change much, because the signals are not mixed, it is a multiplexer that chooses to take the signal coming from option 130, or that of the LIN/LOG output A14.

Option 130 has its own LIN/LOG amplifier with an IF of 8.56kHz instead of 21.4MHz.

?

If you vary the level of the external RF signal by 10dB jumps, if the jumps also appear by 10dB jumps on the 8591E screen (without changing the REF level), then the log amplifier curve is normal.

Now if the level is too high, there is an offset.

According to the tests, this offset only affects the LOG mode and not the LIN mode.

So, is this offset created by digital compensation (after ADC), or does it appear in the A14 module.

?

What I will do: there are test points, so I will measure them all in LIN and LOG mode from the calibrator @ -20dBm, and you can compare.

?

I have already repaired a log amplifier for an 8562A.

There were three defective potentiometers.

Adjusting all that was quite painful (several hours), but I managed it. The problem is that each adjustment affected all the other stages.

Here, all the stages are DC coupled except the first one.

?

Yves

?

De?: [email protected] <[email protected]> De la part de jansen.marco90 via groups.io
·¡²Ô±¹´Ç²â¨¦?: 21 novembre 2024 16:41
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] Troubleshooting a 8591e with opt 130

?

Yves,

?

Agreed, I won't touch any adjustment yet. Wouldn't surprise me though if a previous owner already did.?

Anyway it seems we are locking in on the issue thanks to all your help which is great. I hope we can fully tackle it.

?

Wouldn't it be easier to debug this without the opt130 installed to reduce the rf path?

?

Marco
Re: Any experts on Old HP Oscilloscope Probes Thick Bodies & Screw On Tips

 

Brian I realise this was written a while ago but I have the operating note on the 10035A probe tip kit and 7 part number 5060-0417 of the pincer-jaw tips (6-32) for those probes you listed if your still interested?
--
Jeffeelcr.
Re: HP 339A Distortion meter problem

 

I had an issue with my 339, where it would work in some switch positions but not others, and even depending on which direction the switches were moved (probably why I scored it so cheap!). I traced it to an alignment problem between switch wafers on the various boards, coupled with a small amount of backlash in the wafers. It was quite awkward to see, but once I knew what I was looking for I could clearly see that in some cases the quite thin moving switch contact was not quite connecting as it should.
Even more awkward to fix because of the nature of the construction - required a bit of mechanical twisting and turning, but the unit seems quite reliable now..
Don¡¯t know if this is your issue, but possibly worth a look.
Roman
Re: Troubleshooting a 8591e with opt 130

 

Yves,
?
Agreed, I won't touch any adjustment yet. Wouldn't surprise me though if a previous owner already did.?
Anyway it seems we are locking in on the issue thanks to all your help which is great. I hope we can fully tackle it.
?
Wouldn't it be easier to debug this without the opt130 installed to reduce the rf path?
?
Marco
Re: Troubleshooting a 8591e with opt 130

 

¿ªÔÆÌåÓý

Marco,

?

Obviously, it seems that it is the LOG section that is lacking, since the LIN mode works with the correct RF level.

It may be one of the gain controls in module A.

I will look at the behavior according to the level of the control signals.

But before touching an adjustment, it is necessary to have analyzed the circuit, because the alignment of a LOG amplifier is very complex.

?

It is necessary to check the gains of the stages according to the signals IFG4,5 and 6, VLOG12 and3 and finally VLIN and VLOG.

Maybe one of the potentiometers has a bad contact.

?

Yves

?

De?: [email protected] <[email protected]> De la part de jansen.marco90 via groups.io
·¡²Ô±¹´Ç²â¨¦?: 21 novembre 2024 03:01
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] Troubleshooting a 8591e with opt 130

?

So considering all the RBWs with the Log path are off, should I search for a fault in the A14 Log amplifier Assy? Or do you still think it's somewhere in the filters??

I could try to do the 7. Log and Linear Amplifier adjustments in the service manual.?

I could have that made, it will take some time though. Feels a bit overdone just to get a signal from a header too.?

?

One other remark, i'm assuming it doesn't matter but I had a look at the firmware version, my unit seems to be on rev 950914, the newest seems to be 991130, normally i'd say If it's not broken don't update it...

?

Marco
Re: Troubleshooting a 8591e with opt 130

 

Hey Gordon,
?
Thanks for the additional info! For now I'll keep trying to fix it with this firmware installed, I like the HP logo more anyway. ;)
?
Marco
Re: HP 8662A + 8663A Power Supply

 

My 8663 was a flea market "bargain" (well - not really) but it was repairable by replacing
the inverter transistors with BUX48 as well as a bunch of electrolytic capacitors
and some other components that looked "suspicous". The generator works but
I would gladly invest in the switch-mode power supplies pictured.
?
The generator also suffered from bad phase noise. So far I have removed and opened
almost all RF modules only to find one burned resistor in the modulator section.
The PN have been reduced by replacing the fan as well as improving its rubber mounts
using PC fan vibration dampers. It helped to some extent but since the specifications
exceeds those of any spectrum analyzer I own, I will not be able to verify the repairs.
?
A BOM of the new SMPS would be appreciated.
?
Ulf
SM6GXV
Re: Troubleshooting a 8591e with opt 130

 

HI Marco

?

I have two HP8591E spectrum analysers one has several options installed including opt 130 the other had no option installed. I found opt 130 and opt 004 on eBay I just copied the wiring from the other HP8591E with the 130 installed so it was easy it worked ok no problem and option 130 calibrated ok and works well. I also replaced the battery as well as updating the firmware. One of the 8591E had the battery on the main board the other must be a newer 8591E has the battery on a daughter board with the ram and a super cap so a lot easier to change. I don¡¯t think you will find the 991130 it only changes from HP to Agilent logo so I am told but I did update to 980615 it has some bug fixes.

?

Gordon GM1THS

Re: HP 8662A + 8663A Power Supply

 

Hi Dan
I would be interested in purchasing a set of spare boards. I am located in Australia zip 3095z.?
My unit 8663a has been working perfectly but the original power supply has taken out the switching power transistors again. Your solution sounds the most practical solution to this vulnerability.
Kind regards
Jon Cosgrove
Re: Troubleshooting a 8591e with opt 130

 

So considering all the RBWs with the Log path are off, should I search for a fault in the A14 Log amplifier Assy? Or do you still think it's somewhere in the filters??
I could try to do the 7. Log and Linear Amplifier adjustments in the service manual.?
I could have that made, it will take some time though. Feels a bit overdone just to get a signal from a header too.?
?
One other remark, i'm assuming it doesn't matter but I had a look at the firmware version, my unit seems to be on rev 950914, the newest seems to be 991130, normally i'd say If it's not broken don't update it...
?
Marco
Re: HP 339A Distortion meter problem

 

MG has some interesting alternatives, some even more expensive than the Deoxit offerings (!!). For instance, the 801B. I still rely mostly on the Deoxit, but in some?cases (high impedance?instrumentation?circuitry, low levels/metrology), I try to sort out the issues by just cleaning with IPA, if that works, or ponder?over a wider range of products depending on the application, which includes the MG range.
Radu.?

On Wed, Nov 20, 2024 at 3:12?PM Mark Moulding via <mark=[email protected]> wrote:
I was going to recommend De-Oxit as well - I haven't found any other cleaner that works as well, which seems to justify its higher-than-I-think-it-should-be price.? I usually use De-Oxit Gold, except for composition potentiometers, for which there is a special formulation: De-Oxit-F ("F" for fader).
Re: Connector identification

 

Hi Scott,
I think you solved the mystery. OSMT connector has the right shape and dimensions. ?
Ozan
?
?
On Wed, Nov 20, 2024 at 04:34 AM, Scott Vance wrote:

This was a tricky one.? I believe that it is an OSMT or SSMT connector made by Tyco.? See ? You will need to verify the exact dimensions.
?
In general, you can find a good listing of connectors at this page: ?? , but in this case this connector was not on the list.
Re: HP 339A Distortion meter problem

 

I was going to recommend De-Oxit as well - I haven't found any other cleaner that works as well, which seems to justify its higher-than-I-think-it-should-be price.? I usually use De-Oxit Gold, except for composition potentiometers, for which there is a special formulation: De-Oxit-F ("F" for fader).
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