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HP 10430A Probe compensation

 

Recently got an HP 54502A scope to play with and a set of HP 10430A probes. When compensating the probes the adjustment seems to make very little difference. As in almost none. However the probes seem to work fine and the leading edge of the square wave is good. I tried them on a Tek 465 scope with the same result.
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To see how crazy I was tried a pair of Tek 6106 probes on the HP 54502A and the compensation adjustment worked just as I expected which is to say made a definite difference and had to be set correctly for the square wave to display properly.
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I at first thought both HP probes were 'bad'; they are after all 'vintage'. But they seem to function. What am I missing here?
--
W0MPM John
Hp 8590 A

 

Good morning to the whole group. I am new ?I wanted to be part of this group, as an electronics enthusiast and owner of old HP equipment. Specifically, this is my first post, to ask you what you think of the list that my HP8509A, purchased used about 2 weeks ago, gives me, when in the calibration section, I request the cal data. Following the instructions in the service manual and based on other lists seen online, of other 8590, I have the feeling that something is not entirely ok. I attach a photo of the screen. I am grateful to anyone who can provide me with opinions on the matter. Best regards. Carlo.
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IMG_20250419_035119.jpg

Re: HP 8590 A

 

On Sun, 20 Apr 2025 at 05:34, ik1gkh via <ik1gkh=[email protected]> wrote:
Good morning to the whole group. I am new here...and I wanted to be part of this group, as an electronics enthusiast and owner of old HP equipment. Specifically, this is my first post, to ask you what you think of the list that my HP8509A,

I don't know how big your attachment was, but it's too large for whatever settings I have. I suggest you reduce the resolution or run it through some software to make it a more manageable size.?
Re: HP 8590 A

 

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Hi Carlo,

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you would need more details on what you think seems abnormal, more pictures would be helpful.

It is difficult to know from the calibration constants table alone if you have a problem with your 8590A.

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However, I notice that some correction values ??for the input attenuator are high, there is probably a problem, but it would be necessary to check it to be sure.

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So, if you have noticed that there is frequency drift, this is normal, if the Spectrum respects the specification here.

For a hp8590A, frequency precision is ¡À5.1MHz.

Frequency stability, after 2 hours warmup and 5 min after setting center frequency, is about 50kHz/5min.

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Yves

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CAL DATA EXPLANATION.PNG
CAL DATA 8590A.jpg

Re: HP 8590 A

 

Hi and welcome aboard!
For some reason your post hasn't come out properly. I'd suggest re-posting it plus another photo of your wider set-up and not just a section of the screen.
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Jinxie
Re: KO4BB manuals site error

 

No problem in Bulgaria.

On Mon, Apr 21, 2025 at 1:46?PM JLJ via <jlj=[email protected]> wrote:
Wrong there is a problem sorry.
Re: KO4BB manuals site error

 

Wrong there is a problem sorry.
Re: KO4BB manuals site error

 

No problems in DK
Unterminated 'TEST' ports

 

Hi all,
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I note HP have thoughtfully provided an SMB 'TEST' nipple for the RF sampler section of the analyzer I'm currently working on (HP8754A). However, I'd kind of expected to see a 50 ohm termination in situ there to prevent internal reflections from messing things up. But there is none; just the bare nipple. The manual states I should expect to see a 3Vp-p signal at this port if that makes any difference. Should it be terminated with 50 ohms when not plugged into for testing purposes?
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Thanks,
J.
Re: HP853A+8559A spectrum analyzer.

 

Hey guys,
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Sorry the first one was awful I did it quickly without thinking about it. It's only about the plug-in side power supply for now, I haven't started the display yet.?
The Agilent scan is awful as expected but the schematics survived. The parts list is barely useable, I may invest in Artek scans just for this.
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I've performed the measurements with both the plug-in installed and out, and with and without the enable pin (T3 "EN", base of Q6) manualy grounded aswell.?
So far only the plug-in out and T3 (Q6 base) manually grounded configuration will give me 100V at T4, otherwise it's more or less 12V all the time.?
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Transistor is NPN. I've tested it again, this time with the power supply and it's switching with no problems up to 50V and with more than the fuse current. So probably good. I'll put it back together tomorrow, and do some more probing. I may have been too tired.
The fuse and series resistor for the LED are 100% bad though.?
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Re: HP853A+8559A spectrum analyzer.

 

In case anyone is wondering what the 1854-0232 (selected from 2N3440) is, a 2N3440 is normally rated with BCVE of 250V, the fiche gives an increased BVCE of 300V, HFE can have a wider range too.
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Odd they didn't just use the 2N3439 with BVCE of 350V.
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The "selected 2N3440" comment was from the ancestor to this SA, the 8552A plug-in for the 140/1 series, the 8552 manual doesn't give the "A" suffix, that is an error somewhere from me.
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David
Re: HP853A+8559A spectrum analyzer.

 

I'm getting confused which one is still faulty, or are both still faulty?
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Looking at the barely readable pdf, these are the transistors for the two power supplies;
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A3 Display power supply, output +158V
Q1 = 1854-0311 NPN 2N4240
Q2, Q4, Q5 = 1854-0232 NPN (selected 2N3440A)
Q3 = 1853-0221 PNP 2N5416
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A8 Plug-in power supply, output +100V
Q1, Q2, Q3, Q6 = 1854-0232 NPN (selected 2N3440A)
Q4 = 1854-0311 NPN 2N4240
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David
Re: HP853A+8559A spectrum analyzer.

 

I don¡¯t have the circuitry in front of me. If your voltages are all positive, and if the pass transistor is PNP, then it should be conducting and pulling the collector voltage down to the 158V you indicated, so my impression is that the pass transistor is open E-C., it could also be something in the E path that is open, not allowing it to sink current.
Anything on the B that is + 0.6 V above E should cause E-C to conduct.

Don Bitters
Re: HP853A+8559A spectrum analyzer.

 

AArnaud,
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Could you clarify if you are performing your measurements with or without plug-in installed?? The 100V rail is enabled by the connecting the plug-in.? Q6 is turned on when the plug-in is removed, which gives the unregulated 200V a path to ground through R2 and R20, thus sinking current away from Q2.? Q2 drives Q4.? So if the plug-in is not installed, it sounds like Q4 is working as it should.? You could ground the base of Q6 if you want to work on the supply without a plug-in installed.? That should enable the 100V rail.??
Re: KO4BB manuals site error

 

?
... It seems that KO4BB again has run out of disk space.
Tried downloading ROM-images for the 70004A.
The site returned an error message, "Unable to create"...
some temorary space...
?
Ulf
SM6GXV
Re: HP3585B Option 001 Firmware

 

Hello everyone,
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It's been more than a year now.
So I would like to ask again if anyone has this software?
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A82U11 03585-60336
A82U12 03585-60337
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Many greetings Rico
HP 8590 A

  

Good morning to the whole group. I am new here...and I wanted to be part of this group, as an electronics enthusiast and owner of old HP equipment. Specifically, this is my first post, to ask you what you think of the list that my HP8509A, purchased used about 2 weeks ago, gives me, when in the calibration section, I request the cal data. Following the instructions in the service manual and based on other lists seen online, of other 8590, I have the feeling that something is not entirely ok. I attach a photo of the screen. I am grateful to anyone who can provide me with opinions on the matter. Best regards. Carlo.



















				
				
				
			

			
				

				

					
						
	
		
			
				
			
		
		

			
				
			
			
			

				
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							Re: HP853A+8559A spectrum analyzer.
							
						
					

				

				

			
			

				

					


						
							

								
								
							

						
					

					

						
							


						
						 
						
							
							
						
						
					

				

			

			

			

				
It's getting harder for me to understand. It's also getting late. Also maybe the pass transistor is dead.

First, F3 fuse was blown. I did not pick this up immediately, I should have. Shorting the fuse with the multimeter i'm seeing a 6mA draw and still no 100V output.


I'm kinda bad on transistor theory. I'm seeing the 200V on the collector of Q4, something like 13V on the base and 12V on the emitter. To me it sounds like Q4 is bad.?


What do you guys think?

				
				
				
			

			
			

	

	
			

			

				
					

				
				
			

			

				

					

				

			

			
			
			

			


				
	



		
			
		
			
				
	
		
	

		
			

			
			

			
			
				
				

					

						
							
							

							Re: HP853A+8559A spectrum analyzer.
							
						
					

				

				

			
			

				

					


						
							

								
								
							

						
					

					

						
							


						
						 
						
							
							
						
						
					

				

			

			

			

				
R9, the series resistor for the 100V LED, has failed. This explains the lack of LED.

				
				
				
			

			
			

	

	
			

			

				
					

				
				
			

			

				

					

				

			

			
			
			

			


				
	



		
			
		
			
				
	
		
	

		
			

			
			

			
			
				
				

					

						
							
							

							Re: HP853A+8559A spectrum analyzer.
							
						
					

				

				

			
			

				

					


						
							

								
								
							

						
					

					

						
							


						
						 
						
							
							
						
						
					

				

			

			

			

				
Hey Don,


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I suppose you meant the pass transistor for the 100V plug-in supply as the 158V is display side.


Good point about the associated components creating a spurious voltage, didn't think of that.


I've taken the Motorola 2N4240 pass transistor out and it reads good on the multimeter and on the chinese component tester.?


I'm checking the rest of the circuit. I've digged the groups.io and people have reported just about every possible component can fail.?


We'll see what I find.


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Arnaud.


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