Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- HP-Agilent-Keysight-Equipment
- Messages
Search
|
HP 1725A oscilloscope, first displayed cycle is weird
Dear all,
I've continued to work on the 1725A and most recently replaced 32 capacitors (mostly tantalum, one electrolytic and one tubular ceramic that looked weird) on the three boards for main and delayed sweep, and the vertical preamp board. The sweep triggering works quite well now. The scope has one remaining glitch: using my HP 3325A as a signal source, when a square wave signal is displayed with a frequency of around 7 MHz or more, the top of the first pulse is irregular (with slightly wavy ups and downs in the signal) compared to the following pulses. Similarly, when a sine wave is displayed, the first pulse looks slightly irregular compared to the others. When I press the 20 MHz bandwidth button, the signal clears up. Of course the square wave then looks more curved, more like a sine than a square. Is this indicative of a fault in the vertical section or the horizontal sweep? I know that the vertical output has adjustments for frequency response, but wouldn't those adjustments affect all displayed pulses, not just the first? Thanks for your comments. Patrick Wong AK6C |
|
Re: Want to buy: HP 3325A attenuator board
Hi Dickson,
toggle quoted message
Show quoted text
The Omron low signal relay that I used to replace the original Aromat relay in the div by 100 position has a manufacturer PN of G6AK-274P-ST-US-DC12 and at Mouser Electronics is priced at $5.43 plus shipping. The new relay is rectangular. I positioned it to minimize the lead length from the relay to the PCB holes that lead to the input RCA jack and to the next relay. I suggest you measure the resistance between the positive voltage wiring harness connectors (pins 1 and 2) and ground. If you do not measure this to be rising to infinity as the capacitors charge up, then you'll know that at least one of the 14 0.1 uF 50V capacitors is bad. A 51 ohm resistor (R1) on the board was missing so I replaced that with a 51 ohm 1W Xicon carbon film resistor. The board has a copper layer serving as a ground plane, and that is a very good heatsink so my 25W soldering pencil did not produce sufficient heat to properly solder the end of the resistor connected to ground. I had to get out my 100W soldering gun to solder that one connection. Using my oscilloscope to monitor RF voltage output and switching between the various functions, I have noticed that *occasionally* the voltage is less than it should be, for example, 2V p-p instead of 3V p-p. I don't think this is a relay problem since the voltage difference is too small to be caused by a relay. Good luck and 73. Patrick Wong AK6C --- In hp_agilent_equipment@..., "Dickson" <dicksonfuhk@...> wrote:
|
|
WTB : HP8591C Parts also used on 8590L, 8591E
Hi all,
I've got an 8591C here that is missing some parts. Agilent does have stock, but their prices are way out of my budget. 0955-1005 UTG Impedance Matching Pad (75-50 ohm) It's also used on the following models with 75 ohm input 8590L 8591E E4900B 85128A The associated solid coax line is also missing, plus the 75ohm cal out too. Thanks, - Guy. |
|
HP 182 display issue
Hi all,
I have a 182T with CRT horizontal scan failure, I haven't done any troubleshooting yet but according to the schematics I suspect 1853-0038 output transistors failure. I have search for a replacement in Sphere catalogues but with no luck, any suggestions? Thanks, Konstantinos |
|
looking to buy
Greetings,
Thanks for the bandwidth! I'm looking for a fully functional and modestly priced HP-34703A DCV/DCA/Ohm meter "section". Of course, I'll gladly consider a complete unit comprised of either an HP-34740A or HP-34750A and the HP-34703A (DVM section). Your welcome, and encouraged, to reply to me outside of the group at: kpchalfant@... My preferred method of payment would be through Pay Pal. Thanks for your consideration. Regards, Ken |
|
Re: 3324A VS 3325A?
Hi all,
toggle quoted message
Show quoted text
Really strange. I feel like HP made the 3324A later than 3325A. I saw the pictures of 3324A that having a dot matrix VFD display and new "HP logo", so 3324A seems to be a generator later than 3325A. Regards, Dickson Fu VR2WHF --- In hp_agilent_equipment@..., "mrcschrdrs" <mrcschrdrs@...> wrote:
|
|
Re: Want to buy: HP 3325A attenuator board
Hi all,
toggle quoted message
Show quoted text
My 3325A has the attenuator board marked as "03325-66523 Rev B" which uses 4 yellow "PRINTACT" Latching Relay (12 BW4LD). I think Patrick's attenuator board is the newer "03325-66523 Rev C" which used the relay made by Aromat (Japan). I think Aromat is being merged with the Japanese giant Panasonic. It seems to me "Rev C" is a cost down version because it is not longer having the gold plated PCB. Regards, Dickson Fu VR2WHF P.S. Really wanted to know the model number of the Omron relay used to replace the original Amron relay. --- In hp_agilent_equipment@..., "mrcschrdrs" <mrcschrdrs@...> wrote:
|
|
Re: OT ac outlet socket / done
Jerry Massengale
Hi,
toggle quoted message
Show quoted text
I have 2 sockets coming, Thanks to all. jerry -----Original Message-----
From: David <dgminala@...> To: hp_agilent_equipment <hp_agilent_equipment@...> Sent: Sat, Aug 27, 2011 8:22 am Subject: [hp_agilent_equipment] Re: OT ac outlet socket Heathkit IP-5220 Variac --- In hp_agilent_equipment@..., Jerry Massengale <jmassen418a@...> wrote: Perhaps one of these connectors will be what you need. From www.mouser.com, catalog numbers 693-4300.0701, 693-4300.0702 or 693-4300.0703 Cheers, Dave M [Non-text portions of this message have been removed] |
|
HP-8640B all-zeros flashing display
Jose V. Gavila
Hi all,
My trusty HP-8640B (the first unit I got years ago) has suddenly stopped working :-(. I used it last time yesterday night and worked fine but today, upon powering it up, it shows an all-zeros blinking display and does not generate any output at any frequency nor setting. Any hint of what is happening? (BTW it is NOT a pushed-in LOCK button problem) Thanks for your help! Regards, JOSE -- 73 EB5AGV - JOSE V. GAVILA - IM99sm La Canyada - Valencia(SPAIN) Radio and Test Equipment....... RadioRepair BLOG............... |
|
Re: OT ac outlet socket Heathkit IP-5220 Variac
--- In hp_agilent_equipment@..., Jerry Massengale <jmassen418a@...> wrote:
Perhaps one of these connectors will be what you need. From www.mouser.com, catalog numbers 693-4300.0701, 693-4300.0702 or 693-4300.0703 Cheers, Dave M |
|
Re: OT ac outlet socket Heathkit IP-5220 Variac
Leviton 1374-1 is the socket - had ne go bad in a power strip. Fits a .95" x .95" square hole. Add a -W if you want it in white. 5 bucks max at most industrial suppliers.
toggle quoted message
Show quoted text
Cheers, -B --- In hp_agilent_equipment@..., Jerry Massengale <jmassen418a@...> wrote:
|
|
Re: HP 85662A Power supply issue help needed
mrcschrdrs
Hallo Guy,
we are talking about the IF section PowerSupply (85662A) yes? I concur with Jose, and can add that the +15V is the one you should concentrate on, because this is used as reference for -15V and 100V Besides the foldback current limit there is also a thermal shutdown circuit influencing the 15V supply. Marc |
|
Re: HP 85662A Power supply issue help needed
Jose V. Gavila
Hello Guy,
I know this is a very general message but I think it may help you... those HP multi-voltage supplies usually have one of them as a reference. If it is bad, all of them will show wrong voltages. I am guessing the reference may be the 100V one (if I recall it right, on HP-141 series it was that way, but of course they are ages appart) Have you followed the Service Manual PS troubleshooting section?. For sure it will be clear there which one is the reference PS. If I have some time later, I will check the 85662 Service Manual but now I am in a hurry and must leave, so sorry for this so-generic message. Good luck! JOSE At 10:31 27/08/2011, you wrote: Hello group , I own an Hp8566B SA which went in-- 73 EB5AGV - JOSE V. GAVILA - IM99sm La Canyada - Valencia(SPAIN) Radio and Test Equipment....... RadioRepair BLOG............... |
|
HP 85662A Power supply issue help needed
Hello group , I own an Hp8566B SA which went in trouble suddenly ,the display disappear and the instrument LED N¡ã1 still lit, I have checked all the cables as state in the manual, and no results,I have open the display unit and checked the Power supply 100V is now 60 volts and the -15V & +15V shows around 12V and -12V respectively, what seems strange is that I see a very high ripple at the output regulated and nearly nothing like ripple at the input unregulated. I cannot adjust the voltage ,and I have checked the intensity to see if the foldback section is not in action the intensity is around 0.8A so no over current there.
The component of the power supply have been changed as the pass transistor ,I have checked the capacitors elko , ervery thing is good , checked also the esr, any help will be very kind I have posted photographs of my measurements in the photos Cheers ON1EV Guy |
|
Re: Which HP spectrum analzyer is structurally most similar to that of HP 8565A?
Amos Ku
Tim,
I do not have choice. The prices to get a good working SA is outrageous for my limited budget. I have been very glad I can afford to buy a broken SA. I only wish to restore at least one of the broken HP8565As first. Then, I wish to get the display digitized so that I can get rid of the CRT and that I can capture what has been measured and displayed on screen. No matter what I will invest, I believe will be a lot cheaper to get a working SA. Thank you for giving the tips about EMC. Actually, I have bought that book very recently for my current job as an electronic design engineer at a R&D company. I just measured the display dimensions. It is a 5" display. Should be easy to find a replacement, provided that I will need to design the circuits behind the LCD module first. There sure to be problems when I start working with this project. I am not denying the fact that there are always problems for some project no one has ever attempted or done. But I will not be getting anywhere if I only talk about my plans and worry about all of the possible problems but do nothing about them. Setting a high goal may not guarantee success but will land me at a higher ground than where I currently am. I do not have much expectation about the performance of this HP 8565A because it is already old and has been beaten up. Currently, I just need some tools for me to work on some RF projects at home. If I have to get accurate results, I will then bring my projects to test with those modern test SAs at my company. So, accuracy or stabilization may not so important for me. Amos ________________________________ From: mai1grp8s <mai1grp8s@...> To: hp_agilent_equipment@... Sent: Saturday, August 27, 2011 12:01 AM Subject: Re: [hp_agilent_equipment] Which HP spectrum analzyer is structurally most similar to that of HP 8565A? ? Yep - might have to read up on the EMC - have a google for Henry Ott. Be careful you don't over invest in the SA. They are good but the YTO drift will still be there. If your tube is really suffed you can always use the signals on the back for your CRO or pc sound card. A good pro stereo sound card with 24bit digitising would do a good job. Software required. One thin that could be worth investigating is auto stabiliser circuit. It locks to the 2000th harmonics of a 1MHz VCXO - changing this could be intresting. Yes those lcd panels are too expensive - cheaper than a new 8566b. They hook into the video display and read the vectors into a raster. The 8565a is a fully analog SA with a bit if digital to control sweep and display parameters. Tim [Non-text portions of this message have been removed] |
|
Re: Which HP spectrum analzyer is structurally most similar to that of HP 8565A?
Yep - might have to read up on the EMC - have a google for Henry Ott. Be careful you don't over invest in the SA. They are good but the YTO drift will still be there. If your tube is really suffed you can always use the signals on the back for your CRO or pc sound card. A good pro stereo sound card with 24bit digitising would do a good job. Software required.
One thin that could be worth investigating is auto stabiliser circuit. It locks to the 2000th harmonics of a 1MHz VCXO - changing this could be intresting. Yes those lcd panels are too expensive - cheaper than a new 8566b. They hook into the video display and read the vectors into a raster. The 8565a is a fully analog SA with a bit if digital to control sweep and display parameters. Tim |
|
Re: Which HP spectrum analzyer is structurally most similar to that of HP 8565A?
Amos Ku
Don't have room outside.
Best Regards, Amos Ku On Aug 26, 2011, at 9:52 PM, Jim Cotton <n8qoh@...> wrote:
[Non-text portions of this message have been removed] |
|
Re: Which HP spectrum analzyer is structurally most similar to that of HP 8565A?
The real fun is keeping all the digital stuff that you add OUT of the existing analog?
system... Jim Cotton n8qoh ________________________________ From: Amos Ku <amosku@...> To: "hp_agilent_equipment@..." <hp_agilent_equipment@...> Sent: Friday, August 26, 2011 2:41 PM Subject: Re: [hp_agilent_equipment] Which HP spectrum analzyer is structurally most similar to that of HP 8565A? ? Tim, This email is to respond to your earlier email about having some VGA kit to replace the CRT. I have an idea. Since all the display section does is to take the signal to be display (y-axis) and sweep the screen with sweep signal (x-axis), I can make up a digitized circuit that does the same thing as what CRT will do and connect the output to a LCD module that fits right into the window of HP 8565A, I can have a cheap solution for replacement of CRT tube circuit. My idea came from here: . About the normalizer part. I am thinking about build up something based on the same design of normalizer in SMD and place the circuits inside the large cavity where CRT is in. I can then have all the functions I need in the same box. I am thinking about changing the weird AUX connectors to some easy to get connectors from Digikey (same pin numbers, same dimensions.) Amos [Non-text portions of this message have been removed] |
to navigate to use esc to dismiss