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HP3325 - no output, but sync works

Randy Newman All Messages By This Member #103538 New to the group, but have used HP gear for decades. I have a 3325 which appears to have an output attenuators issue. I can see the sync output on my Tek (555) scope, but do not see anything from the signal output connector. I have tried switching amplitudes, but do not hear any relay clicking (I had read some other post about the relays being audible). This unit was purchased years back as surplus, and had a red “not economical to repair” tag on it. I think I paid $25 for it. All the 7-segment displays work, and I can set for various frequencies, and see the sync....just no output, Any ideas appreciated!
Joe / KN5U All Messages By This Member #103540 Hi Randy, Welcome to the group! I assume that your unit is a 3325A, but both the A and B models are quite similar. Place your scope probe (high impedance) on the A16/A26 AMP OUT pin. If you have signal here, then the issue is in the attenuator board or output cables. If there is no signal at AMP OUT, then the fuse F3 on the A16/A26 amplifier board could be open. Since you are not hearing clicking of the relays, the problem could be a few other things: 1) Bad or missing ribbon cable between the attenuator board and the A26 amplifier board. 2) Missing relay power 3) Open relay coils (not likely that all coils are open) 3) Faulty logic from the A14 board that enables relay switching. Hope that helps! Let me know what you find and we can dig a little deeper.. Regards, Joe
Szabolcs Szigeti All Messages By This Member #103554 Hi, If you do not hear the relays clicking, first thing to check is the ribbon cable between the attenuator board and the A14 board. They are notoriously bad, to the level that on one of my 3325A I replaced the pin headers and the ribbon cables. The newer ones are ok, but the older version which somewhat looks like a flatflex cable, they are bad. If that is not the case, then on some versions there is a fuse on the power supply board, which fuses unregulated 15V power to the relays. it is quite easy to blow, if accidentally shorting the separate cable that is supplying it. Otherwise follow the service manual of the troubleshooting and follow the signal path. Szabolcs Randy Newman <randy.n.at.home@...> ezt írta (id?pont: 2020. márc. 1., V, 2:30): toggle quoted message Show quoted text New to the group, but have used HP gear for decades. I have a 3325 which appears to have an output attenuators issue. I can see the sync output on my Tek (555) scope, but do not see anything from the signal output connector. I have tried switching amplitudes, but do not hear any relay clicking (I had read some other post about the relays being audible). This unit was purchased years back as surplus, and had a red “not economical to repair” tag on it. I think I paid $25 for it. All the 7-segment displays work, and I can set for various frequencies, and see the sync....just no output, Any ideas appreciated!
Randy Newman All Messages By This Member #103562 Joe and Szabolcs: thanks for the ideas! I have not yet opened the box (after years...). Since this unit came from my employer, who has a metrology, and calibration group, I‘m betting on the bad cable, bad power, or fuse. Once I open it up ( hopefully in the next 2 months, I will post what I find out). My unit has the ovenized stall oscillator and the high voltage option. I’m hoping to use it as a calibration source.....just need to check it against a stable reference (I also have an HP 105A reference source). Thanks again!
Stephen Hanselman All Messages By This Member #103568 开云体育 Odds are the attenuators is shot. ?If it has the flat black aeromat relays you won’t hear them even if the work. They are latching type so checking the drive signal will only give you a plus. ? You probably will not want this but we have both replacement relays, for the aeromat’s and a replacement pca. ?If you’re interested shoot me an e-mail at s.hanselman at datagatesystems dot com Regards, ? Stephen Hanselman Datagate Systems, LLC toggle quoted message Show quoted text On Mar 1, 2020, at 08:30, Randy Newman <randy.n.at.home@...> wrote: ?New to the group, but have used HP gear for decades. I have a 3325 which appears to have an output attenuators issue. I can see the sync output on my Tek (555) scope, but do not see anything from the signal output connector. I have tried switching amplitudes, but do not hear any relay clicking (I had read some other post about the relays being audible). This unit was purchased years back as surplus, and had a red “not economical to repair” tag on it. I think I paid $25 for it. All the 7-segment displays work, and I can set for various frequencies, and see the sync....just no output, Any ideas appreciated!
nigel adams All Messages By This Member #103569 开云体育 Simple check is to take the cover off, locate the attenuator board and find the input cable. Put a scope on that and it should have a signal – this would prove the rest of the generator is functional. Regards ? Nigel Adams – Marconi Instruments Heritage Collection ? toggle quoted message Show quoted text From: [email protected] <[email protected]> On Behalf Of Stephen Hanselman Sent: 02 March 2020 11:31 To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] HP3325 - no output, but sync works ? Odds are the attenuators is shot. ?If it has the flat black aeromat relays you won’t hear them even if the work. They are latching type so checking the drive signal will only give you a plus. ? You probably will not want this but we have both replacement relays, for the aeromat’s and a replacement pca. ?If you’re interested shoot me an e-mail at s.hanselman at datagatesystems dot com Regards, ? Stephen Hanselman Datagate Systems, LLC ? ? On Mar 1, 2020, at 08:30, Randy Newman <randy.n.at.home@...> wrote: ?New to the group, but have used HP gear for decades. I have a 3325 which appears to have an output attenuators issue. I can see the sync output on my Tek (555) scope, but do not see anything from the signal output connector. I have tried switching amplitudes, but do not hear any relay clicking (I had read some other post about the relays being audible). This unit was purchased years back as surplus, and had a red “not economical to repair” tag on it. I think I paid $25 for it. All the 7-segment displays work, and I can set for various frequencies, and see the sync....just no output, Any ideas appreciated!
Michael A. Terrell All Messages By This Member #103612 Some of these use one of the relays for Front/Rear output. If the wrong output is selected, you have no output. I am looking into a small run of new A23 compatible boards, with modern surface mount relays and resistors. toggle quoted message Show quoted text On Sat, Feb 29, 2020 at 8:30 PM Randy Newman <randy.n.at.home@...> wrote: New to the group, but have used HP gear for decades. I have a 3325 which appears to have an output attenuators issue. I can see the sync output on my Tek (555) scope, but do not see anything from the signal output connector. I have tried switching amplitudes, but do not hear any relay clicking (I had read some other post about the relays being audible). This unit was purchased years back as surplus, and had a red “not economical to repair” tag on it. I think I paid $25 for it. All the 7-segment displays work, and I can set for various frequencies, and see the sync....just no output, Any ideas appreciated!
Stephen Hanselman All Messages By This Member #103649 开云体育 All ready have one using all surface mount 50 ohm stripline Form, Fit, Function 2-way interchange? Regards, ? Stephen Hanselman Datagate Systems, LLC toggle quoted message Show quoted text On Mar 5, 2020, at 02:13, Michael A. Terrell <terrell.michael.a@...> wrote: ? Some of these use one of the relays for Front/Rear output. If the wrong output is selected, you have no output. I am looking into a small run of new A23 compatible boards, with modern surface mount relays and resistors. On Sat, Feb 29, 2020 at 8:30 PM Randy Newman <randy.n.at.home@...> wrote: New to the group, but have used HP gear for decades. I have a 3325 which appears to have an output attenuators issue. I can see the sync output on my Tek (555) scope, but do not see anything from the signal output connector. I have tried switching amplitudes, but do not hear any relay clicking (I had read some other post about the relays being audible). This unit was purchased years back as surplus, and had a red “not economical to repair” tag on it. I think I paid $25 for it. All the 7-segment displays work, and I can set for various frequencies, and see the sync....just no output, Any ideas appreciated!

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