HP 8340B Signal Generator
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- Опубліковано 5 вер 2024
- I've been looking to buy another 8673B but when this came up for auction I couldn't resist. The 8340B is a 10 MHz to 26.5 GHz sweeper that I intend to use along with my 8902A.
When it arrived it had some bad news on the tags so let's take a look.
Sometimes just packing up equipment and sending it thru a carrier to another location fixes problems. The carrier throwing around and dropping it during shipment helps.
Certainly, had that happen before - From memory I think the issue I ended up having with the 8340B was a failure of the memory constants and twiddling on the pots - I need to get it back on the bench to finish up. Thanks for watching.
Beautiful piece of kit. Thanks for sharing!
Thanks - I need to get back to the 8340 as the level isn't in spec but I first have to clear the bench :)
Thank you for your great videos.
Thanks - I'm actually going to do another one on adjusting this when I get back from vacation and can get the bench empty.
This was a good call. A 8673B is great but its range is limited to "high band" (2-26 GHz) Also depending on the serial #, you are left in the dust if you have to do certain adjustments. Ive been trying to find the 11726A data tapes for 7 years now. Even if I find it, theres a good chance the tape is degraded..... I have its big brother 8673D. This weighs worse than the 8340B. So much metal in it. The "low band" (10MHz-2Ghz) filters in the bottom portion make it weigh so much.
Thanks - I'm using this as the LO for my 8902A so that I can do 2-18 Ghz (I have the N type 11792A that only goes to 18 GHz) - I'm hoping to use the 8340, along with my 8657B, as my primary signal source.
Thank you for your explanations.
Glad you're enjoying the videos.
does this SG do two tone outputs for intermods analysis?
No, just one at a time - You'd need a second SigGen and an isolator to use this for intermodulation tests.
@@tgsoapbox Thanks! We're considering getting one, but we're evaluating how bad we want to measure the harmonics of active devices
@@RIVvideos they're great units, not as good phase noise as the 8663. They are somewhat challenging to get adjusted but once they are, they work really well. I use mine as my primary SigGen now with my 8673 as the LO for my 8902/11793 setup
I just bought a 8341B, can't wait for it to arrive and mess with the guts of the beast. Maybe I need some advice from an expert 😁
Wouldn't class myself as an expert but one piece of advice I can give you about these great units, is to get a 26GHz crystal detector, any leveling will require one as you try to adjust.
@@tgsoapbox I'll take your advice! For now only have a 8472B. The vendor said that the unit starts and shut down after a few. Sounds like psu overload...
@@rrb6544 Hmm could be - Do you have the PSU schematics? I found on one of my units (apologies, I can't remember which model) that the PSU would shut down if the fan doesn't run - Probably not the case here though.
I have seen a bunch of these units with the PSU scavenged from them so I suspect that you're on the right track with it being supply related.
@@tgsoapbox The unit arrived today.
I'm using my variac with 120 vac (the unit came from the States and I am in Spain). It's working for about four hours and don't make any noise, smell or weird thing related to the power supply, so I don't know why the seller said that.
The +20 volt rail is spot on since the variac reaches 90 vac, and the other rails are reasonably on specs (later I'll adjust the all eight rails). Fan runs ok, I was thinking my 8663A are loud... this sweeper sounds like a subway train :D (maybe because of running without all panels for inspection).
My first impressions in CW mode:
- frequency chopping is pretty accurate all over the four bands, checked with my 5342A and sharing the counter's 10 MHz reference.
- leveling is an absolute disaster all over the four bands, but looking better arround 0 dBm in the 2.3-7.0 GHz zone. The behavior of the entry display vs the power display (which is always loyal to the actual output) is very tricky to explain :D My unit is equiped with -90 dBm attenuator at the output, but I think it works properly… some loop jumps randomly taking down the level while the frequency varies… very weird behavior.
Sweep and modulations aren't tested because I haven't a SA or broadband mixer nor splitter for now.
You recommend maybe I should do like you, re-enter de cal constants, I found a paper like yours (dated may '85) inside the unit.
Update: I tried entering the cal constants and still the same behavior. Only have to change the value of constants 9, 10 and 11 (YTM gain) and 50, 51 and 52 (YTM BX gain). So I'm afraid I have to deal with leveling section troubleshooting...
At 21:46 there are some PCB-s on the right side of the picture. Do you know what is the name of those little colored clamps that are on the edge of the PCB-s? They always break and without them it is very hard to remove the panel. I hope there is someone on ebay who sells them by the hundreds..
I've never replaced a card ejector but there was a thread on the HPAK Group about them that might provide some ideas - groups.io/g/HP-Agilent-Keysight-equipment/topic/85087711#118274 - Let me know if you do find one that works or end up going the 3D printing route.
@@tgsoapbox Card ejector. That was what I was looking for. Thank you. Looking at what Mouser sells, I think it will be a CNC job, because 3D printing resin is not strong enough.
Good job I am working on a unit with a lock problem Thanks
Thanks - I've set the unit aside for the moment (work is intruding) but I'll get back to it soon I hope.
Am trying to repair my surplus 8340 unit, it is slightly butchered.
Wondering if you could look at 3 photos of my HP 8340 unit.. and tell me what parts I am missing.
How to contact you off line ??
Happy to help - Drop the images online somewhere (like imgur.com) and reply with the link to them. I'd like to keep the information available to everyone by using the comment system here if possible.
no good