I've picked up a handful of Fluke 8050A's over the last few weeks. I picked up the top three for $70 shipped. At least two of them have good batteries, but I haven't had a chance to examine them beyond that. Something about cleaning up and refurbishing old gear like this makes me really happy. I've also been blown away at just how in-spec these meters seem to be decades after they were last calibrated.
I was particularly surprised at how clear and readable the LCD is on the third meter up from the bottom. I'm guessing it's a much newer replacement.
That's a nice stack there.
I picked up one of those with the case and hardly any wear on it for 5 dollars from a local ham swap. I was pretty sure right away that the batteries were the reason for the "needs repair" post it note on it.
I replaced the cells with 4 ni-cads and all is good. I wouldn't mind have a couple more.
I ran across an ebay auction titled, "KC901S 3GHZ 100KHz Network analyzer. Sweep Frequency. I need to sell this!!!". The auction had about a day to go and bidding was up to $129.00 + $17.00 shipping. I'd seen this model go for around $1000 so I figured it would sell for around $400 and bid my Xmas gift of $300 to keep everyone else honest. Bidding hopped up to $200 over the next 12 hours and then stopped. I figured that, as usual, the snipers were waiting for the last few minutes to bid and kind of forgot about it. When I checked on the bidding with about ten minutes to go, I was still the highest bidder at $229.00. I re-checked the item description to see if maybe I had missed something about the item being non-functional or misread the shipping cost. I then noticed that this was the seller's first listing and started wondering if no one else was bidding because they were worried that the seller did not have a history. Well I won the auction at $229.00 and it was hard for me to get excited because I really didn't believe the seller was going to deliver at that price. I figured I would end up having to file a Paypal dispute to get my money back.
A package from the seller arrived today and it was heavy enough to actually have the KC901S in it. When I opened the box, sure enough there was the KS901S with case, power supply, and operating manual. The KS901S was in excellent physical condition and I turned the unit on to see if it was operational and if the battery pack was charged. The unit powered up without errors and, after reading the manual, I performed an S21 measurement on some known attenuators and an S11 measurement on some precision mismatches that I had previously bought. The measurement results were beyond my level of expectation, but then again I had never had a chance to use anything like this unit before. All I can do is thank the seller (emericvarg_0) and make note to never sell a high dollar item on eBay until I have some seller history under my belt.
I got an HP 5314A universal counter for $20. I bought it untested with 2 broken button caps from the local surplus shop for the caps to fix my 3312A function generator broken button caps. Turns out it works just fine. Now 2 pieces of equipment that needs button caps.
I got an HP 5314A universal counter for $20. I bought it untested with 2 broken button caps from the local surplus shop for the caps to fix my 3312A function generator broken button caps. Turns out it works just fine. Now 2 pieces of equipment that needs button caps.
That is how it usually works.
That is how it usually works.
Nope! That's EXACTLY how it works!
I bought my first HP3325A and needed a new front panel assembly because the shift keyswitch assembly was smashed. So I bought a second 'for parts' HP3325A and swapped the front panels. Problem is the second one also works just fine so I STILL have an HP3325A that needs a front panel. I've resisted the urge to buy a third one to repair the second one...
That is how it usually works.
Nope! That's EXACTLY how it works!
I bought my first HP3325A and needed a new front panel assembly because the shift keyswitch assembly was smashed. So I bought a second 'for parts' HP3325A and swapped the front panels. Problem is the second one also works just fine so I STILL have an HP3325A that needs a front panel. I've resisted the urge to buy a third one to repair the second one...
When I get done with the second 8569B I will have two (one 8569A one 8569B) that will need front panel switch rotors.
You have my undying admiration for persevering with the HP8569's - nice spectrum analyser but when I had to repair them (35 years ago) I absolutely hated them because of the time and patience needed to take them apart and get them back together again (and this was working for Hewlett Packard!). *The* major reason I went with an HP8568B for myself - much easier to repair even if they do sound like a 747 taxiing!
And yes, I've been following along with your repair posts - just haven't had anything worth adding.
That is how it usually works.
Nope! That's EXACTLY how it works!
I bought my first HP3325A and needed a new front panel assembly because the shift keyswitch assembly was smashed. So I bought a second 'for parts' HP3325A and swapped the front panels. Problem is the second one also works just fine so I STILL have an HP3325A that needs a front panel. I've resisted the urge to buy a third one to repair the second one...
So true, at one stage I had 4 Tek 453s
One 'parts unit' I bought for not much more than the post came with a "spare". I then made 3 working units, one real parts unit which I gave away when I sold one, still have two that work.
Just picked up a GW Instek 3020 variable 2 channel power supply. $70 usd shipped. I think one of those ITT bankruptcy sale pieces. Works perfectly and is in good cosmetic condition. Kind of big and a bit noisy, but not too bad. My first "store bought" power supply, very happy
You have my undying admiration for persevering with the HP8569's - nice spectrum analyser but when I had to repair them (35 years ago) I absolutely hated them because of the time and patience needed to take them apart and get them back together again (and this was working for Hewlett Packard!). *The* major reason I went with an HP8568B for myself - much easier to repair even if they do sound like a 747 taxiing!
And yes, I've been following along with your repair posts - just haven't had anything worth adding.
I have a HP8566B and they are indeed nice and easy to take apart. The hardest part is moving the ridiculously heavy thing onto the workbench.
Actually the thought of having to get it out of the rack and on to my bench is the main thing that's holding me back from fixing mine again. All of a sudden something power related seams to have blown because the fan starts going as soon as you plug in the power, power switch does nothing and it doesn't do its blinky lights self test or show anything on the screen. Im hoping its just a bad capacitor in the PSU, i hear that the caps in these are not all that reliable and mine still has all original caps in it.
Picked up a decent shape, working 485 Tek scope for a whopping 25 bucks. I need to go through and replace all the old tantalum caps in it.
And my latest toy is an HP5335A counter with an HP 10811A OCXO and Option 40. Got it for $90 including shipping.
The OCXO was about 300Hz low as received. (Comparing it to the OCXO in my HP3325A and also against the OCXO in the HP8568B). Since those two agreed to within 0.2Hz it seemed reasonable to believe it was the 5335 that was the odd man out. (Of course this is the age old problem, a man with one clock always knows the time, with two he's never quite sure!).
Ran the 5335 for an hour and the OCXO was still cold to the touch but it's output frequency slowly rose to about 90 Hz low. So I followed the trouble shooting tree in the 10811 OCXO manual and the thermal fuse was open.
With that replaced the OCXO output after 15 minutes from cold was within 0.2Hz of of the 3325A and 0.3Hz of the 8568B. Since the 3325A was last calibrated in Sep 2016 and there's no calibration date whatsoever on the 8568B I chose (after 24 hours warmup) to adjust against the 3325A. Will do that again a couple of times over the next 12 months.
And so on to the next little problem The Channel A input was working fine - not so the Channel B input. There are two flatpack IC's, one per channel. There's a hole in the PCB directly behind each IC and a post poking through from each IC onto which HP mounted a star shaped heatsink. Both of those fell out of the unit when I turned it over. I took the entire input PCB assembly out (not a trival task) before attempting to put them back on. It seems someone had been there before me and tried to put the heatsinks back on without removing the PCB because the Channel B IC had been almost entirely ripped off the PCB traces. Channel A seemed ok. So I resoldered the Channel B IC, carefully refitted the heatsinks and reassembled. Luck was with me; Channel B now works! (Thankfully. Those IC's look like HP custom unobtanium!).
I'm almost ashamed to admit the third problem. This unit has the C10 option as well. These are rear panel inputs. I ran through some basic checks and the input sensitivity seemed odd. The spec is 25mV RMS. At 10 MHz it can read reliably down to 10 mV RMS. At 50 MHz the same. At 200 MHz it needs 11 mV RMS. But at 100 MHz it needed 35 mV RMS. So I did some basic troubleshooting but could see no good reason for a dip in sensitivity right in the middle of the range. And then the penny dropped. Hmmm option C10. So I tried a 50 Ohm terminator on the unused rear panel input and bingo! 10 mV RMS at 100 MHz and the other frequencies abovementioned also 10 mV RMS. Naturally there's nothing I can find anywhere (not on the Keysight site, not in the manuals at K04BB nor anywhere else) actually describing option C10.
It tops out at 260 MHz with 25 mV RMS input. A fine counter.
Oh, I also replaced the fan with a much lower noise one from Digikey (Papst number 8414NGM). That increased the overall price of the unit to $120 but I can barely hear it now.
Answering the question of I wonder what is in the box
Cambridge Voltage divider box. Hand wound wire resistor networks and air gap clearance high voltage binding posts
And my latest toy is an HP5335A counter with an HP 10811A OCXO and Option 40. Got it for $90 including shipping.
Nice score! Those usually go for much more.
Naturally there's nothing I can find anywhere (not on the Keysight site, not in the manuals at K04BB nor anywhere else) actually describing option C10.
Yeah, there are some other HP counters that have option C10 as well. I couldn't find any published info for them either.
Oh, I also replaced the fan with a much lower noise one from Digikey (Papst number 8414NGM). That increased the overall price of the unit to $120 but I can barely hear it now.
Still a great deal.
Answering the question of I wonder what is in the box
Cambridge Voltage divider box. Hand wound wire resistor networks and air gap clearance high voltage binding posts
Thanks for tearing it down , can we get some more pics, eventually.
Even better , its own thread.
Answering the question of I wonder what is in the box
Cambridge Voltage divider box. Hand wound wire resistor networks and air gap clearance high voltage binding posts
Thanks for tearing it down , can we get some more pics, eventually.
Even better , its own thread.
Having a bit more of a poke around in it I think it's own thread with some recalibration fixes (re winding bobbins) on the lower dividers as they are a bit out (quite possibly overloaded at some stage). Top 4 are digit perfect however
Also a circuit diagram of some sort will make sense.
My stash of decade resistor and cap boxes is growing and I have the bits arranged for a Harmon divider build too.
And todays arrival.
Sitting low and out of cal range but otherwise everything else works great.
HP735A Btw
edit : Sometime later after stroking of gray beard while sitting naked in my shack with appropriate tongue angle
And todays arrival. Sitting low and out of cal range but otherwise everything else works great.
HP735A Btw
edit : Sometime later after stroking of gray beard while sitting naked in my shack with appropriate tongue angle
Nice one!
They are not often available, probably too old now.
I used to have one from 1969.
The only thing missing would be the 10V output range.
For those looking for a real SCORE....free shipping on this one.
For those looking for a real SCORE....free shipping on this one.
Probably because it is "out of stock" or why would sellers do that?
For those looking for a real SCORE....free shipping on this one.
Probably because it is "out of stock" or why would sellers do that?
Not even that makes sense, as they could find an flawless from the US for around 1k (and have it hand delivered for a fraction of the price asked).
I picked up these two from my local gumtree website. Paid 200 bucks for both which is about 12 UK Pounds depending on the day. Both are in original condition inside and both work great. I use the standard insulation tester quite regularly.