HP 8566AB, is it worth $250 risk - Page 1
Forum section: electronics / testgear

author: xwarp
author_rank: Frequent Contributor
timestamp: July 01, 2019, 10:54:13 pm
content: Local fellow is selling one of these. Does not have cables. Condition is unknown at this time. I understand that the AB model is the A retrofitted with a kit, (upgrades HP-IB functionality), that essentially has nothing I would use anyway.Is $250 worth the risk?

author: 0culus
author_rank: Super Contributor
timestamp: July 02, 2019, 12:02:32 am
content: If you want to take on a possible repair job, I'd say it's not terrible IF it came with cables. You might have to spend that much again to get the two cables unless you have some laying around.

author: xwarp
author_rank: Frequent Contributor
timestamp: July 02, 2019, 12:21:52 am
content: Hmmm...tough choices....I've got an 8591e that I don't use a whole lot as it is.......

author: coromonadalix
author_rank: Super Contributor
timestamp: July 02, 2019, 12:25:19 am
content: Do you really need it or its an impulse to buy lollYou need very good cables, you have the centronic ones, and the other one with 3 rf coax conductors in them (dont recall the brand / model)Not sure i would buy and try to fiddle with this problem, try on Evilbay to find the missing cable(s) before shelling some money ?Even with the cables, if you cant make a test run or dont have any service manuals, thats a no no

author: 0culus
author_rank: Super Contributor
timestamp: July 02, 2019, 01:57:08 am
content: Fixing any problems would certainly require having a known good unit to swap parts out of to help narrow down the issue. A lot of it is fixable if you have parts. If the YIG is bad, you'll either need another one, or some mad wirebonding repair skills. A "new" one will be spendy. Bad attenuator is fixable too; issue is often the rubber o-rings inside that cushion the solenoid mechanism deteriorating. They can be replaced, with care.If you like I can put you in contact with the guy I bought my HP SAs from...he has a lot more repair experience than I do. Send me a PM with an email address.

author: 0culus
author_rank: Super Contributor
timestamp: July 02, 2019, 02:02:00 am
content: Anyway it's kind of annoying because a marginal A/B unit is exactly what I need scavenge parts from to upgrade my 8566A. OTOH, I'd rather find a nice 66B. And I'm moving soon...

author: xwarp
author_rank: Frequent Contributor
timestamp: July 02, 2019, 09:02:27 am
content: Yeah, it's more of an impulse buy. If you'd like, send me a message and I'll give you more info about this unit.

author: Bicurico
author_rank: Super Contributor
timestamp: July 02, 2019, 02:23:10 pm
content: I recently bought three (!) HP 8594E.They all arrived in working state, but:Unit #1: PSU failed after 30 minutesUnit #2: PSU failed after 2 minutesUnit #3: PSU failed after 10 minutes and I think something on the motherboard failed, as wellI thought that it would be easy to get at least one working PSU out of the three, but I was wrong. After weeks of measuring, comparing exchanging parts and asking a friend for help, I gave up.Managed to buy one good PSU, so I have now Unit #1 working.Unit #2 was not working correctly, because someone disconnected two cables inside. After reconnecting them, the unit passes self-test and works OK. Using the 4th PSU, of course.So now I am in need of another PSU, which is taking longer than I imagined. Ebay had a few on sale, but the asking price is about as much as what I paid for the three units!I replaced the backup battery on Unit #1 and #2. Unit #3 is an older model with a different battery, so I did not change it for now, but I managed to make pictures of all settings, before it broke.Conclusion: 250 US$ is a great price, but by all means try to buy two units, so that you have replacement parts! Even when the unit is working at the day you buy it, chances are that some electrolytic blows up after a few hours of use and without proper documentation or replacement parts, you are screwed...Also, never underestimate the repair of a HPAK power supply. It can be just a blown resistor, but in my experience these PSU's are REALLY complicated with TONS of componentes, some probably unobtainable. If you are not specialized in repairing them, you will hardly succeed.Conclusion: These older ancors are nice, but you should get more than one, so you can maintain them. One single replacement part will cost you as much as the whole unit, if not more. I could sell my spare units as they are, with broken PSU, and probably get more money than I paid for them, if not just for the YIG, which I know is working OK. I am saying this to put your deal into perspective.Another example: I own a total of 3x R&S CRTU and 2x R&S CMU200. They are hardware compatible to a large extend. From those, only one CRTU is not working OK (bad RXTX board and lacks one other board). Why do I have so many? Bought them all as broken and repaired them. What started to be as a bunch of replacement part units, ended up to be repairable except one. Total cost: half of the price of a working unit.This takes a lot of patientence!Final advise: It is OK to buy such a unit, when you are sure you can sell it for the same or higher price. Beware of TEA and hording...Regards,Vitor

author: tkamiya
author_rank: Super Contributor
timestamp: July 02, 2019, 04:00:26 pm
content: For sure, you are taking some risks. Question really is, what $250 means to you.I have 12+ 8568B, the lower frequency version. They all work. But some of them, the display is really dim or unfocused. Some required work. Of course, cables are expensive. About $200 a pair on Ebay, and without it, you cannot test the combo.The difference between A and B is the processor board. A uses HP's proprietary CPU and B uses MC68000. B is much faster when you do more than just view the spectrum. There was a conversion kit at one point. I believe everything else is the same.YIG unlock is really common in these units. To me, the price is the upper limit of untested and site unseen 8566. If you need 8566, plan on having a spare unit for parts. (But you don't need 12) You CAN make your own cables. Parts are still available. But it won't be any cheaper.

author: xwarp
author_rank: Frequent Contributor
timestamp: July 02, 2019, 11:29:38 pm
content: So I am going to try to go test this thing out next week as the seller is out on vacation now. Not sure I really need it so I am going to mull it over the next few days.

author: tkamiya
author_rank: Super Contributor
timestamp: July 02, 2019, 11:37:45 pm
content: How are you going to test it without a set of interconnect cables?

author: xwarp
author_rank: Frequent Contributor
timestamp: July 02, 2019, 11:41:35 pm
content: Will have to figure that one out.

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: October 04, 2019, 02:45:07 pm
content: I have a set of cables for those.. not really ready to part with them, as I have bits and pieces of 8566... (one base three screens), but for the testing purposes I can mail it to you. When you done, mail them back.And if you need a screen I can probably get you a working one out of two I will have available or whatever parts I guess.I think $250 is a great deal on one of those.... even without cables.

author: tkamiya
author_rank: Super Contributor
timestamp: October 04, 2019, 10:31:40 pm
content: So.... what happened with this? I'm also willing to loan a set of working cables.

author: xwarp
author_rank: Frequent Contributor
timestamp: October 04, 2019, 10:40:14 pm
content: I kind of let this drop off my radar. Not sure if the seller still has it. Think I will look and see.