I had very similar experience with my HP 8644B which pretty same unit like yours, but my unit was way much horrifying that i started to laugh after seeing what they sold me, 3 boards modules were loose not even plugged in slots, and two ALC boards duplicate and a missing Doubler board, and all the cables are loose ...not even one single cable was hooked.....!!!! so i ended up using it as spare parts for the other one that i have, took the power button and the covers. if you follow curiousmarc channel he called the technician who was working on a unit that he purchased from ebay...." THE TECHNICIAN FROM HELL" ....lol. probably he is same guy.
Look at those gorgeous VFD displays, none of that poxy impossible to read LCD rubbish. Great job on the troubleshooting, I'm so glad there are people rescuing equipment like this.
I have one of these. I wish the phase continuous sweep capability was greater but it is a beast and probably the most extreme piece of gear I have in my house. I think these were in the $20,000 range when they were new.
Curious... why would you buy one of these with all of the modern options? Is it purely a "this could be fun" interest? I've had the option to buy one of these in working condition but I cannot think of any reason I would want a huge boat anchor like this in my room.
Can you name a few of these "modern options" with equivalent specs that aren't 2k+ $ ? I wouldn't mind something smaller and lighter than this monster, but the modern alternatives are at least 4-5x more expensive than what I paid for this.
@@fenugrec5697 I feel like you're not genuinely interested in a real response but are more interested in defending your purchase. And that's fine. I think your "out" to what would have been my next reply is going to be the "equivalent specs" wording. No matter how I reply or how close the specifications seem to be, I feel like your response is inevitably going take a contrary and argumentative stance which will ride on that phrase's proverbial back since your first response's tone is already rooted in that direction. My question as well as my interest was genuine and I do not have the desire or motivation to argue or validate your purchase. I was simply trying to understand the purchase logic as I am in the market myself.
@@Wil_Bloodworth I don't mind discussing it - it would've been easy enough to simply ignore the comment. I would lie if the challenge of the repair wasn't part of the interest, but I think my point still stands - getting comparable specs, in a new model, is much, much more expensive. ( my research = 5 minutes of looking at rigol and siglent lineups). Some 50$ bargain-bin alternative might exist (I have in mind typical single-chip DDS bare boards that can be found on... "international shopping sites", but I don't expect the specs would compare favourably at all. I'm not aware of a middle ground, but would gladly be proven wrong. I don't even have space on my bench for this machine, I store it in a separate room and set it up on the floor when needed. But that inconvenience doesn't amount to 2k$ for me. So, 3 points : specs per dollar, total price, and repairability.
Didn't see it in the comments, but those front buttons are part of a larger rubberized membrane. So they can not be individually replaced. I had the same issue with a HP 8657B I bought and luckily found a used front panel to havest a replacement membrane from. On the 8657B it used two membranes. Most likely similar on your 8643A. BTW, I was able to still activate the switch using a insulated rod with a small bit of aluminum foil taped to its end. That worked fine until I found the replacement front panel.
Thanks - yes, I eventually realized that it would most likely take a whole new membrane, that realistically would have to come from a complete front panel. Luckily I don't really need that particular button so it will probably remain unrepaired; I just taped over the hole so dust and debris doesn't get in.
Right now have a 8664A coming from eBay; sure hope it's OK. I did not know that they detailed schematics were not available (?). I mainly worry about esoteric unobtanium parts, so I really feel I stuck my neck out but needed the precision and sweep capability. Thanks for sharing this video and I think you did a great job of diagnosing and repair...
Thanks. You're sure your low voltage condition is due to a bad PS and not an overload ? I just shop on the usual online suppliers (DK/mouser/newark) and find mechanically compatible parts with better temperature and endurance ratings if possible.
not systematically, beyond the known-problematic caps in the power supplies that I already replaced even if they looked good. A full recap would be wasteful IMO
No : it was long dead, and the only thing you lose is the self-calibration. From the manual: " When the instrument is off and the Controller Board is removed from the motherboard connectors, the instrument calibration data located in the Controller Assembly RAM will be lost. At the next power-up, the instrument will sense a data lost condition and automatically activate the Recal routine. "