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Help me refurbish a BK Precision / Dynascan 1601 power supply
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Sir Knight:
After years of wanting a B&K Dynascan 1601, one showed up on Craigslist for $25. It was in excellent shape, no gouges, burns, not even a scuff or a sticky residue from inventory control tape. Mine mine mine mine.

When I got it home I turned it over for a more thorough inspection and noticed the rubber feet were missing. Then I heard something rattling inside so I removed the top cover. The inside looked like the lint trap in a barbershop clothes dryer, so I started vacuuming it out. The rattle was nothing more than a piece of jacketed wire, probably fell in there during a project. The lint and hair was probably keeping the wire from shorting anything.

Then I saw there were a few electrolytic caps in there. A couple of radials on a PCB card, a couple of axials that were floating, PtP wired. A relatively large (probably 40x50) filter can, strapped to the bottom of the chassis. The upgrader in me took over, assisted by the side of my brain which says "it aint perfect - yet". I bet I could just put this thing into service right now and it would be fine, but I'm putting in an order for some other projects anyway, and as long as I have the cover off, well... y'know how it goes.

I've gotten the schematic and gone over the cap list. I see C12 is supposed to be a 200uF 75V, but my 1601 has a 220uF 80v in there. Since caps of the 1970s were most likely -10/+70 I'm not going to worry about it. But I plan on using this supply for my actual design projects, like matching transistors with some precision, so I really want to make sure this is working its best. Given the amount of Dynascan fans here, I'm hoping that at least one of you has refurb'd one of these and can offer some advice on what to pursue.

Things I'm looking for:

- What are the best electrolytic replacements? I see two axials, two radials, and a screw can strapped down on the chassis. (I plan on standing that guy up and clamping him in place, if I find a short enough can that won't rub the leads on the top cover). I'm considering Nichicon PW for the radials, and KEMET PEH169 for the can. I have no idea what to replace the axials with. They're PtP and there's no board to worry about, so unless there's some obscure and arcane reason that require axials, I could invert a couple of radials and hot glue them to the bottom of the chassis, right?

- Are there any service bulletins or updates for the 1601? These things were made for a couple of decades, under two or three different corporate owners. At some point they might have discovered some weak points.

- Are there any tricks/hacks or modern parts substitutions that will ensure smoother output and increase the life of this supply? My first project with this will be matching batches of transistors for audio use. Eventually I'll try getting into small signal amplification - I want to learn preamps and voltage gain stages and a bunch of other things I don't understand. Clean power is the basis for audio. These circuits and components are about 40 years old, I'm sure it could be made "better" by whatever definition you want to assign to that term.

- Anything else I should know? Like the air-speed velocity of an unladen swallow, perhaps?
bob91343:
I think you are just playing games.  Rebuild the unit, if you must, using the original design or as close as possible.  It is what it is, and substituting parts without knowing the considerations that went into their original selection is asking for trouble.
Sir Knight:
What exactly did I ask that sounded like I was "playing games"?
bdunham7:
I wouldn't replace any parts, I would test it and see how well it works. 
rsjsouza:
I am of the same opinion; leave the parts alone as long as the unit is working as intended.

I have a B&K Dynascan 3030 Function generator that is completely original and, by any of my measurements of performance, it works just as it left the factory. Changing or modifying any of its original transistors without a specific reason is a gamble, as the parts sometimes were better made 30, 40 years ago when the manufacturing process was tailored for excellence and not volume. An example? It is not uncommon to see TO-3 transistors that have copper housings with its incredible heat transfer properties - nobody in their sane mind would think of using copper on a modern part manufactured at a cost. 
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