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Help me refurbish a BK Precision / Dynascan 1601 power supply
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Sir Knight:
Thanks for checking in and contributing, Floobs. In my original post I mentioned using UPW for those radial at C6, C11, and C12, and a Kemet PEH169 for the can. It matches the dimensions and specs on the short list, I just didn't know if the deeper specs were appropriate for this power supply. Or any power supply, for that matter. Also, do you have any advice on what series I should look for in the axials? Or should I just use radials and glue them in place?
floobydust:
Nichicon PW are a very good capacitor, I use them a lot. Had Panasonic FC leaks so I am no longer a fan of them.
I use radials (with spaghetti on the leads) and tack them down with silicone. Axials are hard to find and just oddballs nowadays. The modern radial parts are so much smaller.
Take pics before, I double-check polarity afterwards and red felt pen mark them.

The main filter cap 1,500uF 75V I think could be upsized to 1,800-2,200uF without penalty if you need to match physical size or a more popular value. Today it would be a snap-in but these are not great for ripple current rating. The 120Hz ripple current is something to look at as a figure of merit, needs to be higher than the 2A DC output current of course which weeds out the small parts e.g. LGY series. ESR is not as important as it is for SMPS applications.
As long as you wire it to the same spot (right at bridge rectifier output) and not somewhere else which can cause extra hum. The PSU should be using a single-point (star) grounding scheme.

Kemet's website goes offline for datasheets on weekends lol so I can't check out the PEH169's but any decent can will be great here.
w9gb:
B&K Precision Model 1601 Regulated DC Power Supply
INSTRUCTION MANUAL (includes Schematic and Parts List)
https://www.mrrenwick.ca/media/B&K 1601 Power Supply User Manual.pdf

B&K Precision Model 1601 Regulated DC Power Supply
First manufactured in 1973 (Carl Korn, president), when B&K was a Division of Dynascan Corp.
At this time (1970s), B&K was located at: 1801 W. Belle Plain Avenue; Chicago, IL 60613.
==
This DC Bench Supply landed on my electronics bench (2017) with a nice layer of dust and a "rattle".
This unit also had a burned out NEON bulb.  Easy NEON Replacement (schematic and Parts List in Manual)

The "Rattle" was one of the two P.C. Board Supports, Plastic (Part number: 380-202-9-001),
that Support had a broken "snap-in" that secures and supports this "Vertical Card Guide" to bottom of metal case.

After 40+ years many e-bench techs would assume that this part is obsolete or unobtainium.
However, from 1950s through the 1970s (before Asian migration) most Chicago-based manufacturers sourced their parts (OEM) from local area manufacturers and distributors.

This specific OEM part, 380-202-9-001 : P.C. Board Support, Plastic
was manufactured by the well-known plastics mfg. : Richco, Inc. of Forest Park, IL
This part was used in other similar B&K bench DC supplies, like model 1602.
http://bama.edebris.com/download/b&k/1602/1602 Parts List.pdf

ESSENTRA (global HQ in United Kingdom)
Three (3) companies: Alliance, Richco Inc., and Micro Plastics
were joined together to form Essentra Components.
https://www.essentracomponents.com/en-us

CBG-3-01 Vertical Card Guide, Product Page (former RICHCO part, Forest Park, IL)
You can Request a Part Sample on the Product Page
https://www.essentracomponents.com/en-gb/p/vertical-card-guides/cbg-3-01

Technical Drawing for CBG-3-01 , Vertical Circuit Board Guide
https://essentracomponents.bynder.com/m/68044e48e22c06a8/original/1279499-pdf.pdf
Chris56000:
When I repair an old piece of T & M I concentrate on getting it working with as many of the original parts as possible and only replace anything if it clearly IS defective!

I would much prefer to have a unit in good condition outside cosmetically and "virgin" condition inside than have to try to resurrect something that someone unknown to me before I got the thing had "recapped" or "upgraded" and added goodness–knows–how–many unknown faults on it!

Modern electrolytic capacitors are made in much smaller sizes than the old original components were and characteristics such as ripple current rating were often quite a bit greater in the old component, therefore the heat generated in the original will be less compared with a small modern component, and the same applies to semiconductor devices, as the many discussions on here regarding "fake" replacements testify!

Original 1970s and 1980s transistors often work in old circuitry with absolutely no problems for years, and then you get oscillations/instability or noise when you replace a faulty device with a new one, because the new replacement part doesn't match the junction capacities, or the lower beta or transition frequency (fT) of the original, this is another topic that has been extensively discussed on here!

Chris Williams
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