Re: Tektronix 577 Regular board capacitor question

Paul Amaranth

I haven't opened up a 577, but those are likely the typical Sprague capacitors
used by Tektronix in that era. They may still be good; I'd check them with a
good capacitor and esr meter before removing them.

If you need to replace them, the neatest repair is one I use in 4xx and 7K scopes - use
a small carrier board to mate the footprint to a commonly available snapcap. This
provides the jumpers that Tek used and the footprint for the new cap. Use
105C caps as replacements. You can find these on ebay and there are gerbers floating
around if you want to send them to a board house yourself. You can also etch them
yourself of course.

Some purists might restuff the cans with a new snapcap.


On Fri, Aug 09, 2019 at 07:15:33AM -0700, DW wrote:
I decided I would replace the electrolytic on the regulator board as I noticed the capacitors appear quite old.

On removing the board and looking at some of the radial style capacitors I noticed they are not your standard capacitors. The bigger capacitors have 4 metal feet towards the rim that seem to serve two purposes, hold the capacitor in place and serve as a electrical connection. And then there is a a 5th connector towards the middle.

I am thinking if I replace these I will need to come up with some kind of retrofit unless they stock similar capacitors like these.

And thoughts? Thanks

Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix & Windows

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