Just to follow up, I was able to take one strand of silver-plated wire from a piece of stranded small-gauge wire, wrap it around the pin to encase the wires to the coil a bit, a very quick soldering, and the relay works fine. I used some CA to reattach the plastic enclosure.
Touchy, but it can be done if that's the problem with the relay.
Thanks,
Barry - N4BUQ
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----- Original Message -----
From: "Barry" <n4buq@...>
To: "tekscopes" <[email protected]>
Sent: Monday, November 29, 2021 5:12:11 PM
Subject: Repairing a 148-0034-00 Relay
After getting my 7B50 to produce a sweep, I noticed that the x10 magnification
function isn't working and traced that to a bad K780 relay (P/N 148-0034-00).
I noticed the TekWiki page for the various relays has links for some repair
techniques and, since my relay's coil checked open circuit, I decided to open
it up.
Fortunately, the wires are intact and it appears that because those were wrapped
around the pins and, possibly, micro-welded(?), enough resistance has built up
over time between the wire and pins such that there's not a good contact
anymore. I can get the relay to function if I apply 15VDC directly to the
wires at the pins but that doesn't work if I just touch the pins where they
protrude through the bottom of the relay.
I'm wondering if I can wrap a fine copper wire around the existing wire/pin,
secure it as snugly as I can get it, and then, perhaps a very light soldering
job might be enough to repair this.
Anyone else tried to repair these and, if so, any good advice as to how to
proceed? That's some extremely fine wire and, apparently, very easily broken
so I'm wanting to tread as lightly as possible.
Thanks,
Barry - N4BUQ
