Re: Help restoring a 547 scope

donald collie
 

Hi Dave,
Sphere Research Corporation have a document available from their website by
Tek, on how to troubleshoot their `scopes - you might like to read it.
Don`t let this `scope beat you, is the correct attitude, and remember :
most faults are simple - you can see or smell them. Are you sure your
`scope is completely dry? I wash my equipment that I import from eBay in a
bath of hot water, and detergent, rinse in hot pure water, and then dry in
front of a fan heater at about 60 degrees celcius, the hottest you can hold
your hand on, for at least 6 hours, preferably overnight. I usually clear
the faults before washing, as washing can provoke faults. Expect multiple
faults in a piece of equipment this age.Your `scope may have the imfamous
"Black Beauty" paper capacitors in it - these go leaky, and are best
replaced. They are recognised by their shiny [now shiny - you`ve cleaned
them!] black plastic cases. These are best replaced by polyester types. You
have a trace! Good! then you have no serious faults. If the `scopes
performance changes with time : Disconnect from the mains, and dry it out
some more. Make a wind tunnel of a cardboard box, and fan heater, so the
whole instrument gets hot, but not too hot. I think you were wise not to
wet the power transformer - I had a transformer fail once after washing.
Next thing i`d ckeck is the various HT`s for correct voltage, using a
meter, and for ripple/noise, using another `scope. This `scope can kill you
, so be careful. If you have a tube checker, I`d then check all the tubes,
because if the PSU`s aren`t 100%, or you have even 1 doubtful tube, your
pushing it up hill, to find a component fault, so to speak, I`ve just done
a 475 - it had leaky restorer diodes, and 2 defective transistors, which
fortunately weren`t soldered in, buy rather socketed. With determination,
patience, and the humility to ask those who have walked this road before
you, your `scope will be in factory condition sooner than you think. I have
a 547 sitting in storage. Perhaps i`ll start on it soon. What goes wrong
with the 547? The group will tell you.
Good luck, and all patience and determination to you!
Cheers!.....................................................................................................................Don
Collie ZL4GX

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On Fri, Jan 19, 2018 at 1:03 PM, Dave Seiter <d.seiter@...> wrote:

Yeah, sometimes you just have to plug it in and go. Waiting for the relay
to kick in can seem like it takes forever!
It is a great scope!
-Dave

From: felix_cantor via Groups.Io <felix_cantor=yahoo.com@groups.io>
To: TekScopes@groups.io
Sent: Thursday, January 18, 2018 8:24 AM
Subject: Re: [TekScopes] Help restoring a 547 scope

ok.... ignorance is the mother of all mistakes. It worked!

god! i love this scope.... the trace is so sharp! Amazing.

now i need to fix all the other issues.







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