Tektronix 503 scope - worth anything?
Kira D. Triea
Hi All,
My compnay was cleaning out its junk room the other day and I acquired
a non-working Tek 503 scope... no leads. I was just wondering what
folks thought about fixing this up and using it for working on my
tube repairs and projects. Like... is it worth it?
I know nothing about using an ocilliscope and would like to learn. I
see that the classic tube compnay in Tempe (forget their real name)
has a book about finding and fixing old Teks... probably just
what I need if the CRT isn't FUBARed.
Thanks... :-)
Kiira
Frank
tr...@qis.net (Kira D. Triea) wrote:
> My compnay was cleaning out its junk room the other day and I acquired
> a non-working Tek 503 scope... no leads. I was just wondering what
> folks thought about fixing this up and using it for working on my
> tube repairs and projects. Like... is it worth it?
>
Definitly worth looking into. And if you decide at some point to junk
it, you'll find it's packed with all sorts of useful goodies you can
use in your amplifier projects.
Frank
Brad Thompson
Kira D. Triea wrote:
>
> Hi All,
>
> My compnay was cleaning out its junk room the other day and I acquired
> a non-working Tek 503 scope... no leads. I was just wondering what
> folks thought about fixing this up and using it for working on my
> tube repairs and projects. Like... is it worth it?
>
> see that the classic tube compnay in Tempe (forget their real name)
> has a book about finding and fixing old Teks... probably just
> what I need if the CRT isn't FUBARed.
>
> Thanks... :-)
>
> Kiira
The book you're looking for is:
Oscilloscopes: Selecting and Restoring A Classic, by Stan Griffiths,
W7NI.
His address (as of a couple of years ago):
18955 SW Blanton
Aloha, OR 97007
(503) 649-0837 (as listed in his book)
I have restored one of these for my sister-in-law, who teaches science
in a school that has no budget for instruments. I have a second scope in
the works (awaiting a high-voltage transformer) and will never pass up
an inexpensive (or free<g>) 503 or its rack-mountable equivalent (the
RM503).
The 503 is a versatile, general-purpose and reasonably rugged scope with
limited frequency response and thus of no interest to anyone who works
with digital circuitry. These scopes are good for displaying Lissajous
patterns and have enough sensitivity to view low-level signals.
Problems I've encountered have included high-voltage transformers
(insulation failures in the CRT heater circuit), leaky plate tuning caps
in the HV driver circuit, mechanically-damaged CRTs and scratchy
controls and switches (easily cleaned).
In general, the older Tek scopes stand as works of technological art--
even if they're big, clunky, power-hungry and slow by today's standards.
I cringe when I read of someone dismembering these veterans for their
tubes-- it's vandalism akin to gutting a 1920s console radio and
converting it to a liquor cabinet.
If you decide to restore the 503, you'll probably need a service
manual-- possibly available from Stan, or from any of the
used-instrument manual suppliers. Also, keep a lookout at hamfests. The
manuals rate as excellent examples of well-written and well-designed
hardware manuals (another of today's lost arts).
The ceramic component-mounting strips in older Tek scopes require a
solder with a small percentage of silver for best results-- repairing
with tin-lead solder eventually causes the bond between the ceramic and
the terminal surface to fail.
Actually, restoring an old scope like this will give you an education
that's applicable to other tube restoration work, and you'll get a
working instrument out of the process. Have fun!
Best Regards,
Brad AA1IP
Vernon H. Brown
Brad Thompson wrote:
snip
>
> The ceramic component-mounting strips in older Tek scopes require a
> solder with a small percentage of silver for best results-- repairing
> with tin-lead solder eventually causes the bond between the ceramic and
> the terminal surface to fail.
Radio Shack sells 2% silver solder part number 64-013
Regards,
Sandy Brown
George R. Gonzalez
IMHO the 503 is not a very good scope. It's quiet (no fan) and
reasonably light compared to most old scopes. But my experience and that
of others is that it is not very reliable. Mine died about once every 10
hours, after the fourth time, the HV transformer started arcing, and this
was unfixable. Rumor is that this happens to every 503 before very long.
It also uses a TV-type HV oscillator that isnt very well shielded--
you'll see little bits of 30KC sine waves all over the place when you
start probing around your own circuits. This is all leakage from the HV
oscillator. Not too keen...
Regards,
George