Discussion:
Wanted: man/schem for Superior Instruments 650 RF sig gen
(too old to reply)
d***@gmail.com
2013-11-10 10:04:39 UTC
Permalink
Looking for a manual and schematic for Superior Instruments
model 650 RF signal generator. This is an oldie, probably
from the 1950s.
Thanks and 73,
Dean / K5DH
Hi Dean...

I know this is a quite old question, but did get any luck with this manual? I just got one of this signal generator and I star to restore it, but I want to be sure about some parts, for instance the resistor between the two power supply capacitor filters (on my unit it is dead) and it was not original and also the snubber capacitor (3x.1uF) that look damaged...

Thanks a lot.

Daniel.
Fred McKenzie
2013-11-11 05:12:37 UTC
Permalink
Post by d***@gmail.com
Looking for a manual and schematic for Superior Instruments
model 650 RF signal generator. This is an oldie, probably
from the 1950s.
Thanks and 73,
Dean / K5DH
Hi Dean...
I know this is a quite old question, but did get any luck with this manual? I
just got one of this signal generator and I star to restore it, but I want to
be sure about some parts, for instance the resistor between the two power
supply capacitor filters (on my unit it is dead) and it was not original and
also the snubber capacitor (3x.1uF) that look damaged...
Daniel-

Its only 14 years old! In case Dean does not find this, I suggest you
try the call sign search at WWW.QRZ.COM, for his E-Mail address.

Fred
K4DII
Scott Dorsey
2013-11-11 14:43:09 UTC
Permalink
I know this is a quite old question, but did get any luck with this manual?=
I just got one of this signal generator and I star to restore it, but I wa=
nt to be sure about some parts, for instance the resistor between the two p=
ower supply capacitor filters (on my unit it is dead) and it was not origin=
al and also the snubber capacitor (3x.1uF) that look damaged...
1. The resistor is bad because something is pulling too much current from
the supply. Replacing the resistor did not fix the problem because nobody
found what was actually wrong.

And of course what was actually wrong was probably the second supply cap
being bad. But it could be some other electrolytic decoupling cap being
bad, or a tube that is severely misbiased, or a tube with an internal short.

If you can't read the value off the resistor, and you don't know what the
plate voltage on the output is supposed to be, you can replace the resistor
with a rheostat and adjust it until you get lowest distortion on the output
(which will presumably be the poing where the plate voltege is correct).
Be sure to have a proper load on the output when you measure.

The thing is, for this to work, everything else in the circuit has to be
good. So check all the plate and cathode resistor values in-circuit and
replace all electrolytics. Test ceramic coupling caps with a megger or just
replace pre-emptively.

The snubber capacitors ought to be replaced with NPOs. They might be fine
but if they look bad it's easier to replace them than test them. And if you
replace them, you know they'll be good.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
f***@gmail.com
2016-02-28 09:58:17 UTC
Permalink
Right, this is an old post. I too am looking for any schematic or, better yet a manual for the superior instrument model 650. Any luck to share?
f***@gmail.com
2016-03-11 22:21:48 UTC
Permalink
The model 650 must be a rare bird. I can't find a schematic either. Any help out there?
c***@gmail.com
2017-12-20 23:13:46 UTC
Permalink
Looking for a manual and schematic for Superior Instruments
model 650 RF signal generator. This is an oldie, probably
from the 1950s.
Thanks and 73,
Dean / K5DH
Hi ...even a long time ... i got some info on schematic at

http://bama.edebris.com/download/superior/650/Superior%20Instrument%20Co%20Signal%20Generator%20Model%20650.pdf

HTH..

Loading...