**I know the feeling. I have three Tek 'scopes (454, 465b and 2430A
digital), one Philips PM3256 and a BWD 521. The BWD and the Philips require
regular cleaning of switches and pots. The Teks do not (the 454 and 465 get
used every day). The BWD has required some power supply rebuilding too.
Having said all that, the BWD is easy to work on, the Philips is a PITA. The
Teks don't ever need servicing, apart from calibration (and the odd Nuvistor
replacement in the 454). Well, except for the 2430A. It requires some work
and I don't have the balls to attempt it (yet).
BTW: If you do buy a Tek 'scope, get a Tek probe with it, if you can.
They're bloody excellent.
I just bought an old 454 recently. It is working but has a few little
problems that I can live with for the moment.
When changing the input attenuator switch, the trace shifts up or
down. The shift control has to be readjusted to bring the trace back
to the same reference position. A slight pain.
This 454 uses nuvistors also. Where did you find your spare
nuvistor Trevor, locally or overseas?
I like the transistor sockets on this 454. Not all the boards have
transistor sockets, just some, but it is a nice thought for the
The BWD 820 model is nice to work on. Easy to get at everything.
I was removing a fan and some associated bits from a junked carcass
453 for another enthusiast and I was disappointed by the way the
wiring prevented assemblies from being moved more than slightly.
I was expecting assemblies to neatly flip out the way on their wiring.
Nope! They didn't.
The Rolls Royce quality that I was expecting from that famous
Tek myth wasn't here, accessibility wise, on this unit.
The other problem with my 454 is all time base ranges are slightly
out by the same amount. I can get over this by just moving the
red knob in the centre of the timebase switch slightly away from
the "cal" position. There is a pot inside that is supposed to adjust
the overall time base accuracy but it is not adjusting as expected.
The displayed waveform lengthens then shrinks as the pot is
turned in the same direction. The pot doesn't check open circuit
but I will look into that later. I have a habit of trying to make
things just a little bit better and then stuffing something.
$100 for a 150MHz CRO, I am happy with it.
If you are into Tekscopes Trevor or if anyone else is interested,
I have a couple of boat anchor size valve types that I would like
to give away to a good home for free. Model 533A and model 549.
Both not working but there was signs of a trace on both scopes.
Here is a picture of similar scopes.
http://www.cse.uta.edu/[email protected]/images/533 scope frmed.jpg
The ones I have are a bit shabby not nice like the pictures.
You mentioned Philips scopes Trevor. Maybe you know this
model from my description. I just can't remember the model
number. Twenty years ago at one place I was working there
was a little two tone grey Philips cro with a grey hard plastic
pouch like container at the back of the CRO for storage
of the operators manual and probes. Pouch suggests something
soft , this thin container was hard plastic but I don't know
what else to call it. The CRO was 15 Mhz bandwidth.
I have been looking for this model PM??? for use as a battery
operated CRO. Back then, I modified one of these CROs to
run off 24 Volts DC.
The power supply was just transformer, bridge and cap to one
main regulator, approximately 24V DC input. So it was easy
to use a couple of small batteries for a few hours running
where 240V was not available on outside jobs or for using
it for testing circuits where the CRO could float. Not earthed.
It was very handy for that.
I just missed out on buying one years ago for $30 and haven't
seen another since. I can't recall the model number. Maybe
you know of it Trevor.