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DIY Stompboxes => Building your own stompbox => Topic started by: David on August 16, 2004, 09:14:06 PM

Title: I don't know if I did a good thing or not...
Post by: David on August 16, 2004, 09:14:06 PM
I won an E-bay auction for an oscilloscope tonight.  It's a Sencore, made sometime between 1968 and 1975.  I don't know what the shipping cost will be yet, but the auction price was sure right --  99 cents!  The thing apparently works, and Sencore has a nice web site.  I bid on eight oscilloscopes since Friday morning, lost out on 6 of them, won this one, and will probably lose another momentarily (good!).

If I don't get killed on the shipping charges, can anyone tell me if I've just bought a boat anchor, or if I might get some use out of this thing?

Please?   :roll:
Title: I don't know if I did a good thing or not...
Post by: Lonestarjohnny on August 16, 2004, 10:01:42 PM
What model is it David, if it work's and you get it shipped right it's a hell of a deal, you can alway's sell it and get your buck's back.
Johnny
Title: I don't know if I did a good thing or not...
Post by: David on August 16, 2004, 10:13:09 PM
Quote from: LonestarjohnnyWhat model is it David, if it work's and you get it shipped right it's a hell of a deal, you can alway's sell it and get your buck's back.
Johnny

JD, the ad copy says it's a PS148.  How's that?
Title: I don't know if I did a good thing or not...
Post by: aron on August 17, 2004, 02:14:43 AM
It looks cool!

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=58282&item=3832888289&rd=1&ssPageName=WDVW

Ship it USPS ground - it shouldn't cost that much. Or UPS ground.

I'm sure you could get use out of it.

Aron
Title: I don't know if I did a good thing or not...
Post by: Fret Wire on August 17, 2004, 03:15:55 AM
Is it a tube model? You can probably find calibration notes on the net no problem.
Title: I don't know if I did a good thing or not...
Post by: David on August 17, 2004, 05:48:54 AM
Quote from: aronIt looks cool!

Whew!  What a relief.  Thanks for the vote of confidence, Aron.  I couldn't get "caveat emptor" out of my mind last night.
Title: I don't know if I did a good thing or not...
Post by: ExpAnonColin on August 17, 2004, 01:28:03 PM
UPS ground or FedEx ground will be the cheapest, I doubt you'll pay over $20.  I shipped an Oscope and some other misc things, like a small powerdrill, via fedex ground for like $18.

-Colin
Title: I don't know if I did a good thing or not...
Post by: aron on August 17, 2004, 03:50:26 PM
When I bought my scope, I felt much the same way.

It took over 1 month to reach here!!!!!

USPS parcel post - i.e. BOAT!!!!

BUt,,,,, I plugged it in and it works perfectly! uh.... I need to use it.

:shock:
Title: I don't know if I did a good thing or not...
Post by: zachary vex on August 18, 2004, 07:31:21 AM
man, aron, i don't know how you can work on effects without having your scope on continuously... i'd be lost without mine.
Title: I don't know if I did a good thing or not...
Post by: Peter Snowberg on August 18, 2004, 11:02:35 AM
That looks cool to me too David. :D

You simply can't go wrong for 99 cents and it looks like it's a perfect 1st scope. Watch out.... having vision can be addicting. ;)

I started with something similar (US Navy surplus) and eventually got up to a 4 channel 1GHz Tektronix storage scope. :twisted: (ultimate for debugging high speed digital!)

These days I use a 3 channel 100MHz scope from Leader. The only things I wish I had above my current scope are dual-timebase and storage because I still deal with lots of digital. Well.... maybe a real 4 channel scope would be a nice upgrade too but then I wouldn't mind driving an Italian sports car either. Hehehehe... ;)
Title: I don't know if I did a good thing or not...
Post by: David on August 18, 2004, 11:27:59 AM
Only problem is, it's in Orlando.  Haven't heard from the seller yet.  Starting to wonder if maybe Hurricane Charley got to it before I did -- I sure hope not!

Doug H -- how badly did the residential areas around Orlando get damaged?
Title: I don't know if I did a good thing or not...
Post by: Michael Allen on August 18, 2004, 01:39:41 PM
I've just got a question on using a scope. Zach said he'd be lost without his so I guess it helps tremendously in troubleshooting. But how would you use it?
Title: I don't know if I did a good thing or not...
Post by: Peter Snowberg on August 18, 2004, 02:50:45 PM
Quote from: Michael AllenI've just got a question on using a scope. Zach said he'd be lost without his so I guess it helps tremendously in troubleshooting. But how would you use it?

The input to a scope is a probe which has a ground connection and a signal connection. You clip the ground to your signal ground and then touch the other wire to the place you want to view.

The scope will then show you the voltage at that point over time.

They're amazing tools! :D
Title: I don't know if I did a good thing or not...
Post by: smoguzbenjamin on August 18, 2004, 06:05:25 PM
Anyone selling a scope in my neighbourhood for say, 10 euros? :mrgreen:

By the way could I put an Oscope on top of my computer monitor without everything going funky? I put a Little Gem Mk2 amp with a 9W speaker on top of my monitor once and the colors went funny, but recovered after about 10-20 seconds. Would an Oscope do the same thing? 'Cause I use 2 monitors on 1 PC and I don't have a lot of space :mrgreen:
Title: I don't know if I did a good thing or not...
Post by: Michael Allen on August 18, 2004, 07:17:52 PM
Ben it was surely the magnet playing tricks on your monitor. You shouldn't have magnets near a comp...

So by looking at the signal wave, what can you deduce? I would assume that unless you can compare to a working model, you would just have to guess what the waveform should look like. They sound badass and I might have to pick one up if I can!
Title: scopes
Post by: donald stringer on August 18, 2004, 08:01:19 PM
http://www.dazyweblabs.com/ds2002/index.html If you dont have a real one nothing beats freeware, theres some pretty cool stuff here, I wish I new what you did with all of it. But I did download this one to play with.
Title: I don't know if I did a good thing or not...
Post by: Chris R on August 18, 2004, 10:17:30 PM
My apartment still dosn't have power... most of the trees around are uprooted and some of the stop lights are still out.. Orlando won't get fixed for a while because everyone is working on the coasts.

i'm just east of Orlando btw.

Chris R
Title: Couple of examples
Post by: ErikMiller on August 18, 2004, 10:33:51 PM
Quote from: Michael AllenI've just got a question on using a scope. Zach said he'd be lost without his so I guess it helps tremendously in troubleshooting. But how would you use it?

The oscilloscope gives you a visual representation of the waveform present wherever you stick the probe tip.

Here's one way to troubleshoot a device: run a 400Hz signal into the input jack, then touch the probe to each point in the circuit until your waveform looks like it shouldn't (either gone or improperly distorted). That will show you where the trouble is.

For design work, you can check to see what the waveform looks like before and after your processing stages.

These are a couple of the more basic things you can do with an oscilloscope; there are entire books on the subject of exploring their capabilities.

It's my "desert island" piece of test equipment (although I'd need an audio signal generator of some kind), even before a VOM.
Title: I don't know if I did a good thing or not...
Post by: Peter Snowberg on August 19, 2004, 01:54:32 AM
Quote from: Michael AllenSo by looking at the signal wave, what can you deduce?

voltage over time
clipping
frequency content
wave shape
response linearity
transient events
.....more :D
Title: I don't know if I did a good thing or not...
Post by: smoguzbenjamin on August 19, 2004, 06:20:11 AM
And even if you can't seem to figure out - it's still cool to look at :D
Title: I don't know if I did a good thing or not...
Post by: David on August 19, 2004, 06:58:09 AM
Quote from: smoguzbenjaminAnd even if you can't seem to figure out - it's still cool to look at :D

Oh, I'll figure it out all right.  I have a reputation for being persistent.
I must be.  This is my third try at pedal building.  I guess the old saying is true.  "Third time's the charm!"   :twisted:  :twisted:

Time to head to the salt mines...   :mrgreen: