Film-Tech Forum ARCHIVE: Good analog oscilloscope for travel

This is topic Good analog oscilloscope for travel in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Michael Schaffer (Member # 1204) on 02-26-2007, 11:20 PM:

I know Mark G. swears by the Tektronix 465B and there are some for little money (so far) on ebay, and Dolby people used to carry the 60MHz Leader scope, but that seems very difficult to find and I wonder if something better and more suitable for digital A-chains hasn't come out since that was made. Are the Dolby people still using it or have they switched to a different model? I have a Protek 60MHz scope which is OK but way too bulky to carry around a lot.
Has anyone used a scope yet for digital cinema signal troubleshooting, if that has come up? What would the required bandwidth be?

Posted by Monte L Fullmer (Member # 2797) on 02-27-2007, 02:20 AM:

I know, I got a 465B as well ...20 mHz is usally the norm.. not too bad to haul around..
lays pretty well flat in the trunk ...

Posted by Steve Guttag (Member # 268) on 02-27-2007, 06:03 AM:

You know, there are some things where I just accept the size it commands....a good scope is one of those things. I carry a Tek now (100MHz) and use it for both film and video set ups. I like the large 8x10cm display and it is tack sharp (much finer than a 20 or 40MHz diplay when setting Dolby Digital up).

Now the D2 can provide scope functions for analog A-chains and I hear that they are working on it to be usable for digital (Dolby) set ups too.

As for a proper scope for Video...I cheat the 100MHz into service when I use it...I tend to use NTSC multiburst patterns since they are well defined and let one see both resistive as well as HF attenuation. However, just to do proper XGA type analog video one really should be up in the 300-500MHz range to really see it well. At this stage, I don't want to carry that much $$$ in a scope for field use if I can get a 100MHz analog one to do what I need it to do. Plus, I just like the look and feel of analog scopes over digital (unless you need the storage faciities of digital...which in video is VERY handy).

My suggestion is look for a Tek on eBay...I want to say the one I use is something like a 2235...not the 465B, which is heavier...that we use in the shop, but it works like a champ for me.

Posted by Gordon McLeod (Member # 33) on 02-27-2007, 08:28 AM:

I swear by the little leaders but they are expensive to repair
The leader is available in 20 40 and 60mhz in the same package
the 20 seems to be the most robust and does Dolby digital fine
the 60mhz is all surface mount and seems to have the biggest problems getting repaired
B&K anlso made a small battery operated scope that is nice I have one somewhere it is a 1422? the crt is a bit smaller than the leaders
Also Sony Tek made a very small one but there are phase issues between the channels

Posted by Mark Gulbrandsen (Member # 72) on 02-27-2007, 04:23 PM:

There is nothing else on the planet like a Tektronix scope.... The Rolls Royce of all scopes for sure. Look for a used 465B which is my personal TEK favorite. I usually reccomend them because of the large availability of new and used parts from a number of different sources. Be sure to get the "B" version of the scope. The regular 465 has incandescent indicator lamps whilst the "B" model has LED's and many circuit refinements. TEK built more 465 scopes than any other since it was for the most part the industry standard scope since about 1973. I don't personally like any of the 22XX series becuase TEK had adopted large monolythic integrated circuits in them. Not that these scopes are not reliable but when an LSI fails you have to either buy a scrapper unit for parts or get another scope... and the overall quality of their CRT's became very inconsistant with that series for some strange reason. But when you get a good one it generally stays that way!! One scope might have a needle sharp trace while the next won't focus worth a hoot. Interestingly the tube TEK scopes 5XX series generally have the best CRT's with the sharpest traces.

TEK 465B POwer supply... typically excellent build quality and the main reason they last for ever.

Yes, I am a TEK scope junkie... as long as I can get em for next to nothing! All of the scopes in the photo have been completely restored, many of them cost under $50 to aquire, the 575 transistor curve tracer cost me just 35 bucks and just two tubes were weak and needed to be replaced. There is also a 7603 I keep at work and the 465B and 214 miniscope are in the van. The green case left of center is a portable Leader scope. The smaller scope on the left is an early 1950's 3" TEK scope that still works perfectly.... 34 tubes and it has a 5mhz bandwidth [Eek!]

Mark

Posted by Phil Hill (Member # 371) on 02-27-2007, 04:34 PM:

Well Mark, you've convinced me...you're one sick puppy! [Razz]

Posted by Mark Gulbrandsen (Member # 72) on 02-27-2007, 04:38 PM:

Ha... you ought to see the garage..... [Big Grin]

Posted by Louis Bornwasser (Member # 3063) on 02-27-2007, 04:44 PM:

We also use the 2235 in the shop; have 2. In the field we use the 2336 and 2337; have 3. All are 100mhz scopes; the 2235 is medium size and the others are smaller, but not "compact." Ebay has been good; prices range from 150-400 bucks. Louis

Posted by Monte L Fullmer (Member # 2797) on 02-27-2007, 06:45 PM:

quote: Mark Gulbrandsen
you ought to see the garage..... .

..it is one massive hobbyist and collector's dream! (along with the Harley..) [Big Grin]

Posted by Mark Gulbrandsen (Member # 72) on 02-27-2007, 09:24 PM:

quote: Monte L Fullmer
..it is one massive hobbyist and collector's dream! (along with the Harley..)

Oh come on Monte... really..... NOT!

Posted by Mike Blakesley (Member # 26) on 02-27-2007, 09:30 PM:

Hey, I think I recognize some of the parts in those Gulbrandsen pics from his last service visit here!!? [Big Grin]

Posted by Jon Paul Johns (Member # 3443) on 02-28-2007, 05:35 AM:

This is my toy, a hand held Fluke 124 ScopeMeter.

Oscilloscope Bandwidth: 40 MHz

Dual input True RMS Fullrange Multimeter: Vdc, Vac, Vac+Vdc, Ohms, Continuity,
Diode-test, Current, °C, °F, Capacitance, dBV, dBM, Crest Factor,
Touch Hold and Zeroset, Hz, Duty Cycle+/-, Pulse Width+/-, Phase

TrendPlot Recording: Automatic vertical scaling and time compression.
Display the actual, MIN, MAX and AVG reading.

Trigger types: Connect-and-View™, Free Run, Single Shot, Edge, Video, External.

Scope measurements: Automatic: 26

Memory: 20 screens and setups.

Maximum record length: 512 min/max pts per input.

Battery Life: 7 hr Rechargable NiMH Battery.

RS232 port to print and download to PC

Not too big not too small just right [thumbsup]

, but I do like the Fluke
199c ScopeMeter it is a 200 MHz bandwidth.

Posted by John Walsh (Member # 168) on 02-28-2007, 06:37 AM:

I'm with Mark about the Tek 465B; great scope for not much money and worth the additional weight for most people. Also agree about the 22xx series; (I used a 2245 for many years) a great scope, but a bit expensive even used, and parts are becoming very hard to come by so I wouldn't suggest one unless you can get it very cheap

Posted by Louis Bornwasser (Member # 3063) on 02-28-2007, 09:03 AM:

We have a (small)collection of Fluke scopemeters. Unfortunately useless for Dolby Digital. Factory rep even agreed, when we showed him the "detail under the trace." Louis

Posted by Michael Schaffer (Member # 1204) on 02-28-2007, 09:19 AM:

That's what I thought, too. Neat as they look, I didn't think they would really work for this application.

What is the minimum bandwidth and resolution that would be required off a *digital* scope or a PC based one to display DD signals properly?

I know we have been over this several times before in the past, but I wanted to see if there aren't new products out there in the PC based scope area. Like this, for instance: www.linkinstruments.com/oscilloscope85.htm

Posted by Steve Guttag (Member # 268) on 02-28-2007, 09:21 AM:

Oddly, I've had more issues with the 465Bs trace than on the 2235s.

As for the Scope meters...I haven't found one that I like yet...the ballistics are just too slow for me. We have an older Fluke Scopemeter that I use for bench work...it is great for setting up amplifiers because one can look at the output on the scope and quickly turn rate the output in Watts and such without disconnecting anything...very handy indeed.

Steve