Hi Be careful buying older Tek scopes. Many of the repair parts are not available any more. You may get lucky and never need to repair one of these scopes but many of the parts were proprietary made custom for Tek or in the case of some of the IC's and CRT's were made only by Tek in there own fab. I worked for Tektronix for many years as a field maintenance instructor in the test and measurement division. My specialty was the 7000 series and the portable scopes among others. The reason the 7000 series is so cheap on Ebay is the problem of getting repair parts. The most common problem is with the cam switches and attenuators in both the 7000 and the 465 and 475 scopes. The 485 is even a generation earlier than the 465 or 475 so I would not ever consider one these scopes unless it had a good CRT, is in excellent condition and was virtually free. It also takes a real expert and some special equipment to properly tweak a 485 so it will meet specs. The 7000 series may be OK if you can buy two for a few hundred dollars. The second one for parts. I have a friend with a cal lab that has a warehouse full of broken 7000's that he uses for parts to keep the stuff he has under contract. Tek has a policy that they do not guarantee parts support seven years after a product is discontinued. The 465, 475 and most of the 7000 has exceeded that by two and the 485 by three
However I personally own a 2465 and can highly recommend it. It is 400 Mhz four channel with both 1 meg ohm and 50 ohm inputs with dual timebase. This was the last of the really great analog scopes Tek made. This scope sold for over $5000 in the mid 80's and was worth every penny. I have seen them on Ebay for well under $1000 (I paid $800 for mine a couple of years ago) I know that is a lot of money to spend on a scope used for hobby work but a new scope with much less capability will cost as much or more. Ron Is correct on the bandwidth specification. Scopes are rated at 3 db down at the rated bandwidth. This means a 100 MHz scope can measure a one volt pk to pk 100 MHz sine wave at .707 volts and still be in spec. Also the probes are rated at a max bandwidth as well. If you use a 100 MHz probe on a 200 MHz scope then you will only have a 100 Mhz bandwidth at best Don Brown KD5NDB ----- Original Message ----- From: "Alexandra Carter" <[EMAIL PROTECTED]> To: "Ron D'Eau Claire" <[EMAIL PROTECTED]> Cc: <elecraft@mailman.qth.net> Sent: Monday, January 23, 2006 9:13 PM Subject: Re: [Elecraft] Oscilloscopes (WAS: spectrogram) > Tektronix 475, baby! The 465 is OK, and the 485 a real 400MHz work of > analog scope art I hope to own someday. Then if you're really serious > you have a 7000-series mainframe and a lot of plugins hehe. > > A really good tutorial on scopes is Tektronix's The XYZ's Of Using A > Scope which they used to give out, now you can download it from the net > and the recent versions have a bunch of stupid stuff about their > digital scopes - they tell such beautiful lies, stick to analog. > > 73 de Alex NS6Y. > > On Jan 23, 2006, at 7:06 PM, Ron D'Eau Claire wrote: > > > Jim, AB4CZ gave you an excellent summary. > > > > If you think you'd like to use the 'scope for general bench work to > > look at > > waveforms, etc., on HF gear, then look for one with at least a 200 MHz > > bandwidth. ...........If you try to observe signals on a narrower > > bandwidth oscilloscope, the > > higher-frequency information is simply lost..... > > At today's Hamfest prices, the price difference between a basic > > waveform > > monitor and a good general purpose scope is often small...., > > Ron AC7AC > > _______________________________________________ _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
