Which one of these oscilloscope to buy ?  - Page 1
Forum section: electronics / beginners

author: yashrk
author_rank: Frequent Contributor
timestamp: March 16, 2014, 11:06:23 am
content: I want to buy an oscilloscope, so I met a guy today who showed me few of these old Oscilloscope, where not looking in good condition but I am getting this in 2000Rs ($35) and he can go bit low than that. But he told me that they may need some repair. I have never spend much time using an oscilloscope before so please tell me which one should I chose (and why) and also few tips on how do I check them - like common problem in them, or should carry any circuit to check if it works (but I think he may not have probes for them) so any way to quickly check if they work ?Hp1722B - 275 MHzLeCroy 9400A 175mhz DSO from 1988TEKTRONIX 2215A ( this one had brand name calledTekHindso make be fake, but they look totally same like tektronix ones )Iwatsu SS-5710 100MHz OscilloscopeTektronix 465B Dual Trace 100 MHz Oscilloscope ( both 465 and 485 didn't said as TEKTRONIX on the scope but I looked online original did neither)TEKTRONIX 485 DUAL TRACE 350 MHz OSCILLOSCOPE"Philips" PM 3213 - 20MHz "Dual Trace Analog" "oscilloscope"Tektronix 475 200 MHz 2 Channel OscilloscopeTektronix 465 100 Mhz Oscilloscope(I am thinking mostly about the "Tektronix 4XX" ones but your views are more valuable)Tell me tricks to spot good one and a list forgood to worst will be betterso I could just chose another if the one that you mentioned didn't worked.Thanks for your favour, really appreciate it

author: KJDS
author_rank: Super Contributor
timestamp: March 16, 2014, 12:12:18 pm
content: buy a cheap probe to take with you so you can use the calibrator on the scopes front panel to test them

author: EEVblog
author_rank: Unknown
timestamp: March 16, 2014, 12:34:24 pm
content: Definitely get one that works if possible, otherwise it might be impossible to fix.A wire on the input and touching it will at least let you pick up the mains hum which will allow you to test the basic operation. If possible take a prob to connect to connect to the cal output.The Tek units are notorious for using custom parts, so best to avoid if not working.The 2215A is a nice basic scope if working. Or the Iwatsu.

author: GreyWoolfe
author_rank: Unknown
timestamp: March 16, 2014, 01:01:28 pm
content: I would go for the 485 because of the bandwidth or the 2215A. Whichever scopes you are interested in, make sure you download the user and service manuals for them. I just did a quick search but couldn't find the service manual for the Phillips or the Iwatsu. +1 for the cheap probe to see if you can get a calibration waveform for each channel on the screen. If you can't get your hands on a probe, a piece of wire from the calibration point to the center conductor of the BNC connector should give you a waveform. Also use the beam finder button to see if you can get anything to show in the screen if it is blank. Common problems are going to be bad or leaking capacitors in the power supplies. You should also expect dirty controls. I bought a Tek 2235 for $40 and when I powered it on the screen only showed a vertical line. I cleaned both channel controls and the time base control with contact cleaner and rotated the controls back and forth a few times and the scope came back to life. Check inside first before powering it on, if possible. If really dirty inside, dust arcing is a possibility and you can check for blown/bulging capacitors at the same time. I'm sure others with way more experience can make useful suggestions. Hopefully your repair, if needed, won't be any more complicated than that.

author: yashrk
author_rank: Frequent Contributor
timestamp: March 16, 2014, 02:02:08 pm
content: Thanx all of you guys for the replies and Dave thanx for you effort and awesome videos.Well I will try for the probe, but I surly will carry one wire with me.I have doubt about 2215A it says TEKHIND on it, did tektronix re-branded it for India or some thing or its a copy ?

author: 6E5
author_rank: Regular Contributor
timestamp: March 16, 2014, 03:24:17 pm
content: The tek 485, if it works, is the Cadillac of bench top analog scopes. It's all discrete transistors, so relatively easy to fix. Thought, they use tunnel diodes in these so if those are dead, good luck trying to find replacements!Here's the manualhttp://bama.edebris.com/manuals/tek/485/Any of the Tek 4X5 series are great. The later 22XXX that Dave has teared down in the past use IC's and are nearly impossible to fix. The hp 1722B is also pretty good.

author: David Hess
author_rank: Super Contributor
timestamp: March 16, 2014, 04:07:42 pm
content: The mentioned Tektronix oscilloscopes and the HP all have full service documentation available. My recollection is that the TekHind oscilloscope was manufactured by Tektronix and renamed for sale in Asia (India?).I prefer the 465B to the 465 or 475 because is as alternate delayed sweep instead of mixed delayed sweep but the 475 has a higher bandwidth. The 485 has a more complicated front end supporting switchable 50 ohm inputs making it more difficult to repair. All of the listed Tektronix oscilloscope use some difficult to replace parts whether they are tunnel diodes or custom ICs but I would consider them all repairable. Note that the faster oscilloscopes also have brighter CRTs which may be an advantage besides their higher bandwidth.The 453, 453A, 454, and 454A are the last Tektronix oscilloscopes which are all discrete.As far as testing, take a cheap x10 probe and use the calibrator output on the oscilloscope as a test signal. Work the vertical and horizontal controls through their full ranges to check for proper operation. At high sweep speeds, triggering on the calibrator output will produce a dim display which is normal.

author: rakesh
author_rank: Unknown
timestamp: March 16, 2014, 05:13:38 pm
content: yes TEKHIND is a tektronix oscilloscope. it was collaboration between tektronix and an indian company by the name of hinditron. i have seen a few tektronix analog oscilloscope bearing the name hinditron sold in india.http://www.hinditron.com/generalinfo/partners.html

author: mtdoc
author_rank: Super Contributor
timestamp: March 16, 2014, 06:01:26 pm
content: Quote from: 6E5 on March 16, 2014, 03:24:17 pmI agree that given similar condition any of the 4x5 series would be a good choice (and yes the 485 is the highest end of these). But if bandwidth is not your primary concern, the newer 22xxx series have nicer user interfaces IMHO - so consider the 2215. Totally disagree about them being "impossible to fix" as they are fixed by home users/hobbyists routinely. Very few custom ICs and with the exception of the notorious U800 chips on the 24xx series, the ICs rarely fail. The tunnel diodes on the 4xx series scopes can also be an issue as mentioned.BTW I own 2 475s (one currently in process of repair), a 2236 and a 2467.

author: echen1024
author_rank: Super Contributor
timestamp: March 16, 2014, 06:10:59 pm
content: The 4x5 scopes are really the definition of an analog oscilloscope. Tek 22xx's are quite nice as well, but as a first scope, the 4x5 would be delightful.

author: vk6zgo
author_rank: Super Contributor
timestamp: March 17, 2014, 02:09:42 am
content: Don't go within a bulls roar of the LeCroy-----1980s DSOs are a bad joke!The HP 1722B sounds nice,but that generation of HPs don't have the same reputation for reliability that the Tek ones do.Among the others,I would say,avoid the 2215--lovely scope,but limited bandwidth & no delayed timebase.All the other Teks sound good.We had an Iwatsu 200MHz scope at one of my jobs,& it was an excellent instrument,so if the one offered is similar,(although lower bandwidth),it is well worth considering.

author: David Hess
author_rank: Super Contributor
timestamp: March 17, 2014, 05:25:45 am
content: Quote from: vk6zgo on March 17, 2014, 02:09:42 amThe original post says it is a 2215A which is not the same as a 2215 internally so they should not be confused. I would have warned about the non-A version because it is a cheaper design known to have reliability problems.The 2215A is 60 MHz and has an alternate dual delayed timebase making it a slower and lower budget version of the 100 MHz 2235. The 2213A is the single timebase version of the 2215A although it includes an uncalibrated delay which is an odd feature.

author: particleman
author_rank: Regular Contributor
timestamp: March 17, 2014, 06:56:12 am
content: IMO you cant go wrong with a working tek scope. If you have no probes at least check the things that you can. Make sure there is a trace ,make sure you can move both horizontal and vertical positions.Make sure there is plenty of intensity and that time/div works.

author: yashrk
author_rank: Frequent Contributor
timestamp: March 17, 2014, 09:34:28 am
content: thank you guys for all your replies just saw that they also have 2235 one also.I will test them all and as soon as I get it I will post its internal photos to you all. Thanks ones again guys.And yaHAPPY HOLITO ALL of you..