What to look for in $50 analog oscilloscope? - Page 1
Forum section: electronics / testgear

author: yami759
author_rank: Contributor
timestamp: November 17, 2014, 06:17:33 am
content: Hello everyone, I hope that someone could help me out with this (this is my first forum post). I am a student who has been learning electronics on my own, and soon will be taking actual courses(I attend a combination high school/college). Only 15, I am still unable to get a job, and, using the little money I have, am hoping to purchase an oscilloscope. I do not have nearly enough for a good, $400 digital one, so am hoping, from what I have heard from Dave's channel, that I will be able to acquire an analog for a good price. Or, if any of you experienced members have an old one in any sort of condition at all that you would like to have taken off your hands, I'll be more than glad to take it off your hands. Now, being more reasonable again, as this would be my first oscilloscope purchase, what is it that I should look for? I know that for $50, the standard is a 2 channel 20 MHz unit, but other than that and it being functional, what else should I be looking for in my search? Again, being just a student, I will not be using this for specific areas; just general electronics. Any help would be greatly appreciated.P.S. I am in the United States, specifically, California.

author: Vgkid
author_rank: Super Contributor
timestamp: November 17, 2014, 07:25:34 am
content: Most important rule is...Does it work?Also, what other gear do you have, in the event that it starts messing up.

author: tautech
author_rank: Super Contributor
timestamp: November 17, 2014, 08:11:43 am
content: Quote from: Vgkid on November 17, 2014, 07:25:34 amNot mine.Rule #1If a Service manual is not available for it....look for another scope.Plenty of links to get manuals in the Repair board.Old CRO's, while cheap have limited features compared to DSO's are less reliable IME.While that should not stop you from owning and experiencing a CRO's UI, use this experience to gain understanding of scope use and then aim to get a DSO as well.Likely you will need the DSO to repair the CRO.This should not put you off, just pre-warn you.

author: xwarp
author_rank: Frequent Contributor
timestamp: November 17, 2014, 08:30:36 am
content: Quote from: tautech on November 17, 2014, 08:11:43 amI've got 2 Tek Type 422's that work just fine and these are late 60's units.The previous mentioned 422's did not work at the time I got them and both were fixed using another CRO, so no, a DSO is not needed to fix a CRO.Just my opinion, but plenty of scopes out there that are 20+ years old still going strong.

author: Pinkus
author_rank: Frequent Contributor
timestamp: November 17, 2014, 08:44:02 am
content: Place a note on some bulletin boards (e.g. at some supermarkets around) and show that you are a looking for a cheap analog scope. I am sure enough people will have an old scope they put away and forgot about it (because they purchased a digital one in the past years). They will give it away for small money or even for free because they are happy that there is a 15 year old boy interested in something real and not just playing around with its smartphone (I would do so - if I still had one).Here is a virtual scope you may try:http://www.virtual-oscilloscope.com/If you became familiar with it, you will be able to check out the basic functions of a real scope.Hint: You need to switch it on first and you need to connect at least on of the cables at the bottom to one of the two channels (then switch ti the correct channel, default is one - the left BNC connector)

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 17, 2014, 11:04:29 am
content: What to look for at $50? Spare parts...Working 465, 475 and 22xx series scopes (the most popular) seem to start around $100.You can buy two non-working and swap around or replace parts until it gets there, but that's a hassle (and not really for a beginner, if I'm reading into that right).Tim

author: PaulAm
author_rank: Frequent Contributor
timestamp: November 17, 2014, 12:17:18 pm
content: You didn't say where in CA you were, but if you're around a largish city, look on the local Craigslist. You might have to look a bit, but you will probably find a working Tek or HP scope for $50-75. You will probably find a working 20 MHz scope for $25-35. They're out there if you're patient. Stay away from Heath and Eico scopes.DSOs are great, have lots of useful features, a requirement for doing some types of work, but you can do quite a lot with an older analog scope.

author: rsjsouza
author_rank: Super Contributor
timestamp: November 17, 2014, 12:31:03 pm
content: As PaulAm mentioned, CA would be a great place to look for in Craigslist. Also, don't restrict your search to Tektronix or HP - my reliable Kenwood CS4025 has full service manuals available, others found and repaired Hitachi and Hameg scopes, and even Dave did a review of a Hameg:Another video from Dave would be interesting for your search.

author: KJDS
author_rank: Super Contributor
timestamp: November 17, 2014, 12:42:19 pm
content: I've had a lot of analog scopes, and the Kikusuis have been the most reliable.

author: Muttley Snickers
author_rank: Unknown
timestamp: November 17, 2014, 12:44:39 pm
content: My advice would probably be for you to go along to a ham radio swap meet, you should find plenty of people to give you a good guide, both seller's and browser's.Never be in a rush to buy anything, your money is worth more than theirs any day of the week, doing all your money cold in a craigslist find doesn't sound like fun at all to me, unless the seller is say a TV repair shop or again a ham radio operator.Q: What you don't want to find in a $50 scope ?A; Mouse droppings and spider webs.Good Hunting.Muttley

author: coppice
author_rank: Super Contributor
timestamp: November 17, 2014, 01:16:25 pm
content: Quote from: KJDS on November 17, 2014, 12:42:19 pmThere are a number of good Japanese scopes that should be available pretty cheap in California - Kikusui, Kenwood, Hitachi, Panasonic, Yokogawa, Iwatsu. In fact, its hard to think of a Japanese brand that sucks, although everyone has made the occasional model that sucks.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: November 17, 2014, 05:02:06 pm
content: Quote from: yami759 on November 17, 2014, 06:17:33 amWhich part of california?

author: Smith
author_rank: Frequent Contributor
timestamp: November 17, 2014, 06:20:20 pm
content: 1. Get a good brand, you are much more likely to get some support on forums2. See if it has a service manual. It can be very difficult to repair a scope without one.3. Does it have probes? Most of the times its cheaper to buy a scope with probes then buy them separately.Getting an analog scope as your first scope is a big plus. You will really learn so much more. It makes you think about your measurements and settings instead of pressing the auto button all day long.

author: yami759
author_rank: Contributor
timestamp: November 18, 2014, 02:15:36 am
content: Thank you all so much! I didn't expect such fast responsesQuote from: Vgkid on November 17, 2014, 07:25:34 amThe only other gear I really have at the moment is my dad's old multimeter (it was quite a good one at the time I believe, however, and still works just fine) and a horrible plug-into-the-wall soldering iron. I am planning on upgrading to a Hakko FX-888D soon. I also am going to convert an old computer power supply into a bench power supply.Quote from: Pinkus on November 17, 2014, 08:44:02 amThanks for the advice and the link! I'll be sure to check it outQuote from: T3sl4co1l on November 17, 2014, 11:04:29 amFrom what I've seen/heard from Dave, it seems to not be very hard to pick up a scope for around that price range, or perhaps for a tad bit more.Quote from: PaulAm on November 17, 2014, 12:17:18 pmI've tried that already; I live in Stockton, CA, not that big of a city. The only oscilloscope I found in my city is a $150 scope. I could, however, try to search for one farther away from me if necessary.Quote from: Muttley Snickers on November 17, 2014, 12:44:39 pmThanks for the advise!Quote from: Smith on November 17, 2014, 06:20:20 pmAgain, thanks for the advice!

author: David Hess
author_rank: Super Contributor
timestamp: November 18, 2014, 06:53:50 pm
content: Given your location, I think you are in a better position than most looking for good used test instruments available locally. I lived in that area including Stockton for many years.I would limit my search to oscilloscopes which have complete service documentation available; before about 1990, Tektronix and HP were really good in this respect and there are online forums covering both in detail.A signal source like a pulse or function generator can be used to test performance and diagnose problems which are not readily apparent.Quote from: T3sl4co1l on November 17, 2014, 11:04:29 amI have found 465 series and the lower end of the 22xx series oscilloscopes in good if not working condition for $50 fairly often. The 465 series have linear power supplies which are easier to repair than the switching power supplies in the 22xx series but being older, they also suffer from more mechanical problems. The tunnel diodes in the 465 series can be difficult to replace.QuoteI have used the method of buying two non-working oscilloscopes to build one working one before but always ended up repairing both easily. Luck and experience were a factor though and I would not want to depend on this happening.Quote from: tautech on November 17, 2014, 08:11:43 amWhen people have asked me what oscilloscopes are good for, I often respond that they are good for repairing other oscilloscopes.

author: lowimpedance
author_rank: Super Contributor
timestamp: November 18, 2014, 10:46:22 pm
content: Not much more to add to all the good advice above except to be patient, given your location something will pop up. (unlike the equipment desert down here in Oz!).One thing I will add is you should consider using your equipment to build your own simple power supply (say a KIT etc), and not use computer supplies. (Of course finances permitting).Or perhaps the next purchase would be an older brand name supply after the CRO.A few general pieces of test gear to start will get you a long way, so have a good look around.Good luck and remember to have fun.

author: DAIRVINE
author_rank: Contributor
timestamp: March 09, 2015, 10:14:12 am
content: Analog scopes have faults and go wrong and require repair. Not a job for a beginner and also potentially lethal. You will be too tempted to open up an old scope when it goes wrong. This is a necessary learning process, but you need to know what you are doing and understand safety first. Only the front of CRTs are protected, damage to the back part can cause an explosion and electric shocks are waiting to happen a long time after power is removed.If you must get an analog scope go for something as young as possible and not too complicated and fully working.If you can get a student discount get the Digilent Analog Discovery for 99$ with a BNC adaptor.

author: Smith
author_rank: Frequent Contributor
timestamp: March 09, 2015, 02:16:47 pm
content: If repairing analog scopes get you killed, this forum would be verry quiet.My advice:1. Get one with a (online) service manual.2. Preferably a well known brand name, means more change anyone online can help you out in case of need.3. Preferably including probes! Sometimes they're more expensive than the scope itself.

author: AF6LJ
author_rank: Unknown
timestamp: March 09, 2015, 02:33:46 pm
content: To be honest; someone here had said that for fifty dollars you would get spare parts and I would have to agree with that poster. I picked up a Tek 466 (storage tube version of the 465) from a former coworker for a hundred dollars. That is about the cheapest I have seen except for the military scope I have that by the time I got it working cost me a hundred dollars.