Advice - purchasing an oscilloscope - Page 1
Forum section: electronics / beginners

author: Pscylo
author_rank: Contributor
timestamp: November 07, 2013, 07:14:15 pm
content: Hi,Just looking to buy a cheap oscilloscope and this one is available.http://www.ebay.co.uk/itm/111207846934?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649Firstly is it any good if working and secondly does that trace look a bit dim? It's fairly local to me but not knowing the first thing thought I would ask, To be honest I wouldn't even know too much about which probes (doesn't come with any by the looks of it) to buy so I'm already talking myself out of it, but equally looks like it will go cheap and it's not far from me so no delivery charge.Any advice most welcome.

author: TopLoser
author_rank: Unknown
timestamp: November 07, 2013, 07:21:15 pm
content: Bring £80 cash and you can have one of these new with a pair of probes. Comes with built in signal generator as well.http://uk.farnell.com/gw-instek/72-6805/oscilloscope-2-channel-20mhz/dp/4283958?ref=lookaheadI'm in Sheffield, S35.

author: Andy Watson
author_rank: Super Contributor
timestamp: November 07, 2013, 08:10:55 pm
content: Quote from: Pscylo on November 07, 2013, 07:14:15 pmCould easily be a camera artefact. Anything that emits light can really mess with the white balance etc., look at the way the LEDs are blazing!There's still two days to go - time to ask the seller for more photos - with a different timebase setting, or ask to view it. Back in the day (and that is quite a way back!) Hitachi scopes were solid, reliable and often the scope of choice if your budget didn't run to a Tek.

author: Pscylo
author_rank: Contributor
timestamp: November 07, 2013, 08:32:28 pm
content: @ AndyOK, If I went and had a look (I probably will - it's really not far), what could I, as a mere mortal, check without a set of probes? Obviously I can see screen brightness etc, but is it possible to bodge something together out of a few everyday bits and bobs in lieu of a probe, make a basic signal generator etc?@TopLoserThanks for the offer but I haven't got that kind of money to spare.

author: TopLoser
author_rank: Unknown
timestamp: November 07, 2013, 08:35:19 pm
content: I'll call in tomorrow morning and check it out for you. It's spitting distance from me.

author: Pscylo
author_rank: Contributor
timestamp: November 07, 2013, 08:43:38 pm
content: That would be very much appreciated and far beyond what I expected. I guess you must work somewhere central, I would have to make a special journey. Generally I avoid the city centre if at all possible.

author: TopLoser
author_rank: Unknown
timestamp: November 07, 2013, 08:46:54 pm
content: It's right next to the Morrisons in Hillsboro, the one behind the B&Q.

author: Pscylo
author_rank: Contributor
timestamp: November 07, 2013, 08:57:37 pm
content: I'm south side, Jordanthorpe so it's a bit of a hike for me. As I say though much appreciated.

author: KJDS
author_rank: Super Contributor
timestamp: November 08, 2013, 08:25:40 am
content: Generally, Hitachi scopes of that era are ok. They are mostly made from readily available leaded parts and are well made.I don't know if that picture is a photo artifact or if it is a timebase fault. I've seen a fair few with timebase faults but they are fairly easy to work on but I've still not found a service manual for those.The other issue I've seen a lot of is a vertical problem on one or two amplitude settings which can be cured just by winding the knobs to and fro for a while, or in extremis, getting some cleaning solution in there.

author: grumpydoc
author_rank: Super Contributor
timestamp: November 08, 2013, 09:34:27 am
content: QuoteDitto that - I sold a couple of Hitachi's (a 665 and 1065) at the beginning of the year and they're nice 'scopes - nearly kept the 1065 for the bench.One thing to watch out for with the 665/1065 (and the related models) is that they're controlled by an odd quad-in-line microcontroller which you'll only be able to get by pulling one from another 'scope. Other than that I think they're pretty totally off the shelf stuff. Bear in mind that what was off the shelf in the 90's is sometimes hard to track down nowadays but most of the stuff should be OK.

author: Yago
author_rank: Frequent Contributor
timestamp: November 08, 2013, 12:33:22 pm
content: Note that EBay listing states "For Parts or Not Working" !

author: grumpydoc
author_rank: Super Contributor
timestamp: November 08, 2013, 01:24:24 pm
content: QuoteTrue but probably irrelevant.You have to look at the auction critically whether a 'scope is labelled working or not. There are a few decent vendors - kjds for instance and I'd like to think that I try to be honest about the stuff I sell but even there an item could leave intact and not work when you power it up through no fault of ours. I usually send 'scopes out with a calibration report - as much as anything so that I know I've tested everything but it takes a lot of time and the only reason I can do it at all is that I sell a fairly low volume of stuff. I don't think anyone else does this, I also check for electrical safety which, again, most sellers would probably laugh at me for despite it actually being a legal requirement in the UK.There are also plenty dealers with low scruples around on ebay - I bought a Hameg 605 sold as "working" last year, when I received it there were so many dry joints on the board I thought it must have previously been owned by one of the temperance societies - several switches actually fell off the board when I removed the shafts to clean and lubricate them so there's no way it ever worked correctly.Finally there are some vendors who genuinely know little about 'scopes so "working" might just mean "didn't go bang and some lights went on when I plugged it in". Of course some of the suspect vendors might try to hide behind "I don't know much about these...."In this case the vendor probably does know little about 'scopes so is being cautious. The trace does look slightly odd but that could just be that the camera shutter only caught half of the trace. It's more significant that the 'scope isn't shown displaying any sort of waveform but there's at least a chance it's OK. It does at least appear to be able to generate a trace so some of the harder and more dangerous bits (the HT transformer and multiplier) are OK and the odds are that the CRT is OK.If a vendor lists an item as "parts or not working" and actually says "this doesn't work" you probably know where you stand, otherwise read the listing carefully and treat everything as potentially needing some work before it is fully functional.

author: TopLoser
author_rank: Unknown
timestamp: November 08, 2013, 01:35:28 pm
content: I'm unexpectedly stuck in Barnsley hospital at the moment, not sure if I'm going to get out before the shop closes today. I spoke to the seller this morning and they don't have any idea what it is or what to do with it. Not sure if they are open Saturday.

author: Yago
author_rank: Frequent Contributor
timestamp: November 08, 2013, 02:47:04 pm
content: Quote from: grumpydoc on November 08, 2013, 01:24:24 pmAgree Doc (especially the photo part) .I was just pointing it out to the OP as he said he said "not knowing the first thing" .If things go pear shaped with a dodgy seller there is no comeback on such a listing .

author: Pscylo
author_rank: Contributor
timestamp: November 08, 2013, 02:59:30 pm
content: There was a little hyperbole with respect to my knowledge.I do know a little about the individual parts that comprise an oscilloscope and have done some very limited work on CRT TVs in the past I just have no experience of oscilloscopes, but I had read the full details.I may not have done myself any favours posting the link here though and I doubt I'll be bidding. I'm aware of how many people are watching this item and it's out of proportion to what the item is.Thanks for your concern though.

author: Yago
author_rank: Frequent Contributor
timestamp: November 08, 2013, 03:36:29 pm
content: No worries bud , I am a hippy at heart

author: Andy Watson
author_rank: Super Contributor
timestamp: November 10, 2013, 01:24:14 pm
content: So ? Did somebody here get it ?

author: Pscylo
author_rank: Contributor
timestamp: November 12, 2013, 12:52:24 pm
content: I didn't bid in the end. Got myself a Tek 465 instead. Two nice sharp traces on it - effectievely with a guarantee though I have got to purchase some probes.

author: grumpydoc
author_rank: Super Contributor
timestamp: November 12, 2013, 01:08:57 pm
content: QuoteI have some fairly OK new 100MHz probes which you can have for £5 ea (plus postage). PM me if interested.