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Electronics => Beginners => Topic started by: AmrasElensar on August 24, 2018, 03:27:58 pm

Title: Philips PM3207 or cheap DSO kit as first scope
Post by: AmrasElensar on August 24, 2018, 03:27:58 pm
Hi all,

I’m looking for my first scope to experiment a bit, mostly while doing Arduino and Rpi projects. Or for trying to find issues when trying to repair old electronics.
I can pick up and old pm3207 scope for 15€ without a probe. The guy selling it doesn’t know anything about it but the picture at least shows a horizontal trace.

My question is: should I still get this or maybe one of those cheap diy kits like from jyetech? (Dso138 mini or so)
Other suggestions always welcome.
Thanks in advance
Maarten
Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: janoc on August 24, 2018, 04:41:20 pm
If that old PM3207 scope works then do get that. That's a decent scope for a beginner and the price is a steal. Probes can be obtained online cheaply, for a 15MHz scope you don't need anything expensive.

The cheap DIY kit "scopes" are toys that are very much completely useless - very low bandwidth (often in tens of kHz tops), low sampling rate, lack proper probes, horrendous user interface, etc. I have tested one, it wasn't able to show even a 20kHz sine wave properly - i.e. useless even for audio.  Those gadgets are just a microcontroller with an LCD using the internal ADC for digitizing the signal + power regulator and a few buttons. Don't waste your time and money on that.

Later on start saving and you can get a very good modern digital scope for some 300-400 euro already - that is more useful for digital stuff because you get single shot captures, you get various serial protocol decoders, etc.
Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: Mr. Scram on August 24, 2018, 04:51:24 pm
Get the real oscilloscope. The DSO138 is a fun thing, but hardly a real oscilloscope. It also is limited in ways that can be confusing to the uninitiated.
Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: Gyro on August 24, 2018, 07:07:33 pm
Get the real PM3207 scope. Do some checks to make sure it's working - a simple piece of wire from the input connector center pin to the Probe Adj. terminal will show you whether it can display a waveform. As janoc says, you can pick up low frequency (probably 60MHz) probes very cheaply on ebay etc.

Quote from: janoc on August 24, 2018, 04:41:20 pm
Later on start saving and you can get a very good modern digital scope for some 300-400 euro already - that is more useful for digital stuff because you get single shot captures, you get various serial protocol decoders, etc.

Pick up one of those cheap 8 bit USB logic analyzer clones for around EUR10, use it with open source Sigrok Pulseview and it will cover all your needs for capturing land decoding data streams and protocol decoding on the Arduino etc. That way you will have the best of both worlds at very little cost, you can look at both the Analogue and Digital domains.





Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: AmrasElensar on August 24, 2018, 07:24:45 pm
Thank you all for your quick responses and insights. My gut was telling me to go for the real scope as well. Waiting for a response from the seller now.
I’ll look in to those Logic analyzers as well.
Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: joseph nicholas on August 24, 2018, 07:29:35 pm
One thing to keep in mind though, with those old scopes, if it needs repair your are probabily in for a car load of problems repairing it.  Everyone says they found it in the atic when their crazy uncle died but in reality many have had a go at repairing it and fucked it up permanently and want to sell it for a profit instead of putting it out on the curb for recycling.
Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: Gyro on August 24, 2018, 07:45:52 pm
The helpful thing is that a scope with that low a bandwidth won't use any special parts. The CRT sounds to be ok if it's showing a horizontal trace, hopefully it's just absence of probes that is preventing further testing. For EUR 15 it doesn't sound like a huge gamble.

Service manual is here (multi-part download)... https://www.eserviceinfo.com/downloadsm/27668/PHILLIPS_PM3207.html (https://www.eserviceinfo.com/downloadsm/27668/PHILLIPS_PM3207.html)
Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: janoc on August 24, 2018, 10:05:33 pm
Quote from: Gyro on August 24, 2018, 07:07:33 pm
Get the real PM3207 scope. Do some checks to make sure it's working - a simple piece of wire from the input connector center pin to the Probe Adj. terminal will show you whether it can display a waveform. As janoc says, you can pick up low frequency (probably 60MHz) probes very cheaply on ebay etc.

Either that or even touching the wire in the input connector should produce some distorted 50/60Hz sinewave on the screen. If it does the scope is likely OK even though it may still need some cleaning (mainly switches) and adjustments.

Quote from: Gyro on August 24, 2018, 07:07:33 pm
Quote from: janoc on August 24, 2018, 04:41:20 pm
Later on start saving and you can get a very good modern digital scope for some 300-400 euro already - that is more useful for digital stuff because you get single shot captures, you get various serial protocol decoders, etc.

Pick up one of those cheap 8 bit USB logic analyzer clones for around EUR10, use it with open source Sigrok Pulseview and it will cover all your needs for capturing land decoding data streams and protocol decoding on the Arduino etc. That way you will have the best of both worlds at very little cost, you can look at both the Analogue and Digital domains.

That $10 logic analyzer is a good thing to get, good idea.

However, I would still say that longterm, assuming he will want to get into the electronics a bit more seriously, the DSO will be still a money well spent. The single shot capture and higher bandwidth (important if you want to see the fast square wave digital edges) are worth it alone when troubleshooting misbehaving digital circuits. The 15MHz analog scope can't capture those glitches and a logic analyzer will not show a noisy/distorted data line.

The decoders on a scope are also convenient even if they are crap - if all you need is a quick check whether the communication is running as it should, a decoder on the DSO is often faster to hook up and set up than setting up a logic analyzer and Sigrok. Of course, for more serious debugging the logic analyzer will likely be better than the serial decoders on the cheap DSOs.


Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: GreyWoolfe on August 25, 2018, 10:41:39 am
Quote from: janoc on August 24, 2018, 10:05:33 pm

However, I would still say that longterm, assuming he will want to get into the electronics a bit more seriously, the DSO will be still a money well spent. The single shot capture and higher bandwidth (important if you want to see the fast square wave digital edges) are worth it alone when troubleshooting misbehaving digital circuits. The 15MHz analog scope can't capture those glitches and a logic analyzer will not show a noisy/distorted data line.


Let him dip his toes in the kiddie pool with the Phillips.  Then he can get the better scope.  And then another better scope.  And another.  And don't forget multiples of signal generators, multimeters and so on until he becomes a fixture on the TEA thread. :-DD
Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: daybyter on August 25, 2018, 10:57:09 am
Maybe a USB scope, like the hantek 6022be or bl is an option, too. See the thread in this forum.
Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: janoc on August 25, 2018, 11:22:50 am
Quote from: daybyter on August 25, 2018, 10:57:09 am
Maybe a USB scope, like the hantek 6022be or bl is an option, too. See the thread in this forum.

Nah, no. Not for a beginner. Great way to get the heck confused out of you if you don't understand the limitations (and crappy software) and to blow up both the scope and your computer if you aren't careful how you connect it. If he blows up the Philips he blew only a 15 euro scope - and then it is likely easy to fix too. Good luck doing that with an USB scope.

A real scope with actual knobs and switches is perfect for someone just starting out and learning how to use it. USB scopes are useful if you need to troubleshoot on the go or in the car but not something I would recommend on a bench.
Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: AmrasElensar on August 25, 2018, 10:52:29 pm
Very valuable info, Thank you all for contributing. Seller had somebody else interested, so I upped my bid to 25€. Still seems Very  I was looking at some cheap USB Logic analyzers. Would this be suitable?

Code: [Select]
http://s.aliexpress.com/yMjEfUnU

Reported to work with pulseview
Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: Mr. Scram on August 25, 2018, 10:57:08 pm
Quote from: AmrasElensar on August 25, 2018, 10:52:29 pm
Very valuable info, Thank you all for contributing. Seller had somebody else interested, so I upped my bid to 25€. Still seems Very  I was looking at some cheap USB Logic analyzers. Would this be suitable?

Code: [Select]
http://s.aliexpress.com/yMjEfUnU

Reported to work with pulseview
Yes. It's great for lots of jobs. Just make sure your use a USB port that is fast enough, as it's a streaming device. It should also work with Sigrok. It's an amazing tool for the money.
Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: AmrasElensar on August 26, 2018, 10:26:45 am
Sadly the Philips was snatched up before me even after bieding more.
I also found a Gould Advance OS245A, he’s asking 40, but I was going to offer 30.

Unless you guys recommend against it?

Code: [Select]
https://www.2dehands.be/link/elektronische-apparatuur/overig-apparatuur/elektronica-meetapparatuur/oscilloscoop-gould-advance-os245a-436714191.html?utm_campaign=socialbuttons&utm_content=app_ios&utm_medium=social&utm_source=other

Or a hameg hm203-6, No asking price. Just asked if it’s still working
Title: Re: Philips PM3207 or cheap DSO kit as first scope
Post by: janoc on August 26, 2018, 02:41:50 pm
That Gould is a bit too ancient and too low end (10MHz is not great ...). That Hameg is better if you can get it.

Or watch eBay - there are plenty of used 100Mhz or so Tek and Phillips scopes showing there. You should be able to find one in a working condition for about $100-$150 quite regularly. It doesn't make sense paying more because then you can get a cheap new scope already for the price.