DSE Q1803 $128 CRO

Hi to all,

Picked up one of these 10MHz, single beam CROs from my local DSE store last Tuesday - there were none on display and the staff seemed unaware of its existence. The unit comes in a carry box, well packed with IEC mains lead,

10:1 probe and small handbook written by DSE staff.

Using a bench sine/ square generator and frequency counter when back at home, I found my unit met published accuracy specs - time base speeds being particularly accurate.

The *green* trace on the 75m dia tube face is particularly sharp and geometry is very good all over the (external) graticule. The vertical and horizontal positioning pots allow the pattern to be moved right off the screen without visible limiting - so the deflection amplifiers have adequate headroom.

The internal (Y) synch appears to function well as does the external and LINE synch inputs. There is an X-Y mode that works fine too. There is no "trace rotate " control, but two screws on the rear can be loosened to allow the tube and hence trace to be lined up with the graticule OK.

Now for the insides:

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With the vinyl coated steel sleeve slid off, there is a nice surprise. This little CRO is *very* well made - reminiscent of the way Aussie firm BWD built their famous CROs.

There are no SMD, all parts are "garden variety" - ie TO92 pack transistors, TO220 regulators, a couple of fets and 3 bog standard ICs. There is one large PCB for the PSU, deflection and synch circuits while a smaller one at the front covers the vertical attenuator, input pre-amp and time base circuitry.

Both sides of these (single sided, through hole) PCBs are fully accessible for servicing !

A very neat, 20 VA, R-core transformer powers the CRO with a ferrite HF inverter supplying 1200 volt DC to the tube. All internal voltages remain regulated down to 200 volts AC input.

The 75mm tube is covered in a black, very snug fitting, full length MAGNETIC SHIELD !! This is practically unheard of in a low cost CRO and means the unit can be used, without annoying trace jitter, quite close to AC power transformers used by other items on the bench or the equipment under test.

The AC current draw was only 84mA rms ( 20 VA ) - so operation from a small 12volt / 240 volt inverter supply is possible.

One anomaly I found - the CRO comes fitted with a 0.75 amp AC fuse. The DSE handbook and the back label on the CRO both say this is the intended value - which is nonsense since it offers no protection for the 20 VA transformer. Best replace it with a 160 mA, slo-blo type.

Although not indicated anywhere, I expect the CRO was manufactured in China or just possibly Korea. One would have to remove the CRO tube to see where that was made.

My conclusion:

At a mere $ 128 inc GST and probe, this has got to be the biggest bargain in

*new* test gear you can buy in Australia.

....... Phil

Reply to
Phil Allison
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Thanks for the excellent review, Phil. Might get one of these myself, I'm sick of making do without a CRO.

Clifford Heath.

Reply to
Clifford Heath

"Clifford Heath"

** Any electronics hobbyist without a basic CRO is flying blind.

Treat yourself before DEE change their mind or delete it.

Then you *will* have something to CRO about !

...... Phil

Reply to
Phil Allison

"Phil Allison" wrote in news: snipped-for-privacy@individual.net: [...]

I'll admit that I haven't used a CRO since high school, and I'm not even sure I know how to operate one anymore. Nonetheless, I still appreciate the detailed review. Thanks Phil.

GB

--
 "Men will never be free until the last king is strangled with the 
  entrails of the last priest." (Diderot, paraphrasing Meslier)
Reply to
GB

They were $118 here in kiwiland, but that offer ended today. Bugger!

Bye. Jasen

Reply to
Jasen Betts

So the truth finally has come out hey Phil? It IS a HOBBY business you're running from that bed-sit flat you rent. LOL!

Reply to
Alan Rutlidge

Ha ha - pretty likely too once they realize they've accidently got a

*good* product at a good price. I've done a fair bit by flying blind, it's amazing what you can improvise, but obviously better not to have to.
Reply to
Clifford Heath

Bug off, Rutlidge. It's obvious that I'm the hobbyist. Try not starting a fight for a change, and offer something of half the value of what Phil has instead. If you can.

Reply to
Clifford Heath

First off Clifford, if I wanted to have a go at you I'd have directed my reply fairly and squarely at YOU, by mentioning YOUR name. Find where I mentioned your name in that reply and I'll be more than prepared to apologise to you.

Secondly, the CRO is quite okay for a hobbyist, and probably perfectly adequate for your personal needs, BUT Phil claims he is a PROFESSIONAL audio technician. Anyone who is or was would know a 10MHz single trace CRO with such a small (75mm) screen wouldn't cut the mustard in the professional ranks. I'm surprised Phil has bothered to buy one, except of course if he didn't have a better CRO to begin with. :P

If I offered one of these DSE CROs in question for use in class, even the 1st year electronics students would LTAO.

Nuff said.....

Cheers, Alan

Reply to
Alan Rutlidge

Thanks for the review Phil. My poor old 1968 vintage BWD521 no longer triggers properly and the vertical attenuator switches keep growing metallic whiskers and shorting. For the amount that I use a CRO at home now, that one would probably do most things I need it to do to more or less replace the 521. It's very tempting, especially with a shielded CRT... Interesting that the photo on the DSE website shows the probe connected to the X input. :)

Bob

Reply to
Bob Parker

"Bob Parker"

** Well, the same pic shows a CRO that is not even powered up.

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........ Phil

Reply to
Phil Allison

The photographer probably switched it off in disgust when he couldn't tune a single TV station....

Reply to
Bob Parker

And he likely connected the probe where he did so it didn't cover any of the other switches and controls in the picture. Who expects a photographer to know how a scope works?

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
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Reply to
Michael A. Terrell

I still have a DSE CRO (5MHz I think) that I bought for at least twice the price of this one. It must have been nearly thirty years ago. It was modest and useful. It still works. I think that this new scope, at this price, is astonishing. And Phil, I forgive you your dreadful pun.

Reply to
T.T.

I knew you weren't having a go at me. I was just objecting at you trying to turn a perfectly focussed and relevant chat about a CRO, into one about Phil. I'm not interested in whatever personality defects you or Phil exhibit, I just wish you'd make an effort to keep things civil and on-topic instead of deliberately up-ending every thread he enters.

Oh, I get it - you aren't even making real money from your knowledge, just teaching it instead. Pot, kettle, black!

Reply to
Clifford Heath

Yeah, that was what I thought too. :) DSE's moving further and further away from nuts & bolts electronics. Maybe it should be renamed to Dick Smith Consumer Electronics? I found an interesting entry about DSE in that Wikipedia thing:

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Bob

Reply to
Bob Parker

All that, and no mention of the only DSE item I've ever bought? ;-)

--
My sig file can beat up your sig file!
Reply to
Michael A. Terrell

Not up ending his post, just commenting - there is a difference. However whilst you are on the subject you might check Phil's track record for squeeky cleanness.

Ha, ha, ha, very funny Clifford, but you left the toaster bit out. :-) It's supposed to go "Pot, kettle, toaster, black." :P

Well, Clifford, teaching electronics must be a significantly more profitable business than fixing it. Take Phil's non-GST reporting business. To qualify to trade as a non-GST reporting entity his annual turnover (yes turnover, before deductions, tax etc - NOT profit) must be under $50k. Now this would be okay if you were semi-retired and just running a part-time business to keep oneself active or to make a bit of pocket money, but you can't seriously make a living from it. Considering Phil rents his flat yadda, yadda, yadda; I can't imagine (and nor can my accountant) how someone could scrap a living out of that business situation.

Phil tells us all the time that he is a professional technician. If the most useful piece of test equipment in his workshop is a $128 DSE CRO - hmmmm well I somehow would question his claimed credentials of being "professional". As I said, the average electronics TAFE level student would laugh their arse off if presented with the DSE CRO and asked to do a lab with it.

Oh, and BTW, I'm not knocking the fact that he has decided to evaluate the DSE CRO and post it here. I think it was a good idea and he should be applauded for doing so.

Cheers, Alan

Reply to
Alan Rutlidge

Now vastly expanded. Might be worth another look ;)

Peter

Reply to
Peter Parker

Oh and there's also a big Tandy rant at:

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Reply to
Peter Parker

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