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Recapped my TDS460. It's definitely of the "replace boards" ilk. No schematics, terse and vague service manual. Hardly any silkscreen on the boards, not even any designators (though at least they had the foresight to keep the "plus" marker on the SMT cap footprints).
Tim
-- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
One of the reasons I never warmed up to that series. In fact, they lost a sale back when I started self-employed because of the lack of schematics. I told the Tek rep in his expensive suit that I'd plunk down the money (the equivalent of a small car back then) if he furnishes schematics. He couldn't do it and hence no sale.
-- Regards, Joerg http://www.analogconsultants.com/
Yep. Next time I'm in the market, it's going to be an Agilent I think. The HP/Agilents from circa the name change seem to be quite good.
My old Tek 475 is still here and works (when it does.. some parts are kind of crunchy and still need replacement). Going from 200MHz dual channel to
350MHz quad channel was a good move; obviously, the next will have to be 4 channels, at least 500MHz. maybe a clean gig. :)Tim
-- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
I had looked at that. Didn't bite. Instead I bought a Taiwan-design scope, built in China. Never regretted it. But one must be careful, the arb gen I bought was a Chinese design and that isn't a very good design, has some serious flaws.
In a DSO that will be expensive. For fast stuff I have a HP54110D. 4-ch
1GHz, but it's a repetive sampling scope from the boat anchor days. Sometimes I wish I had one of the big Tek sampling scopes. When it goes way beyond a GHz, like right now. The problem is lab shelf space.-- Regards, Joerg http://www.analogconsultants.com/
I forget, was that one of the GW Insteks?
Even the Rigols, they used to be worse than the TDS1000s. Nowadays, they've been polished to the point where they're seriously good entry-level (or portable/bench level) hardware.
Rigol has been kind of hit-and-miss over their product line, I guess. I've been watching Dave Jones' reviews and teardowns of various equipment. Their bench PSU for example, he found it had some pretty bad PCB layout and thermal design in it. Thanks to his publicity, they actually fixed it and shipped replacement boards (if you can imagine!). Even so, the interface is rather goofy (a ring-of-buttons instead of a numpad, let alone just a knob?!).
It's my understanding the Instek and such are about as good as big name brands. That said, I'm surprised the entry level Agilents are as cheap as they are (a few $k), for being name brand. (Well, I guess they won't be Agilent anymore, but...)
The 54k series seems to be very popular. I've seen a lot of 54600s, the light bench series ones. Pretty basic 100MHz dual channel, doesn't even have very good sampling performance (muxed 20MSa/s I think), but solid kit, and as much quality as you expect from the name.
In that period (i.e., the 80s-90s, contemporary with the TDSs), HP did right what Tek utterly failed on: the user interface is always instantaneous. It takes me fully several seconds to flip through menus on the TDS460, even just to change something basic like trigger polarity -- insane!
Tim
-- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
Yes, Instek GDS-2204.
Mine was much better than the comparable Tek and cost 30% less. And the remote control software was free.
Are they really still American scopes or re-branded ones?
True. I hadn't used the 54110 in over a year and now, because of a new assignment, needed it. I could operate it as easy as hopping on a bicycle. HP always knew how to do user interfaces.
-- Regards, Joerg http://www.analogconsultants.com/
You have a 7704A, right? I see good 7S12s on sale, from time to time. That and a 7S11 should get you a couple of channels. A few plug-in, plug-ins, and you have nice sampler and TDR. I'm thinking about trying to snag a set for work. Though they don't usually like to buy used, I can't justify $100K, even of their money, for a new TDR.
The 7S series was mediocre. The tunnel diode step generator isn't very clean.
You can get an 11801+SD24 on ebay for a grand or less. They are superb quantitative instruments, super clean 20 GHz response. But they are huge.
That's an 11802, the old b/w version with two head sites and two signal delay lines.
-- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
The 11800 series scopes are things of great beauty. I have two, one courtesy of a friend, and another that was going for a steal on eBay, plus about 16 plugins. If you have a repetitive signal, the bang for the buck is unbeatable. (I'm still fishing for an SD-32 50 GHz sampler, but I have almost all the others.)
I use SD-24 TDR heads to drive laser diodes, among many other things--you set a DC bias right around threshold, then the ~200 mV, 17 ps step makes an excellent torture test for one's prototyping skills. ;)
It's really worth getting an EIA rack to hold some of this stuff.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
He said his problem was lab shelf space. ;-)
I'm not sure what, if anything, we'll buy. Like I said, they frown on used equipment (no process for it and periodic calibration can be an issue with these things). I guess we could use a credit card but the boss would have to provide cover. ;-)
I could sell you some stickers
ENGINEERING USE ONLY calibration not required
-- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
I just don't want another boat anchor. Technically it can't be that expensive to do it via USB and people seem to have done it:
But I haven't seen any real deals offered, with (reasonable) Dollar numbers next to them. Maybe the market is just too small or has shriveled up?
Buy John's "Engineering Use Only!" stickers :-)
-- Regards, Joerg http://www.analogconsultants.com/
That's good enough for ISO9000 but that's not the problem. Decisions and common sense are rare commodities in large corporations, particularly foreign-operated ones.
The 7S series aren't boat anchors. The 1180x certainly qualifies. ;-). PhilH's suggestion of a rack is in order, though I certainly don't have room for either in my office.
No manufacturing gets done at our site (or in this country, even) but they still want up-to-date calibration on Phillips screwdrivers. ;-)
But they aren't very good either.
That's precisely my problem as well. There's been plenty of attempts at USB samplers. But one does not seem to be able to buy them or the dealers are secretive about pricing. This looks enticing:
I remember one company where it was the same. You were measuring, reached up to press the single-shot trigger button but there was no more button. It had disappeared along with the scope around it, only the cables were lying on the shelf. In the distance you saw an electric cart disappearing. Cal time meant full stop at high noon, come hell or high water.
-- Regards, Joerg http://www.analogconsultants.com/
The best? Perhaps not but they aren't useless. I had a bunch, 30 (7S12) and 40 (7S11 & 7T11, IIRC) years ago. They were quite usable.
I never found unobtanium to be very useful.
Well, they give us a weeks notice. But, yeah, it's sorta the same. I lost all my probes for calibration recently. Made for a very productive week.
I haven't seen or heard from Jim in some time. I was wondering about him the other day.
-- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
John Larkin has sent me samples of the SMS7621 (thanks!), both in SC-79 and a two-pin gullwing style that I didn't know until now. Here is what I found for reverse leakage:
Voltage SC79 package Gullwing
0.5V 61nA 59nA 1.0V 96nA 94nA 2.0V 206nA 174nA 3.0V 542nA 342nA 4.0V 2,195nA 700nA 5.0V 10,279nA 4,950nAThis was at room temperature and, unfortunately, the leakage current jumps to several uA when heating them. Could not measure temps on those tiny packages though/
Also, 5V reverse voltage is way past abs max and seems to cause some trauma. The 1V values were stuck about 5% higher afterwards.
-- Regards, Joerg http://www.analogconsultants.com/
The bigger part is the SMS7621-011, which may be obsolete.
There is (I think) a similar NXP part.
Somebody makes a 0.15 pF or some such diode in 0603; I'll try to find that.
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation
His last Usenet post appears to be this one:
Newsgroups: sci.electronics.repair Subject: Re: Tektronix connector From: Jim Yanik Message-ID:
Hope he's still kicking...
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