I had a 7904A recently for a short time. The fan was one reason I sold it - the noise is obnoxious to me. I don't think there was anything wrong with the fan, but I'm sensitive to that white noise - i

1) Go to WalMart, buy the cheapest gadget that has a wal-wart marked "12VAC". Connect it to your headphone amp. 2) Then go to a flea market, buy an old transistor radio, remove a transistor from it, a

Given that the modern practical use for a L.A. is a specific, rather small, subset of Use Cases, it would seem to me that the place to discuss L.A.s in detail is on a forum that is focused on the *app

Hi Harvey; I don't follow... a common (and relatively cheap) protocol analyzer, such as a Beagle ( https://www.totalphase.com/products/beagle-i2cspi/ ), shows protocol details/data, and timing, with a

Fair enough (it is $330 retail I think). I just looked on eBay, and saw a used one for $120 or Offer. But if you need it regularly, and you have limited bench space, and you need a complete set of fea

Hi Ray, I see the "Files" section in the menu on the left side of the page, when looking at this page: https://groups.io/g/TekScopes/topics Here's a link to the "collet" search, which then shows a PDF

And I would add for folks that are going to fabricate a piece: Don't overlook *wood* as a possible material. Wood comes in a zillion types (at a woodworker's supply store), and some types have very us

Looking at the author's site, it *appears* that he has good intentions, and enjoys learning about a wide variety of things, but lacks actual expertise/experience (at least in electronics). He may not

Hi Ken, I'm here in C.S. also, and shopped at OEM many times since the 80's. I worked at DEC, as did Dick's "employee/partner" Robert. I'm curious what you plan to do with all the semiconductors you b

This seems like a "purpose" for my old HP logic analyzers - use an LA to trigger on a complex logic situation, and the Trigger Output triggers the scope to show the analog situation. [I've wanted an e

Hi, On my 2465, the Ch1 BNC is slightly "loose", and the signal is intermittent depending on which way the probe cable/connector tugs on it. The connector seems to be integral to the A10 attenuator as

Thanks for the comments so far! As for knobs: I already played with them, and they all came off easily. One has a piece missing from the plastic 'flange' down inside the knob, but it still stays in pl

Success! The solder joint on the inside end of the BNC was broken. Someone had done a repair before - plastic was melted nearby from their soldering iron. There had been nothing but a bridge of solder

See also my recent post on my 2465: https://groups.io/g/TekScopes/topic/79720337#176586 As you described, the inner part of the BNC was slightly loose when the center contact was broken, but the nut w

Hi, not sure who you're replying to, but in case it's me (regarding the similar issue on my 2465): On the 2465, there is no nut for the BNC. Rather, there is a 'collar' that includes a set-screw, and

Some pix of the the 2465 issue. In one image, on the far left you can see the set screw in the frame. https://groups.io/g/TekScopes/album?id=260014 Pete

In old Motorola databooks (circa late 1960's), some JFETs (such as 2N3823) say "Source and Drain may be interchanged". Many other types do NOT say that. What's up with that? I was thinking that a typi

FWIW, I have this HP ET2294A ( https://hpwiki.mcguirescientificservices.com/et2294a_tunnel_diode_curve_tracer ), which when hooked up to the X and Y on a normal scope, makes a trace that looks like th

My understanding is that by the 1970's or so, TD's were obsolete because most of the practical circuits that used them could be done cheaper with modern transistors and IC's. TD's could do certain thi

The music applications are, by definition, below 20 or 30 KHz (mostly WELL below). There is nothing useful (for audio) that can't be done much easier and better in the digital domain. Any unique sound