开云体育

Colin and Juoko, If the 7A26 is arranged anything like the 475 then cleaning the AC/GND/DC coupling switches is almost exactly the same as cleaning the rest of the attenuator switches: soak a narrow

Wish I had kept my Commodore PET/CBM systems... -Dave

John Goller wrote: I don't have particular issues, other than complaints about this particular process (not being offered the options that would have made this process easy), and about the quality of

Hi Jeff, I've only taken a quick look at the circuit, but it doesn't look overly fussy about the exact resistance value, so the carbon comps you bought are likely to be fine if they are still within

Dave, Thanks. I saved the URL. Ananda

Tom, Yes, I had anticipated that these NOS components might not have retained their specified values. I've been going through my father's effects while working on his scopes and finding all sorts of

Jeff, I don't know what the circuit context is here, but if carbon comp types were originally used, then the exact value isn't that critical. If they have drifted badly (typical after many years), and

Hi Jeff, You are correct that, depending on value, metal film resistors can have significant inductance (relative to the carbon comp version). In this particular circuit, though, you are looking at

Colin, I've looked at five different scopes with a delay vernier and only one of them (a 2215) seems to be set at something other than 0.0 at the extreme CCW rotation. All three 475s and the 475A that

Mark, Call me Michael, I have not designed or printed anything other that these two, mainly because I have not had the need for anything else. I would be glad to try to help with other enclosure

So I feel like a superstitious/nostalgic idiot, but I had second thoughts about replacing the out-of-spec resistor pair with modern metal film resistors. I went to eBay and bought a dozen (allegedly)

I've seen plenty of design errors in all makes of equipment - nobody's perfect. When it comes to high bandwidth circuits like in scope amplifier chains, you may have to cut them some slack. It is a

Mr. Lynch, The photos of your enclosures are nice. I am glad to see a supplier that has these cases for those that have bad multipliers. I brought it up since some have said their multiplier is bad

Oops. The thread: https://www.eevblog.com/forum/repair/renovating-an-early-tektronix-475-oscilloscope-a-few-random-hints-and-tips/

Martin, One other thought is compare the cabling to the service manual. I have often seen 271x's that don't work and when someone got into them and found a bigger problem they just closed up the unit

Scroll down this thread a bit. Good picture of the cap sitting in front of the 1/4" nuts holding A1 (& A2, CH2) to the face. But this is for a 475 and those lucky bastards have a plug in cap. But

Great info. Thanks. If I cannot get that capacitor block to settle down, I will have to get the board out. I will let you know. Ananda

Greetings, A close friend of mine, who is an electronics engineering tech, owns some nice 3D printers as a side business. If there is interest I will give him a “heads up” and offer his contact

Yeah, the delay line definitely needs disconnecting, among a couple of other odds-n-ends. I don't have my notes in front of me. One of the gotcha's that almost got me is the ground strap that goes to

My main pleasure with equipment is finding inoperative or basket cases and restoring them. I just finished a 2230 and an R-631B. This is an account of the projects, skip now if you aren't interested.