No not really ... unless one's reality is "reality T.V. shows." I think, most of the people doing this have a box of old, dusty, and used tubes, sitting in the basement... that will "sell on Ebay,

Good, clean data on the 5687/6900 is available here: https://www.pearl-hifi.com/06_Lit_Archive/08_Tube_Data/Cons_Data/5687_6900_Cons_Data.pdf Having been thru many 100s of 5687s, as seen

Which 500 series was the 6900 used in? (I believe 6900 a twin medium mu triode.) 6AX7/12AX7 was high mu. Bendix was (their gone) an interesting company, involved in the aerospace industrial military

An enterprising and unscrupulous person would pay for the scope, pull the tubes, sell them on eBay at a premium to the audio-nuts, use the proceeds to repopulate the scope with NOS tubes purchased at

I am not sure that you understand what I am trying to say, so let me be clear: Whenever the scrap companies I consult for see a 453/454 valued for less than $50, they tear it to bits, and it becomes

Thanks Roy. Lots of people out there selling tubes I guess.

Stan Winston was ... ESRC Vacuum Tubes + The Tube Center + ABC Vacuum Tubes ... either of those, or all of them.

Hmm. Radio Electric Supply is owned by Dale and Roy Rogalski. I don’t know if anyone else was associated with them. I talked to them today and apparently are doing well. Are you thinking of some

Dave, I restored one of these earlier this year. I upped the capacitance of the condensers and used high temp. low ESR and long life ones. I restuffed the two main screw cans with 1200mfd 250V LGR

Dave,

Just got a nice looking 7904A. Plugged it in with sufficient fear and trembling, exc. for noisy controls, seemed to work OK. Got trace and sweep and expanded sweep. Didnt put any signals into it. I

Hi Dave, thanks Dave, I'll go read the posts of the nanovna-users group. --Cheers Attilio

Hi Tom, you are a great person. Sometimes the bureaucracy can demoralize you, you must not give up. I think I will purchase both the nanoVNA and a noise generator to use my 7L13 while waiting to find

Fellow techies, I'm pleased to announce I've fixed the problems with the Blue Feather file library. It's back up and operating as normal. For those who have requested the login info, please

Hi Attilio, If your intention was/is to make frequency-response measurements with your SA in combination with a noise source, the nanoVNA will do that all by itself; no other device needed -- the

My only Tektronix scope is an RM45A (rack-mount 545A) and my interest in 500 series scopes is the only reason I'm here! My favorite feature of the scope is using "B intensified by A," turning the

I raised a 549 from the grave and it is now working well, except for the memory function. The storage board is of version 'E' (actually indicated as HE, what must stand for Hoogeveen, The Netherlands

I've added photos (and schematic) of waveforms for C1512 and C1513: https://groups.io/g/TekScopes/album?id=258720 What I realized looking at these is that the unregulated 55v top of C1513 is

If anyone's interested, 3 500 series have shown up in the Detroit Craigslist 515A $200 https://detroit.craigslist.org/mcb/ele/d/grosse-pointe-vintage-tektronix-analog/7229304629.html 535 $75

Sounds like your instrument had a Mod Kit field-installed. The VintageTek Museum has lots of microfilm, maybe they have the Mod Summary documentation for it. Mod Kits are sometimes different from