I have a box full of collected 576 fixtures. Many of the 5 pin fixtures are beginning to separate at the body mating joint. Not having dissected one yet, it looks like screw boss standoff failure. I'm

Yea, if it ain't broke, dont fix it!

I think my main concern in this thread was that after replacing power supply caps in the SG505, how could I determine that I used the best components to maintain the THD spec. In particular, I replace

@Steve, Craig, Bruce Yea, I saw that fixture in the SG505 service manual. (Thanks for the reference). I might try to build a limited version. But what you are saying is that the 333A Wien-bridge rejec

Well, power line harmonics from the SG505(&TM504) alone are -110dBV or lower (using the HP3582A ). The power line harmonics from the HP333A (in distortion mode) with a shorted input and meter attenuat

Is anyone here familiar with the internal operations of the SG505? I replaced some bad caps in the power supply on a unit that was not working. when I go to measure THD I get @1K ~0.0037% and @4K ~0.0

For Glenn... context is good. In my younger days I had less patience and there was much less easily available information. Kjo --------------------------------------------

Ah.... Well that was in my younger days (-20y) when i had less patience! Sent from my iPad

Another insidious failure mode is aging of rotary wafer switches. Older HP & Tek gear used these a lot. I had a spectrum analyzer once, HP modular I think, where span switching was erratic or non-func

Hi Dennis, If you do make some boards, I'll take one too! kevin kjo@... BTW, I've built a Tek 577 plug-in adapter for testing/matching Nuvistor triodes directly on the 577. It is much simpler t

wow! 53 485s! Best all round Tek portable scope for 20 years. Mine is 38 and still going strong. What Hughes location? I was at Culver City in late 70's. What a change in that place!!! Sent from my iP

Wow! This sounds like a broken 2440 I sold on eBay several years ago. It had major CCD converter problems. Once I got the service manual, I concluded I would never get replacement parts except from a

Does anyone know the type of backlight used in the THS7XX series of portable scopes? I have a 720 that seems to have gotten dimmer over the years. I wouldn't expect this from white LEDs. But I dont th

Hey Paul, what's a213? Sent from kjo iPhone

I had similar issues with one. The attenuator section is particularly sensitive to contamination and leakage. Even from IPA residues which took 4-5 hrs to clear. Also it is imperative to clean rotary

Hi Dennis, Yea, I agree with u fully. Didn't mean to imply I condoned it. Problem was you would eventually learn those sticks would frequently break off and get stuck. I never trusted the switch or wa

It is interesting to hear of the "hobby" interest in safely using the high voltage ranges on tracers who the DUT safety cover. It is commendable since the current is lethal. Professionally, in 25 year

TI used bubble memory in some of their Silent 700 portable thermal printer terminals back in the late 70s. It was a flaky concept; type in pages of text offline and hit a send key when online. No easy

I have built custom fixtures using Pomona 72918 banana studs. They fit the Tek sockets nicely. Longer than the OEM split plugs though. From Mouser of course. Sent from kjo iPhone

I've been following this TM504 thread, and in my experience with 3 of these units, an alarm goes off in my head if any plugins mis-function. There are a lot of different plugin design styles, each usi