I have a DM501 that seems to need calibration. Very hard to do plugged into a mainframe. The DM501 works in the mainframe, albeit with an improper display. I built an extension cable about 3ft long th

I have a friend, not too eBay savvy, with some equipment to sell. I don't think he is likely to try shipping these, so maybe local pickup only. I believe all this stuff is in working order. All is loc

I have both a DM501A and 502A DMM. These are identical except for the front panels being mirror images. Anyone know why Tek would create such a pair?

I never noticed the auto ranging button on the DM 502A! The DM501A is in need of repair. Display seems functional but none of the modes or ranges produce results that are expected. I know that this is

Thanks Szabolcs, Those are exactly the tips I'm looking for! Sent from my iPad

@Szabolcs /others Fixing a DM501A: So cleaning the switch matrix did the 1st order trick. I can calibrate the 200mv & 2v ranges. But when I switch to the higher ranges, there is a clear offset that ca

After just setting for several hours it started to work! Must have adsorbed water from the IPA I used. Calibration good and back working. 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

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

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

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

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

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

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

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

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

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

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

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

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