Tektronix 576 Curve Tracer Adapters

[jonpaul]

Rebonjour NF6X:

Solder: The special silver alloy solder is used on the Tek ceramic terminal strips. A small roll is usually located inside the cabinet.

All the other solder joints are normal 60/40 or 63/37 Sn/Pb solder.

Cover Interlock: It is easy to open the   front porch and short or add a small toggle switch to defeat the HV cover interlock.

Fixtures:  test fixtures, original TEK, DIY acrylic two level  with banna plugs and test sockets.

Last  ... 576 with a typical TO-220 BJT.

Enjoy!


Jon

PS: These decades old TEK have plastic bushings, knobs, control whose plastic deteriorates and brittles, thue easy to break.

Most susceptible are the large contriol for V/H scale, steps, etc the Volts/power selector and the focus/intens

[Stray Electron]

It works!

I temporarily kludged the 10-turn pot to not short out anything nearby, brought the power up with a variac, and tried out a random diode I had laying about. I'm sure there will be things to fix, and I bet I'll need to calibrate everything. But it lives! As I suspected, the readout intensity knob just needed to be turned up to bring the readouts to life. I see some dead "pixels", so maybe I'll need to dig into the readout bulbs?

I'll start ordering necessities like tin/lead/silver solder. I'd like to find one of the safety covers so I don't have to fabricate one from scratch. I have one of the FET adapters sitting my in PO box waiting for me to pick it up already, and I still don't know how the other FET/BJT adapter differs. The only one I see listed is part of an expensive lot of 4 adapters.

   That's great news!  You'll like using that lead/tin/silver solder.  I now use that for everything. If you watch E-Greed rolls of the stuff still turn up there occasionally that don't cost both arms and both legs. My CT is missing the safety cover and someone installed a bypass switch on it and I'm satisfied using it that way.  If I allowed some ignorant parts-changer monkey to use the CT then I would be more worried about the missing cover but I learned LONG AGO not to touch any circuit under power.

[NF6X]

Those are some nice shop-made adapters there. I spent some stupid money (again, not adding it up) on several original adapters out of laziness, but I expect that I'll make a bunch more adapters of my own.

I don't think any of the shaft couplings are broken on mine yet. Yet. The display offset knob is not only missing a chunk, but the higher numbers on the clear skirt are smudged to the point of being unreadable. Rather than trying to keep this machine looking factory new, I think I'll upgrade any plastic stuff that I need to replace. I'm not sure what I'll do about the display offset knob, but I have a plan for the broken plastic 10-turn pot mounting cup: I have some brass round bar that is big enough, and I'll turn a deluxe replacement on the lathe at work next week! That part doesn't function as an insulator; the pot shaft is grounded to the front panel anyway by the rectangular plate that goes on the inside of the panel. I'm calling it a cup instead of a bezel now, because I found it in the manual and that is what Tektronix called it. I guess they might have done that because the front panel was too thick to get the turns counter to fit the pot properly?

I'd rather have a functional safety cover in place than routinely bypassing the interlock, but I'll bypass it for some careful testing before I get around to making a replacement cover. I gather from the manual that the early production models had an interlock bypass button? I presume that Tek's lawyers had a fit over that and made them change it.

[Johnny10]

There are so many great threads on the 576 on this forum.

And once you get one, you will want another !

[NF6X]

I'd think that I'd want a 577 for my second one, with its sexy storage screen.

[jonpaul]

Rebonjour had both 577 and 576.


577 has a store and nonstore version
the storage CRT is easily damaged by inexperienced users and burnin. With today's digital cameras and mobiles the storage features are not as valuable.

The 577 test fixtures include a rare opamp tester.

The 576, 577 voltage and current ranges are different.

576 has 20A pulsed capabilities and a special 100A pulsed current front porch

The protection cover is a poor design, delicate and awkward to use.

As we always start with the volts variables at zero, there is no exposed votage till we turn up the controls.

Finally the interlock switch mechanical is not reliable and may take fiddling to get the closed cover to release the interlock.

Guaranted disappointing!

Enjoy

Jon

[NF6X]

I have other equipment with storage displays. I just like the things, regardless of practicality.

[David Aurora]

I got a bulk lot of interlock bypass keys at a pretty good price, you should be able to find similar in your area:

https://shop.coles.com.au/a/national/product/coles-toothpicks

 

(Obviously never stick your fingers near a test fixture or show the work experience kid where you keep the box of toothpicks, but yeah- just jamming one through the hole works fine)

[CatalinaWOW]

You can find a file for 3D printing the safety cover here.

https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg3504168/?topicseen#msg3504168

[NF6X]

Thank you! I'll take a look at the cover.

I made a replacement for the broken plastic mounting cup out of brass, and I also made a spanner socket for the Kilo counting knob nut out of some 1144 steel. I had to get creative with the mounting cup dimensions, since I didn't have enough of the plastic cup left to measure all of its details. I am happy with how it turned out.

[CatalinaWOW]

That looks really elegant.  Only problem is that everyone will want one.

[NF6X]

Thank you! I think it will outlast the plastic one.

I considered just 3D printing a replacement, but the side walls of the mounting cup are pretty thin. I think the layers might separate under mounting tension. Then I considered turning one out of delrin... and then I remembered that lovely brass round bar I had left over from another project.

[David Aurora]

Thank you! I'll take a look at the cover.

I made a replacement for the broken plastic mounting cup out of brass, and I also made a spanner socket for the Kilo counting knob nut out of some 1144 steel. I had to get creative with the mounting cup dimensions, since I didn't have enough of the plastic cup left to measure all of its details. I am happy with how it turned out.

Oh snap! That looks killer!

[SoundTech-LG]

So did you get it all fixed up???  I spent some time gluing in the CUP tonight with JB Weld.
https://www.eevblog.com/forum/testgear/type-576-an-interesting-day/new/#new

[SoundTech-LG]

That brass cup redesign is a real Beauty!!! I want one!  But I already JB Welded the plastic one in there 

[pac1085]

That brass cup is really nice. I made a 3d model of the plastic one, seems to work fine, since a 576 I bought also had the thing flapping in the breeze like that... still need to find the knob for the tip of the thing though.  Looks like a Kilo / clarostat 461 but more $$ than I want to spend for a function I barely ever use.

https://www.printables.com/model/907974-tektronix-576-offset-multiplier-mounting-ring