July 14, 201114 yr So i got some of the peek screws from andy, and tested them. People... These are what you want. Unbelieveably strong and virtually unstripable.
July 14, 201114 yr So i got some of the peek screws from andy, and tested them. People... These are what you want. Unbelieveably strong and virtually unstripable. Are we talking about thisstuff?
July 14, 201114 yr That's where I got them, but mine were longer, wanted 15mm, but they did not have them so gave me 16mm for the same price since the lady on the phone told me they would be delivered in 7-10 days and they were late. Edited July 15, 201114 yr by blubliss
July 15, 201114 yr M3 nut goes on an M3 screw and i fogot to order washers from them so i used polycarbonate ones from Mouser. Look for M3 washer.
July 15, 201114 yr So i got some of the peek screws from andy, and tested them. People... These are what you want. Unbelieveably strong and virtually unstripable. We did manage to strip one nut.
July 15, 201114 yr Hey Andy, Do you think the 12mm PEEK bolts would be cutting it too close on length? For some reason they are $23 less then the 15mm long bolts.
July 16, 201114 yr Wow this looks fantastic!! Pity i wont be able to hear it when its finished Getting very close now, only sockets, pots, and knob to finish. I am so happy about completing it, I'm reluctant to turn it on and deal with the potential to sour my mood if it is not perfect.
July 17, 201114 yr This reminded me, I needs to find me a compartmentalized storage box like the one in the background of the picture above. Dropped 5C today on EOL sand and T2 FR4. Still gotz a long way to go...
July 17, 201114 yr Thanks all. Lil Knight said it is the first rev2 board up. I think a lot of the other people have to deal with case work, which I am so glad I did not. I'll stick a scope on it to make sure there are no oscillations. What design issues does the rev2 board set address / change? Are the crossed resistors now uncrossed? Is the DACT hole spacing footprint revised? Is the R identifier(s) nomeclature fixed? Are the Craig Sawyers capacitor additions implemented? Others?
July 17, 201114 yr More stupid questions, What does one look for when hooking up a scope to the outputs of a stat amp / psu? I would imagine no unwanted oscillations and a clean waveform? What bandwidth scope is needed? Settings? Are special probe/input adapters needed for the high voltage? Is a signal generator used in conjunction? What type of signal is injected at the inputs - 1kHz square wave? It would be a big help to have an idea when it comes time to test this.
July 17, 201114 yr Hey Andy, Do you think the 12mm PEEK bolts would be cutting it too close on length? For some reason they are $23 less then the 15mm long bolts. Maximum thickness with the 2sa1486 and ceramic washer is 12.35 mm, So 12mm is just a little bit too small. If you add a .1mm washer its even worse.
July 17, 201114 yr What design issues does the rev2 board set address / change? Are the crossed resistors now uncrossed? Is the DACT hole spacing footprint revised? Is the R identifier(s) nomeclature fixed? Are the Craig Sawyers capacitor additions implemented? Others? Resistors are uncrossed Dact hole spacing is now .1 Resistor labels fixed Craig sawyers cap additions, and resistors moved.
July 17, 201114 yr I could be wrong, but I think Craig actually ended up removing capacitors, not adding them, when it was all said and done. Edited July 17, 201114 yr by luvdunhill
July 17, 201114 yr More stupid questions, What does one look for when hooking up a scope to the outputs of a stat amp / psu? I would imagine no unwanted oscillations and a clean waveform? What bandwidth scope is needed? Settings? Are special probe/input adapters needed for the high voltage? Is a signal generator used in conjunction? What type of signal is injected at the inputs - 1kHz square wave? It would be a big help to have an idea when it comes time to test this. I think this is all pretty subjective. For example, you could ask Andy what he did, as he was the most recent person that would have comparable experience and equipment to what you might have. I really want a differential high voltage probe, namely a Tektronix P5200. That being siad, it's not like I've never floated the earth connection of my scope, I'm just not going to sit down and explain how to do something unsafe here...
July 17, 201114 yr Back when oscilliscopes were actually really oscilliscopes, i saw people lift the ground, put them in series with a high voltage isolation transformer, chunks of plexiglass under the scope et all. At zenith this was standard practice when working on the high voltage sections. Complete with plastic knob extenders. These days, oscilliscopes are nothing but highly computerized digital things, and would likely completely blow up with any number of simple mistakes. Isolation circuits can be built that safely do this kind of thing. But i really don't want to show people how to do this. I don't want to be responsible for any dead bodies. I have already been present when it has happened. TWICE. Seriously.
July 17, 201114 yr Thanks for the replies guys. @KG - interesting stuff regarding your time at Zenith.
July 17, 201114 yr Woah. Yeah, the plexi stuff, isn't that some sorta of safety standard? I remember reading about that somewhere, definitely before my time... If I had to choose, I'd rather use an isolation transformer than ground lift the scope, but again best not to propagate safety risks. But what I really want is a P5200 or someone to nick a circuit so I can DIY one The other option is of course matched HV probes. Tek used to (still does?) sell probes this way. Then you do the invert and sum trick across the two channels. Not as cool as the above though, and cannot really be used on PSUs where you want a floating measurement. Seriously though, ask Andy. He satisfied himself and whomever was working with him, so thats worth something I'd suspect.
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