"Kill meeee eeaaeegh"
Nah, That should be an interesting PSU.
"Kill meeee eeaaeegh"
Nah, That should be an interesting PSU.
I just got a stereo set in for repair, just look at these specs!
I love me some square waves.
That's nothing strange, actually. They sometimes refer to this as a "PWM DAC". The amp most likely has some class D architecture (http://en.wikipedia.org/wiki/Class-D_amplifier). But I agree, "1 bit DAC" looks kind of funny.
Fuck the inside case of this tube radio is horrible, it has a thick layer of tobacco residue that's very hard to shift, at the moment I'm practically washing it with IPA and going at it like mad with a toothbrush.
Smokers should be banned from owning electronics, it's fucking disgusting.
Got most of it off *vomit* so it looks (and smells) a lot nicer, going to get some Brasso to polish it to a nice shine and finish it off with some wax.
My scope previously was owned by a smoker, but it barely smells anymore.
I just scored a canon scanner, a box full of banana plug cables and a TI30 scientific calculator at a yard sale for all of $3. Cannon's gonna get dissected but the ti-30 is easily gonna be my main calculator around the workbench. Oh and my brother gave me a 32 inch LCD tv that doesn't work, repair time!
Oh yeah and I got a tape recorder/stereo from mom to disassemble and I found an old satelite tv box, plus I'm going out today to check out some more yard sales.
Grandparents gave me a nice old MAP sensor, hoping it still works. Not sure what I could use it on though.
So enabling i2c drivers on the raspberry pi is a bit of a pain in the ass and requires recompiling the entire kernel. I'm currently still compiling, but I hope I can finally access the i2c (and spi) devices afterwards :)
I2C gives alot of people problems :(
Or maybe thats just me
Here's a pretty comprehensive guide on how to compile the newest kernel. Just note that you have to transfer the old config file, then run "make menuconfig" and enable the i2c and spi module.
Sorted out the rectifier, I think I'm going to just use a half-wave rectifier to save on parts and space, The transformer is only small so my usable maximum current is probably only in the 250mA region which does not really matter much I just want a decent dual rail supply which are pretty much required for experimenting with op-amps and many transistor circuits unless you want to screw around with single rail operation which is not always ideal.
(Note: the negative rail in blue is offset from 0V on purpose for visual clarity)
So I ask dad to keep a lookout for something to knick at the electronic waste section of the recycling center as he's dumping some old TV's. Half an hour later he comes back with nothing less than a goddamn keithley instruments 155 microvolt meter. It goes from 1ÁV to 1kV and supposedly has better than 150nV resolution at 1% accuracy.
Don't know about that though, it has a cal sticker dated 22/4 1970. Still all that seems wrong with it is that the batteries are dead, they're old style pp6 9 volt batteries, think I'll just replace it with modern 9 volts after I clean out this melted sticky 40 year old foam tape.
Other than that, one of the mounts on the pcb has cracked and obviously I'll need to recalibrate it at some point.
Gotta love finding junk where you work. Working in the HVAC field has netted me an old Carrier 3-phase motor speed controller which had, among other things, 2 rather beefy 400uF 1000V capacitors. There's also a rather large ceramic mystery part which, considering it's bolted to the rather large heatsink, is likely the do-whatsit that delivers the final 3-phase output (anywhere from 40Hz to 240Hz if I recall).
I was also able to nab an old water-cooled condenser coil from an old ice machine which, with a few alterations, should work nicely for another project I've been working on.
looks more like a normal BJT with some diodes in it
Anyway I bet my left leg it's an IGBT module.
Reading up on it, I bet that's what it is too. Has alot of pins in it though so I thnk it's safe to assume there's multiple devices in this one module. Methinks I could use it to make an inverter should I ever get that windmill off the ground. Score!
So I just fired up my keithley 155 using an ATX power supply to get +-12 volts. It originally runs off of four 9 volt batteries to get +-18 volts but I don't have any 9 volts at home right now so +-12 had to do for a test.
As far as I can tell it works just fine, not horribly out of spec either though I was comparing it to the readout of a $10 multimeter and only measuring down to a few millivolts. The Ávolts range was almost completely unuseable due to the switching noise from the atx psu but I just wanted to see it was working.
Gonna order a 10 pack of 9 volts from dealextreme for $10 within the week probably and once they arrive I'll make a neat installation and then I'll take pictures and upload them here and probably on the eevblog forums.
You'll probably get more value if you invest the 10 dollars in better batteries at your local store (+ it won't take a year and a half to arrive)
And yes, I do have a compressor/condenser coil already, gutted them out of a 5,000BTU/H window unit. It was a R-410A system, but the idea is to use R-134a instead, which the oil used is the same for both so there's no issue there, and a 410 compressor can certainly handle any pressures 134a could ever hope to exert under normal operating conditions.
Yeah, yikes, this thing is designed to handle 1.66 tons of refrigeration. Starting to think it may not be suitable after all. I might still be able to get away with it, if I reduce airflow over the condenser I can effectively "trick" the thing into acting like a 1/2 ton system. But still, this is sad news as it means I've likely just salvaged a very bizarre-looking door-stop.
You'd have to keep that mineral oil pressurized pretty good, I can imagine it just collecting once its condensed in that unit. Agreed, you might want to start small.
I mean hell, 5,000 BTU/H is kind of over-kill since the maximum power-draw on the system in question is less than 350W (1195.25 BTU/H roughly), but meh, the compressor was dirt-cheap. Can't beat a working compressor with condenser coil for $60.
Absolute worst-case scenario, I might just go redundant and make heat exchangers for both the GPU and CPU and use the mineral oil purely as insulation (though obviously it would get cooled too, and cool the other shit like MB/RAM).
Hopefully that mineral oil is at a low enough viscosity for the compressor.
You have any ideas on how I could make a compact expansion valve? Just make a pinch point?
And the mineral oil isn't going into the compressor at all, most HFC refrigerants don't play nice with mineral oil nor, in some cases, alkybenzene.
You can achieve this using any two isolated power supplies, the reason this thing uses batteries is because any other power supply would have been too noisy for the really low level measurements. I just used an atx power supply to see if it worked at all while I wait for the batteries. To do what you propose I would need two atx power supplies that I would have to mod to be mains earth isolated, and it would all be very unnecessary because I just wanted to see if it worked and +-12v did that just fine.
Very, very informative video on good electrician practices. I hope you'll learn new tricks from it.
You know, for a country which hates gore in their video games, they sure know how to make their safety videos graphic as fuck.
Edited: Finalizing the overlay for the programmer. Not sure what else to change. Any ideas?
I also need two new knobs. the ones I got are too big and interfere with the big EPROM TEXTOOL socket and leave no room to not what each position does.