eccerr0r
Solder Sloth
Last Activity: Yesterday, 08:40 AM
Joined: 11-08-2012
Location: CO
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ebay.com item 166827180887 is a 16GB ddr3 UDIMM SODIMM...so they do exist... seeing a lot of references to apple hardware for these large modules, so assuming they're of the intel age with server cpus... -
Since it's a consumer grade intel machine it likely won't handle 16's but you should check. It's the server grade intel machines that may support 16's but not always. Theoretically the m/b I have has a firmware update to allow 16GiB modules due to it being a server chip with server memory controller...alas not sure if I'll ever see any 16GiB modules, cheaply... so I filled it with 8GiB units... cobbled together from multiple sources...Leave a comment:
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solder another socket
then again it probably isn't drawn on the pcb...but the mem controller should have the pins...
Dang I'm still using ddr3 (and some ddr2) machines... alas I now have a 64GiB DDR3 machine (UDIMM)... 8x8 and theoretically can use 16's, but I don't have any.Leave a comment:
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Yeah it's a line powered scope. The coupling problem seems sound but if it's driven by a DC signal, it should also be stable......Leave a comment:
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Unless you have a memory controller with support for registered memory, you're limited to 16GiB/module. If you have an Intel memory controller, it's probably 8GiB/module (The only Intel udimm ddr3 memory controller that supports 16GiB/module are atoms/avoton.) I have heard anectdotal evidence some amd memory controllers can work with 16GiB modules ... and they are sorta rare as not all machines can work with them.Leave a comment:
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correct, it should be in series not in parallel, alas, at 3.3V rail and the charge time, it shouldn't be too long until it's charged and shut off.
TBH dangit, i'm too used to cmos and ttl devices where input current limiting is implicit/built-in...aaaahhh...
​Dammit I need to fix my Tek scope, one of the latching relays in it is stuck... *sigh* Not sure why Tek decided to use latching relays in their attenuators......Last edited by eccerr0r; 07-05-2024, 07:39 PM.Leave a comment:
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If you really have nothing else, yeah you probably can. Due to ambiguity in the English language you could either lose a bit of speaker protection or power output....Leave a comment:
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Yes I'm feeding it directly to the AC input (set to 220V if switchable because the doubler for 120V will not work when fed DC.) Diode loss will be less than 1% for me anyway, so I think that's fine - more loss in downstream components.Leave a comment:
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It's a risk I'm willing to take but it stresses two of the bridge diodes 100% duty cycle. Theoretically if I just swap the inputs of the psu every once in a while, it'd heat up the other two diodes and we're back at as if I was powering from AC.
Then again the 120/220 switchable psus the diodes already need to handle 2x current (usually) so it should be good to go.
I'm running DC because...that's all I've got... converting to AC to convert to DC to convert back to AC is kind of ridiculous actually lol....Leave a comment:
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Currently trying ~250VDC on these PSUs and they're holding up as expected. Next step up is getting close to that 360ish volts at least theoretical. This is still part of my solar panel experiment - I just got four 90V+ OCV (but not at MPP) panels that I want to reduce the amount of wire so I'll have upwards 360VDC that I want to feed into these PSUs straight. Unfortunately I don't have space for 4 panels yet, so that is the limiting factor for the 360-400VDC experiment.
These PSUs are series connected and fed into my grid tie inverter. I figure this is the cheapest way to tie these...Last edited by eccerr0r; 04-23-2024, 11:20 AM.Leave a comment:
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220VAC locales... ever used DC to feed switch mode power supples...and how many volts is generally okay?
For those in 220V locales, anyone power their SMPS with DC, and how high of a voltage is okay?
What kind of PSU?
I suspect that 240V * sqrt(2) = 340V DC is probably fine because that would be about how much the the primary rectifier ends up with peak voltage. Just wondering, other than input capacitor voltages, can one go up above this 340V without damage? Will that input capacitor be the upper bound?
Wondering if exactly that, can I feed near 400VDC into bona fide specced at 220V SMPS without damage?
Currently have a 120/220V switchable SMPS I want to see if I... -
No.
The 31V at 34V is the way it is, and is fine. The other voltages should not budge too much with the higher voltage (maybe a tenth or so of a volt tops) but the 31V line is unregulated and could very well be 32V or 34 or even 30V depending on your line voltage.Leave a comment:
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Eh... GaAs is fairly "recent" ... Is that a dual source or dual gate MOSFET? Depletion or enhancement?Leave a comment:
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Before all the rage of MOSFETs being used as switches, they were used as class C signal amplifiers, and this is a dual gate MOSFET....Leave a comment:
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Nope, sorry to get your hopes up, it's different though reminiscent...
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"fbt.jpg","data-attachmentid":3240536}[/ATTACH]...Leave a comment:
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reminds me of a 14" VGA monitor I fixed years ago... there was a hole in the FBT that leaked HV out the side to the closest chassis ground, wicked spark... I stuffed it with plastic and it insulated enough for the crt to work... hah.
hmm that fbt looks similar to one i pulled from a 17" crt I drop cracked... wonder if i still have it...Leave a comment:
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TBH I have no clue what the value add of the TO-92 LED is... other than it looks like a light emitting transistor...Leave a comment:
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Current is defined as the rate of electrons going through a point, so you have to get in between to know what's going on.
Technically if you know the voltage across two points and the resistance, you can compute current. The problem is that the resistance between the nodes tends to be unknown and may even change. Without it known and stable, there's no way to know current through two points (plus it may "leak" to another node).
Best you can do is using a clamp meter if you can't split the node.Leave a comment:
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I'd imagine that DIACs (btw how do most people test these without a high voltage curve tracer?) would fail short or end up blackened/burned, and it's not conclusive here if you see an open DIAC with a modern multimeter?...Leave a comment:
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