Changing voltages.

[Spork Schivago]

Re: Changing voltages.

i have seen caps where the uF value shoots up, it is acompanied by very high leakage.

Hmm, since it's not detecting any leakage, maybe the values aren't 680uF. Could dying batteries cause a false reading? They're button cell batteries or whatever they're called. I honestly can't remember ever replacing them. Can't say for certain because my memories all messed up...

It's not the meter. I tested those good, never used ones I have (the 680uF 6.3v ones) and the capacitance shows normal. I guess it's time to just pull the rest of the caps on that board and see what they register as.

[Spork Schivago]

Re: Changing voltages.

Wester547 said it's normal for polymers to have many times the leakage current of regular electrolytics. Is it possible that my Peak Atlas ESR 70+ meter doesn't really know much about polymers and even though they might be leaking, it's not detecting it because the leakage current threshold or whatever is different for polymers than it is for electrolytics?

[stj]

Re: Changing voltages.

no idea - peak are pertty secretive.
having it displayed in % on my meter, i suspect that bad cap is 30-40% leaking right now.

a good poly usually is under 5%, a good electrolytic is under 2%

[Spork Schivago]

Re: Changing voltages.

no idea - peak are pertty secretive.
having it displayed in % on my meter, i suspect that bad cap is 30-40% leaking right now.

a good poly usually is under 5%, a good electrolytic is under 2%

Wait, you have an ESR meter that displays how much the capacitors are actually leaking by? If so, what make / model do you have? I would love something like that.

[Spork Schivago]

Re: Changing voltages.

I wish there was some non destructive way to determine how much voltage a capacitor was rated for. I need to buy some ten nanofarad SMD caps for an oscilloscope module. The original caps are missing but there's no markings at all on the other caps in that area. I took an educated guess that they were 10 nanofarads. Just not sure which voltage I should go for. I guess that's for another thread though.

[Spork Schivago]

Re: Changing voltages.

904.4uF capacitance, 0.02ohm ESR for the second "working" capacitor I just removed. What do you think Stj? Are these 680uF that are just leaking and showing much higher capacitance? 680uF + 136uF (20%) = 816uF, so I could see a bad one maybe reaching 904.4uF. The low ESR is throwing me off though. I wish we could identify these so we could be sure of the markings. Does the 680 mean 680uF or maybe the 89 on the top means 890uF? The 4j marking, I took a guess that they were 4V because they're for the VRM circuit, but maybe they're higher than 4V as well.

[stj]

Re: Changing voltages.

hard to say, but as one blew, - i would replace them as a set.

some pics i just took

4MHz crystal - because i can
4MHz 3pin resonator - because i can!

1000uF 6.3v rubycon MBZ (used)
510uF 4v sanyo OS-CON (used)
560uF 4v ncc poly (from a motherboard vrm)

[Spork Schivago]

Re: Changing voltages.

For the crystal, what do those values mean? The first line says Crystal C<something> = 2ff...then there's ser and par...

That looks like a device you built yourself. What is it? Did you have any plans you followed off the net or anything?

[Spork Schivago]

Re: Changing voltages.

Is it an M328 component tester?

[stj]

Re: Changing voltages.

it is a GM328A but the stock setup cant do crystals.
you have to replace the crystal and firmware.

the bit about <something> = 2fF i think is a spelling error that should be 2pF
it's the capacitance needed to get the crystal to resonate.
the ser / par is serial and parallel resonance.
you need to read up on crystals to get that bit.
when you buy them, there are 2 distinct types.

[Spork Schivago]

Re: Changing voltages.

it is a GM328A but the stock setup cant do crystals.
you have to replace the crystal and firmware.

the bit about <something> = 2fF i think is a spelling error that should be 2pF
it's the capacitance needed to get the crystal to resonate.
the ser / par is serial and parallel resonance.
you need to read up on crystals to get that bit.
when you buy them, there are 2 distinct types.

That's cool as hell! I learned a little bit about crystals in digital logic. We just learned how it could be used to create a clock pulse. Didn't go into detail or anything. I'll read up on it in the near future. They have some really nice looking DIY kits out there and the price is very reasonable.

[stj]

Re: Changing voltages.

it only reads crystals upto about 12MHz btw.

[stj]

Re: Changing voltages.

btw, i just picked up one of those Arduino-killer dev boards from ST for someone.
look at how compact it is (i put a AA battery on it for scale)

that's a $10 board complete with detachable usb programmer!!!

[Spork Schivago]

Re: Changing voltages.

it only reads crystals upto about 12MHz btw.

Is that a hardware limit or software limit? I guess once I study up on a Xtals a bit, I should be able to figure it out myself.

[stj]

Re: Changing voltages.

both, the tester is only clocking at 16MHz

that's why you need to change the crystal, the original product clocks at 8MHz

[Spork Schivago]

Re: Changing voltages.

both, the tester is only clocking at 16MHz

that's why you need to change the crystal, the original product clocks at 8MHz

I'll try to study the schematics and try to learn a bit more about this. I'd think there'd be more that needed to be done than just switching out the crystal for a faster one. I guess that shows how much learning I still have to do.

[stj]

Re: Changing voltages.

you cant catch a signal twice in a single clock period that's all.
you could enable the crystal tester at 8MHz but it would have such a limited range that there is no point.

[Spork Schivago]

Re: Changing voltages.

867.1uF, 0.02 ohm ESR again for the last good one.

Do you think the 680uF 6.3v is what I should put in there or should I go with a higher capacitance?

I have three caps that I can test (out of the five). I get 867.1uF for one, 904.4uF for another, and 1370uF for the third. I'm really questioning the whole 680uF thing now. What do you guys think?

[Spork Schivago]

Re: Changing voltages.

I think I found them. I think they're FJD 680uF 4v capacitors. According to aliexpress, they're Aluminum Electrolytic Capacitors....

Can I use the polymers I have as replacements?

Here's the link to what I believe are the ones I have. I cannot find a datasheet on them though.
http://www.aliexpress.com/item/Alumi...208.4.9.5ebbCx

[stj]

Re: Changing voltages.

use 680uf poly's - it can only improve the shit he had.