Diary PCBuds mini-grow

[PCBuds]

Fail...

The fuse popped right away and I thought that I saw sparks coming from under the board, so I removed the board.

I thought about replacing the capacitor, but it it was reading 40 volts, so I guess it's something else.

Maybe the triac or power transitor or whatever it's called.
That's what the capacitor is connected to.

So the project has gone over my head.

It's dead.

 

[f-e]

You could rinse it, but it shouldn't matter if you use the cap, to stop it drying. Next time it see's a solution, the old brine will wash away if it's not hardened on.
iirc these are not fully waterproof, so it's a good idea to store them upright. Flat is alright, if they have a belt clip to just keep them tipped a little. You want to be sure no salty water seeps past the weak seals.
The 5% seems low, when you see how people treat these things. An EC meter is a lot more resilient than a pH meter though.

I have had a few of their pH meters. They break on certain people. You visit the grow, to find acid bottles that have never been washed, and tank numbers that are never quite right. Sometimes the meter will be there without it's lid. Hearing claims they were in the middle of setting the tank, and it won't hurt it. Some people refuse to accept it's them that's shit, not the tools.

 

[f-e]

That cap has a serious solder deficiency. I'm not sure it was a dry joint, as to call it a joint is a bit ambitious.
Check the main switching fets for continuity. If they are not closed circuit, you might save it still.
Does the top of the cap feel flat still?

 

[PCBuds]

OK, Great. Thanks.

I won't be using it that often, so I'll rinse it off in clean water.

You could rinse it, but it shouldn't matter if you use the cap, to stop it drying.

I thought you were talking about my capacitor.

You want me to rinse it ??
Then keep it wet ??

Lol

 

[PCBuds]

That cap has a serious solder deficiency. I'm not sure it was a dry joint, as to call it a joint is a bit ambitious.
Check the main switching fets for continuity. If they are not closed circuit, you might save it still.
Does the top of the cap feel flat still?

The capacitor looks fine, I think?

​

I checked across the three terminals of the power transitor (I assume that's the FET) and I didn't get a short between them.

The numbers were floating around as low as 22 Ohms, but I figure that's because I didn't desolder it from the board.

Some read "open line".


I'll just clean up the board and resolder it back in.

​​​​​​​The fuse blew again, could a cold solder joint blow the fuse ?

 

[f-e]

It's a 105c cap. It got hotter. It could be something like a short circuit, once power is applied. Caps are hard to test in that respect. They can look fine on the bench, but not work under load. It's like a 2 ply toilet roll, with the electrolyte between the sheets. The warmth of being put to work can cause physical changes. I would expect it's dried out at this point. Nearly always, the top disc will dish or their will be leakage by the pins. The dishing can need light shining off it, or a light touch to find it.
There is no reason for the burning there, other than a poor connection. Your transistors seem to of survived. Little else is likely.

 

[PCBuds]

No luck.
I resoldered the capacitor back in and used a 7.5 amp fuse.
The fuse popped right away.

Then I tried a 15 amp fuse, and the voltage indicator came on for about 1 second and it popped again.

Everything looks fine. The board and all the components look normal, but it popped a 15 amp fuse when it was supposed to have a 5 amp fuse.

I'm going to plug in my spare power supply.

 

[PCBuds]

All better now...

​

​​


I like the old power supply better. (the one on the left.)
It has a potentiometer to adjust the voltage, and it's not as touchy as the dial on the other power supply.

That will help keep me from messing with the damn dials so much because it's a bit of a procedure.

It will help me with my LIFTA too. Lol



I checked my purchases and realized that my blown supply was a 500 Watt supply, but it was a 0-48 Volt 10 Amp supply.

I thought it was a 20 Amp supply.
So even though I was running it at less than half the maximum voltage, I had the amperage almost maxxed out.


I kept the supply on 24/7 and switched the output on and off, but last night the power went off 4-5 times and I figure that was the last straw.

The old supply is 24 Volt 20 Amp supply.

​​​​​​

 

[PCBuds]

I bought another power supply because I'm wasted and feel like buying stuff. Lol

I bought a multi pack of fuses too, because I tend to blow shit up.
Sometimes on purpose. Lol

 

[PCBuds]

That cap has a serious solder deficiency. I'm not sure it was a dry joint, as to call it a joint is a bit ambitious.

I think this was a cold solder joint from New.

That burnt mark looks like it had been hot for a long time.

A slow burn over time with melting solder.


I'm going to take the new one apart when it arrives and inspect the board.

 

[PCBuds]

I can't stop buying stuff. Lol

It may not work, but I'm willing to gamble with four dollars and forty four cents. Lol

 

[exploziv]

Have you checked if there was metal on metal contact in the metal case with that solder joint (maybe some debris inside that made that contact?) What you are describing is weird. If its not that there'a probably some component that got out of specs or gone out and makes the whole power draw too much for the old psu.

 

[f-e]

That's a big gamble. I hope it pays off



Cap fails are common. It's a big lump swinging around, and the manufacturers are forever trying to go faster. It's a big lump.. it needs some heat. They are in too big a rush to wait though.

 

[PCBuds]

Have you checked if there was metal on metal contact in the metal case with that solder joint (maybe some debris inside that made that contact?) What you are describing is weird.

The capacitor itself looked fine.
(I should have taken more pictures)

The one pin was brown and burnt,
but it was reading 40 Volts.

If its not that there'a probably some component that got out of specs or gone out and makes the whole power draw too much for the old psu.

That's what I'm worried about, but I'll throw a 4 dollar capacitor at it and see what happens.

 

[PCBuds]

Cap fails are common. It's a big lump swinging around, and the manufacturers are forever trying to go faster. It's a big lump.. it needs some heat. They are in too big a rush to wait though.

Yup, molten solder dripping and splattering around.

So with what you said, I think the capacitor is cooked.

Slowly cooked since it was new.

I'm thinking that the capacitor didn't bulge out because it wasn't an instantaneous failure, so the electrolyte slowly degraded and shorted.


I'm going to remove the capacitor and plug it back in and see what happens.

I figure that if the supply has a bad capacitor, it should stay on but not put out voltage without a capacitor?

 

[PCBuds]

I changed my mind.

I'm going to wait for my new capacitor to arrive to install it and test it.

I don't want to wreck the psu if plugging it in without a capacitor is wrong.
And I've run out of fuses. Lol


Here's the capacitor.

It looks fine to me.
It was reading 40 volts, but maybe it shorts out voltage above 40 volts?

 

[f-e]

You got a lighting cap about? I would be hesitant about using it with no cap at all. Just 10uf will do though, if you don't load up the supply.

It looks like 110v in. With rectification to DC where a 0v is found. So...110 gives about 160? so 80-0-80 rails. It's unusual to see two cap tbh, but it hints at two rails. It's this high voltage DC in these reservoir caps that some of the fets/transistors send back in forth through a transformer. It's a page away, but I think it was on a yellow former. The transformer will have yet another rectifier after it, and lower voltage smoothing caps. Somehow, usually an optoisolator, the voltage at these last caps to sent back to the brain, which decides when the fets/transistors need to run. To top up the little caps. From the big caps. If there are no big caps, it will probably drop into protect, as it lets power flow, but there isn't any for half the AC cycle.

Oh.. I just wanna deliver pizza. It hurts.


Edit: your cap has shrunk since the label was heatshrunk onto it

 

[PCBuds]

Well, this sucks...

I might have to wait 3 1/2 months for my capacitor. Lol


Amazon could have it here sooner, but I didn't want to gamble away 14 bucks. Lol

 

[PCBuds]

You got a lightning cap about?

No, but I can make one.

I've got two rolls of tin foil. Lol

 

[PCBuds]

Edit: your cap has shrunk since the label was heatshrunk onto it

Yup...