Identifying a part is it a 6A fuse?

am i correct to assume that the encircled part is a 6A fuse?

diode test result to no contact.

Maybe... Looking at the abbreviation and the device next to it: Y4, which I believe is a 12-somethingHz crystal and thinking the "fuse" says Y9, if it has two leads on the same side it may be like a small - for exemple - watch 32,768 Hz crystal, and if it has a clock battery next to it, perhaps moreso - but not necessarily - it's a crystal. Any clues as to what U10 is/does?
Without knowing anything about the circuit, strange place/layout (insofar as anything is "strange" where layout is concerned) for a fuse as it is not next to a connector and/nor before a capacitor, etc.

Agreed - almost certainly it is a quartz crystal just like the one labeled Y4 beside it. Given the fact that a coin cell is right beside it, I would guess the board contains a real-time clock (wall time clock) and the crystal is 32.768KHz, similar to the one found in digital clocks and wristwatches. Is there a 'Y' number next to the other crystal behind the blue socket?

Brian.

actually its a cctv. it just stop working. i was trying to figure out which component is busted. could anyone guide me through this? like which to test first.

Hi,
If you can describe anything related to its stopping working (like: Was there an electrical storm at the time? Was it functioning normally but the next time you turned it on it didn't work, or did it stop working halfway through a normal situation?)

Someone-else would have to guide you through trouble-shooting that circuit I guess, and I doubt it has anything to do with the failure: the vent lid of the capacitor (top right) inbetween the battery and the "molex" connector looks a bit swollen compared to the others nearby - did it "pop"? Is the watch crystal lead burnt, is that why you asked about it?

One first way of trouble-shooting is (if it turns on, and you are familiar with the board) to check the voltages into and out of the ICs (unless their leads are too small to do so safely without shorting something in the process), etc. Some-one told me that continuity throughout an IC's pins means it's blown, but that is a very relative assumption as some pins will have continuity due to internal design anyway.

Fault finding equipment like that is virtualy impossible without a schematic and diagrams of waveforms to expect at various test points. Almost certainly it has nothing whatsoever to do with that crystal, it's purpose is to keep a clock running so the time can be inserted into the picture. If it broke, which is very unlikely, at worst the clock would freeze, showing some random time.

DO NOT try to measure continuity between IC legs, it proves nothing but could damage a good part. The best you can do I'm afraid is check the incoming power is OK and check the voltages where marked on the board. Place the black wire of a DVM on the metal screen around the USB socket and place the red probe on the points marked 1.0V, 3.3V and 1V8, you should measure those voltages on the meter. If they are present, the PSU part is good and I'm afraid that is the only part you realistically stand any chance of repairing.

Brian.

betwixt said:

DO NOT try to measure continuity between IC legs, it proves nothing but could damage a good part.

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That's very interesting to know. (even though it's not my thread) thank you. I'd had my doubts about that being a possible outcome of testing for continuity as I imagine a person could pass the continuity voltage through an output into the device, for example.

DVMs produce as much as 9V across their probes when unloaded. Many IC's are damaged by as little as 0.6V across pins, especially MOS devices.

Brian.

before it went dead a water dispenser was plugged in and it busted. turns out that the water dispenser has its wires fused together by water dripping.
yes the capacitor's top is swollen
the crystal's surrounding is also blackened.

if ever i have to buy a tester that test capacitors how high would you recomend? currently my tester is 200uf while the capacitors on the board are 400uf so i cant test it for now.

squirrel online said:

am i correct to assume that the encircled part is a 6A fuse?

diode test result to no contact.

Click to expand...

If it is a gapped part, it is probably a polyfuse with 6A above it. I see these a lot.

- - - Updated - - -

More likely your cheap supply has no reverse blocking diode or cap so secondary inductance will exceed Schottky Vr and it's surge rating for Pr is much lower than Pf on intermittent arc contact from Vin=Ldi/dt at charging currents of 10A or so.

400uF?? you mean you released a design to production without protected or tested inrush current and kickback voltage? tisk tisk

another view

Hi,

As Brian said, could be beyond hard finding the cause without circuit schematic and so on. Anyway, where there's a will there's a way sometimes with a bit of luck: if a great part of the circuit isn't zapped, I'd forget buying another tester for now. You (may) need to discharge the capacitors somehow before fiddling with things, not sure how to do that, you'd need to find a suitable way.

What's the oil slick gunk on the back of the battery? Is it silicon/glue or something that shouldn't be there? Perhaps you could try starting with changing that capacitor, perhaps the cell battery (if it doesn't give - presumably - 3V on the voltmeter), maybe the crystal if it's got burn marks on the pins - but Brian said that is last one unlikely. If you turn it on and it dies quickly like it tries to work but can't that could be a short somewhere - I had a capacitor fail a few days ago on a breadboard driving me mad looking for the sudden odd circuit behaviour as I thought it was anything but a bypass capacitor.

You may just have to replace the whole board, to be honest with you as it may be very time-consuming locating the actual fault. Or if there was a short-circuit/surge of current - just how far into the circuit are things fried? I would have a go at least replacing the suspect capacitor though, if you really can't send off for an instant under guarantee replacement board.

If it is a gapped part, it is probably a polyfuse with 6A above it. I see these a lot.

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You are reading it upside down Tony! It says Y9 not 6A. The crystal beside it is marked Y4. The manufacturer is using 'Y' as the designation for quartz crystals.

The black gunk is probably a hot-melt glue, it is quite often used to secure large components like the battery holder where a risk of wire/joint fracture exists if the unit is dropped. Possibly there was also a drop on the end of Y9 as it has thin wires and it doesn't appear the can itself was soldered to the pad below it. It isn't possible to be sure visually but those capacitors all look fine to me. The yellow mark on their tops is ink from the tester/inspectors pen to confirm it passed test. You cannot test them while on the board anyway but you might be able to measure the effect on the voltages of them not working properly.

Having served my time in the mass manufacturing industry, I still say that aside from a possible PSU fault, it is best to replace the whole board. Unless you have specialized soldering equipment, including an IR oven and X-Ray machine, you have no chance of replacing some of those parts, even if you could find a source to get them from. Even tracing who manufactured the parts is difficult and some will be custom made specifically for that board. In the past when I've traced a manufacturer of an obscure IC and tried to get a replacement, they have said something like "No problem, they are $2 each, delivery within 6 weeks - Oh, and the minimum order is 10,000".

Brian.

poor photo, sorry I was too quick to suggest.

Looks like you need a new board. TO play with it, measure impedance using a good DMM with 1mA CC limit of each input for power supply connections to ground and in series. Digital DMM's are +V on + input. ANalog VOM's are reverse.

Looking at the board the device marked 6A or correctly as Y9 is a crystal. Looking even more closely the IC starting S29GL has a c r a c k and is burnt and is almost certainly faulty. If you replace the chip then you should change the bulging capacitor as well.
However the IC is a flash memory device and the only place you would get a correctly programed one is from the manufacture of the board.

I see no c r a c k. There is a line along the edge of the IC but that is normal for that kind of package. The 'burn' mark looks to me like the same stuff used to secure the battery holder and similarly scraped away. It an IC like that really did burn the mark would be in the middle and there would be a visible bulge.

Brian.

I see no c r a c k.

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It maybe the second picture is misleading, but in the middle of the dark patch on the IC is a small c r a c k, I don't mean the long line running along the IC. I have seen this many times where an IC has blown out. A better close up picture of this IC would help.

basing on your replies it is sad to know that there is a "limitation" to what can be repaired
for now i will play with it.
change the capacitor with a bulging top since i have not yet bought a capacitor tester.
im also attaching a picture with the clearest pix i can.

one question. what happens to the electric current when it reaches a defective capacitor? does it go through?

That would depend on what were wrong with the capacitor. Mine had a short. They can fail open or short, or apparently intermittently.

This link is better than my ill-informed muttering (page 17 onwards describes capacitor failures):

https://www.niccomp.com/help/NIC-LED-Light-AlumECaps-092010r.pdf