identification
I'm trying to identify a component I salvaged off a projection TV PCB. It's blue or cyan with three legs marked 270S. Unfortunately I can't figure out where I pulled it off the board from so I don't have the board marking or location to help.
I didn't see continuity, capacitance, or diode drops between any of the three legs when I checked it with a multimeter.
Your best bet is not to identify what part it is, but what function it had and replace that function. You will have to unsolder the part anyway. After that, you can start working out if and how it is connected to the USB port. If it is, you know what it does and can replace it with something else.
It is possible USB might work after you unsolder the part. Perhaps it is just some peripheral part, not the power supply to USB. In this case, the fried part might just be shorting USB power, which then shuts down.
If not, maybe (danger!) you can connect the USB 5V directly with Mainboard 5V from, say the harddisk plug. This would change how safe USB is (usually it is limited to a certain amperage), and you could fry the notebook with USB. But then again it is already toasted...
Usual warnings etc: dont burn down the house.
On the input to the PCB from the alternator, this large Diode-case-like component appears to be a bi-directional (due to AC, and before the bridge rectification) Transient Voltage Suppressor (TVS) diode.
These act as surge voltage absorbing components, which dissipate any voltage above the clamped voltage (as heat) by redirecting the current to the return path.
These are very important for automotive style power supplies like alternators, because the voltage output of these can have seriously high spikes. A car may output a "steady" 14-16V while the engine is running above idle, with spikes in the 40-60V range occurring frequently.
Without these voltage clamps, the diode bridge (probably rated to 40V) would probably fail, any further capacitors or CMOS devices would instantly fail from destructive voltage breakdown.
Inside the package it looks like this (ignore the default device names shown..):
simulate this circuit – Schematic created using CircuitLab
Best Answer
Its almost certainly a Ceramic Resonator.
These are three terminal devices that have a similar function to a crystal when used in an oscillator circuit, but are much cheaper and consequently have poor tolerances. Unlike most crystals, the ceramic oscillator contains built-in capacitors, so the extra pin (usually the middle one) is ground.
The marking
270will almost certainly indicate 27MHz. This is a very common frequency in TVs - being the reference frequency for both PAL and NTSC video standards.The
Scould be tolerance information, or it could be a date code. As an EIAJ monthly code,Swould be May 2010 or some multiple of 8 years either side of it (e.g. 2002 or 2018)There is no manufacturer information, so it won't be possible to find the exact specifications, however something like Murata CSTLS27M0X51 would be a similar type of device.