Expecting this part to either be a Fuse or a Resistor ... 7.2 MH Battery Terminal on a 5W handheld Radio (Marine Transceiver) has a component showing no signs of overheating but is open circuit ... this component is white and has a # 32 marked on it ... 32 amps would be too extreme for 5W at 7.2V ... 3.2 amps, possibly, but not a standard value, and 320mA would be too Small ... if this was a resistor at 32ohms then I would expect there to be some sign of overheating for it to be open ... the radio works when bypassing the component ... this is a UNIDEN MHS 350 ... as there is some room under the hood I am currently thinking of tacking a 1.5A mini fuse in place of this component.

Thoughts?

 

Please post a picture. That would greatly help in identifying it. Also are you sure it is not a capacitor?

 

And what is the part designation printed on the PCB?

 

And what is the part designation printed on the PCB?

Not all manufacturers silkscreen the designations onto the board. If the item is not intended to ever be serviced and if production line failures are not worth fixing then there would be no labels. To see if it could be a fuse a resistance check back to the power inlet connector could verify if it is. And then from the other side to power return. If the other side does connect to return then it is a capacitor, not a fuse.

 

Thanks for all the replies.

There was no silk screen around the component (might be under the component) ... found an online manual for this Radio ... Specs: 1400mA draw at full power 5 Watt Transmission ... following the * 2 rule of thumb means a 3 Amp fuse should be more than ample ... also gives credence to this being a 3.2 Amp Fuse ... just haven't seen an SMD component identified like this before ... both Digikey and Mouser photos either show an F or nothing on the SMD's they source.

SMD chip caps tend to be flesh or brownish in color ... this component is white ... taking a picture might be useful but sometimes without a some reference can be more confusing. I use a Electronic Microscope when things get too small ... this component was big enough that I didn't need to use it.

Tested the Power Switch (Rotary) and the Ribbon Cable from the Switch assembly, all ok ... applied power on the other side of this component and the radio springs back to life ... so ... really thinking this has to be nothing more then a fuse. There is a zener, power transistor and various other SMD caps/resistors on the other side of this component ... without a schematic it is hard to determine if there are any other connections directly to the + of the battery terminal on the multi layer board.

The original 7.2V MH 1100mAHR Battery Pack was apparently just replaced with a rebuilt MH pack, so there may have been some issues with the original battery pack that could explain a blown fuse. The rebuilt pack appears to be fine in terms of voltage and charging. One thing I didn't try was attempt to transmit with power applied, if there is an issue with the transmitter, that might also explain a blown fuse.

At this point I am returning the radio to the owner to let him decide how to proceed ... besides the owner was hoping to use this radio in the 2M HAM band but looking at the specs I doubt this radio will work for him ... 2M is 144-148 MHz ... this radio is only provides 156-158 MHz

 

Sometimes parts are marked with a code that is pretty much completely meaningless by itself and you must have the manufacturers data to decipher the code. For example, see this datasheet:
http://www.littelfuse.com/~/media/electronics/datasheets/fuses/littelfuse_fuse_437_datasheet.pdf.pdf

32 is an unlikely marking for a resistor. 33 ohms is a standard value, but typically that value would be marked as 33R.

SM components that are actually white on the upper surface are pretty rare except for some C0G capacitors (which usually have no marking of any sort). If the device has what look like pressed-on end caps rather than just metalization on the ends, it is almost certainly a fuse, but as you have seen at DigiKey, some fuse look just like resistors.

 

Not all manufacturers silkscreen the designations onto the board. If the item is not intended to ever be serviced and if production line failures are not worth fixing then there would be no labels. To see if it could be a fuse a resistance check back to the power inlet connector could verify if it is. And then from the other side to power return. If the other side does connect to return then it is a capacitor, not a fuse.

I very much doubt this is a cap as it is in line with the + from the Battery to the + of the rest of the Radio ... either has to be a resistor or a Fuse ... there are other Silk Screen Values on the board so expect the F1 or other designation is under the component ... because there is a Zener on the other side of this component the thought was it could be a current limiting resistor but now that I do the math a 32 ohm resistor at 1.4 amps would drop the entire amount of battery voltage so again I am certain now this has to be a fuse ... just confused by the 32 being stamped on it.

 

Sometimes parts are marked with a code that is pretty much completely meaningless by itself and you must have the manufacturers data to decipher the code. For example, see this datasheet:
http://www.littelfuse.com/~/media/electronics/datasheets/fuses/littelfuse_fuse_437_datasheet.pdf.pdf

The littelfuse 437 32 volt chart might suggest the 32 on the device as being the voltage rating ... the device looks very much like the blank white pic with just 32 stamped on it in black lettering

32 is an unlikely marking for a resistor. 33 ohms is a standard value, but typically that value would be marked as 33R.

while 33 ohms is a standard value for traditional axial carbon resistors at certain power ratings, SMD ceramic chip resistors no longer have to follow Standard Values ... before SMD's, in the early 80's, I was involved with manufacturing/printing ceramic substrates, which included resistive material pads in place of resistors ... these resistors were first laser trimmed to predetermined values and then once these substrates were fully assembled, these resistors were again actively trimmed using either laser or abrasive (sandblasting) processes ... I haven't researched how SMD resistors are made but expect they could easily use similar processes. Resistance of pads on ceramic substrates was simply determined by the area of the resistive pads ... L shaped laser trims were used to fine tune values ... abrasive trims were used to quickly reduce the size/area of the resistive pads ... as SMD's of various resistance values appear to be the same physical size, they may be doing some additional tricks (chemical, thickness, other) to increase Resistance without increasing the physical size of the SMD.