help to identify component

Thread Starter

montarbo

Joined May 5, 2014
9
Thanks for reply. Very good links, thanks again.

Would make sense according to little tables but in general that explanation indicates three number where as the third is the multiplier and j would stand for saturation. As of the picture indicate 1000j not 102j??

Well shall say its a capacitor, is it one with polarity or without? polarity indicator in such case?
 

AnalogKid

Joined Aug 1, 2013
11,055
Look at the PIC pinout and see what the closest pins are for. It is a 1000 KHz (1 MHz) crystal or ceramic resonator.

ak
 

Thread Starter

montarbo

Joined May 5, 2014
9
Thanks again.

I thought that too and I think its a Murata CSB1000j but I wasn't sure.

Does these go bad?
As you can see its a car FOB ( brand CARGARD ) board. First time defective revealed the right leg solder was broken, re-soldering made it work for a few months, now defective again.
 

Thread Starter

montarbo

Joined May 5, 2014
9
Look at the PIC pinout and see what the closest pins are for. It is a 1000 KHz (1 MHz) crystal or ceramic resonator.

ak
According to datasheet of the
PIC16C54C
the legs 15 and 16 are the osci/CLKIN-OUT which indeed connects to the resonator respectively.

Does this mean its replaceable with oscillator, where as to get to same working frequency it need one with 1.5- 2 MHz. Or it must be a resonator given if its gone bad?
 

alfacliff

Joined Dec 13, 2013
2,458
if its a 1000 kHz (1mHz) crystal, hold the fob near an am radio tuned to 1000kHz and listen for the signal. if its working, it should have a signal near 1000 kHz.
 

Thread Starter

montarbo

Joined May 5, 2014
9
if its a 1000 kHz (1mHz) crystal, hold the fob near an am radio tuned to 1000kHz and listen for the signal. if its working, it should have a signal near 1000 kHz.
Wish I had an AM radio.
The FOB had a small flat speaker ( buzzer ) which used to buzz when working, it doesn't have any live signs now. Not a battery issue, no dirt ...etc. Would've been great having the schem for this little fella.
 

Thread Starter

montarbo

Joined May 5, 2014
9
Switched the one in the second FOB, worked fine. There was the culprit but how on earth does these goes bad. Ordered one already.

Thanks everyone for help.
 

ian field

Joined Oct 27, 2012
6,536
Thanks again.

I thought that too and I think its a Murata CSB1000j but I wasn't sure.

Does these go bad?
As you can see its a car FOB ( brand CARGARD ) board. First time defective revealed the right leg solder was broken, re-soldering made it work for a few months, now defective again.
The ceramic resonators tend to stop working if you clean the board in an ultrasonic cleaner. Otherwise, failure is relatively rare - but not entirely unknown.

The oscillator pins on a MCU usually bring out the input and output terminals of a CMOS inverter - the signal on the output side pin should be easy to scope, it should be more or less a sinewave as there's usually a resistor biasing the inverter into linear region.
 

THE_RB

Joined Feb 11, 2008
5,438
It's a 1000 kHz ceramic resonator for sure, I have many here in different sizes.

I will disagree with Ian Field about failure being rare though. ;)

We used to replace a couple a week in TV and VCR remote controls, they stop working after shock damage (dropped remote). Most I have seen marked 455 or 455kHz.
 

ErnieHorning

Joined Apr 17, 2014
65
Ceramic resonators are actually more tolerant of shock and vibration than quartz crystal. What kills a resonator is age. They drift over time and your tuned circuit will no longer oscillate at the correct frequency.

Ceramic resonators are used where cost is a greater desired rather than the actual frequency, just that it oscillates somewhere around a particular frequency. In fact, I bet if you could get an oscilloscope on it, it’s still osculating. Because it’s out of tune, the level is too low of a voltage for the micro’s internal oscillator circuit.
 

Thread Starter

montarbo

Joined May 5, 2014
9
Wow, great answers.

Stopped at an auto service and got one complete PCB for free but its working one. Switched the resonator on mine and worked like charm. Did it just to have two fob in hands, in case of dysfunction of the other. That seemed much easier than trying to recode the free one. Otherwise expecting delivery of new ones in a week. Think i'll stick to this used one so long it keeps functional.
 

THE_RB

Joined Feb 11, 2008
5,438
Ceramic resonators are actually more tolerant of shock and vibration than quartz crystal. What kills a resonator is age. They drift over time and your tuned circuit will no longer oscillate at the correct frequency.
...
Good point, but I don't think was the case with the TV and VCR remotes.

The resonator there is used to clock the micro, which generates the RC code pulses. Even a large freq change of a few percent would probably not matter, and definitely not a tiny change in freq. And customers often reported a drop incident too. :)
 

Thread Starter

montarbo

Joined May 5, 2014
9
Good point, but I don't think was the case with the TV and VCR remotes.

The resonator there is used to clock the micro, which generates the RC code pulses. Even a large freq change of a few percent would probably not matter, and definitely not a tiny change in freq. And customers often reported a drop incident too. :)
I actually did drop my keychain including the fob a bunch of times.
 

ian field

Joined Oct 27, 2012
6,536
Good point, but I don't think was the case with the TV and VCR remotes.

:)
The rooms where people watch TV are usually carpeted, so dropping the remote doesn't often damage the resonator.

In my TV servicing days I frequently had to clean remote PCBs after drink spillages - it was an absolute rule; remove the resonator before putting the board in the ultrasonic cleaner.
 

ErnieHorning

Joined Apr 17, 2014
65
In my TV servicing days I frequently had to clean remote PCBs after drink spillages...
If they were lucky, it was only water, tea, coffee or club soda. Simply drying off the board and wit was back in business. If it was something like Mountain Dew, it would remove the gold plating on the contacts within 24 hours. I was still able resurrect one by cleaning the contacts with and eraser down to the bare copper and then covering them with some lite electronic oil. A cheap recovery for one that would normally be thrown away.
 
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