Need help identifying component

[lyvemyche]

Good afternoon everyone and Happy Easter!
I have the head unit (radio) out of my mustang because it works fine for a while, then occasionally it just dies. It acts as if there is a short on the board, I can tap on the chassis and it will come back on for and work perfectly again... I have traced the problem back to this component here. if it isn't working, I can tap directly on this and it will come back on. Can someone help me to identify what this is so that I can then order a replacement?

Thank you in advance for your help.

[petehall347]

Re: Need help identifying component

sup might mean suppressor .. have you checked the solder ?

[lyvemyche]

Re: Need help identifying component

I think Ill try to resolder it and see if that helps. I believe it is a suppressor. I also posted in another forum and that has been the best guess...

[R_J]

Re: Need help identifying component

You could post the make and model of the radio, or the year of mustang it is from, there might be a schematic around

[stj]

Re: Need help identifying component

it's a spark-gap device, sometimes called a GDT (gas discharge tube)
the colours indicate the trigger voltage.

[petehall347]

Re: Need help identifying component

it's a spark-gap device, sometimes called a GDT (gas discharge tube)
the colours indicate the trigger voltage.

what use is one of those in car audio ?

[CapLeaker]

Re: Need help identifying component

here is a run in I had with a KIA radio.
https://www.badcaps.net/forum/showthread.php?t=60291

[petehall347]

Re: Need help identifying component

here is a run in I had with a KIA radio.
https://www.badcaps.net/forum/showthread.php?t=60291

tvs..suppression diode .. spark gap is something else . or so i heard

[CapLeaker]

Re: Need help identifying component

it would be nice to see the whole board.

difference between gas discharge and a TVS is, that the first one is a crowbar and the second one a clamp. Both will protect and as long as the TVS is low in capacitance, there is no ill effect either. I use mostly TVS (do a lot with RF and phone lines), they either clamp or short, depending on the event.

[budm]

Re: Need help identifying component

The device is not needed for the circuit to function, its job is for protection, it will stop the circuit if it is shorted out. You can just lift one legs off the board and check its resistance, it should show infinite resistance.
It sounds like you have bad connection.

[CapLeaker]

Re: Need help identifying component

yeah, it is between the antenna and the RF input to GND. All it does (if it is shorted) send the antenna to GND on which you'll have a deaf VHF receiver.
Problem is that the description of the op is kinda vague.

[stj]

Re: Need help identifying component

if it's across the antenna then it's to protect the radio in a thunderstorm.
if it does fail, it will just stop you recieving any stations though, so i think you have other issues.

that said, it looks blackened inside - they should be crystal clear so you can see the electrodes.

about the difference between a spark-gap and a semiconductor like a tvs or a mov.
semiconductors switch off at the same point they trip,
a spark-gap latches till the energy is gone, but they have a lower capacitance - good for tuned circuits.

[Agent24]

Re: Need help identifying component

it's a spark-gap device, sometimes called a GDT (gas discharge tube)
the colours indicate the trigger voltage.

what use is one of those in car audio ?

Running from a 12v battery might sound really simple, but the power supply in a car can be very noisy, lots of voltage spikes etc, especially when the engine is starting or when it is shut off, EMI from ignition system when running, etc.

Also lots of potential for ESD events since the car is insulated by the tires and high voltages can build up (Ever get a static shock when stepping out of your car?)

Check the attached document: Protection of automotive electronics from electrical hazards, guidelines for design and component selection.

[lyvemyche]

Re: Need help identifying component

Thanks for all of your input guys, I really do appreciate it. From what I have learned in the last few days... Its a gas discharge supressor that protects the radio from static discharge. I understand that normally this suppressor is an open circuit and it protects by absorbing, or shorting any static charge to ground, which is the right suppressor lead as shown in the photo. I have also been told that if this has protected the head enough times, the gap may be damaged and is shorting out, perhaps a loose speck of metal in the gap randomly shorts it and it works again... I have ordered another one and I am now waiting on it to arrive. What has been happening is that radio will work fine, then one day, you'll get in and it just wont power up again. The clock will randomly flash, that's about it. With the radio opened up I plugged it all back in and turned on the key, still nothing. If I lightly tap directly on the suppressor, it comes right back on again, everytime and works perfectly until a couple of cycles of the key then its out again.

[Agent24]

Re: Need help identifying component

It may also be a bad solder joint or other faulty component near the suppressor.