EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: lyvemyche on April 01, 2018, 06:02:29 pm
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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 gain... 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.
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my first inclination was that it looked like a resistor, but I have never seen one that has that sort of clear look to it. also... Typically they are either good or bad but not intermittent. however, I guess all bets would be off with bad solder joints.
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Looks more like a glass-body diode to me.
A 9.8M resistor doesn't seem like it would be found in a car radio, nor would it be a standard value.
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Hi Iyvemyche,
it should be a glass gas discharge suppressor from mitsubishi:
https://docs-emea.rs-online.com/webdocs/13b8/0900766b813b84bc.pdf
Best,
0xfede
EDIT: forgot to add that is a DSP-141N
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So it acts as a surge suppressor type of thing?
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So it acts as a surge suppressor type of thing?
Yep.
Best,
0xfede
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Cool, Thanks for your help. I am going to try to resolder it first and see if that fixes it, if not, Ill just order another one and replace it.
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I don't think resoldering it will help. I'm assuming this gas discharge device is to protect the head from static damage when the head is reconnected to the radio. So 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 your photo. 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.
If you can tap it with an ohmmeter connected you should see it be either open or shorted as you tap. It has worked as designed so even though it will allow the radio to work if it isn't in the circuit, without it the next static discharge will damage any number of more expensive parts. Well worth replacing it.
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Thanks ArthurDent, I think I will go ahead and try to locate one. Swapping it out wont be much trouble so I may as well just replace it.
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Do you guys have any ideas as to where I might could order one from? I have searched and searched and cannot seem to locate one...
Mouser, MCM, Digikey, etc... nothing ever comes up with that part number (DSP-141N-S00B or DSP-141N)
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Apparently they just sell to OEMs so no one stocks them. Check for Littlefuse CG75L and see if that might physically fit. It is about 1/3 inch diameter and where it would be sitting on the pc board ground plane you'd have to insulate it from the board. It is rated 75V instead of the original 140 but where it is being used on a 12 volt auto system that shouldn't matter. I'll let you decide if it's suitable. It won't hurt anything if it fails, you just have to replace it again.
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Thanks again for your help, I really do appreciate that. I THINK I have located a replacement for the original one finally. It looks like PacParts has them. I placed the order today, but if for some reason they cancel it tomorrow because they cant get it, then I will Definitely order one of these, they are even available on amazon.