Car Stereos: replaced 93 Honda accord Car Radio, honda accord car, digital multimeter

Question
hi I hope you can help....
the stereo in my friends car (93 honda accord) died and i replaced it with one I had sitting in my garage....it is not working....when I checked the fuse, I realized that every time I put the fuse back in, the stereo has power for a couple of seconds and then stops again. Now I fear this has to do with the anti theft code and I don't know how to fix this. Also my friend threw the old stereo away so....
my question is if there is a way around this anti theft thing or what else I could do
Thanks

Answer
Hi Ranier,

Is the stereo model you're installing a factory Honda unit, or an after-market replacement?  If after-market, what's the brand and model?

I'm doubtful that your problems are caused by an anti-theft system.  All of the in-dash stereos I'm familiar with, whether OEM or after-market, will usually display a message if the anti-theft system is preventing operation.  It might read "code" or "locked" or "safe", but it won't just be dead.

Many after-market decks will go through a short reset mode when the constant power source is first connected. I think that may be what you're seeing when you replace the fuse.  The screen may light up for a few seconds and the CD loading mechanism will cycle, but then the deck shuts off again.  

If this is occurring, but you can't power it up afterward, then the problem may be with the "accessory" power source.  This is the key-switched power wire, and it's usually red in an after-market deck's harness.  If you have power on the constant (yellow) wire, but none on the accessory wire, the deck won't work because it thinks the key is switched off.  Often, decks will still load and eject CD's in this case, but won't show anything on the display or respond to the power button.

A digital multimeter will make troubleshooting easier.  An after-market deck won't work unless there's 12 volts on both the yellow and the red power wires.  If one of the two isn't getting powered, you'll either need to correct the problem or find an alternate power source.

You might try going back to the fuse box.  Just about all vehicles will have two different fuses that control radio power: one for the constant power lead, and one for the accessory power.  It sounds to me like you've found the constant power fuse, but you may still have a blown fuse in the accessory position.

Good luck!

Brian