Subwoofer Amp - Resistor Values Wanted

[Hokie.Fans]

The subwoofer amplifier on my '97 Merc Mountaineer just blew. I took apart the subwoofer amplifier and determined it is resistors R807 and R808 on the breadboard that are the problem. My problem is as they are fried; I can't read the resistance on them. Does anyone have one they can take a look at and tell me the resistance?

Thanks.

Joe

 

[aaronajb1981]

Not off hand, but you can still see the color stripes on them that is the resistance.

here is a reference chart
http://www.elexp.com/t_resist.htm

 

[Hokie.Fans]

Can't read them - the stripes were fried away.

 

[skipwillson]

Ever find an answer

I have the very same problem. R807 & R808 are toast. I'd prefer not to replace the whole amp.

 

[Cobraguy]

factory subwoofer amps are dirt cheap on eBay. And they are basically the same across several lines. I might even have one laying around. I'll look and see. You could pull one apart and check a good one.

You could also call your Ford dealer and ask them who the Service Center is they send their radios to for repair. Google would help too. Maybe they could look it up for you and give you a part number/value.

 

[kevinspann]

R807 has green-blue-black-gold striping, from top to bottom.
R808 is the same.

So, they should be 56 ohm resistors, according to the charts I found.

 

[skipwillson]

Thanks very much!

 

[fixxxer]

Those output resistors control the fwd bias to the output amplifier stage. Check the output transistors or IC pack to make sure it is not shorted out. And that last resistor color code, Gold, means they have to be within 5% of that 56 ohm value or you could risk toasting the whole circuit board.

 

[Hokie.Fans]

Thanks for the help folks.

Next question: Do any of you have a schematic for the amp? One of my guys is curious about it.

Thanks.

 

[skipwillson]

I tried replacing R807& R808 with 51 Ohm resistors (closest I could find to the 56). No luck and I'm not sure what else to try. I may just bite the bullet and go buy a cheap aftermarket amp. I haven't found any stock ones for sale after limited searching - p/n F5TZ-18D849-A (a.k.a. F57F-18C808-AA).

 

[kevinspann]

I tried replacing R807& R808 with 51 Ohm resistors (closest I could find to the 56). No luck and I'm not sure what else to try. I may just bite the bullet and go buy a cheap aftermarket amp. I haven't found any stock ones for sale after limited searching - p/n F5TZ-18D849-A (a.k.a. F57F-18C808-AA).

They also use metal film resistors...not sure if it makes a difference.

I have an amp here that should work, if you want it. I haven't tested it, since I had already gotten a replacement for mine, but when i opened it to look at the resistors, it looked okay.

PN is F8OF-18C808-BA

 

[BrooklynBay]

Here's a good program for calculating resistor values: http://myadcopy.com/downloads/Resistor Color Coder.exe

 

[torqlox]

Just took my 96 Limited amp apart and same problem. Did anyone ever have any success from replacing these two resistors?

 

[Hokie.Fans]

No - in fact I did what someone else suggested - I bought a stock amp off e-bay.