71 Johnson CD Amplifier needs repaired

7

70wellcraft

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Aug 6, 2008
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I have a bad amplifier and need to know if I could remove the bad components from the circuit board and solder new one in. This amplifier is causing intermittent stalls on my 100 hp engine. Its at least $200 for a new one. Attached is a pic showing an area that looks dark and smokey (just left of wires and above large blue capacitor) Can anyone help me with a circuit diagram or parts list?
 

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Joe Reeves

Joe Reeves

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13,262
Re: 71 Johnson CD Amplifier needs repaired

If you can get at those items, of course you could replace any of the components. It simply depends on your capabilities. I'd be interested in knowing just how you would get rid of all of that epoxy.
 
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bigpoppakdog

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Re: 71 Johnson CD Amplifier needs repaired

i have a powerpack for a 1970 115 evinrude that I would sell you at a very low cost if it works for that engine and if you would be interested. bombardier part# 398363
 
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70wellcraft

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Re: 71 Johnson CD Amplifier needs repaired

Well I was able to remove the epoxy around that smoked part which was a 100 ohm 1 watt resistor and replaced it. I just used an exacto knife with a long blade and cut around the part to pop out the epoxy. I then reassembled with some new thermal silicon for the SCRs then put back into engine. I also added that diode between the amplifier power in and the 12V at the starter solenoid but when I went to start it it blew the ignition fuse :(near the solenoid so I got scared and just took it out. Then replaced fuse and ran for 5 - 10 minutes with no stall. If this works I'll be happy:D. I need to test on water.
 
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70wellcraft

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Re: 71 Johnson CD Amplifier needs repaired

:(Took on water yesteday with same problem. Its frustrating because I think these things fail the same everytime. There is some component or solder joint causing the problem. If I had a schematic or if the manufacturer has done any post mortem analysis on these parts they may know what is going wrong. Guess I'll just spend the $200.
 
T

tx1961whaler

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May 31, 2008
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Re: 71 Johnson CD Amplifier needs repaired

When you get the new one, you might write down all of the component values/Part numbers, in case the darn thing blows up again.
I had a VW Rabbit that would blow voltage regulators all of the time, and it was just a $2.00 (3) terminal regulator in a metal case that they charged 50 bucks for. I learned to re-do those quickly....
 
patrick4266

patrick4266

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Re: 71 Johnson CD Amplifier needs repaired

I have the same amplifier and am very curious if they can be repaired that way. I am no electrician but I may be able to pull it off with instructions. I do have a spare for my motor, but i also have a old blown one that I would like to fix just for the hell of it and to learn something. As i said I am no electircian but before I spent 200 bucks I would ask these guys if there is some other problem blowing your amp.
 
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