rf 325.1 bad outputs? repairable?

DO NOT ADJUST the controls inside of the amp.  These are the Bias adjustments.  If you turned them any at all, turn them full counter clockwise and leave them there.  If you did not adjust them DO NOT TURN THEM FULL CCW.    The voltage jumping around is normal with music playing.  What exactly is the amp doing or not doing?

Power the amp up and check the amount of DC voltage between the positive and the negative speaker terminal.  The only way it can hurt your speaker is if there is a boatload of DC voltage between the terminals.

If there is no metal clamp holding the transistors to the heat sink, those transistors are soldered to the thermal strip that is mounted to the heat sink.  It requires a torch to remove and resolder those transistors.  Were there any 36P15's, or were all of the outputs the 28N15's?

just4today wrote:

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Lots of different settings on DMM . I used ohms . I know . . . you said diode right . Well , i`m just not seeing it . Seems like a nice enough meter , surprised it`s not on there .
Q120 - 28n15 = .0 ohms
Q123 - 28n15 = 11.5 ohms
Q118 - 36p15 = 8.15 m ohms
Q122 - 36p15 = 8.02 m ohms

Was this any help to you ? Thanks again for your help tonight . You seem to have been around a few amps .

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I don't think MCM sells those.  You can check though.  I would recommend buying a butane torch from Radio Shack.  20 bucks.  I would not use a plumbing torch.  The transistors are soldered to that thermal strip.  This is not going to be an easy task.  The amp needs to be unmounted from the heat sink, all components that are mounted to the strip that contains the output need to be unsoldered from the circuit board.  You need to go to Office Depot and purchase some medium size binder clips.  Spring clips to hold a stack of papers together. Whatever other devices are mounted to that strip need to be clamped down with the clips. If ther are 3 metal legs that connect to the strip, they need to be retained also.  A pair of Hemostats works really well for this.  Once you have all other devices clamped down, place the strip in a vice.  Have the strip horizontal and the end away from the parts you are working with is to be clamped in the vise.  With the radio Shack torch turned up all the way, start heating area below the transistors to be removed.  Place a small screwdriver in the hole at the top of the transistor.  While heating it, keep a little pressure on the transistor so when it comes off the strip, you can move it off of the strip with the screwdriver.  There are a couple tiny surface mount components near the transistors, you need to make sure that you do not disturb them.  The solder will heat up on them, but they will remain in place if they are not disturbed.  Continue heating the other one and remove it the same way. 

Before you start the above procedure you need to scuff the back side of the new transistors, 400 grit sand paper or a very fine file will work,  just scuff till the shine is gone.  If you do get the Fairchild parts, you may not need to scuff them.  You need to heat the back of the transistors and apply solder to the entire back of the transistor. 

After removing the transistors from the strip while the strip is still hot, you need to add a little solder to the pads where the transistors came off of.   Use the gold dot on the strip as a sight along with the hole in the tranny.  A pair of Vice Grip brand C Clamp works really well for the reinstallation of the new transistors.  They make several sizes.  The small ones work great.  With the transistor placed over the gold dot, start heating the bottom of the strip, with the c clamp pliers opened all the way up, have the top of the clamp resting on top of the transistor to apply gentle downward pressure to the tranny.  When the solder begins to heat up and the transistor sits down on the strip, close the pliers and hold in place untill the solder hardens up,  20 to 30 seconds.  Put a clamp on that one too.  Then install the other one. 

Hey if you have a digital camera, before you remove the amp from the heat sink, take a few pictures of the strip and the output transistors.  Pay close attention to the tiny components mounted next to the outputs.  You may have to put your camera in the Macro setting.  That is the picture of a flower.  This will allow the camera to focus in an extreme close up shot. 

Also on the 3 metal legs that connect the circuit board to the strip, there is a fiberglass rectangle with a hole in the middle, the screw goes through this part.  When attempting to keep the metal legs in place while torching, put this piece over the legs when attaching the hemostats.  The hemostats alone will not keep all 3 legs in place.  As far as repair difficulty, on a scale of 1 to 10, this repair because of the mounting system, comes in at an easy 12.