Marantz PM-25 circuit

SOURCE: marantz pm 7200

Could be a power supply failure or a Power "On" switch failure.

Kev

SOURCE: Kenwood KR11000G and Marantz 1152DC Integrated Amplifier

Hi spanky, replied to one of you other posts. Just clearing this ticket out of the system:)

robotek

SOURCE: Marantz PM-34 Problem

Hi there

The part that you speak of is called the emitter stabilizer resistor. It is common to the output pair on one channel. You will find that the large "output" transistors mounted to the heat sink either side of this resistor will most probably be faulty.

Best not to run the amp at all whilst in this condition.

To be sure that you have an effective repair, you will need to change both these parts, and also the "driver" transistors that connect to the outputs. They too are in symmetrical positions close to the the output transistors. You should also check that the 3 legged resistor you mentioned is measuring its correct value, and check all other low value resistors in the output stage area to that channel.

If you are not familiar with repairing this sort of equipment, perhaps you can find a repair guy with some experience on audio equipment, then this work should be all he needs to do to repair the amp. I would also ask him to "blanket resolder" the output/bias stages and power regulator stages in the amp as problems with heat stressed cracked/failed soldering and dry joints often cause these amps to blow the output transistors.

BE SURE THAT THE CORRECT PARTS ONLY are used for the repairs. Different transistors could cause future problems with the amp. The parts can be obtained relatively easily from a marantz distributor(we can find one in a country near to you). OR if you can give me the markings to each of the parts you need, I can provide you with an international source to get them from.

The amp is decent HiFi, and worth repair. Happy to provide you any assitance I can, Good Luck

regards
robotek

Michael Mittelsdorf

• 58 Answers
• Posted on Jan 05, 2009

SOURCE: marantz pm 7200 integ.amplifier

Dear Sushant,    I do not think your use of an equalizer has caused any problems.  I will explain the proper use of the source/direct button.  This button's function is to monitor the output of a recorder connected to the record outputs of your amp.  When this button is pressed on the sound going to the speakers comes direct from the "source" (cd, radio tuner, phonograph etc.) when in the off position you can monitor the recording of whatever source is being recorded via the tape deck.  This switch must be off to record through the amps record outputs.    To test this, put a blank tape in the tape deck, choose the source as phono and place the dec in record/pause.  With the source direct button pressed on you should hear a change in volume when moving the amp's volume knob only.  When source direct is off you will be able to hear the output of the tape deck, so adjusting the tape deck's record level will also affect the volume coming out of the speakers.  more record level in/ more level out.!    Below is copied from page 9 of your user operation manual for Marantz's explanation of the source/direct button. 
best of wishes, Michael Mittelsdorf

SOURCE: How do I connect a subwoofer to an amplifier marantz pm-68

double up the speaker and then use the two extra screw to hook sub and center