Hi there, we have a marantz 8100 receiver - sent in to repair and the technician advised cct board blown - potentially due to faulty speakers. Now looking to try and repair but unsure where we could pick up a second hand cct board from - any thoughts?

If the right input on your Behringer Ultracoustic ACX1800 CD is not working, it could be due to a number of reasons, including:

1. A faulty cable or connection: The problem could be as simple as a loose or damaged cable. Try swapping out the cable with a known working cable or check the connection to ensure that it is secure.
2. A blown fuse: The ACX1800 CD has a built-in fuse that protects the internal components from power surges or other electrical issues. Check the fuse to make sure it is not blown and replace it if necessary.
3. A damaged preamp or amplifier circuit: If the problem is not with the cable or fuse, it could be due to a damaged preamp or amplifier circuit. This can be caused by a number of factors, such as overheating, power surges, or other electrical issues. In this case, you may need to take the ACX1800 CD to a professional repair technician to diagnose and fix the problem.
4. A faulty right channel input jack: It is also possible that the right channel input jack itself is faulty. This can be caused by wear and tear over time or physical damage. In this case, you may need to replace the input jack or have it repaired by a professional technician.

Fuzz and pop sounds like bad capacitor or blown transistor.
Best to take it back to service center.
While there, throw your toys out of the cot, explaining that they did a 'b*m' job.

There is a repair manual http://www.manualsparadise.com/service-repair-manuals/Marantz/SR870/RWSPFM-63663893-1

I cannot speak to the company that sells its reputation. The issue is most likely due to the protection circuit in the final audio section. Most use a relay to disconnect the speakers in the event of an overcurrent condition. The relay can fail for a number of reasons.

you can get the know right from the dealer at this link http://us.marantz.com/us/Support/Pages/ServiceCenter.aspx as far as the one speaker working, switch the speakers to make sure its the unit and not the speaker box, if that doesn't help you probably have a blown output in the unit itself,, since its a Marantz Its worth the cost of having it repaired,, as with all High end receivers or amps, Be sure the unit is in the off position before you attach or disconnect any speakers ,, if they short out,, our gonna blow the output

Hello Sergio.

Sounds like a bare wire (speaker wire) most probably is touching your SR's metal body.

Remove all speaker cables, re-terminate them clean (cut, trim, and twist again) and then re-plug them in to the binding posts.

When you go puredirect, it overcoms some filtering circuits of the board and this should be the reason why it stops.

Try that & advise.

Hi friend,when something goes wrong in the output of the amplifier the protection circuit take place to prevent further damage could cause by DC power such as speakers or other related circuits...I think in your situation either one or both output amp stage have blown,then the protection cct turned on (not blown protection circuit!?). If so you have to check all the output transistors for short cct, if shorted you must also check all the DC bias cct nearby such as small transistors,resistors...If you are not familar with amplifier it better to find a tech as all amplifiers need a very precide repair technic , If the DC BIAS were wrong , when you turn on the power it will blow straight away! All times and cost will be waisted!
GOOD LUCK!
Tan Ta

The f-l channel of the sr18, & sr18ex & sr19 is a common failure location due to the heating and cooling over the years. The crackling an/or distortion, is most commonly due to the amplifier going into a high idle, or d.c. offset that can no longer be controlled by the adjustment potentiometers on the board. usually the two 2sc3200 transistors become unstable, and as well a 47mfd and a 470 mfd elect. caps nearby. Also distortion is caused by one or more of the zener and germanium diodes all grouped near the big dual ceramic white resistor. The amp block is held in by six screws. first remove the cross bracket, then cut the cable tie free from the hole on the board. Ten screws hold the top board on, the pull the boards apart from the connectors. before replacing it, resolder ALL of the connector pins to BOTH boards.

Probably similar problem to that I've got. On inspection found Inverter board blown up, due to the cheap capacitors having blown. I can't get a cct diagram for this board, so can't repair it. Need a replacement.

This is the problem with computerized stereo's. The old analog stuff we could fix forever, but many of these digital problems, only the maker has the tools to repair. Feel fortunate that yours will even offer you support, even though expensive.
Good luck.

It is likely that the PA stage has developed an offset voltage in the output stage. The faulty amplifier channel can be found by progressively disconnecting the collectors of the of the power transistors until the protection fault disappears. Once the faulty channel is found the the cause of the offset has to be traced to the faulty transistor or resistor. Don't forget that if you can smell smoke or burning then there are likely to be components(esp transistors) that have been damaged by the fault.
I had a Luxman unit that destroyed 5 transistors in the output stage that was due to an open .5W resistor in the driver stage.
Good luck.