Marantz 2245 problem

[marantz_2245]

When i turn my reciever on it will work for a while but after a while it will start with a low hum and increase to pure white noise. I know it is not the speakers because i have already trouble shooted them. So any ideas on what this could be?


Another question..Is there an easy way to bridge this reciever with an outside amp but still use the power from both?

Thanks for the help in advance

[jblmar]

Welcome to AK.

Is the problem in all modes?
Please be more specific.

Ron

[marantz_2245]

yes the problem is in all modes,it will start randomly as a low humm and increase to strong white noise then eventualy the reciever loses all sound. After this happens it takes the reciever about an hour to have audio again but eventually the same problem will occur. Sometimes this problem takes 30 seconds other times it takes 10 minutes

[jpdylon]

First, Clean all the switches and controls. Sounds silly, but you really can't judge a unit's problems until you've done this

Next, remove the jumpers on he back panel that are connecting the pre-out/main-in RCA jacks. Then connect the pre-out to another power amp and see if you can still hear the problem while connected to another power amp. If so, then the problem is in the preamp. If it goes away, the problem is in the power amp of the 2245

[marantz_2245]

so if the pre amp on the marantz is blown what would u recommend? Buy a new pre-amp? :) o get it repaired

[jpdylon]

get it repaired.

If the problem lies in both channels and is the same amplitude in both channels, I would be more inclined to suspect a regulated power supply failure. If it is in one channel only, look to the preamp. Find a good technician near you who knows about vintage audio. Ask him what a 2245 is. If he doesn't tell you its a marantz receiver from the early 70s with 45wpc, don't take it to him.

[marantz_2245]

the omron my2 relay is not picking up. I cleaned the contacts and this did not do anything. The electromagnetic coil doesnt seem to be getting the signal to open. When the relay is manually engaged the reciever works fine. Does anyone have any expierience with this problem?

[catrafter]

Did you get the 'white noise' problem fixed? Is this a new problem or an extension of the previous one?
Have you checked the DC offset? If that is OK, then the problem may be with the power supply or the relay driver circuitry that is on the P800 board (the one with the relay), or R013 which is off board, 150 Ohms between J806 ans J807.

See this thread on DC offset, and thank EchoWars.

http://www.audiokarma.org/forums/showthread.php?t=5634

Tom

[marantz_2245]

I found a broken resistor thats for the electromagnet and so i believe this is the only problem since when the relay is manually engaged the receiver works fine

[catrafter]

Great news, should be an easy fix.

Tom