McIntosh Mac 1700 Popping/Motorboating issue HELP!

[johndoe10]

Hi All -- I am trying to repair a Mac 1700 stereo receiver. The issues it's displaying are: A loud pop sound in the right channel when the unit is first turned on. As the volume is increased with an audio signal, the popping becomes more frequent, like motor boating in the right channel. The right channel heatsink becomes very hot within about a minute. Both channels appear to be playing clearly, but when the popping in the right channel begins, it cuts the audio signal out in that channel.

Any help, advice or suggestions would be greatly appreciated.

Thanks in advance -- John

 

[c_dk]

The amp is oscillating heavily and ready to blow up......what tools do you have to monitor and discover what devices are ready to fail.

If you do not have the right tools it is time to engage a local tech.

 

[johndoe10]

The amp is oscillating heavily and ready to blow up......what tools do you have to monitor and discover what devices are ready to fail.

If you do not have the right tools it is time to engage a local tech.

My bench is well equipped and able to handle the task. Just curious if any one else has had a similar issue, and what was the remedy...coupling caps, mylar caps, etc...?

Regards -- John

 

[Mikeorg]

John did you ever find what was going on with your right channel, I have a 1700 doing the same thing...

 

[Refugee]

I suggest you start with the cheap easy stuff. It very well could be a loose solder joint or a dirty/loose tube socket although probably not tube socket since only the tuner section is tube. Give the unit a good cleaning and look for problems as you clean. Reflow questionable solder joints. Clean switches and pots with the right chemicals. Keep a schematic on hand while you do this and identify sections and parts as you go in case you have to go deeper. I have found more issues cleaning units than I have with test gear (Might be my test gear chops! Ha) Maybe you will get lucky!
Let us know when you find it.