Fisher MC-3000 Receiver Repair

I purchased a turntable recently for playing music around my apartment. I find that when using online services I spend more time searching for songs or skipping songs that I never actually listen to any music. I figured using a turntable would force me to listen to only the music I have on hand and give me a reason to check out the local record stores. I purchased a new turntable based on reading many reviews online. Unfortunately you can’t just plug speakers/headphones into it. Hard to imagine when even the simplest devices have a headphone jack built in, I think even my toaster has one. I’m joking of course, I don’t think my toaster has a headphone jack. Now that I am writing about it let me go check. Nope, I was right. No headphone output.

To get the sound out of the turntable a receiver is required between the turntable and the sound reproducing transducers. Luckily the dumpster provided such an item for the interim use until I can budget for a newer one. Behold the Fisher MC-3000 Integrated Music System, the best Japan had to offer in the 1970s. Ok, maybe the best the dumpster had to offer. This beauty features an AM/FM radio, integrated 8 track player and, most importantly for me, an aux in feature with outputs for speakers and headphones.

Function switch … functions

The receiver in all its glory

Inputs are a touch crusty

As with most dumpster findings this receiver needs a little repair. For starters the function selection dial has a tendency to cause the audio on the right channel to cut out. Nothing a bit of contact cleaning should not be able to solve. I also am not impressed with the power cord. I have been hesitant to leave this plugged in for extended periods of time and will be replacing that cord during this repair. Aside from the wood case falling apart in the back there is not much else that needs repair. Now to open it up.

Analog Circuitry

Function Switch

Front Panel Pots

Bottom View of Function Switch

Out of the case

The inside was exactly what I would expect from 1970s (?) audio gear. Lots of adjustment pots and analog circuitry. The function select pot is not encased in a can so it took no time at all to spray it a few times with some electrical contact cleaner. I would have liked to take it apart to look at the contacts and maybe clean them up with some fine grain sandpaper but it looks to be a more involved job then I am up for, plus I am hoping that the cleaner is more than enough to do the job.

Old Wiring, the black shielded ground cable is attached to one of the AC mains legs.

The Old Power Plug

This cord will be a good fit

Cord Replaced

I am so glad that I will be replacing the power cord. IT WAS SCARY. Not only was the plug and cord disintegrating but the internal connections could have caused a shocking experience. One leg of the plug is connected to the chassis, presumably the neutral circuit but since the plug is not keyed you have a 50/50 shot of it being the hot circuit. This would explain why the device is encased in non conductive wood with the front panel being plastic and insulated knobs. The only chance of actual contact with the cassis is the back plate holding the audio inputs and the mounting bolts on the underside of the receiver. I disconnected the old power cord and using a new cord tested it out with the earth ground connected to the chassis instead of the neutral line. It works without a flaw, no more possibility of shocks.

Everything buttoned up nicely and the receiver is now in its proper place, under the turntable. For the low low price of free I can not complain, I will be sure to thank the dumpster for its gift. Time to drop the needle on this repair and move on to the next project/repair.

Update 10/27/2016: There was a brief but wonderful few days where my repair seemed to have been successful but in the end the receiver went back to randomly switching the audio between the left and right ear. Doing a little more poking and prodding (I mean this literally) I discovered that the issue must be with the chassis as a whole. Removing the heavy turntable from on top the sound would return to both channels but when I would apply pressure to the top center of the case I could cause the sound to switch channels. Applying pressure elsewhere would also cause the sound to switch channels. In the end I admitted defeat and found a nice used stereo system on Craigslist for $50. It looks like this receiver will be returning to the dumpster or just maybe it will find a use in an upcoming project.