JVC RC-M71 Updated.

Tinman

Member (SA)
Mar 4, 2019
510
256
63
USA
I bought this box in pretty bad shape.
It was filthy with the paint speckles so many of these boxes have.
The dial light wasn't working and there was a power problem that was keeping the cassette player from working.
Cleaning the front and rear shells was pretty straight forward.
I cleaned all sliders and switches and added some electrical grease to help with the feel and ease of sliding.
They now slide really easy with no static or crackling.
The speaker cones were faded to a dull blue.
A new blue permanent marker took care of that, now they have a nice deep blue color showing through the freshly painted satin black grilles.
I installed new belts but was getting varying voltage to both the light and cassette (the power light was also dull).
2, 7, 10, 11, 12, it was all over.
It took me 3 days of looking (and going crazy).
I definitely thought I'd be selling this in partially working condition especially since I don't have any kind of electronics training except my previous experiences.
As a last ditch effort, I was planning on replacing all capacitors, the four power transistors and the three zener diodes in the power section of the board.
I removed and tested the main power capacitor (I really hoped that was the problem) and it tested good so I went over things again.
Finally, I tracked the power loss to a bad resistor, R517.
I replaced it and the cassette and dial lights were up and running as well as the power light glowing bright.
I added three amber LEDs.
I figured the amber kind of goes with the gold accents of the M71.
I installed one at the dial and one under each VU meter.
It's a nice even looking lighting, definitely better than the pictures show.
I wired them so you can use the original momentary button or keep them on with an on/off switch I installed by the plug receptacle.
I thought something was wrong with the meters since they were barely moving but when I turned the volume up, the meters responded.
I'm used to the few other boxes I have where the meters respond to the music regardless of the volume.
I have to say, I'm blown away by this box.
The sound is clear in radio, tape and cassette modes at all volume levels.
I'm a treble guy and this is probably the first radio I've ever had that I don't have it turned all the way up all the time.
I'll turn it all the way up when listening to a cassette but with the radio or line in, I turn it down slightly.
When I played Phil Collin's In the Air Tonight on my cell through the line in, holy $h!t.
That's when I still had it apart so I was watching the speaker cones jumping, I thought they were going to blow out the front of the box.
I always assumed this was an over hyped box but it really is as good as people say.
I'd definitely recommend the M70/71 to someone who doesn't have one yet.
 

Attachments

Fatdog

Well-Known Member
Staff member
May 3, 2009
10,898
112
63
Another great story of a boombox made happy again! And I agree with the others on the amber LEDs - great choice. It reminds me of the older BMWs with the amber lighting.
 

blu_fuz

Moderator
Staff member
Jun 3, 2009
10,665
153
63
40
WI
Can't go wrong with a M71 resto. Great job it looks fantastic!
 

Tinman

Member (SA)
Mar 4, 2019
510
256
63
USA
Yep, I always did like the amber BMW lighting and, I believe, some 80s & 90s Pontiacs had it too.

Thanks guys, I really appreciate the compliments.