JVC M70 Tape deck issue

[s52]

Greetings,

First post here, I have just acquired my first boom box a JVC M70 (US version)

The radio and line inputs work great it sounds awesome. The tape deck however is giving me issues.

When I press play the play button will pop up automatically after 2-3 seconds. It sort of seems like the pause mechanism is stuck. I have read some other threads here describing similar issues but I haven't found one yet that describes what the issue wound up being and how it was resolved.

The fast forward/ rewind work ok but the buttons have to be held down.

I have removed the rear cover of the box and can see the main belt is spinning the flywheel- the tape counter also moves when fast forward is held down.

If I hold the rewind button down the mechanism makes a ratcheting sound.

I also noticed a metal bar is blocking the friction tire from contacting the capstan when play is pressed.

I have just ordered a new set of belts in case that is the issue- and plan on removing the tape deck to re belt and see whats going on with the mechanism but it seems like something is mechanically "stuck" in there.

9731201CT Main belt FRM9.6 (Flat belt/medium) inner circumference 9.6 inches
8001602T Counter belt SCY7.0 (square cut .035 X0.035) inner circumference 7 inches


I made a short video showing the issues I described above- just wondering if there is any advice or pointers to get this tape deck running again!

Thank you!

-Christian

 

[Tinman]

I've had an M71 and 70 but never had this problem.
It definitely seems like a mechanical problem since the tire won't drop down to the capstan.
Unless someone chimes in that knows exactly what it is, you're going to have to get in there and do some investigating.
There could be a spring off, something in the wrong place or bent, etc.
There's a good chance it's the result of someone monkeying around in there and not reassembling things correctly.
When you do start tearing it down, take lots of pics and from all different angles.
Luckily there's a manual available for this in the library if you need it.

 

[Fatdog]

I'm pretty sure that's the "auto stop" mechanism kicking in because the one tape spindle is not moving. Have you tried it with a cassette in the M70?

 

[BoomboxLover48]

Have worked on all 3 M70s in my collection and never had this problem. It took me a while to figure out the problem with record button not going down and lock in place. For that I had to separate the mechanical section and fix the problem. It was a bend internal lever. Removed old grease and lubricated moving parts.

Pause button can give problems if that is not fully disengaging. This happened to many other decks also. Dried up grease and lack of lubrication can cause issues.

Very careful not to break the tuning cord (that long section with the dial moving plastic piece attachment) when you remove the deck section from the unit. I used a 2" wide paper like a sheath and covered the tuning cord. Any sharp leads on the PC board can cause damage to the cord.

 

[s52]

Thank you for the replies and the advice! I was waiting on the belts to arrive before I take the tape deck out since I figure I might as well change those while I'm in there too.

I have tried it with a tape inserted and it still behaves the same. I will make an attempt to disassemble and report back my findings.

Thank you again!

-Christian

 

[s52]

Update:

Got the tape assembly out (what a finicky nightmare that was!)

I can see the pause button is working ok- but the pause mechanism is jammed in the "on" position. It seems to be binding up on something and I can't for the life of me figure out what is going on with it. I have used my fingers and tried the blade of a screwdriver to pop it free to no avail...

Here is a video to show the issue:

Any ideas!?

-Christian

 

[s52]

Update:

Well it works! (sorta)

I was poking around with the casette mechanism and not exactly sure what I did but I fiddled with the stop/eject mechanism and bam! The pause clicked off and released.

I played with the buttons and it seemed to be working on the bench.

Also replaced both the belts while I was in there.

I re assembled the boom box inserted a tape and it plays great! Play, pause, FFW, REW all work great.

The only weird thing is now the stop button wont stop the deck from playing. I have to hold FF or REW while simultaneously hitting the stop button to get it to stop playing.


One other bummer is the little white record safety lever (part 14) snapped off. The plastic looked very brittle- not sure if it was because I rough handled the mechanism or it was just on its last legs.

Gonna have to see if I can sort a new piece- any ideas? Are there other boxes that shared the part?

Not looking forward to having to tear it down again but eventually I'd like to sort that out- along with the stop button issue.

Thank you again for all the advice and suggestions. I wouldn't have been able to get this far without you or this forums help!

-Christian

 

[BoomboxLover48]

Pause button gave so much problems in many decks from my experience. It was always a nightmare on many Hitachi decks. Same was the case how the stop button fully release other functions. I would try to remove old grease and lubricate it well. Some cassette decks are a real nightmare. I have a few soft touch types that I am still struggling to make it work. It’s a real challenge! The good thing is that you have always something to work on.

 

[Tinman]

It looks like that pivoting fork piece goes through to the other side and is what moves the pinch roller mechanism away from the capstan while paused.
I'd remove the pinch roller and see if anything frees up.
You might have to do more disassembling of the whole mechanism to figure everything out.
Again, take lots of pics if you do.

 

[s52]

Update:

Tore the mechanism down again to figure out the stop issue.

I took a video which will do a better job describing my findings- Basically a metal bar is popping back about a millimeter too far which is not allowing the stop mechanism from engaging a metal ramp to stop the play, ffwd, or rewind.

I have cleaned out all the old grease and gunk from the mechanism and everything seems to be moving around freely- almost too much so it seems like maybe theres too much spring tension?

Watch the video and let me know what you guys think or if you have ever figured out a solution to this issue!

Thanks,

-Christian

 

[Tinkererman]

Good video, I have a JVC RC-555L here that the play button won't stay engaged, it drove me nuts I had to put it on the back burner. It goes all the way down, it just won't lock down. All the others lock down engaged. Just goes to show you the precision that was used in the manufacturing process, so now 45 years later, something is off by 1 mm and totally screwing up everything, LOL Could be worse and be a Junk late 90's mechanism that sounds like garbage even when new.

 

[Tinman]

Just throwing this out there, could the bottom part of the stop arm be bent to the right (away from the angle in the slide mechanism)?
I'm not sure what they look like at the bottom but maybe it needs a little bend to the left so it can engage that angle.