JVC-M90 Arrived

[prg333]

Well folks my M90 That I got off E-Bay and was
Covered under the post JVC -M90 advise needed has arrived.

Has arrived. It was double boxed and packed
Fairly well. Plenty of bubble wrap all around
The radio. It does look very very good
Cosmetically

Some problems have come up. When the
Selector for meter / mode is In Stereo position the right channel will
Occasionally cut out. But not when stitched to mono.

Also the antennas not being original . Affects the fm
Stereo reception . As the fm stereo light does not
Come on unless the station is strong . I

I did push the FM button several times. Which for now appears
To have solved the problem. Prob the contact was dirty internally.

The bigger problem is with the tape deck. It will
Play fine . But when it came to the end of the tape
Instead of shutting off. It made a loud chattering
Sound. Not the ker plunk when starting off.
Which is Normal from what I understand
When it making this noise . The deck did
Not respond when I pressed stop.
Even powering off the radio using the power
Button did not work. I had to pull out the batteries ( no power cord i have
Fits ) when the batterys were pulled out. The deck
Stopped .

I played a tape all the way thru . But stopped it
Before it got to the clear leader where auto stop
Would engage.
What could be causing this? How serious is it?
Can it be fixed relatively easily ?
The radio sounds very good. The deck sounds
Good as well .
This problem was not described by the seller. But to be
Fair they may have not tested the deck long enough to
See the problem occur , when tape came to the stop
Point. But I should alert the seller to the problem
Thank you for your help

 

[gsbadbmr]

It's pretty normal to have some kind of issues with a 30+ year old boombox, it's almost to be expected...i would be thankful it arrived undamaged in transit and made it to your place in 1 piece...and leave it at that I'm sure you can find a technician to get it back %100

 

[hemiguy2006]

First of all, Congrats on the new arrival!!!!
I hope you are enjoying it thorouly.
On the stereo/mono problem, you should try to move the phono/line switch at the back of the unit
Back and fourth several times with unit powered off and a complete switch cleaning on the entire unit is
Definitely first course of action before worrying there is something major wrong with it.
That switch is a typical problem with this model.
Hope you get it all sorted
All the best to ya!

 

[prg333]

Yes it is in very very good shape for its
Age and unknown history. I played another
Tape and it got to the end of the tape and
Stopped automatiy with no problem .

So hopefully just using it will work out any
Problems . As it prob sat being unused
For quite some time.
I do have a friend who fixes old tube radios .
He is amazing and does fantastic work
He rebuilt 3 German tube radios for me.
They sound BETTER then new. He just does
Not like working on boom boxes. Harder more
Tedious. But the right amount of $$$ will hopefully do
The trick

 

[prg333]

I am plesently supprised with the sound
Quality. I put my M70 next to it. While the
M70 sounds very good. The MIGHTY
M90 has a bigger , fuller richer more
Rounded more balanced sound

The M70 sounds very good . But flatter
Then the M-90.

While it can't match my Pioneer 1010 amp
And AR-3a speakers . It does sound quite
Good for a boom box.

 

[gsbadbmr]

I would say you did well with this M90 as it sits

 

[prg333]

Where can I get an original copy of the
Service Manuel and the instruction Manuel ? As well as the
Correct tape deck belts

 

[SLO]

Congratulations on a nice, clean, example of a vintage boombox that's sought after by so many people, myself included. I'm positive you will get all the little quirks worked out and fixed, and be one proud owner of that bad boy for a long time to come.

 

[-GZ-]

It's pretty normal to have some kind of issues with a 30+ year old boombox, it's almost to be expected...i would be thankful it arrived undamaged in transit and made it to your place in 1 piece...and leave it at that I'm sure you can find a technician to get it back %100

What he said.

 

[Ghettoboom767]

Congratulations there,very nice M90!!
I have one also but my deck doesn't work, hopefully getting it going as I'm going to fully restore mine this winter.

Yours is very nice!!
They are special!!

 

[Ken]

Gorgeous, absolutely gorgeous!

Score!

 

[bklyn sound]

congrats

 

[ford93]

Where can I get an original copy of the
Service Manuel and the instruction Manuel ? As well as the
Correct tape deck belts

First congrats and I'am glad it arrived in one piece and enjoy it as this box will keep you smiling.

As for the antenna and belt size issues I'm pretty confident that a member here can help you with that issue.

Welcome to the M-90 elite club.

 

[Beosystem10]

Well done, glad it worked out for you.

Regarding the FM MPX issue, this is extremely unlikely to be anything to do with the aerials. JVC FM heads of the era - in P-Compos and one piece boxes - all seem prone to one (or both) of two faults that can cause similar symptoms. The detector diode can fail, but that would prevent the MPX beacon from coming up at all and - as is more likely in your case - there's a variable resistor on the FM tuner board that tends to suffer from poor contact. In the first instance, wiggle the wiper back and forth having sprayed some switch spray (Deoxit?) onto the track, taking note of where it was and making sure that you put it to the same position when you've finished. This has worked for me in more than half of such cases. If cleaning that VR alone isn't sufficient, then it could have been moved by someone before you got in about at it so in that case, follow the instructions in the workshop manual (attached and there's a copy in the manuals section of the board) and reset the VR using a suitable signal generator with a >/< 19KHz test tone and a meter across the points specified in the manual to check for best positioning.

It's a darned sight simpler than it all sounds though but.
The procedure is outlined on page 14 of the attached manual, don't worry about the actual FM alignment to I/F and scale calibration, that'll rarely need attention and in case of a simple MPX beacon issue all will be well once the above procedure has been attended to. Now go forth and make an already very nice radio perfect!
View attachment hfe_jvc_rc-m90_service.pdf

 

[prg333]

Thank you for the info and the attachment. 😄
I will work on it

 

[Michiel]

For what it's worth, regarding stereo ... I had to replace IC AN7410N several times now in different boxes because of poor stereo. Including an M90.... In case the 19KHz pilot resistor doesn't solve it.

 

[Beosystem10]

I have a few NTE 1560s kicking around if it is that IC and you get stuck for a replacement. That's IC2 on page 16. The only one of those I ever had to change was in a Ferguson 3T13 (UK JVC 656 AKA and identical in the tuner area) and the one that was removed was accidentally mixed in among a bunch of new ones. I didn't look closely at the pins before using it, or I'd have picked up that it wasn't split new, so it found its way into another box that uses the same chip and works perfectly in there to this day! The only difference in that (Hacker SP80) decoder is that it uses an otherwise discrete FM head but hey, who questions why something does work?

You have most of the options now, start easy and work your way harder!

 

[prg333]

John thank you for the tips. I will be away until sat.
But uponmy retry i can test out the radio and tape deck some
More

 

[prg333]

Got home and have been enjoying the
Mighty M90 I have experienced
Some intermittent problems with the tape
Deck. When I push stop from playing a
Tape. A loud chattering sound can be heard.
The deck still plays and the meeeters still
Move. But no audio is herd. Pushing
Stop will not dis-engage the deck. The
Power button will not turn off the radio or
Stop the deck from moving or making
The chattering sound. Only taking out
The batteries ( I don't have the correct
AC cord) will stop the deck .
Then upon powering up the radio . The tape
Deck will work as it should.
Could a slipping belt be causing this? Or one
Of the deck motors or both , needing service
( cleaning oil )

This happens occasionally .

Thank you for the help