Sony CF-1990 JDM aka CF-490S or CF-495L serviced not exploded

Update: Having purchased this same CF-1990 it was shipped up to Canada from Texas and I am now working on it! I will post work progress here in this same thread for continuity and to help readers.

Yesterday removed the cassette mechanism from the unit and began about 5 hours of cleaning. The old grease has the consistency of orange gelatinous ear wax or glue. Metal cassette mechanism parts are not moving properly. Idler tire arm not able to position idler tire in correct position due to being unable to move. The record button could not depress due to the cassette "protected no tab mechanism" not being able to retract, stuck with grease etc.,CF-1980 has same cassette mechanism and suffers from the same old hard grease issue. (I think it is worth noting that the older CF-550 mechanism uses a different grey grease that is still smooth and soft after 53 years. Proving to my mind different design teams, different factories etc.,)

All grease removed and 100% synthetic oil to pivots and new Labelle #106 grease applied to slide points. All movement restored. Idler tire now contacts correctly and fast forward and rewind work perfectly! Recapped motor speed control board while in the area so I don't have to remove the chassis part again to access it.

ALSO: dial lights do work on battery! That was a relief. See video below.

 

Why is your video unlisted and I subscribed to your video camera feed channel. That's interesting. LOL. You should have spoken during whatever you're pointing to and such with the camera. At least we would understand what you're showing with the camera.
I'm glad you went further than I did in the repair and degreasing and cleaning and making it work better.

 

That video was just for you and any readers here so I am sure it is easy to figure out. No point subscribing. I always have vids unlisted because that channel is for work related stuff, security camera clips to show damage and garbage and thefts etc.,

Update #2: Recapped radio circuit, AM was still very faint / weak, was a bit worried, so continued on and recapped on the main board about 8 more... tested it... the AM and shortwave is loud and strong! That too is just a capacitor issue, I never experienced weak very faint AM reception on a radio before.

 

I only ever tried recapping this one radio and I failed doing so so I stopped doing that kind of repair. And after I got this I discovered how the light work and I didn't like how that circuit was. So I'm no longer interested in this model, so it's kind of a rare. Adam as they made different models of this but here it is picture
Yes it has a flashlight and then it has a two brightness room light on top which is just different.
As I have a fascination for flashlights when I saw this I just had to have one but then when I tried repaired I couldn't so. Jvc rc-207s as the model number

 

That's an interesting radio with the light. Ugly but interesting. An emergency radio no doubt. I am not interested in any more Mono's. Got enough thanks.

For replacing the capacitors without a vacuum pump de-soldering device one has to have dexterous and steady hands. Not the proper way of doing it. But I always get a precise and clean result. To make a good video of that I would need to try and put the camera on the headlamp so the viewer could see both sides of the board and what is going on from my perspective. Probably better vids on youtube.

Basically you need a temperature controlled iron, tiny small flat square tip, prop the board up on its edge steady, prep your new capacitors, lined up, trimmed leads, then pick an old cap on the board edge to start with, get it's value, select the replacement and set aside, identify the solder pads, wet the tip of the iron just a tiny blip of solder, hold old cap with left hand and melt one pad while bending back, then go to the other pad but wait till previous pad cools hard, repeat, see-saw back and forward a few time and the old cap just plucks out. 3 or 4 seconds. Clean soldering tip. Apply new solder blip, bigger this time, put new cap into holes, correct polarity checked 3 times (!) and repeat in reverse. Done right the pad never gets damaged or lifted up or broken. It can be as little as 10 - 15 seconds for removal and replacement. Or up to a minute or two for hard to reach ones that are hard to grab onto (Use hemostat or other locking forceps to get the old capacitor held) Then clean up with fresh new cotton swap stick and 99% alcohol to clean flux and examine the pads are perfect and like the factory ones. Re-touch up if they are not etc., Tedious as heck.

Once I get these 3 Mono's boxes done... I swear... not bothering with any more! Need to get back to my other interests and move on.

 

Sony CF-1990 update: Recapped main cassette board with mostly Nichicon FG and some FW capacitors. Only 3 old ones remain. Currently waiting on:

• Another capacitor order with more 2200uf as I only have a mis-matched pair of new ones remaining.
• Also the 2.2uf 50v Bi-Polar capacitor.
• Rubber Renew
• DeOxit Fader Lube
• Once I get into the Sanyo M2448 and Sony CF-470 I want to measure the belts and may send for more fresh new ones from turntableneedles. Including belts for CF-480 and CF-1990.

 

Sony CF-1990 belt sizes as measured precisely by a non stretching thread. Small belt = 145mm. Large belt = 275mm.

​

 

Had time to work on the Sony CF-1990 all day Saturday.

1.) Replaced all 3 cassette belts with new ones from turntableneedles. Here are the ones:

SQUARE BELT SMALL
"SBS" Square cross section belt about .046" (1.2mm) thick.

Square Belt, Small 10.0 Inch (link)
1.2mm x 1.2mm

Square Belt, Small 5.3 Inch (link)
1.2mm x 1.2mm

Square Belt, Small 6.0 Inch This one is for the counter numbers only (link)
1.2mm x 1.2mm


2.) Put in the new Nichicon 2200uf caps. Oversized but there is plenty of room.
3.) Replaced the shredded signal cable leading to the cassette head also.
Replace with copper "28 gauge UL2547 Twist Shielded Cable Audio Signal Wire" from e-bay vendor.

4.) EDIT: Forgot to add: I used the "Rubber Renue" on the 3 idler tires only. Not the pinch roller. It did not need it and I did not want to contaminate any tapes. I applied it with use of a cotton swap / Q-tip. Having cleaned again with 70% alcohol on cotton swab first. Dipped the end half of a cotton swab Q-tip into the Rubber Renue and then wiped it around and around the circumference of the idler tire about 3 times. Each idler tire with a fresh cotton swap each time. It took about 20 seconds to dry.

Then the side "corners" of the idler tires carefully around and around. Well ventilated with fan running. Smell of the Rubber Renue reminded me of a menthol type pain relief rub or cough syrup. Very mild door with roaring fans in the window.

5.) Spent time to understand how / why the cassette Auto Repeat and Auto Rewind don't work.
6.) Cassette motor speed set accurately with use of 3khz test tone tape and WFGUI free program.

The Auto Repeat and Auto Rewind features were not working due to sticky grease again on one critical area that I missed last time. So out came the entire cassette mechanism again. There is a white plastic cam arm that needs to be free to move about 4mm. That is all. Very slight movement and aided by a spring. The spring can't overcome the old grease. The pivot point needs to be cleaned. But to do so one would have to take apart a lot of the mechanism.

Ok so how do we avoid this? All we need to do is attack the old grease with new synthetic oil for it to dissolve and run out as orange liquid. There is 1 screw nearby that can be safely removed without the mechanism falling apart on you. This allows more flex and room to open up and expose this cam part.

I used a syringe loaded with WD40 to apply a small drop to each side of the pivot.
Then unhook the spring and place a hook tool in place and "exercise" the hell out of it to get the old grease busted up. Rapidly wobble this white plastic cam arm thing through the small range of its movement. Wiggle it on super turbo like you were racking up 1UP's in an old nintendo game

The WD40 quickly got the old grease to a liquid. It only took 20 seconds or so. Use an absorbent tissue and a pick to pack it in and soak up the muck. Then apply regular 100% synthetic oil with that separate syringe. Now the little spring can move the plastic part its tiny few mm of required travel. That's it. Auto Repeat and Auto Rewind work now! OK so will the old grease mystically reconstitute itself into a glue and gum up this mechanism again? I don't know. I doubt it has any substance left after this dissolution of WD40 and subsequent flooding with synth oil and mop up. But if it does, well, repeat as needed every 2o years I guess. Avoid opening up that big can of worms in taking the entire mechanism apart. No service manual or exploded parts diagrams exists to help you put it back.

At the end of a cassette it will automatically go into reverse and stop again at the beginning of the cassette. In Auto Repeat it will do this with the tape heads still down. So it can start up again playing and Auto Repeat. I would imagine this is bad for the tape head to run a tape all the way back while the heads are in contact. Anyway. I will never use this feature. Auto Stop is the only one we need. And that works without loosening this small plastic part.
So you can not bother with it and skip this if you want. But.... why not get the cassette deck 100% functional again?


All that remains to be done is replace the old 2.2uf 50v Bi-Polar crossover capacitor. Waiting on parts to arrive.
Meanwhile the CF-1990 plays great. New belts are good. Used 3khz test tape to set correct speed.


Open and observe the operation of the cassette mechanism. It will soon
become apparent to the observer why the Auto Reverse and Auto Repeat
are not working. Is there anything that is not moving? But which can be
made to move stiffly? What is that white bar post thing that never moves?
What if I move it... ah ha. So stiff! Old grease. This must be loosened up!


This small white plastic cam arm thing... is the sole culprit in not allowing
the Auro Reverse and Auto Repeat features to work. It needs to move just
a little bit. About 3mm or 4mm only! Hardly anything. But it must move
freely and easily so the little spring can pull it back each time. So it needs
to be loose and the old grease must be busted up / dissolved.


Old signal cable leading to the tape head had the insulating wire jacket
shredded somehow sometime. Messy. Replace with 28 gauge
UL2547 Twist Shielded Cable Audio Signal Wire from e-bay vendor.








Remove the actuating spring (very weak spring to unhook without danger)
and grab the plastic with a hook tool and exercise it and get the oil to
bust up and dissolve the old hard grease.


New cable to cassette head. Bit larger than original due to outer
insulating jacket being thicker.

 

Using a 3 khz test tape, what all equipment does one person need to do this correctly cuz I've never done it this way. Obviously you need a 3 khz recorded cassette tape and I know how to adjust the speed. What? I don't know is what piece of equipment I have to say like that because I don't know what to call it. It is a vom. What is it? Do I need a frequency counter? Can I get a frequency counter and a vom and then what do you attach? What leads to what at what settings I mean I know it's all dirt simple but I've never done it before and I don't know what equipment to get. I would get the equipment if I knew what to get.

 

Just go onto e-bay and buy a 3khz test tape. There are quite a few available.
Then download that free little program WFGUI.
Put any tape into the boombox to be tested.
Plug an audio wire into line out going into an old PC "line in" to the soundcard.
Play around with the settings till you can hear the boom box music playing on the PC
Then put the test tape with the continuous 3khz buzz tone into the boombox.
Run that WFGUI program and it will "hear" what the boombox plays.
And you can see the wow and flutter reading. With a bunch of settings etc. ,
Then you adjust the boombox motor speed while looking at the screen where it shows the frequency.
Adjust close as you can get to 3khz.

OR

I believe there are free apps for phones that do the same thing. Play a test tape and the phone app will "hear" it without wires and hassle and give you a read out right there. Then you adjust the motor speed while watching the phone frequency read out.

 

Just started on my CF-480 yesterday. It took me a bit of time to figure out that after removing the back and the knobs at the side and buttons on the top, you can pull the whole system from its enclosure. I couldn't figure out how to get the front off. The answer is you do not need to. I had not seen your post (...)

I managed to replace the cassette belts by just flipping the electronics board sideways and remove the steel plate on top of the belts / motors.

Most of the issues I had were due to fixed up grease. I loosened it with alcohol. Also the tuning knob was extremely difficult to turn. Alcohol on the shaft fixed that.
Now I got most of the cassette functions working except for FF /CUE. It's not engaging with the cassette and so nothing happens. The motor turns and it shuts off after a while, but the cassette spools are not turning. Rewind works fine.

I've added a small video showing that actually noting is happening. Now I am trying to figure out what should be happening in order to determine what is preventing this from happening.

Not sure if this can be explained in a post? Perhaps a video of a properly working ff can put me on the right track?

 

I watched ed your button pushing clicking doing nothing. Not seeing this from the right side. Meaning I should be seeing this from the back side where the motor is turning and then rotating something else which is then not engaging your take-up reel or the fast forward reel.
What I would do is I would get the unit where you have it now and see what makes rewind work and then hit stop and then see what makes fast forward work and if it's not working then while still in fast forward mode. Rotate with your fingers to take up reel. Spindle and see what rotates inside the mechanism and then see what is not making contact with you're rotating things. Gears tires. I don't know belts West not making contact while it is in motion and working but not touching and rotating what you need to do or what you needed to do. Understand me. In other words work it backwards but while it is under power so you can understand what needs to be moving. Got it? under power

 

Thanks, here is a video from the motor side:

My guess is that the white wheel in the middle (seen from the front side in the 1st video) that also drives the REW - albeit with a wheel in between to turn direction - shoud also be driving the left cassette pickup wheel. But it is not touching it and its not turning either.

 

Once again, you need to investigate when you depress the button for a fast forward queue to see what it does and what it moves and what is not moving when you depress that button. I'm guarantee you that something is stuck with grease. When you took this apart and serviced it with a new belt and everything, did you ensure that everything that could slide or pivot could move freely? This is what I do before I get everything all back together. This is what you need to do. I've never had this exact model, although I've had other models that are similar to it that I've tried to make all work and the main thing I try to do is get the basic functions working. You know rewind fast forward and play when you get into the extra functions of the auto repeat and autoplay and all that that's beyond me as I learned with another person that bought the unit that I had and was able to get those parts working which were beyond me. You need to investigate the basics and make sure that everything is working freely. You could be missing a spring if it's not dried grease I don't know. I don't know this model yet LOL.

 

Thanks. I was hoping yours would be similar. I have looked at REW, it's quite different from FF. I had hoped not to have to take the whole unit apart. What I have done so far was all with the mechanism left in place. Not sure if I want to go there, I can FF with REW if I flip the cassette first.

Thinking: in FF it shuts off after a while. That could suggest that it thinks it has reached the end of the tape. The end of the tape is triggered by friction I assume: something is not moving / turning. It's not the cassette pick-up wheels, these run freely when FF is pressed.

After checking: no, that's not the case: without cassette, REW shuts off also after some time. So it is the opposite pickup wheel not turning that engages the shut off.

The white wheel in de middle of the 1st video is driven by the flywheel. When pressing REW it moves up and thus touches the wheel. When pressing FF it moves a tiny bit down just to touch the left cassette pickup wheel. That makes sense although it is always touching this wheel anyway and turning when the left pickup wheel turns. (This seems a bit wasteful?) Yet, it doesn't make contact with the flywheel in the back. So it's not driven and hence no FF.

 

Well I don't know your situation in life. Me, I live with Mom and I'm not working as I resigned in January of 2024 from my previous job. So repairing the hundreds of boomboxes and hundred or so of walkmans I have is my full-time job and then of course trying to sell them. Bottom line you need to take apart fully the mechanism you have and you'll need a space. Patience and Time to do so. Take pictures as you go. Like I do so when you get to a point you don't know what happened. You can refer back to your pictures and see what you missed when you took it apart, putting it back together. In this Sanyo Mr-U4gp I had to take it all apart and thoroughly cleaned the blue ink out of it, no I have no idea how the blue ink got in there. And I went through a zillion cotton swabs cleaning this and getting all the tar out of it and finally making it work
In the foreground is the Mr. U4gp and in the background I'm playing my Sanyo m7790 which is the AKA of the red one

 

I have been restoring my home for the last 4 years. I work half days per week on average as a consultant / project manager. The rest of the time I am doing construction, painting, plumming etc. I am now getting to a point that most of my house is done - tomorrow I will be receiving my furniture from the storage - although there is many years of restoration work left to do. I cannot paint outside at the moment - autumn / winter - so I had a few hours spare to pick this recorder apart.

I like to get them working, but I am not fixing what ain't broken and there is a limit to what I want to do. I am a civil engineer by training. I have learned to think before doing. This is how I approach electronics too. I don't sell at the moment, I select my gear carefully to be used by myself. I grew up in the 70s, so this the era I like best. Same applies to analog camera's.

 

I have yet to even start work on my Sony CF-480...

So, like the CF-1990 (CF-490), the CF-480 shares similar cassette mechanism with the orange / amber/ yellow grease that goes hard. In the CF-1990 I just recently worked on, it too could not FF or RW because the idler tire arm would not move and contact properly. Because of hardened grease.

I suggest you have more work to do in restoring full range of motion to the idler tire. Dissolve and loosen with alcohol or 100% synthetic oil from syringe. Carefully and gently move the parts through their range of movement and get the old grease dissolved. Mop up old "juice" with absorbent tissue as you go.

 

Well, my dad has his Masters from the college in civil engineering but he passed away in 2005 and he worked as a city public works director nearby. Me I'm a jack of all trades and a master of none with a background of electronics and computers and photography. Actually photography was first then electronics, then computers and then boomboxes LOL. There isn't anything I'm not afraid to tackle to tear apart, fix, repair and make it work again. As far as making it pretty, I let someone else do that. Been around the world by way of the army and Navy three in the army two in the Navy years so I've been to Africa and back and I've been to Europe and back so I've been there. I live in USA and I visited about 35 states out of the 50 course. I haven't been to Alaska but I got relatives up there and I've been to Hawaii. I wear the Navy and Asia and Germany by way of the army. Worked in computers for 3 years. Worked in a restaurant for 7 years. Drove a bus for almost 15 years. Presently just here repairing boomboxes and making videos of myself doing such for people that I feel that are too afraid to lift a screwdriver. Not rich. I'm not poor but I'm definitely handicapped.
I'm 6 ft 6 tall and carrying the big boomboxes around is becoming a problem so I'm trying to sell them off and keep the smaller ones. And that's my story in a nutshell.

 

I'd love to see a video of the FF in action when you decide to fix yours.