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

I have a Sony cf- 1990 that works well but needs the cassette deck to work again and this probably needs new belts installed. I'm going to take you through how to unassemble install belts and other necessary service if needed and reassemble.

Back label

Top controls

Input side

Other side AC input. Can you see how close together those pins are as you must have the Sony specific power cord to plug into this unit. If you do not you must run it off of batteries or find some other way of powering this on AC, by using a wall wart utilizing AC to DC to the round DC pin input is the only other way other than batteries on the other side of this radio.

4d batteries power this unit. I have Znter lithium 1.5 volt rechargeable batteries in here.

The tuning and Dial light only work when plugged into the AC. Not on batteries and depressing the yellow button on top of the radio. As it is momentary switch, It does not stay on.

This is about 16 and 3/8 in wide and this is the front and the last picture of this group maybe.

 

After removing six very long screws that are all the same size from the back, then the back simply comes off with no wires attached from the back to the front and then you get to look at this.



I Believe the inside is on a chassis.



The next step should be to remove the front tuning knob and then the six button cap sliders from the top and I am not certain what else just yet.

Edit, I just found out that I have to unsolder this blue wire from the circuit board that is attached to the front of the unit somehow. So we are going to do that next before we try to remove the chassis from the front of the unit. But here let me show you a picture of the wire that I'm going
done solder next and I use a pointer to point to it



Yeah now I got to take a break and go get my Weller Hi-Tech 30 w soldering pencil and warm it up.



Off subject but I have a service manual for a 14-778 radio shack boombox. I just found it the other day. Never used it.

 

Now that I've gotten clean up and unsoldered that wire allow me to show you what it connects to



It's just a grounding wire to the front panel.



That's what the inside of the front looks like.



I'm no expert, but I do know if you follow the yellow wire from the motor to the circuit board, you'll see a adjustable resistor I'm guessing and that should be the speed control for the motor.



Speaker view



Cassette deck overview



Top view without the cover.




Angle shot rear circuit board



Hopefully removing those two screws will allow me to gain access to the belts behind the cassette deck to replace them.



Yes, I was able to swing away the circuit board to see this and the pointer is magnetically touching the white wheel that is driven by a belt from the flywheel. That is very very hard to rotate so it's not working and the belt is good from the motor to the flywheel but it's loose and
the motor does run.



Now I need to figure out if I need to remove that plate covering the flywheel on the right hand side of this picture and or should I try to remove the entire cassette deck from the front? But of doing so I need to remove other parts like the ones where the two orange wires are going to.
This is a very thoughtful process.



Just another picture of the inside back of the cassette deck.



Trying to show you the secondary belt driven from the flywheel to the white wheel as I can see it's from the side.



Making a note of the grounding wire and the polarity of the wires. Not that it really matters going to the woofer so we can remove it before we advance on repairing the cassette deck.

 

One screw from the hole near the white gear near the Vu meter removes the entire tuning window



And with it comes the entire tuning string. So don't tune the radio while doing anything else at this time



I'm not sure but I think somebody tried greasing the deck because it's very stiff to operate some of its buttons.

 

The recording button will not go down. I don't know why. We'll just figure that out later. To remove the cassette deck from the chassis, I removed two leaf switches. The small one used the small screw and a large one which has two leaf switches on. It used the larger screw and they're in my magnetic tray and I'm just making a point of that and here they are and the screws



Here's a look without the switches in place



Here are the amp chips for someone to Google and find out what they are



Well that's upside down but you get the idea



Well, if you're careful like I am, I don't need to flip over the board to see where those leaf switches wires are going to because you shouldn't need to.

 

So now you remove these four screws. They have a flat tip and you need to use a small screwdriver because a regular size screwdriver won't fit. So here's my little tiny driver at the end if you see it in the picture, great. If not, oh well
And then you can finally flop the tape deck out of the way so you can work on it. And yes you can never have enough or too many magnetic pickup tools I actually have six of them
Now I'm going to delve into taking that panel off which is near the motor and over the flywheel and to see just what's rotating there or not in Belts to replace and all that

 

Remove three screws and this came off finally. Now we can see the belt arrangement and the necessary need for a tight belt as the one belt needs to ride against that other white wheel and we need to find out why the belt driven white wheel off of the flywheel doesn't rotate easily

 

Okay I got the belt driven stuff off. I pulled out the flywheel and then I was successful in releasing the micro tiny c-clip and got the pulley driven from the flywheel off which then has a small little gear which then turns a larger gear which I'm guessing has to do with the auto stop feature and that bigger gear is extremely hard to rotate just by my fingers so there's no way it will rotate by a belt. So I'm going to try and see if I can get that little tiny c-clip off and not lose it and then if I can clean the axles and remove all the grease and then I still can't figure out why the record button will not go down at all. Even though I've released everything it still won't move so still working on that. But here's a picture
No I didn't angle the picture so you can see it. But the little c-clip is on the end of the magnetic tool and the little black washer goes on top or behind that on the white wheel that I've already taken off first. Just so I can remember all this next, we'll try to take off that 1-in diameter gear and it's c-clip.

Well that clip went flying. I hope that my little tiny clips that I have bought will fit but it was a Pull and rotate pull and rotate. I'm saying pull and rotate to get that white wheel off and it looks like there's old grease or I'm not sure but this really was stuck on there. It was very hard to get off. I was afraid of breaking into gear cuz it was bending as I was trying to pull and rotate it off

 

Well now the little white wheel rotates and I got it back on and used one of my eighth of an inch c-clips and it works and I measured it against the other silver one which I still had which is on the ends of my magnetic clip. If you can see it, it's so damn tiny but here is a bag of the few that I have left from repairing other cassette spindles. Here's a picture
And I cleaned the grease off of the other gear which is driven off the flywheel and all that. So here it is. I'm going to put it on next
And then I got to go search for a belt for this and the main belt and we haven't even talked about the counter belt which is on the other side of this unit LOL

 

Okay, the old main belt which is stretched is about 140 mm
And the secondary belt for the auto stop I believe, measures about 75 mm for the old belt

And now installed new belts. I'm going to start putting it back together but first I want to see about this upper mechanism why it's still sticking?

New belts and everything rotates like it should. Yes.

 

I need an idler tire but this tire is Sony specific. I don't have anything that matches it and I have quite a selection of idler tires.

That's an upside down view of most of my tires now. Let me give you a close-up of what I'm trying to find. It's a stepped idler tire if you can see inside that it has a inner tire to make a smaller tire fit inside of a larger tire. See if I can get a close-up picture

That tire goes here on this small white wheel and is driven by the white and brass jackshaft and when it's in rewind mode it would touch on the spindle to make it rotate but it won't because it's a smaller diameter because it's worn
I just don't have any tire that will fit there in the stock of tires that I have.

Maybe if you zoom into this picture you can see is the inner ridge that this sits on the white wheel with.

 

Something like these? Maybe the top one...

Idler tire Idler ring for SONY TC-D5M ,TC-D5PRO ,TC-D5PROII Cassette Recorder
T-shape idler tire for Technics RS-M02, RS-M45, RS-M65, RS-M85, RS-M95, RS-M88
T-shape idler tire for TELEFUNKEN MC1, HC750M, NORDMENDE CD-1500, SONY TC-20F
T-shape idler tire for Technics RS-610, RS-615, RS-630
Idler tire Idler ring for Technics RS-B100 cassette deck / Zwischenrad gummi

It is unfortunate that the small white wheel that holds this idler tire does not have enough movement to overcome the worn smaller size. How much extra rubber does it need to contact... or how much extra does that wheel need to move. That's a shame. Maybe contact cement on a "wrong" tire to the plastic wheel if all else fails

So far excellent pictures and very helpful for all present and future explorers of this model Sony

 

Thanks for those links. However, I'm only able to get this to play. Not fast forward or rewind it wants to but the mechanicals are archaic and really hard to understand without a service manual.
Basically I'm just happy if I can get this to play a cassette and not be concerned about fast forwarding and rewinding. I'll just leave that to the next person to delve into.
Then there's the issue of the heads not retracting and I had to spend a long time very long time taking out the old grease out of the mechanism to allow the heads to retract in stop position. There is an over abundance of old grease, dried grease and just grease in general that I've tried to remove to allow the heads to retract in stop mode.
I'm at the point that I just want to try to get it back together with it playing a cassette and that's it.
The auto stop feature works really well as it was totally locked up from before I got to it. As you can see in my unassembly pictures above, I'm ready to move on to another project but I need to finish this first and at least be able to play cassette and then I'm done with this model.

 

Here I made a update video so you could see and Hear my progress with this model.
(10:15) minutes.

 

That's great, fantastic, I will deal with the tire and try different things etc,.
(How long was that tape counter belt?)

Yes these models suffer from too much grease that dries up and turns to glue, weird, the CF-550 and CF160 I have had small amounts of grey grease that was smooth and butter like, totally different grease they used, different cassette mechanism, different design team also.

 

I think the counterbelt was 70 mm and I put a new one in this one.
This one has orange grease in it in some areas. It was like baked on and I didn't take it fully apart and clean all of it but it does work now, it will play the cassette and the auto stop works great in all modes including play.

 

Finished as best as I can and willing to do.
Sony CF-1990 JDM aka CF-490S or CF-495L restored play cassette August 2024 (10:17) minutes

 

It looks pristine. Nice work!

 

Sony CF-1990 & Sony CF-470L Hear difference via cassette outside on batteries (11:32) minutes

 

Since you have a cord from that other Sony boombox that fit CF-1990... what type power cord plug would fit? Would one of these styles work, does it look about right?