Technic SL-XP700 Repair

I bought this cheap a few weeks ago off eBay. I had the SL-XP300 back in 1992 and really wanted the 700...but coudn't afford it.

The plastic section of case was very broken (as seems quite common with these) but I maanged to fix it. It works but the disc seems to hit the case as it's spinning - it can't get upto speed. I assume that the motor is worn out, but I could be wrong...

Is it possible to source replacement motors? The motor is much smaller than on my 300 - maybe half the size.

 

Your motor is fine! What happened is the platter got pushed a bit too far onto the motor shaft by an eager user when placing CD. Either pull it back a bit or manipulate the grommets so that CD floats above the case.

 

I was hopeful for a minute but I think it is the motor - it makes a high pitched whining noise as it tries to start the disc. I think the platter is correctly positioned but the shaft may be worn...or something similar...

 

It sounds like the disc is hitting the case as it spins but it's still getting up to quite high rpms - so it can't be hitting very much. This did happen to another Technics CD player I had after about 10 or more years - I believe the motors are normally the first things to go (reading around).

When you turn on the player you have to encourage the disc to turn, it makes a high pitched whine - typical worn out motor type of whine. I plan to removed the motor - which I think means that I have to take off the platter to access the screws which secure it.

 

If CD is hitting the case it means that CD platter got pushed down onto the motor shaft by an eager previous user, ... or the lid with magnetic puck got dislodged.
Find the switch for the Lid (indicating for the Servo that it is closed), jump it! Disassemble the lid and remove magnetic puck for CD, place CD and magnetic puck,... press Play...
I hope that you had checked more than a single CD, I had one in my collection soo warped (like a bad LP) that it just refused to play no matter what. Full story here: BAD CDs (sorry, I could not finish that project because my house and all my toys got burned by the Woolsey Fire last year)

 

Thanks for the reply. Unlike my SL-XP300 the platter can't really be pushed down - it's a much tighter fit due to its slimness. I have tried a few CD's but I'm sure it's the motor as it won't start without encouragement - the high pitched tone before it starts turning indicates that it is struggling to get going.

I used an external CD drive yesterday - the motor looks about the same size as the Technics one - I wonder if one could be adapted to fit?

 

Had another look at the 700 this evening, I think the motor is fine but it may be the focus coil - need to read up on how to check this...

After spending a lot of time on my aiwa cassette players and replacing the caps I'm slightly concerned to see so many of the same type in the 700 - but none look like they have leaked...why all in the aiwa but none in the technics - both 1992/3.


Below is the sl-xp300 - the next model down from the 700, but robust, has glass laser lense and 8 times oversampling and 18 bit digital filter.

 

Motor is fine, I said it already...
Checking focus coil is easy: jump the lid switch and without CD (!) press Play. All servos have the same protocol:
Laser mech moves to the center to hit the switch, bounces back
Laser fires
Lens goes up and down trying to lock onto (absent) CD
Player shuts down

If lens fails to go up-down, then focus coil or its controller is busted

 

Took another look at this and the focus coil is broken - the service manual says 'replace', however, with what - parts are NLA. Is repair possible?

 

I bought another 700 off eBay - not tested. Batteries had leaked inside and made a bit of a mess but it did actually work - these are obviously very robust machines!

I swaped out the laser transport into the first one, but it still didn't work. I put the transport from the first machine into my new one and it does work. So good news that I have two working laser transports as they are not readily available. Of course I'm not sure where to look next?

When in the first machine the laser doesn't focus (move up and down) but this must be due to a problem with the main circuit board. Any tips?

 

Fit the working board in the best case. Unless you have a full service manual, test equipment, and a good understanding of CD players it is unlikely that you will be able to find the fault. Even if you did parts like the ICs probably aren't available now.

p.s Did you still get the motor squealing when you tried the transport with the working board ?

 

I think it worked fine with the good board. I now have a working one - very pleased!

 

Whilst enjoying The Who this morning there was a pop and then no sound through the headphones - it was nice while it lasted! The line out still works. I have a spare machine but only the circuit diagram for the simular sl-xp300. Any ideas what the problem might be?

 

I've identified three possible components which could cause the loss of audio - the headphone amp chips, a trasistor and a capcitor. I have replaced the transistor (shown removed below but still not working), I know which chip it is and am waiting for the service book so I can identify the position of the capacitor (I have been using the SL XP300 diagram - different layout). My guess is that the cap has gone... I want to leave the amp chip till last as it's the highest risk component to replace.

 

Success! The 700 is working again...and on battery power too.

I bought a Service manual for the 700 and replaced the suspect components (see second photo). I thought it might be the headphone amp chips, but as mentioned previously these are the most risky to replace, so I left them until last. Sure enough it was the amps that had gone, but I'm not sure why both went at the same time - possibly a problem with the current from the mains adapter. Just in case, I also replaced the diode (?) which helps protect the circuit from fluctuations in the incoming current.

Using vapex gumstick batterys I now have a working and very nice looking Technics CD player - not too much work!

 

@randall977 Oh, Man! You are persistent!!! When I get a Discman I wont be able to fix, now I know where to send it for a repair

 

I've been playing around with another couple of these which I got off eBay - not working. Both appear to have been hardly used from new - in really good condition apart from the plastic mid section of case which has started to break up around the hinge area. These machines are great when working, super sound quality. They suffer from two very common faults, which the next model down, the SL-XP300, doesn't;

1. The delicate plastic mid section of case breaks up around the hinge area - never seen one which hasn't.
2. The focus coils fail - therefore they shut down - I only have one which doesn't have this fault.

The case can be carefully glued with plastic epoxy, as long as all of the bits are there.

The focus coil cannot be fix (as far as I know), but...if you lightly move the player up and down / tap the lid immediately after turning on this can manually focus the laser and it will oftern then play.

The other issue is leaked gum stick batteries, but this is not a design fault.

 

wow great job!

I barely cannot see and replace SMD's in size 1206 neither would I get enough coffee to get a steady hand to handle smaller components.

 

Hello @randall977, can you give a link to the Vapex gumstick batteries for this model ? I have the same SL-XP700 in perfect working order. Would be better with internal batteries. Thanks !