Advice needed: Startup sequence changed, slim metal EX808, won’t run.

on my slim metal WM-EX808, normally when I would change the battery, there was a short “click” that sounded like the motor engaging then disengaging, very brief. Kind of like a quick circuit check.

However last night, after I cleaned the head and capstans with IPA and cotton swab, played one tape normally, then when I changed the tape, something changed and the unit stopped playing...

Now, when I replace the battery and close the battery cover, it goes through a new sequence, with one reel turning forward, then backwards (slight gear grinding noise) then stops and will not run normally. Then pushing any button, including STOP, with or without a tape, it goes through this same short sequence. Now it won’t play a tape at all!

I believe something must have gotten out of position, and this change in start up sequence is trying to tell me something… because that first tape played great!

Does anyone have experience with this symptom? Does anyone know what these slim units are checking when the power is first applied? Or what things are needed to allow the unit to run? I’m not sure what all sensors or switches are in that start cycle.
Any advice from more experienced heads is greatly appreciated!

 

Question: what switches and sensors are used before Walkman can run? and where are they?

I think this would really help me know where to start checking:
Regarding start up sequence, can anyone tell me what switches or sensors are needed to allow the Walkman to start?
For example:
- Lid closed switch? (is there one? is it a limit switch or hall effect , where is it?)
- Tape present switch? (is there one? is it a limit switch or hall effect , where is it?)
- Aor B side switch: (i think its a limit switch, not sure it's needed to run)
- Are there any other switches checked before the Walkman can run?
Thanks, hope this can give me an idea where to check!

 

OK thank you i will definitely check this!
I've been scouring for models similar, but having trouble finding exactly what is checked at startup... that tape mechanism is used by many of the thin metal Sony's ... i'm trying to figure out if I accidentally moved something... even though i didn't purposely move anything...

 

Just as example, could the unit somehow have lost its direction info? I didn't mess with the board, remove it, or change this switch, but how do you know where it should be? what is behavior if it's in the wrong place?

(no way to add images?)

 

So, to answer a couple of your questions: most walkmans of this type (not just SONY) have a similar starup sequence: after the TAPE IN switch is closed (some have a cassette lid switch as well, others don't) it will try to detect that there is tape inserted.
For that, it will briefly fast forward (1 second) and then rewind (1 second), trying to detect that the table reel with the sensor on it is rotating (if there is not tape, only one of the reels will be rotating, not both). After this the microcontroller is ready to accept commands from the buttons.

On this particular device there seem to be 4 switches/sensors:
- there's a hall effect sensor (H701) that detects the table reel rotation;
- there's a tape in switch and a tape EQ select switch (these are in the cassette compartment, near the record tab of the cassette);
- there is a mode switch (A/B side switch) and a FWD/REV switch;

Also note that the buttons produce an analog voltage through a resistor ladder, so if one of those would have increased resistance from oxidation, it can confuse the microcontroller. I don't believe this is the problem in your particular case, but stating for other people reading the thread.

My opinion is one or both of the abovementioned mode switches does not produce the correct signal. You need to check that they are in the correct position in relationship with the mechanism and they might also need cleaning (I recommend Kontakt 60/Deoxit).
Also make sure the battery contacts are firm, so there is no voltage drop across the contacts, as that can also create problems. I assume the belt is in good condition and tight. A mechanical fault also cannot be excluded: does the solenoid engage when you press play ?

I attach a picture of the sensors mentioned (on the schematic) and a link to the service manual.
Service manual: https://elektrotanya.com/sony_wm-ex808hg.pdf/download.html#dl

As for uploading pictures, use the "Upload a File" button on the bottom right. You may encounter an error where the uploaded file does not appear, although the progress bar disappeared. If that is the case just ignore it, as the picture will appear after save/post.

 

Excellent analysis of Block Diagram! That will help me! This was exactly what I needed! I did not know how to read!
I have learned my lesson to make sure PC board switches line up with cover switches(Dolby, ESB, BL Skip),

Repair Tutorials page is excellent, great work! I believe the EX-808 should fit the long list of Walkman EX, i will follow that list,
and will follow the Capstan Lubrication procedure, (I was actually trying to measure rubber pinch rollers to order from Marian)
I have a new belt installed from FixYourAudio,
No corrosion in battery compartment. looks new, but I will clean again
So far I have not removed the PC board, only opened the back to replace belt, (I did set speed with Marian's 3kHz tape)
I will deOxit all the switchs mentioned,

I feel one table reel is "engaged", and other one loose when no tape installed:
The below described sequence is new, and started when the unit stopped working correctly:
when battery installed or any button pushed, only the engaged reel turns forward momentarily, then backwards (slight gear grinding noise) then stops and will not run normally. Pushing any button, including STOP, with or without a tape, it goes through this same short sequence.

I will try to attach photo, I believe the switch is the FF/REW switch on the main PCB, and question is the position correct?
I have not figured out what moves this switch, it doesn't move as easily as other switches and i don't want to break it!
Thank you again, these are great starting points!

 

Interesting, when I went to upload photo, I noticed this earlier photo, the FF/REW switch is centered!
I don't want to get the logic circuit confused, but can i just center this switch manually?

 

Clarification:
the belt was new but not from FixYourAudio: I will order the correct belt and rubber pinch rollers from Marian.

I applied gentle force to the fork, it seems stuck, so I will removePCB and look more closely at the lever/slide mechanism.

I will also look at lubrication of capstan bearing while in there, excellent photos/instructions thank you Valentin.

 

I agree that removing the PCB is the best coruse of action. It's possible that somehing in the mechanism is jammed.

Once the PCB is removed you should be able to move the mechanism manually though different postions by pulling on the solenoid and rotating the driving flywheel.

Please post pictures with the mechanism as well.

 

To remove PC board: 1) Remove the 5 screws (well described in the Service Manual) around the board:


Suggested to keep track of exact screw locations, different sizes; use scotch re-usable stickers:

Disconnect Flexible Ribbon Corner to allow lifting Main PC Board, specified in Service Manual, Pull Back Brown Retainer, then Cable:


Board will lift and pivot around this ribbon near headphone jack: could de-solder if you're good: don't remove these two screws:


View of mechanical mechanism


Another view of interior:


Closer view of the FWD/REV arm:



Looking up at bottom of playback head:


This is an overview of the mechanism and moving the Main PC Board

 

I couldn't figure out how to move the FWD/REV arm... I gently pushed, pulled: Pretty sure this is the solenoid: i pushed and pulled, rotated the spindle pulley marked, no luck... what am i missing?

I did measure the belt: installed belt was about 79mm , another belt that measures 83mm
thickness installed belt about 0.78 mm, other belt about 1.0 mm
Could the correct size belt be the key?
I still don't understand why I can not shift the FWD/REV arm...

 

Ok. That FWD/REV arm should be moved by the cam gear on the left (gray). If you push that white lever into the solenoid, that should engage the camgear, so you can rotate it with the flywheel marked. Then you should be able to move it from STOP to FWD to REV.
You won't be able to move the arm without rotating the cam gear. As for the belt, the thickness is ~0.6mm, 0.8mm and 1mm are too large for this type of mechanism. As for the diameter, both 79 and 83mm seem too large at first glance.

I suggest checking this list: https://fixyouraudio.com/product/set-of-13-belts-for-walkmans/
74 x 0.6 seems to be the biggest one used in slim models and even this one is significantly smaller in diameter than the 79mm you state. So belt could be the problem, as if it's too loose it will slip.

I have a question: where is the second mode switch ? On the schematic there seemed to be 2 switches and I can see only one lever in the mechanism. What's the purpose of the second one and where is it located ?

 

Valentin,
Procedure to hold lever up into solenoid worked, after turning capstan wheel, FWD/REV lever easily moved to center position! Thank you,

I re-checked belts, the thickness I gave before was correct, measured across flats. 0.78 and 0.99mm: very large
The lengths are even longer than i stated before, so the belts are much longer than shown on FixYourAudio page.

So this may be solved; wrong dimension belt, causing "loose" condition and slippage during operation.

I will order the belt set you suggested; thank you for that information.

One question, I noticed the small black reverse pulley (lower right in photo) has some drag: lubricate with oil or grease?
And you simply lift split rings with tip of a X-acto knife?

Regarding a second mode switch; can you tell me where you see this on the Service Manual? I will try to find it while unit is open.

Thank you for all your help. I'll work on lubricating the Capstans next, while I wait for new belt!

 

I recommend lubricating everything that can be lubricated: capstan bearings, gear shafts. I recommend oil, not grease, as grease it too thick and it also tends to dry over time.
For removing the cut washers, you can use an x-acto knife ot a small pair of tweezers. Just be careful and keep a finger over them, as they tend to fly out.

The switches are marked in my picture with a light blue. I'm not sure if both are engaged with the mechanism or one of them is just a button.

As far as the belt goes, keep in mind those dimensions are the diameter, not the length. Length will always be higher than diameter.

 

mode switch #1 is the A/B cassette detector switch
mode switch #2 is the 3 position switch moved by the FWD/REW arm

 

Lubricated Capstans/shafts, ordered belt


Split lock washers are really small, lost one for 30 minutes and it appeared a foot away from where i thought i dropped it! Note there is a plastic washer on top of the brass bushing where the capstan inserts...



and there was a plastic washer for each capstan shaft... used "Horace Whitlocks" synthetic watch oil...

 

Purpose of Post beside Idler Pulley?
What is the purpose of this post?
I measured clearance with feeler gages: 0.6mm would go, 0,63mm will not go.
Is this just to make sure you don't put on wrong belt size?

 

I didn't measure how it is in the WM-EX811 (pretty much the same but newer model), but this gap is very small and I have to push the belt to get in. If it was thicker it would be hard to push. It could be to prevent belt to slip from the wheel.

 

I ordered belts from FixYourAudio, and that is the size of the square cross section, 0.6mm... I am excited for the belts to arrive so I can confirm loose belt was the primary issue, and with the correct belt the problems are fixed! Appreciate all the help and advice, I've learned a lot!
Valentin thanks for explaining better how to post photos, I think they help explain very well!