Sony D6 Playing Fast and No Sound

Hello friends, I've recently gotten a decent deal on a sony D6 (Not D6C). It's in pretty perfect cosmetic condition, barely any scratches and zero dents. There is a tiny bit of battery leak on the battery case but none in the compartment. I put in some rechargeable batteries, and when I pressed play it runs fast and there is no sound. Also the battery light only shows one bar, and peak doesn't show at all. Fast forward works, but rewind does not, it makes a gear grinding noise when rewinding, so I immediately stopped there.

I'm aware that it might be things regarding the CP602 module, but I have no electrical tools to test for voltages and other readings. What should I do? I have yet to open this, should I open it? I'm afraid I might break something.

 

Here it is, with the serial number

 

Runs fast eh?

*Mutters something inaudible... avoids eye contact and starts walking away...*

But seriously, yes, it sounds like the notorious CP602 potting issue. And the other potted modules need to be replaced / solved at the same time, really. And of course all the rubber parts need to be replaced. And a bunch of other things checked out. So the D6 needs to be sent off for many many months and many hundreds of dollars of work. Or do the work yourself and suffer a break down after cracking an irreplaceable gear or losing another spring or C-clip. And have to be taken away by some guys in white coats in a little white van lol.

OR if the e-bay seller took returns one might consider returning it asap.

I really like the idea of getting a D6 too and occasionally browse e-bay for one. But the total real cost to get a good one is quite high. Factoring in all the restoration work and 4 to 6 month wait time etc,.

 

I did all that you mention and was a joy, jajaja I learnt a lot in the process... bought it for 199 3 months of work... this is the result.

https://www.youtube.com/shorts/_bsFCO0ZKWo

I don't know after all the effort It's now like a family jewel

the other option is to pay but here were I live it would be more expensive and no option to send it abroad.

 

Thanks for the reply Hyperscope. I did some more research and found out that you can buy the other 3 potted ICs from Deb, which is an expert on these guys. I wonder where in the world I can get hold of that CP602 circuit? Is buying another donor the only way? or is there anything that can be done? since there is a way to fix this, unlike the D6C CX20086 chip which is literally nothing you can do, how? Thank you once again and cheers

 

If you are not getting any sound out and the motor is running fast, check to see if you have 11V coming out of the DC-DC converter. The 11V rail powers the Dolby chips and the FG amplifier. No power on the Dolby chips = no sound. No power on the FG amplifier will cause the motor to run fast.
Another possible cause of no sound is the mute module (CP301) having failed. I have replacements for these available on Ebay but you can test it by removing the mute module. The sound should return but you will get loud thumps on the audio when starting and stopping without a mute module fitted.

Unfortunately it is not possible to make up new CP602 modules as the CX20024 chip used is not available. The good news is that the CP602 can be repaired. Please see my method here:

Sony WM-D6 Motor runs fast; Repair of CP602 Servo Circuit Unit

You should also replace C607 as these capacitors can fail over time and cause fast running.

 

Thank you Deb64, appreciate the reply. Unfortunately my multimeter has recently broke, so I will go get a new one and update as soon as possible.

 

Update! Finally received my new meter today, upon opening the unit...I found something strange...here are the pictures...I don't think the blue tape is OEM, and the chips...seems like they've been replaced? I'm really confused. Unfortunately there is no way to contact the person again as he deleted the ad off of my local marketplace...

Regarding the voltage testing, there was zero voltage on the 11v pin, and 5.5v on the 6v pin...seems like i know what my next step is...rebuild the DC-DC converter?

Anyways, thanks for the help again Deb64. If you can give me anymore pointers that would be very much appreciated, thanks again!

 

The blue tape is definately not factory tape. The tape is normally black.
The potted modules have been replaced. The EQ modules, CP601 (FG amplifier) and CP301 (muting module) all look like the replacements which I manufacture.
The CP602, however, is very interesting. It looks as if somebody has removed the CX20024 chip (not to be confused with the CX20084 used on the D6C) and tranferred it to a new printed circuit board. It is a GRP board with screen printed component idents. The original board is a ceramic base with printed resistors and no screen printed idents. The CX20024 is not available and hasn't been for many years which is why the original one will have been used.
Some years ago I was asked by another repairer about the possibility of making a new circuit board for the CP602 and transferring the CX20024 to it (as has been done here) but never got round to it. It is interesting to see that somebody has done this and good news for @Walking_Man as the CP602 repair has been carried out already.
The problems with the old ceramic board, apart from being difficult to solder on, are possible chemical changes in the green solder resist over time and occasional dendrite formation, normally between the pins at the edges of the potting compound.



When repairing a CP602 module, I clean between the pins thoroughly and also scrape away the green solder resist around the FET and NPN transistor which I replace.
I also clean out any remaining potting from under the pins of the CX20024 and check all the solder joints of the chip and other components. I have found some very bad solder joints on these modules underneath the potting. This cleaning and reworking needs to be done thoroughly otherwise the wow and flutter will be affected.

Finally I always replace C607. I have had a couple of cases where this tantalum capacitor is bad, which causes the D6 to run quickly at first and then slow down after a few seconds. In this case it may have already been replaced but, if in doubt, I would replace it anyway.

From the measurements you have found on the DC-DC converter, that is the place to start looking.
I daresay you have found it but, for anyone looking at this thread, here is Mihokm's guide to fixing the DC-DC converter:

WM-D6C DC-DC converter fixed

Normally a blown DC-DC converter is caused by connection of a reverse polarity DC power supply (wired centre pin positive when it should be centre pin negative). If this was a D6C then it would have blown the CX20084 chip as well, however the motor drive system on a D6 is a bit more robust and the CX20024 has some protection in the form of a 100R resistor on the 6V power supply line. Also the internal architecture of the CX20024 may be more robust than the CX20084. I have come across a few D6s with blown DC-DC converters which, once the DC-DC converter is repaired and the normal repair of the CP602 and servicing has been carried out, have worked fine.

In this case, it looks as if it has been serviced previously to a high standard and, some time later, had a reverse polarity power supply plugged in.
One other point from your first post; you will only get one LED illuminated when checking the battery. It's a very basic system (also used on the D6C) where you get the one LED and when it starts to get dim then it's time to change your batteries.

 

Thank you Deb for the reply and so much helpful information! I will get to work on fixing the DC-DC converter.

While looking for solutions, I found another post where they used a MT3068 DC-DC converter to replace the whole thing. I'm not sure if this is a viable option as well, if I somehow mess up the method you suggested, this would be a nice back up option. here is the link to that other post: https://stereo2go.com/forums/threads/sony-wm-d6-wm-d6c-dc-dc-converter-alternative.9378/

Also regarding the inductor, would this one work?https://www.mouser.ca/ProductDetail/EPCOS-TDK/B82141A1333K000?qs=WdVyEdaTxrqjRf%2B8PvB98w==

Thanks again!

 

Update, upon disassembling the DC-DC converter (hopefully i didn't break anything), I discovered more strange things....it appears to be different from the one shown in Mikhom's guide...is this a different variation? Or did someone temper with this as well? Or am I missing something? Really appreciate the support so far.

 

What a surprise! Someone already did a rebuild. Hope the issue can be found and repaired! Good luck!

 

Yeah, I'm quite surprised by this. I am hoping too that this would go well. Thanks!

 

The DC-DC converter is an earlier version, which was used on some D6s. I have repaired at least one of these.
The principle is the same; replace the two tantalum caps and the open circuit inductor and replace the 2SD1048 transistor (marked "X-7")



The 33uH inductor you have found looks OK but check the physical size before ordering. There isn't much room inside those small cans. This also applies with ordering the tantalum caps.

Don't forget to check the operation of the converter before sealing it back inside the can.

I have never tried using a MT3068 DC-DC converter so I have no idea how well or not it works.

 

Thanks for the information and the clear-up Deb64. I have ordered the parts that seemed similar, not sure if they are the right ones. I guess I will have to find out when they arrive! Hopefully they will work. I have ordered a bunch of parts that seemed to be a match since they are so cheap and the shipping is more expensive than the parts. I will find the ones that match and fit the best. Will keep updated and thanks again for the help so far, I really couldn't have gone this far without it!

 

Update ...bad news? I think I've managed to fix the DC-DC converter, as now I am getting 11V on the orange pin. But the problem persists, still running fast. However, I am getting sound. So there's an upside, and it sounds quite good despite being sped up. Rewind still doesn't work, but that's a later issue. I'm going to try to do some more research; in the meantime, any comments would be appreciated. Thanks a bunch.

 

UPDATE!!! GOOD NEWS!!! After doing some research I found this https://stereo2go.com/forums/threads/sony-wm-d6-repair-restoration-and-now-speed-issues.9935/ which mentioned the FG coil wires. And sure enough one of the wires were broken off. Now it seems to be playing at a correct speed. I will now do more testing but I hope it is going uphill from here! Thank you so much Deb64 for providing so much support!!!

 

After some testing, I am ninety percent sure it's fixed. Finished calibrating speed and head position. I tried to manage the wires to the best of my abilities...why so much wires...

Anyways, there's still one little thing. I discovered that the rewind reel is cracked, so I glued it onto the shaft. Still, it resists to rewind. I'm thinking it's something to do with the clutch, because when I press it, it starts rewinding but slows down gradually. Its not the dried grease as the inside of this is extremely clean, and all the grease looks new; The last person who worked on this was clearly a professional. Also, with no tape in the machine, both reels turn oppositely...and the VU meter/LEDs doesn't seems to work when selecting "peak". I guess those are my next tasks.

For now the rewind works while paused. So it kind of works.

Thanks again for the massive help Deb has provided. Thank you so, so much.

 

Firstly, congratulations on getting the DC-DC converter fixed and sorting out the FG wires. I saw your first post this morning and was going to suggest checking the FG wires but you beat me to it.

The rewind problem sounds rather unusual. You should not get both reels turning if you put the walkman into rewind with no tape in it. Also the fact that rewind works when the machine is paused seems to suggest that the take up reel is being driven when in rewind. It sounds as if the take up spool is being driven by the small rubber idler, as it normally is when in play. When you press "pause" the small idler is moved away from the outer edge of the take up spool drive assembly.
When you press stop, the small idler should be moved away from the take up spool assembly and from the black plastic belt driven gear, which drives the small idler. You should check if this is happening.

The level meter not working is possibly the TA7654P LED driver chip. This is a standard Toshiba chip and it is normally possible to find a replacement on Ebay. First of all check that you are getting 6V on pin 8 of the chip when the switch is set to "Peak". When in "Batt" mode, the chip is disabled by removing the 6V power supply from pin 8. I have had a couple of these chips fail on D6s before now.

 

Thank you once again for the reply Deb. I think I do remember seeing the small idler touching the plastic gear assembly. I will check that and the LED chip, and get back to you. Thanks again!