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Sony D6C problem...

michiel - 2013-01-31 09:10

FILE - Sony D6C 1000Hz in.mp3

Hi All! My first post to this nice forum, but I'm a reader for some time now.. I hope you guys can help me with my Sony D6C walkman, as its doing strange things lately.

Most things are working quit well. Speed is okay, pause button works etc... Only this; I get a lot of strange random spiking kind of noise during playback and recording. Also volume is going up and down randomly. As is the VU meter. It does this while on batteries or with the adapter connected.

I already replaced the DC-DC caps, without any effect. The output of the DC-board is a steady 11.5 Volts in all situations.... Checked the motherboard for cold connections and cleaned all the switches.

As its difficult to explain the symptoms. I fed the line-in with a constant 1000Hz tone. The output signal via the line-out is attached as a mp3 to this message... The results via the tapehead and the headphone-out are exactly the same. When I playback a recorded 1000Hz tone (recorded with a good recorder) I get the same results. Spikes, volume up-down and the VU meter jumps with it. It also happens with other frequencies.

The serial is 39876, so its an oldie! Hope someone can get me on the right track, cause I'm out of ideas at the moment....

plop - 2013-01-31 10:12

I can definitely hear the crackle. It sounds so random almost like static build up on the tape, but could probably also be a loose connection to the amp section or even the cabling.

michiel - 2013-01-31 10:36

Hi Plop, thanks for your suggestion! The tape was not involved. I plugged in a tone generator into the line-in, hit the record button and got the result via the line-out. But indeed its very random.

Getting the motherboard out of its housing while playing back didn't give an other results either (except some extra earthing hums etc). Nor did pressing all the soldering points on the motherboard while playing. Nor did shaking the walkman violently have any effect.... I'm pretty sure by now its not a lose connecting....

plop - 2013-01-31 10:57

Well if you get fed up trying to fix it, drop me a private message. I may make you an offer for it.

michiel - 2013-02-04 10:29

This weekend I poked the motherboard with a scope. It seems the Muting board is toast. Has anybody ever tried to make a replica of CP301 or to repair it? The internal parts are shown in the schema of the newer D6C version......

walkgirl - 2013-02-04 10:36

Welkom hier!

snowcrab - 2013-02-04 10:42

Ohhhhh, Walkgirl is ook hollands!

I mean.. Is Walkgirl maybe dutch?

michiel - 2013-02-04 10:59

Heeeiii, dank je wel...

walkgirl - 2013-02-05 03:56

Jup ik ben ook Kaas  

michiel - 2013-02-05 14:33

Haha, nu weet ik wie al die leuke Walmans voor mn neus wegkaapt op mp!...

nak.d - 2013-02-05 15:09

Originally Posted by walkgirl:

Jup ik ben ook Kaas  

Google translate had fun with that one... " Jup I'm Cheese"

walkgirl - 2013-02-06 08:11

Indeed cheese!

michiel - 2013-02-07 09:53

Okay, an other CP301 is on it's way to Holland. Hope it's not broken, as it's impossible to test it without a working recorder..... Secondly an other complete D6C with unknown defect is on its way....

kin - 2013-02-07 14:12

Hollakidee!

walkgirl - 2013-02-07 15:07

kin - 2013-02-08 12:44

lol Holland, bycicles,... walkmans... aint we a retro vintage loving Country.

michiel - 2013-02-11 12:30

Nice! Replacing the Muting board did solve everything. it's working great and sounds awsome again. D6C no. 39876 is saved...

michiel - 2013-02-12 09:26

Even nicer, got the complete but broken Walkman fixed today. Traces on the motherboard had micro cracks. It took some time to find the them all, but after mounting some extra wires on the mb everything works again! Symptoms were some kind of distorted mono like of sound. So DC6 no. 98301 has resurrected too... Really start to enjoy fixing these recorders! Looking around for more specimens locally to get more practice.

Next project is making a repro gear for my D8614 boombox on a lasercutter. The rev/fwd gear part no. 482240340117. In theory it should be possible to make it, as it is within tolerance of the cutter... Will see...

brutus442 - 2013-02-12 10:08

Originally Posted by Michiel:

Even nicer, got the complete but broken Walkman fixed today. Traces on the motherboard had micro cracks. It took some time to find the them all, but after mounting some extra wires on the mb everything works again! Symptoms were some kind of distorted mono like of sound. So DC6 no. 98301 has resurrected too... Really start to enjoy fixing these recorders! Looking around for more specimens locally to get more practice.

Next project is making a repro gear for my D8614 boombox on a lasercutter. The rev/fwd gear part no. 482240340117. In theory it should be possible to make it, as it is within tolerance of the cutter... Will see...


Congratulations Michiel! It's nice to see a saved walkman! Perhaps next time could you post some pics during your repairs !

 

I love to see the "in's and out's" of the repairs

michiel - 2013-02-12 10:57

Hi Brutus, thanks...  I got lots of fotos, but they are not interesting cause they just show how the wires and mb were before I worked on it. Just for me to remember....

 

I'll try to take fotos during my next project as it could reveal if high-tech machines can help us to keep our old boxes going...

plop - 2013-02-12 11:56

@Michiel

 

Can you tell us if either or both of these D6C have the original 'pointy' amorphous heads?

michiel - 2013-02-12 12:48

The 39876 does have it. The 98301 doesn't. My third 169379 doesn't have it either. All three of them have the "Amorphous head" badge on the side... 

michiel - 2013-02-12 13:05

I also got a D5M which has (by eye) exactly the same head as the lowest serial D6C. You could consider to get a trashed D5M and build the head into one of your post 270.000 recorders. I didn't notice any differences between the motherboards of the three D6Cs...

michiel - 2013-02-12 13:13

It should be pre-270000 of course.... 270000 and lower..

plop - 2013-02-12 14:15

Originally Posted by Michiel:

The 39876 does have it. The 98301 doesn't. My third 169379 doesn't have it either. All three of them have the "Amorphous head" badge on the side... 

Michiel,

 

Thanks for taking the time to check.

retro - 2013-02-12 14:16

Guess I'm a little late to the party, but welcome to the forum Michiel. 

michiel - 2013-02-13 00:26

Hi thanks retro... U're welcome plop..

kin - 2013-02-13 15:42

Awesome repair man!

 

(I smell local repairservice )

michiel - 2013-02-15 23:59

@kin, I'm still very very amateurish.... Broke the mb of an Pannie SX45 yesterday, cause I thought I could just pull the mb of the drive....  it should have been desoldered... But I managed to fix a tcs-430 the same day... easy fix though, just mechanical. You should definitely not love your device if it's in my hands lol....