walkman wm-f23
 

I have a sony walkman, wm-f23, a 1989/90 device I think, which I'm trying to
identify a component it uses. This is a SOT23-3 PNP transistor marked "94 F".
Actually the "94" is underlined at the left and the "F" is much smaller at the
far right. I think the latter is not related to the chip identification but
maybe to processing plant or other thing. This transistor is used to preamplify
the signal out of the tape head before going to the main audio amplifier which
is the sanyo LA4570, an SOIC-16-N chip. Here is the photo :
http://cdn.sur.ly/favicon_sur.ly_white_32px.png

walkman wm-f23
 

On 2017-08-01, jethro tull wrote:

I have a sony walkman, wm-f23, a 1989/90 device I think, which I'm trying to
identify a component it uses. This is a SOT23-3 PNP transistor marked "94 F".
Actually the "94" is underlined at the left and the "F" is much smaller at
the far right. I think the latter is not related to the chip identification
but maybe to processing plant or other thing. This transistor is used to
preamplify the signal out of the tape head before going to the main audio
amplifier which is the sanyo LA4570, an SOIC-16-N chip. Here is the photo :
http://cdn.sur.ly/favicon_sur.ly_white_32px.png

I forgot, I'm searching for its full reference code.

walkman wm-f23
 

On Tuesday, August 1, 2017 at 5:52:31 PM UTC-4, jethro tull wrote:
I have a sony walkman, wm-f23, a 1989/90 device I think, which I'm trying to
identify a component it uses. This is a SOT23-3 PNP transistor marked "94 F".
Actually the "94" is underlined at the left and the "F" is much smaller at the
far right. I think the latter is not related to the chip identification but
maybe to processing plant or other thing. This transistor is used to preamplify
the signal out of the tape head before going to the main audio amplifier which
is the sanyo LA4570, an SOIC-16-N chip. Here is the photo :
http://cdn.sur.ly/favicon_sur.ly_white_32px.png

Near as I can tell, this is a DTA114. If I get a chance, I'll look up the service manual and verify.

Dan

walkman wm-f23
 

On 01/08/2017 22:52, jethro tull wrote:
I have a sony walkman, wm-f23, a 1989/90 device I think, which I'm trying to
identify a component it uses. This is a SOT23-3 PNP transistor marked "94 F".
Actually the "94" is underlined at the left and the "F" is much smaller at the
far right. I think the latter is not related to the chip identification but
maybe to processing plant or other thing. This transistor is used to preamplify
the signal out of the tape head before going to the main audio amplifier which
is the sanyo LA4570, an SOIC-16-N chip. Here is the photo :
http://cdn.sur.ly/favicon_sur.ly_white_32px.png


FWIW the WM F36 uses 1 discrete Q, a 2sd1012 for switching record bias
on and off

walkman not wm-f23 but wm-bf23
 

On 2017-08-02, N_Cook wrote:
FWIW the WM F36 uses 1 discrete Q, a 2sd1012 for switching record bias
on and off
actually it is WM-BF23

walkman wm-f23
 

On 2017-08-01, wrote:
Near as I can tell, this is a DTA114. If I get a chance, I'll look up the
service manual and verify.

Dan
I searched quite a lot for the service manual of this player and found nothing.
I think sony does not like sharing such data.

walkman wm-f23
 

On 02/08/17 21:21, jethro tull wrote:
On 2017-08-01, wrote:
Near as I can tell, this is a DTA114. If I get a chance, I'll look up the
service manual and verify.

Dan
I searched quite a lot for the service manual of this player and found nothing.
I think sony does not like sharing such data.


Hmmm, "WM-BF23"

The Canadian WM-AF23 is probably similar, looking at the

http://www.manualscenter.com/manuals...ce-manual.html

So have a look at

https://elektrotanya.com/sony_wm-af23.pdf/download.html

Look for the line,

This file is downloadable free of charge:

and wait for the "Get Manual" link to appear next to it.

Do not click any other download buttons!!


--
Adrian C

walkman wm-f23
 

On 02/08/17 21:58, Adrian Caspersz wrote:
On 02/08/17 21:21, jethro tull wrote:
On 2017-08-01,
wrote:
Near as I can tell, this is a DTA114. If I get a chance, I'll look
up the
service manual and verify.

Dan
I searched quite a lot for the service manual of this player and found
nothing.
I think sony does not like sharing such data.


Hmmm, "WM-BF23"

The Canadian WM-AF23 is probably similar, looking at the


Hmmm (2) - Scrap that, can't see the PNP part you mentioned.

--
Adrian C

walkman wm-f23
 

On 2017-08-02, Adrian Caspersz wrote:

Hmmm, "WM-BF23"

The Canadian WM-AF23 is probably similar, looking at the

http://www.manualscenter.com/manuals...ce-manual.html

So have a look at

https://elektrotanya.com/sony_wm-af23.pdf/download.html

Look for the line,

This file is downloadable free of charge:

and wait for the "Get Manual" link to appear next to it.

Do not click any other download buttons!!


I got it. This player is slightly different in the circuit. The 5 and 6-pin
IC's are not on mine. as for IC's I only have the tuner, the amplifer and the
transistor I'm searching the part number with this post. But I'm surprised
because the only difference the AF23 has with mine is the "normal / CrO2"
switch which does "DX / local" when radio is on while for my device it does
"mono / stereo". While this shouldn't affect significantly the amplifier
stage, it does. The transistors around the pre-amp stage are not the same and
the 5 and 6-pin IC's are being used here.

walkman wm-f23
 

On Wednesday, August 2, 2017 at 4:21:35 PM UTC-4, jethro tull wrote:
On 2017-08-01, wrote:
Near as I can tell, this is a DTA114. If I get a chance, I'll look up the
service manual and verify.

Dan
I searched quite a lot for the service manual of this player and found nothing.
I think sony does not like sharing such data.

I was a warranty service center for Sony, so I still have the service manuals on disc. I won't get a chance to fire the system up until Friday though.

Dan

walkman wm-f23
 

I was a warranty service center for Sony, so I still have the service manuals
on disc. I won't get a chance to fire the system up until Friday though.

Dan

so do you have the manual? at least can you confirm the device is indeed
DTA114?

walkman wm-f23
 

On Thursday, 17 August 2017 10:20:45 UTC+1, jethro tull wrote:
I was a warranty service center for Sony, so I still have the service manuals
on disc. I won't get a chance to fire the system up until Friday though.

Dan

so do you have the manual? at least can you confirm the device is indeed
DTA114?

Why would you need to know? You know you need low power, low voltage, maybe low noise, maybe high beta, and you should be able to work out npn or pnp from the circuitry immediately around it.


NT