walkman wm-f23

[jethro tull]

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

[jethro tull]

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

[dansabr...@yahoo.com]

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

Dan

[N_Cook]

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

[jethro tull]

On 2017-08-02, N_Cook <div...@tcp.co.uk> wrote:
> FWIW the WM F36 uses 1 discrete Q, a 2sd1012 for switching record bias
> on and off

actually it is WM-BF23

[jethro tull]

On 2017-08-01, dansabr...@yahoo.com <dansabr...@yahoo.com> 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.

[Adrian Caspersz]

Hmmm, "WM-BF23"

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

www.manualscenter.com/manuals/sony/wmbf23-service-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

[Adrian Caspersz]

On 02/08/17 21:58, Adrian Caspersz wrote:
> On 02/08/17 21:21, jethro tull wrote:
>> On 2017-08-01, dansabr...@yahoo.com <dansabr...@yahoo.com>
>> 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

[jethro tull]

On 2017-08-02, Adrian Caspersz <em...@here.invalid> wrote:
>
> Hmmm, "WM-BF23"
>
> The Canadian WM-AF23 is probably similar, looking at the
>
> www.manualscenter.com/manuals/sony/wmbf23-service-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.

[dansabr...@yahoo.com]

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

[jethro tull]

> 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?

[tabb...@gmail.com]

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