Adding Aux in to old Cst/FM/AM/MW stereo

spyking · 8th May 2009, 20:31

Hey!

I just successfully (to an extent) finished adding an AUX in to my old Sony XR-1804 HU..

Here's what I have done..

From the Tuner L-out,R-out, I soldered an old Headphones cable L and R wires. the ground was soldered to a ground nearby..

Adding Aux in to old Cst/FM/AM/MW stereo-mainboardu.jpg

The jack is then routed through the Tape slot..

This setup works, for an extent.. When I switch to tuner and then to FM, the radio plays normally, when I plug in my player, the FM volume reduces to really low and the music from the player comes.

I knew that this was going to happen, as I did not cut the traces, rather soldering directly to the points,

My question now,
1. Would anyone know how I could tap another source? Ie not FM but say AM or MW, cause we never use that, but Fm once in a bluemoon
2. My other option would be to solder the leads into the Lin and Rin of the Volume control chip,

Adding Aux in to old Cst/FM/AM/MW stereo-volumecontrolic450.jpg

Currently, FM goes into R3 and L3..
But the chip is soldered directly to one side of the PCB (the technical term escapes me right now) So should I try that or just search for the Mw/AM outs from the tuner? If someone could help i'd be really glad

Pic's of the work next time I open it up :| forgot to take them in my excitement.. :P

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DerAlte · 10th May 2009, 20:38

Quote:

Originally Posted by spyking

...
1. Would anyone know how I could tap another source? Ie not FM but say AM or MW, cause we never use that, but Fm once in a bluemoon
2. My other option would be to solder the leads into the Lin and Rin of the Volume control chip,

Currently, FM goes into R3 and L3..
But the chip is soldered directly to one side of the PCB (the technical term escapes me right now) So should I try that or just search for the Mw/AM outs from the tuner? ...

Difficult to figure out since the only parts of the schematic are visible.

The LC75372E volume control chip caters to 3 input channel pairs (L1/L2/L3 resp. R1/R2/R3). If you are seeing L3+R3 connected to the FM tuner, does the schematic say where the L1/R1 and L2/R2 are connected? AM seems to be connected to L2/R2, in that case L1/R1 must be the cassette signal.

IMHO you should try connecting to the cassette pins (L1=pin 13 and R1=pin 21) rather than the radio section. Make sure you use a large enough resistor (say something >= 10K) in series with the signal from the EP socket. Solder one end of the resistor to the PCB track, and the other end to the wire.

Careful: that's an SMD device (Surface Mount Device - "directly to one side") which is bonded with a silver solder to the track. If the track gets too hot, the lead bond might open out if there is stress in the PCB. Better take a multimeter and trace out a point as far away from the device as possible, and then quickly solder the resistor to the track (you will need to clean and presolder the lead to do that).

BTW, you could have achieved your Aux-in without these calisthenics. There are casette adapters available that plug directly into the EP socket of your music player! And quite decent signal play-back too - much better than the ubiquitous FM gizmos. Anyhow, I wouldn't want to discourage your DIY venture. All the best, buddy!

spyking · 11th May 2009, 07:14

Hey!

I managed to finish this project..

here's what I did.. I soldered one set of wires to the FM tuner Rout and Lout from the tuner board.. next, I traced the the track to the next component, (two SMD resistors) I googled a bit about SMD and saw couple of vids, so felt confidant, so soldered another set of wires to the input of the resistors.. then ground from the shielded cable was soldered to the ground on the FM board, next, I cut the track from Rout,Lout to the resistors, and wired the 5 wires into a Stereo 3.5mm jack.. hence, when nothing is pluged in, I have normal FM.. but when i plug in a source, I get the sources signal

I know about the tape adapters... infact, we have been using those for the past 2 years or so.. this has kinda spoiled the tape head of the system, resulting in only left side audio, as well as tape eating tendencies :P hence this modification.. also, the tape adaptor didn't sound THAT great.. along with the added noise of the tape rotating inside..

DerAlte · 11th May 2009, 14:18

Kwool! That's a great job done. Enjoy, @spyking. Pics?

esteem_lover · 11th May 2009, 14:23

Nice job spyking. Please let us know how good it is over a period of time.

spyking · 11th May 2009, 17:49

Pic's.. Hmm I'll be removing set to do some minor beatification.. that time get some good ones..

the current pics just show 5 wires badly soldered to the pcb :P

and thanks

will let ya know how it goes...

8th May 2009, 20:31	#1
spyking BHPian Join Date: Sep 2007 Location: Chennai Posts: 95 Thanked: 5 Times	Adding Aux in to old Cst/FM/AM/MW stereo Hey! I just successfully (to an extent) finished adding an AUX in to my old Sony XR-1804 HU.. Here's what I have done.. From the Tuner L-out,R-out, I soldered an old Headphones cable L and R wires. the ground was soldered to a ground nearby.. The jack is then routed through the Tape slot.. This setup works, for an extent.. When I switch to tuner and then to FM, the radio plays normally, when I plug in my player, the FM volume reduces to really low and the music from the player comes. I knew that this was going to happen, as I did not cut the traces, rather soldering directly to the points, My question now, 1. Would anyone know how I could tap another source? Ie not FM but say AM or MW, cause we never use that, but Fm once in a bluemoon 2. My other option would be to solder the leads into the Lin and Rin of the Volume control chip, Currently, FM goes into R3 and L3.. But the chip is soldered directly to one side of the PCB (the technical term escapes me right now) So should I try that or just search for the Mw/AM outs from the tuner? If someone could help i'd be really glad Pic's of the work next time I open it up :\| forgot to take them in my excitement.. :P Note from Team-BHP Support : Please note that it is imperative for you to upload pictures directly to the Team-BHP Server. Click here (Uploading photographs directly to Team-BHP) to view our simple help article on uploading pictures. Thanks. Last edited by Rehaan : 11th May 2009 at 03:59. Reason: Please see the note that has been put at the end of your post by the Support Team.
	() Thanks

11th May 2009, 07:14	#3
spyking BHPian Join Date: Sep 2007 Location: Chennai Posts: 95 Thanked: 5 Times	Hey! I managed to finish this project.. here's what I did.. I soldered one set of wires to the FM tuner Rout and Lout from the tuner board.. next, I traced the the track to the next component, (two SMD resistors) I googled a bit about SMD and saw couple of vids, so felt confidant, so soldered another set of wires to the input of the resistors.. then ground from the shielded cable was soldered to the ground on the FM board, next, I cut the track from Rout,Lout to the resistors, and wired the 5 wires into a Stereo 3.5mm jack.. hence, when nothing is pluged in, I have normal FM.. but when i plug in a source, I get the sources signal I know about the tape adapters... infact, we have been using those for the past 2 years or so.. this has kinda spoiled the tape head of the system, resulting in only left side audio, as well as tape eating tendencies :P hence this modification.. also, the tape adaptor didn't sound THAT great.. along with the added noise of the tape rotating inside..
	() Thanks

11th May 2009, 14:18	#4
DerAlte Senior - BHPian Join Date: Mar 2007 Location: Bangalore Posts: 8,069 Thanked: 2,919 Times	Kwool! That's a great job done. Enjoy, @spyking. Pics?
	() Thanks

11th May 2009, 14:23	#5
esteem_lover Senior - BHPian Join Date: Jul 2006 Location: Madras/Py Posts: 7,556 Thanked: 502 Times View My Garage	Nice job spyking. Please let us know how good it is over a period of time.
	() Thanks

11th May 2009, 17:49	#6
spyking BHPian Join Date: Sep 2007 Location: Chennai Posts: 95 Thanked: 5 Times	Pic's.. Hmm I'll be removing set to do some minor beatification.. that time get some good ones.. the current pics just show 5 wires badly soldered to the pcb :P and thanks will let ya know how it goes...
	() Thanks