Hi, All.

I have an old Hitachi stereo with cassette player (circa. 1970s) in an old car. The cassette player doesn't work but the AM radio does. I would like to have a go at adding a 3.5mm headphone jack to the stereo as per the videos linked below.

I have removed the stereo from the car and have the schematics — attached. Would anyone be able to help with the following?
1) In the first video SuperTrix4U bypasses the AM/FM tuner outputs. The Hitachi is AM only. Can the same installation method be used?
2) If the same method can be used, can some help identify which capacitors are linked to the tuner outputs?

If anyone thinks I have chosen the wrong starting point and has a suggestion for a better method of adding a 3.5mm headphone jack, I more than welcome any advice.

Thank you.

 

Try to add the jack plug wires Left and Right across the volume control marked (here) in red, use the ground near to the volume control, disconnect the tape heads wires, and see if it works,.

 

As an alternative you could try one of these – but it would require the tape head (to pick up the signal) to be working. But it is more likely that the tape deck has a mechanical fault resulting in it not working.

https://www.ebay.co.uk/itm/18421897...Hwsw6QB%2BZDt4kUE%3D|ampid:PL_CLK|clp:4429486

 

As an alternative you could try one of these – but it would require the tape head (to pick up the signal) to be working. But it is more likely that the tape deck has a mechanical fault resulting in it not working.

https://www.ebay.co.uk/itm/184218971374?_trkparms=amclksrc=ITM&aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=252698&meid=225ba25471f842778f550db12a069937&pid=101195&rk=3&rkt=12&sd=384346118413&itm=184218971374&pmt=1&noa=0&pg=4429486&algv=SimplAMLv11WebTrimmedV3MskuWithLambda85KnnRecallV1V2V4ItemNrtInQueryAndCassiniVisualRankerAndBertRecallWithVMEV3&_trksid=p4429486.c101195.m1851&amdata=cksum:184218971374225ba25471f842778f550db12a069937|enc:AQAIAAABYPqB0EgCndAssfMWNy0AT0GytGzF9%2By0G%2BlcW69DgBK3Qlz4BjwJQqPkN4K8I7qz9GoVciN1QNWqyS8EeqYS8rZRsDvyvw34m3N%2FyJKokwCTIIc3RNym2SNW8ARudP72DyiwgIY0dfUnIr5%2BMZDTaovONmC8fvEaFBEaQZQXBjxjgGF37%2BkMkgTYI4yAL8PGTBQMI4UaBCPJFjwJ9vhWVhN7hjsFJOssCQLGLNUj8yxL52ZVPTWKf85TCtpTdVIFeV6c2W1WpMTo3tNdCewZZKhX2yuI35ucNbJTLO8l%2BfnNcEQ9v2w38PfvRfbhzQfykp1Rb%2FoJX5biIQP8hhgD8jxrf003J2UNX5tP129M1z7qHvGQKH0ptm6%2Bj65jZZIcBy8O5xSRI%2BTzd%2B47pq%2FsLGSqSAj6IeCTC2HixCtoTVlVomLY0TG2KTNFwha0PmqQ3iYyVnLRHwsw6QB%2BZDt4kUE%3D|ampidL_CLK|clp:4429486

Thanks, Hymie.
I had previously disregarded a Tape Cassette Aux because the cassette player doesn't work and just assumed an Aux adapter wouldn't work. However, I'm too far down the path of installing a headphone port that I kind of want to test myself.

Thank you again.

 

Try to add the jack plug wires Left and Right across the volume control marked (here) in red, use the ground near to the volume control, disconnect the tape heads wires, and see if it works,.View attachment 300455

Thanks, Dodgydave.

I'll follow your advice and report back. Let's see if I can correctly identify everything on the stereo.

 

Further to Dodgydave’s advice, the signal attachment points are on the volume control potentiometers (and should be easy to find). But the volume control pot is for the stereo signal, so pots RV208A and RV208B will be a double ganged 20KΩ pot.

One end of each pot will be commoned (the 0V), with the other ends being stereo signal in. Once wired correctly, the volume control on the cassette player will act as volume control for the Aux in.

I don’t think you need disconnect the tape heads as there are resistors and semiconductors between the Aux in and heads that will prevent loading, and there should be no signal input from the heads (with no magnetic tape passing over the heads).

 

Check with the laws where you live. I remember that in some states in the United Stages listening to headphones feeding both ear while driving is illegal. That is because stereo audio fed into your ears makes it difficult to react properly to sounds what might be important to your driving. Even now, I do not use any kind of earphone while driving so I can be aware of what's going on around me.

 

Check with the laws where you live. I remember that in some states in the United Stages listening to headphones feeding both ear while driving is illegal. That is because stereo audio fed into your ears makes it difficult to react properly to sounds what might be important to your driving. Even now, I do not use any kind of earphone while driving so I can be aware of what's going on around me.

He wants to feed his MP3 songs into the radio amplifier from his phone making it louder, he's not adding an headphones socket ..