Converting old caasette/radio for computer use

[tjohnson]

I have an old small cassette recorder radio in the loft which I'm going to repair and get going again rather than throw out but thought could I convert this by adding the play/mic/rem sockets? 


This is probably one for @Bryce or @gerald really, the resident hardware experts! I have a spare 5 pin din lying around, I can't believe it would be too difficult to hook this up to the pcb to provide the fictionally.


Any help or suggestions welcomed.

[GUNHED]

Which plugs does your device have? In case you have tape in and tape out it should work for the CPC.

[tjohnson]

Which plugs does your device have? In case you have tape in and tape out it should work for the CPC.

I don't think it has any, possibley has headphones, pretty sure I doesn't have mic or line in, will look tonight.

[Bryce]

Two options:  1. Let me know the exact model of the device and I can see if the schematics are available. Then I can tell you exactly where to tap the signals from. If the schematics aren't available, there's option 2:  You could take photos of the cassettes amplifier PCB and I could suggest points to connect to.

Bryce.

[tjohnson]

Its a real cheap watson thing (RR5525), some generic china made this from the late 90s or early 2000s.  I think we used it in the kitchen for the radio until we got a DAB radio.  The cassette deck was a very easy repair, one of the belts had failed it was an extremely flimsy belt.  Fortunately I had a pack of belts and found another one.   Sounds ok for a basic deck, seems louder out the right speaker than left.

I haven't disconnected the PCB but took some quick pictures, looks to me like the head is configured for mono although the head looked like a stereo head to me.  It has a headphone jack but no mic.  I assume the remote could be connected in line to one of the motor wires so it would kill the motor?


edit no the head is definitely stereo, on closer inspection I can see another wire

[Bryce]

Stereo tape decks are usually a bit less reliable for retro tape loading, but here's what you could try:

Ouput: Connect a low ohm resistor (around 47R) to the red and white wires at each speaker. The other end of these resistors get connected together and that point is the output (together with ground).

Give that a go and if it works we can find an input point after.

Bryce.

[tjohnson]

Stereo tape decks are usually a bit less reliable for retro tape loading, but here's what you could try:8

Ouput: Connect a low ohm resistor (around 47R) to the red and white wires at each speaker. The other end of these resistors get connected together and that point is the output (together with ground).

Give that a go and if it works we can find an input point after.

Bryce.

It has got a headphone socket would it be worth tapping off there, I haven't looked but assume it's a stereo socket, on the speakers are you suggesting bridging the l and r channels together?

[Bryce]

If it has a headphone socket then you're sorted for output, just need to find a suitable input, but you are only going to need that if you intend saving things to tape.

Bryce.

[tjohnson]

Hi @Bryce I managed to test it with the headphone socket and it works OK once I found the right vol.  It would be nice to add the mic and rem functionality.


To add rem could I connect the socket to one of the motor wires, from what I gather this is just a relay inside the cpc that cuts the circuit, would I cut the positive or negative wire to the motor or does it not really matter?


On the mic I get get the board out to see the other side  if you would be willing to help identify a suitable place to tap into the pcb?

[Bryce]

To find a suitable input, I'd need to see the other side of the larger PCB. It looks like the radio and cassette amplifier are all on one board. Or does the smaller PCB have an IC on it?

Bryce.

[tjohnson]

I got a couple of photos of the PCB.  There is an IC on the small board which is an LS22241.  The main board has a Toshiba TA2111N which appears to be a radio IC.  It looks a real gash pcb!
I see the ribbon cable between the boards has L/O R/O L/RA R/RA GN and CN+  I'm thinking this indicates in and out not sure what the CN+ means.

[Bryce]

Ok, to feed a signal in from the CPC, you would need to connect the CPC signal to pins 2 and 8 of that chip. However, you'll need to do this via a switch to "enable" the CPC function, otherwise the entire device would become a mono cassette and radio. Or you could use two resistors to divide the signal, but the levels might be too low then.


Bryce.

[tjohnson]

Ok, to feed a signal in from the CPC, you would need to connect the CPC signal to pins 2 and 8 of that chip. However, you'll need to do this via a switch to "enable" the CPC function, otherwise the entire device would become a mono cassette and radio. Or you could use two resistors to divide the signal, but the levels might be too low then.


Bryce.

The LS22241?

[Bryce]

Yes.

Bryce.

[tjohnson]

Small update on this, I've wired up the port and testing, the input doesn't seem to work, I can vaguely hear the sound when inputting but doesn't record anything or if it does the level is exceptionally low.  I need to switch to radio and try recording then when the radio is tuned to noise to see if that works.


On the rem functionality I wired a switch to enable rem or disable.


Need to have a think about getting the input working.

[Bryce]

Would it not be easier just to buy something like this: https://www.ebay.co.uk/itm/GPO-Cassette-Player-Desk-Top-Portable-Tape-Recorder-Push-Button-Black-Silver/401134217985

Bryce.

[tjohnson]

Would it not be easier just to buy something like this: https://www.ebay.co.uk/itm/GPO-Cassette-Player-Desk-Top-Portable-Tape-Recorder-Push-Button-Black-Silver/401134217985

Bryce.

@Bryce, it probably would but I'm only doing it out of interest really, kind of a pointless project because I found this thing in they loft and thought I could make use of it.

[tjohnson]

I've given up trying to put MIC in for now I haven't got time to analyse the PCB and work out whats going on.  Thanks for you help @Bryce I may revisit this at some point in the future.