Author Topic: Fool My A56405 Toyota Radio To Think It Is Playing A Cassette?  (Read 2040 times)

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Offline iamdarkyoshi

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Hello again everyone. I took apart my 97 toyota rav 4's original radio to modify it by adding bluetooth and a line in. I got the lines traced for the output of the head amplifier, and if I split those wires, I could inject my own audio into the radio, and it would play.

However, this ONLY worked if I had a cassette playing. Once it ran to the end of the tape or the tape was removed, it stopped playing my injected audio.

So I took apart the tape assembly and removed all the boards, motors, and switches from it. Then I just placed them on a plastic sheet and played with the switches until it stayed in tape mode. I got it to stay in tape mode by holding down two switches, but the eject motor and spindle motor just pulse on and off. I figured that it would be okay as long as it played audio... but it doesn't.

Anyone have any suggestions for me to try to get it working without a tape in the cassette desk? I wanted to completely remove any moving parts, which is why I didnt just use an infinite tape. The mechanics in this thing are about dead anyway, they barely work and make a lot of noise.

Below are pictures of the front and underside.

Toyota A56405


Model 86120-AC010
Ref CQ-LS7410Z

Any ideas? I can't find a service manual anywhere :(
 

Offline evb149

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Re: Fool My A56405 Toyota Radio To Think It Is Playing A Cassette?
« Reply #1 on: July 20, 2016, 12:21:44 am »
Inject your signals somewhere else other than the tape output audio signall path so you don't have to be in tape playing mode?

Also they have cassettes that don't have tape in them but do have a magnetic head positioned where a tape cassette having tape in it would ordinarily be read by the head mechanism in the audio player.  The output head in the cassette is coupled to an external "audio input wire" which lets you inject externally sourced audio from a MP3/CD player or whatever into the tape player by coupling the audio from the head in the cassette to the head in your audio unit magnetically.  They were commonly used for portable CD player interfacing to cars having tape players.  Anyway the "tape cassette" of that type just spins and never of course runs out of tape because there isn't any so a "dumb" cassette player would just keep playing the externally supplied signal forever always staying in tape playing mode.  I guess some "smart" players might time out and stop playing after a couple of hours but I see no reason why they would do that if not sensing "end of tape" or mechanical fault.

Anyway that sort of cassette coupler mechanism could solve your electrical and mechanical problems.
Or a cassette like that could solve your mechanical problems even if you still couple audio through your add-on interface.

I don't know if you just could literally break the tape and pull it out of a junk cassette to achieve mechanically the "never ending tape" effect as those purpose made cartridges do or if it has to sense some pressure against the read head as if a tape was there though in that case I suspect a bit of fabric padding glued in place would do.  Or just buy the electrical CD player interface cassette from ebay they've got to be basically free now that almost nobody wants them.

As for the noisy mechanism well I guess you could stop the motors by cutting the wires and see if it still stays in play mode with nothing continually moving or if that produces a problem of some kind.

 

Offline lowimpedance

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Re: Fool My A56405 Toyota Radio To Think It Is Playing A Cassette?
« Reply #2 on: July 20, 2016, 12:33:54 am »
Just a thought, what about a car wrecking yard and a later model rav4 with a more suitable radio (cd type) if such a thing exists that could be made to fit.
Seems like a lenghty exercise if easier alternatives are available.
Is it that costly to just buy an aftermarket player that probably comes with USB too ? (even second hand? )
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline iamdarkyoshi

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Re: Fool My A56405 Toyota Radio To Think It Is Playing A Cassette?
« Reply #3 on: July 20, 2016, 02:11:58 am »
Just a thought, what about a car wrecking yard and a later model rav4 with a more suitable radio (cd type) if such a thing exists that could be made to fit.
Seems like a lenghty exercise if easier alternatives are available.
Is it that costly to just buy an aftermarket player that probably comes with USB too ? (even second hand? )
Trying to do this without spending anything. My current Sony CDX u8000 has a missing walkman button, disk player doesn't work (who plays disks anyway?) and the LCD is starting to bleed or something.

Inject your signals somewhere else other than the tape output audio signall path so you don't have to be in tape playing mode?

Also they have cassettes that don't have tape in them but do have a magnetic head positioned where a tape cassette having tape in it would ordinarily be read by the head mechanism in the audio player.  The output head in the cassette is coupled to an external "audio input wire" which lets you inject externally sourced audio from a MP3/CD player or whatever into the tape player by coupling the audio from the head in the cassette to the head in your audio unit magnetically.  They were commonly used for portable CD player interfacing to cars having tape players.  Anyway the "tape cassette" of that type just spins and never of course runs out of tape because there isn't any so a "dumb" cassette player would just keep playing the externally supplied signal forever always staying in tape playing mode.  I guess some "smart" players might time out and stop playing after a couple of hours but I see no reason why they would do that if not sensing "end of tape" or mechanical fault.

Anyway that sort of cassette coupler mechanism could solve your electrical and mechanical problems.
Or a cassette like that could solve your mechanical problems even if you still couple audio through your add-on interface.

I don't know if you just could literally break the tape and pull it out of a junk cassette to achieve mechanically the "never ending tape" effect as those purpose made cartridges do or if it has to sense some pressure against the read head as if a tape was there though in that case I suspect a bit of fabric padding glued in place would do.  Or just buy the electrical CD player interface cassette from ebay they've got to be basically free now that almost nobody wants them.

As for the noisy mechanism well I guess you could stop the motors by cutting the wires and see if it still stays in play mode with nothing continually moving or if that produces a problem of some kind.



I have one of those tapes. It does work with it but the stereo separation is absolutely terrible. Its going to be a huge work trying to get the board and motors back into the assembly :(
 

Offline SeanB

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Re: Fool My A56405 Toyota Radio To Think It Is Playing A Cassette?
« Reply #4 on: July 20, 2016, 08:00:47 am »
There wil be either an optosensor or a small magnetic switch that is getting pulses from the tape rotation. You need to find it and just feed in a low frequency pulse ( around 1-5Hz) to fool it into thinking there is a tape in there and it is moving.
 


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