modding the mic input of an old tape recorder

[snk]

Hello,
I have a cheap old tape recorder (hifivox M38, but also sold under various brands an names) from the early 70s. It works, and it is fun.
It features a dedicated microphone (with a remote integrated), but I wish I could also use it to record sounds from a mixer.
It uses a nowadays unusual 6 pins DIN plug, and I don't really know if i could "hack" it to make it act as a "regular" audio input (at mic level obviously)?



I have found a schematic of a similar model, using the same kind of 6pin DIN plug.

Which pin would be audio in ("tip") and which pin would be ground ("sleeve")?
Is it safe to try?

Thank you!

[Digital Larry]

The thing at upper left, with a 4-pin connector, looks more like the record/playback head if you ask me.

[snk]

Sorry, I mightn't have been clear enough : I was speaking about the 6 pin plug at the right of the picture

[anotherjim]

Pin 5 signal, pins 3 & 4 screen/return.
Signal feeds to transistor T1 when not in tape play.

[snk]

The upper left block should indeed be the play/write heads.
We can also see at the bottom right the output jack (phones) as well as the integrated speaker output.
Above it, we can see the mains power input (followed by a trafo, a diodes bridge and batteries).

pin4 seems to be the sleeve?
pin3 goes to the out jack (?)
I would suppose that pins 1 & 2 are not for audio signal (as there is a switch right after the pin socket, which could be a symbol for the microphone "playback/record" remote switch).
pin 5 goes to the left of the schematic, to an arrow

[snk]

oops, cross-posting

Thank you, AnotherJim !
So, I could use a switched jack socket with the tip going to DIN's pin 5, and sleeve going to DIN pin 3 or 4, right?

[anotherjim]

oops, cross-posting

Thank you, AnotherJim !
So, I could use a switched jack socket with the tip going to DIN's pin 5, and sleeve going to DIN pin 3 or 4, right?

Yes but depends on the switched jack & where you put it.
If it's a normal type, it works as an insert. If you can fit it in the case, I'd find the screened cable from the 6pin and cut it somewhere where both cut ends can reach the jack. The 6pin end goes to the switched tip and sleeve contacts and the unswitched contacts have the cable end going to the play/record switch. That way, the normal 6-pin mic connection works until you plug in to the jack.

Note that in play mode, the mic signal is grounded by the recorders switching. Whatever you plug in needs to not mind being shorted to ground.

[snk]

Thank you, AnotherJim. I will try tomorrow, and see how it works.
(I am also considering not adding a socket to the case, but just using a cable with a jack on one side, and two wires on the other side to put in the DIN's 5 & 3. it wouldn't be a world class solution, but should work).

[snk]

Hi,
It's all good and working (I think the wiring was quite different than on the schematic, but in the end it worked fine).
I have put a mini jack socket on the enclosure, it fits nicely and behaves as expected 
I changed some old leaky electrolytic caps, and now the tape machine is a bit less noisy (obviously it's not a hifi, high end recorded, but nonetheless it is fun to use, and much more easy now to play along with other gear.

Thank you all for your help and tips !