Radio tape recorder Hitachi TRK 8010k - How to install aux in place of am band?

[UNITRAX]

Hitachi TRK 8010k
Is it possible to have an aux input in place of the radio on the am band range? When connecting to the tape recorder, I have additional tape noise. There is an integrated circuit HA11251 in the schematic. Which pin is the am radio output on?
Radio tape recorder diagrams and HA11251 datasheet included

[jiroy]

Re: Radio tape recorder Hitachi TRK 8010k - How to install aux in place of am band?

According to the attached pictures , it's pin 11 for AM Vcc..

Here is a more clear and expanded view for the HA11251 diagram..

[jiroy]

Re: Radio tape recorder Hitachi TRK 8010k - How to install aux in place of am band?

First observations , it can be done but with lot of lot of modifications , like for instance , instead of disabling AM , using a multi-switch AM/FM/AUX , and this switch should also handle an extra function to switch between AM and Aux at the point AM out coming from pin 13 , or another switching before the amplification stage .

[UNITRAX]

Re: Radio tape recorder Hitachi TRK 8010k - How to install aux in place of am band?

Good idea with the am/aux switch. The receiver is made for the old fm oirt range (63 - 74Mhz). Therefore, radio is useless and the am range could serve as an aux.

How in practice should I put the signal from the aux there? If the am is only on pin 13, how is the split between the right and left channels done? Do I need to put the signal from the aux into mono there?

[jiroy]

Re: Radio tape recorder Hitachi TRK 8010k - How to install aux in place of am band?

If you disable AM , you've then put a lot of extra work on your modifications , like cutting rails to the RF AM section or the meter detector , and frankly , I don't advise you to do it but it's up to you in the end .

About the mono issue , I'll take a look and see what I can come up with , hopefully tomorrow .

[jiroy]

Re: Radio tape recorder Hitachi TRK 8010k - How to install aux in place of am band?

What I reached so far plus my experience , Basically , the source is holding the full wave , so in case it was recorded on one head (we can't say mono actually) , it doesn't mean it won't be stereo on stereo devices unless the source was originally mono .

Anyway , here's a good video for different techniques ..

https://www.youtube.com/watch?v=ZKoIAIbXc0o

[UNITRAX]

Re: Radio tape recorder Hitachi TRK 8010k - How to install aux in place of am band?

Topic solved.
I cut the path from pin 13 and put the switch in this place. Audio signal from bt is delivered to the volume potentiometer, so that in radio mode the VU meter and volume control works without modification. Bluetooth module has a separate switch, so that it does not interfere with the AM signal.