Hitachi TRK-5280E internal microphones/rec mode help

[fivefootnine]

Hi, this is my first post here!
I recently bought an HITACHI 5280-E in mint condition on swedish ebay and my main purpose is to record music with the internal condenser microphones.

I will record digitally by connecting my record source to the phone output from the boombox and record while I monitor the internal microphones.

The problem is that the internal mics will only be activated when the record button is pushed, which will turn the boombox in REC mode, but this will produce some noise,(like a motor is going, capstans?), even when its in REC/PAUSE mode.

Is there some way to get around this, so I can somehow turn on the internal microphones without the noise that comes from the REC mode? Any method, including destructive?

I have only tried this when using an AC power chord, there is also a DC power connection and the option to use batteries.
Would any of these options minimize the noise?

Thanks for any help!

 

[Northerner]

Hello and welcome to the forum!

Slightly strange thing to do? why use the cheap little microphones in a boombox, why not just use, oh I don't know maybe a microphone I know that boomboxes are clearly the best things ever but they have their limits Why are you using a boombox for this? (as I'm really nosy! )

You could probably just disconnect the power cable to the motor which would then stop the movement and therefore background noise, tho you could still get a little bit of transformer hum. Just open it up, find the motor and desolder it, tho you'd need to then isolate the cable end as you don't want live cables bouncing around inside the box!

 

[fivefootnine]

Hi! Thanks for the reply! Well, I like experiment with different sounds and the stereo sound you get from the two internal mics is in my opinion quite interesting, and nice!

https://soundcloud.com/hitachi-trk5280e/trk-5280-mono1

I did a recording from the internal mics while in REC/PAUSE mode from the headphone out straight into a Minidisc, have a listen! What could be causing that noise? The motor is clearly prominent, but what about that "old vinyl" like noise??

If I should destroy the motor, would it still be able to be in REC mode you think?


Thanks!

 

[baddboybill]

Hi! Thanks for the reply! Well, I like experiment with different sounds and the stereo sound you get from the two internal mics is in my opinion quite interesting, and nice!

https://soundcloud.com/hitachi-trk5280e/trk-5280-mono1

I did a recording from the internal mics while in REC/PAUSE mode from the headphone out straight into a Minidisc, have a listen! What could be causing that noise? The motor is clearly prominent, but what about that "old vinyl" like noise??

If I should destroy the motor, would it still be able to be in REC mode you think?


Thanks!

I wouldn't destroy it just unhook it and tape up wire or maybe you can just press record without play as the play button micro switch won't kick on motor

 

[fivefootnine]

Okey, I have never opened a boombox but if I can get the manual It could probably be a good help to see what need to be done..

or maybe you can just press record without play as the play button micro switch won't kick on motor

Would this involve some other operation? Right now the record button won´t do anything unless the tape button is pressed.,??

Have you listened to the wav file? What is that "vinyl" like noise? What could be the reason for that? The AC power?
Maybe it would dissapear if I used batteries instead?

 

[baddboybill]

Well depressing record activates the record bar. The noise could be from the AC current

 

[Northerner]

Just had a listen...are you sure yours isn't running using a steam engine?

 

[fivefootnine]

Just had a listen...are you sure yours isn't running using a steam engine?

Haha,,I know it´s sounds like it!, Well, the volume is really maximized so that the problem would be audible!

Do you think the record head could be involved somehow, causing that "vinyl crackle" sound?
It would be strange though since I dont record to tape, just monitor the internal mics, but maybe the headphone output signal is taken from the REC head when in REC mode?

 

[Northerner]

Just had a listen...are you sure yours isn't running using a steam engine?

Haha,,I know it´s sounds like it!, Well, the volume is really maximized so that the problem would be audible!

Do you think the record head could be involved somehow, causing that "vinyl crackle" sound?
It would be strange though since I dont record to tape, just monitor the internal mics, but maybe the headphone output signal is taken from the REC head when in REC mode?

Mmm...I don't know I'm afraid...I suppose it would make sense rather than it coming direct from the microphone to the headphone socket...beyond my level of expertise I'm afraid

 

[fivefootnine]

Just had a listen...are you sure yours isn't running using a steam engine?

Haha,,I know it´s sounds like it!, Well, the volume is really maximized so that the problem would be audible!

Do you think the record head could be involved somehow, causing that "vinyl crackle" sound?
It would be strange though since I dont record to tape, just monitor the internal mics, but maybe the headphone output signal is taken from the REC head when in REC mode?

Mmm...I don't know I'm afraid...I suppose it would make sense rather than it coming direct from the microphone to the headphone socket...beyond my level of expertise I'm afraid

I will demagnitize the heads today and have another try, hopefully the crackling noise will be gone, leaving me with just the steam boat engine to worry about.

 

[fivefootnine]

I demagnetized the heads but the crackling did´nt go awyay, so the problem is´nt the heads,assuming I did a well-performed demagnetization. Maybe this schematic could tell wether the heads are involved in the head output signal at all,
I marked the inner mics with a red square and the phone output with a bue square, I cant seem to find the heads among that mess , but maybe someone a little bit more familiar with these kind of schematics could spot them?

Maybe this schematic could also give an final answer to the easiest or best way to get rid of the motor sound as heard in the wav file here,


https://soundcloud.com/hitachi-trk5280e/trk-5280-mono1

HERE IS A BIGGER VERSION OF THE SCHEMATIC DIAGRAM
http://homerecording.com/bbs/attachment ... 1361441042