Audio help for a TRK-7800E

smalltabby

Member (SA)
Aug 17, 2019
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Hello all! This is my first time on this forum.

Just today I found an abandoned boombox next to the trash collection bins and decided to take it home with me. It's a Hitachi TRK-7800E. On the outside it looks fine, just a little dusty. The power cable works and the antenna picks up radio on FM. However the audio crackles a lot and loudly when using the controls, and the speakers use a different level of volume on each off/on switch and occasionally only use either of the two speakers, but both do work. I suspect the speakers have a loose cable inside?

It would be wonderful to restore this old boombox! My technical experience is limited to woodworks in primary school, although we did do some wire welding there and made some battery powers cars and boats :) So where should I start and what do I need to know?



Thank you!
 

Fatdog

Well-Known Member
Staff member
May 3, 2009
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That Hitachi is super clean! Congratulations!

I would say that the controls only need a good cleaning. You will need to open the Hitachi to get to the controls on the inside. A contact cleaner like DeOxit works very well at getting rid of the crackling in sliders, switches, and potentiometers. Controls usually have small holes where you can apply cleaner. You don't need too much. Also, be sure to allow enough time for the cleaner to evaporate before testing.

Welcome aboard!!!! :thumbsup: :hi:
 

mtamin

New Member
Feb 12, 2021
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1
Birmingham UK
I have one of these also. I am not very technically gifted but I managed to get as far as changing the belts. However this did not result in making it work as although the capstan spins ok the pinch roller does not come into contact with the capstan so the tape is not being drawn through and fast forward and rewind do not work (could be worn tyre on the wheel that drives this function. I will have to try again with it. It was reasonable to disassemble if plenty of photographs are taken for reference.
 

mtamin

New Member
Feb 12, 2021
2
0
1
Birmingham UK
Check the pause function isn’t stuck.
Thanks I will recheck that. The pause button does move in and out and the roller seems to move rather further away when pause is activated (and the spindle stops turning). I am wondering the pinch roller housing is not travelling the fully in its movement due to congealed grease or something. I shall take apart again and have a further look. I have to look at the idler wheel/tyre as well as fast forward and rewind do not work.