Exelvision tape recorder vibrating

[Liartes]

Hello,


I use an Exelvision tape recorder on my CPC 6128, this is working allright powered on AA batteries.
When I plug it with the AC cable, the tape recorder buzz and vibrate ! I was too scared to try to use it... I did not find anything related to this tape deck or clones of the Phillips VG5000 tape deck about vibrating when AC powered.
My questions are : do you have any clue on what is going on here ? Is it a normal behaviour for this particular piece of hardware ?

[pelrun]

I'm guessing bad caps in the power supply circuit, so the AC isn't being smoothed properly.

[Liartes]

Thank you, I will test the capacitors then by curiosity. A I prefer powering it on batteries, maybe I will just remove the AC power board.

[Liartes]

To follow up : I opened the Exelvision tape recorder, the AC cord go to a copper coil, then the copper coil is connected to a diode bridge on a daughter board.
The AA batteries cables are connected to this daughter board and protected by a diode in the case there is AA batteries in the device and the power cord is plug to AC at the same time.
Finally the daughter board is connected to the main board, which hold the capacitors.
As the rest of the device is shared by both power sources and I experienced no buzzing or vibrations issue with the AA batteries scenario, I just removed the copper coil and the AC cable.

[Bryce]

The "coil" (it's a transformer) has probably loosened up over the years and now vibrates in time with the AC source (50Hz).

Bryce.