Cassette Deck Hum

[EEZABLADE32]

Hi, noticed that my Sony cassette deck makes a low humming noise when turned on, even though not near nor connected to amp. Not sure if this is normal or something that needs looking at.

Thx

Tony

[sunny-dave]

Sounds like transformer hum - it comes to most hi-fi kit with old age ... not a problem unless anything is getting overly warm to the touch.

[douglas9401]

Hmmmmmmmmmmmmm.

[sunny-dave]

Is that 50Hz or 60Hz, doogie?

[douglas9401]

50 I think but I'll check with ummmm. :)

[Togo]

It is possible for the smoothing capacitor in the power supply to cause a mains hum. It is part of the circuit that renders the AC supply to DC and after rectification "smoothes" the resultant chopped AC sine wave to a steady DC supply. Does the amp pick it up? You will hear that through your speakers for sure.

[EEZABLADE32]

Thought so! Thx

[Togo]

What make and model is the deck Eeza? Also a ground(or earth) leak or break can cause the same. Some models, are also prone to dirty play switches causing a mains hum. No one can possibly definitely give you a positive reason, without opening the machine up and making a few checks. If you post the model and make I will try to see if there is indeed a "stock" fault for it. I used to repair them and still have pals in the business. Quick check. Does the hum lessen if you lift the deck up whilst it is on, does the hum stop if you put pressure on the play, or record switch without fully engaging them?

[Old_Geezer]

It probably just doesn't know the words.

[Togo]

Haha give over Geezer.

[EEZABLADE32]

Hi Togo,
the deck is a Sony TC-TX 333. Plays and works great apart from the hum.

Thx

Tony

[Togo]

Hi again Eezablade. Have done a bit of Google Fu and found a service manual. I have had a look at a video on youtube and all I can say is that not an easy bit of kit to service. The mains transformer has a cover that appears to have been glued onto the metal sub chassis and this may well have cooked and is making the hum. The two capacitors that are suspect are C63 and C65 but not really a diy job I'm afraid.

[EEZABLADE32]

Thx for your effort. Only bought it second hand so I guess the cost of repair would be more than the purchase price. I'll just have to put up with it.

[Togo]

That's OK. I love that old kit. Clever reverse play gearing in the cassette deck that is not solenoid controlled. The solenoids and movement detectors used to be a mare on the ones that had that set up.