hum from my much loved 1200's

[Steve 'B']

I am getting a slight hum off my Technics 1200's. It seems to be on both decks. They are both around 8 years old and to be honest have not seen the easiest of lives but do you have any ideas. It is not the mixer or the external gear. I have narrowed it down to the decks themselves.

Many thanks in advance.

Steve

[sleah]

Steve,
It's most likely some kind of earth/common fault, as there are no active components between the needle and the mixer (usually!). You say it's not the mixer, but it could be the ground connection on the mixer that you connect the 1200's ground cable to. It may have worked loose inside the mixer, which would only affect the turntable inputs. Also check all your mains cables for loose earths.
Buzzes are one of those things can can be a fault where you least expect it and is only apparent under a certain set of circumstances, eg when your 1200's are hooked up.
Of course it's possible there is a loose wire inside the 1200's, but the chances of both decks suffering the same fault are remote to say the least, but worth a look anyway!

HTH

Simon

[Steve 'B']

The reason I say its not the mixer is that I have had it hooked up to 3 mixers and I get the same fault right the way through. A Pioneer, a Vestax and a Citronic. I have even tried (dont tell the HSE!!) to wire it direct to the earth core on a plug and still the same problem. I have just serviced the decks myself and I am totally stumped. This is not a simple problem, I assure you.

[leighinstoke]

Try the ground-loop isolator then - you can always take it back to Maplin if it still doesn't cure the problem.

Leigh.....

[Steve 'B']

Done it. Changed the needle too before someone recomends that.

[sleah]

Have you tried changing the whole cartridge (as opposed to just the stylus) or even the headshell?
Also check all the signal connections inside the decks, try connecting a 'real' earth to different points (not that there's many) or lifting the earth etc.
Did this occur after you had changed a cartridge or services both decks??

You've probably thought of the above but it's worth mentioning just in case!

Ohhh, just thought.... do they hum if you hook them up to the mixer, but leave the mains unplugged from each deck, spinning the deck by hand will still produce sound.
That would show/eliminate mains hum from inside the deck.

Bizzare problem!

[Steve 'B']

Have you tried changing the whole cartridge (as opposed to just the stylus) or even the headshell?


Yes


Ohhh, just thought.... do they hum if you hook them up to the mixer, but leave the mains unplugged from each deck, spinning the deck by hand will still produce sound.
That would show/eliminate mains hum from inside the deck.


Good idea. Will try.

[symo]

Could be a fault in the tonearm assembly, where it connects to tha annoying little circuit board.

[Steve 'B']

Could be a fault in the tonearm assembly, where it connects to tha annoying little circuit board.

Any advance on this suggestion. Still getting hum with decks un plugged. On one deck it seems to get louder when you plug it in (the hum that is!!).:bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang: :bang:

Please help me!!!!

[symo]

Sounds more like an earth fault

[Steve 'B']

I am thinking the same thing to be honest. I have to send it to Panasonic up near Fleet, Hampshire. Should be a nice drive!!

[Steve 'B']

Help me please someone!!:bang: :bang: :bang: :bang:
Can you see the HUM??