Sony TC-540 low recorded volume - UK Vintage Radio Repair and Restoration Discussion Forum

vampyretim · 19th Nov 2019, 5:31 pm

Hello,

I'm working on a Sony TC-540 reel to reel recorder. I've replaced the leaking motor caps and the unserviceable level input pots. I have a problem that on both left and right channels however loudly you set the input to be recorded you get a very weak and muddy recording on the tape.

Has anyone had any experience with this reel to reel?

Many thanks.

ms660 · 19th Nov 2019, 6:02 pm

Used to service these back in the 1970's, most problems were either switch related or tape path related, eg: dirty switch contacts, dirty heads, they must be spotless...difficult to tell for sure without a magnifying inspection mirror, poor tape to head contact due to other reasons eg: pressure pad problems also goes without saying that the tape needs the correct bias and that the head mustn't be worn out.

Lawrence.

vampyretim · 25th Nov 2019, 8:40 pm

Quote:

Originally Posted by ms660

Used to service these back in the 1970's, most problems were either switch related or tape path related, eg: dirty switch contacts, dirty heads, they must be spotless...difficult to tell for sure without a magnifying inspection mirror, poor tape to head contact due to other reasons eg: pressure pad problems also goes without saying that the tape needs the correct bias and that the head mustn't be worn out.

Lawrence.

Thanks Lawrence, I've had another look at it today and it seems that after a good clean of all the switches the only problem I've now got is that one channel is pretty muddy, a bit like a speaker with a downed tweeter. The other channel works as it should. I'm going to get a scope on it tomorrow and see what's going on.

Thanks again.

vampyretim · 26th Nov 2019, 6:42 pm

I've had a weird thing happen as I was trying to fault find this today. Every time that I plugged another item into it that was hooked up to the mains (external amp. Sig gen) it drew a massive current from the power supply and took out its 1.5A fuse. I even got a shock when I tried to inject a signal. It's like there's a potential difference with whatever electronic item that you connect to it. It's acting like a short in the tape machines power supply I even had it when only the earth conductor of my sig gen was connected to the chassis of the tape machine.

Any idea what's going on?

19th Nov 2019, 5:31 pm	#1
vampyretim Heptode Join Date: Aug 2011 Location: Bristol, UK. Posts: 538	Sony TC-540 low recorded volume Hello, I'm working on a Sony TC-540 reel to reel recorder. I've replaced the leaking motor caps and the unserviceable level input pots. I have a problem that on both left and right channels however loudly you set the input to be recorded you get a very weak and muddy recording on the tape. Has anyone had any experience with this reel to reel? Many thanks.

19th Nov 2019, 6:02 pm	#2
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Sony TC-540 low recorded volume Used to service these back in the 1970's, most problems were either switch related or tape path related, eg: dirty switch contacts, dirty heads, they must be spotless...difficult to tell for sure without a magnifying inspection mirror, poor tape to head contact due to other reasons eg: pressure pad problems also goes without saying that the tape needs the correct bias and that the head mustn't be worn out. Lawrence.

26th Nov 2019, 6:42 pm	#4
vampyretim Heptode Join Date: Aug 2011 Location: Bristol, UK. Posts: 538	Re: Sony TC-540 low recorded volume I've had a weird thing happen as I was trying to fault find this today. Every time that I plugged another item into it that was hooked up to the mains (external amp. Sig gen) it drew a massive current from the power supply and took out its 1.5A fuse. I even got a shock when I tried to inject a signal. It's like there's a potential difference with whatever electronic item that you connect to it. It's acting like a short in the tape machines power supply I even had it when only the earth conductor of my sig gen was connected to the chassis of the tape machine. Any idea what's going on?