Trying to repair a Sony TC-366 Reel to Reel machine

[cipinthesky]

Hi, I'm new here and I'm sorry if this'll sound stupid, but I'm no master in electronic repair. So I got myself a reel to reel machine (Sony TC-366). Not the best available but it will serve well as a real "not-so-good tape simulation" in my studio. Now, despite a couple of mechanical issues which I already managed to fix, I have a problem with the auxiliary left recording channel. When I send a stereo signal in the aux input, the left channel volume pot acts as some sort of low-pass filter unless I push it to the max. When on 10 the freq response is fine, but obviosly the signal is completely distorted. Could it be the pot itself the problem?

Thank you

 

[Tony Stewart]

Ii needs more elbow grease.

 

[Nigel Goodwin]

Probably just a dirty pot, try a small squirt of WD40 in the pot, and work it backwards and forwards - WD40 works better than most switch-cleaners, as it adds a little lubricant to replace what has dried out.

It's a nice enough little machine (I used to repair them occasionally 'back in the day'), particularly as it has 7.5 inches per second.

 

[Lightium]

Probably just a dirty pot, try a small squirt of WD40 in the pot, and work it backwards and forwards - WD40 works better than most switch-cleaners, as it adds a little lubricant to replace what has dried out.

It's a nice enough little machine (I used to repair them occasionally 'back in the day'), particularly as it has 7.5 inches per second.

That's interesting. I have two portable radios that could use your magic WD40.

 

[cipinthesky]

Probably just a dirty pot, try a small squirt of WD40 in the pot, and work it backwards and forwards - WD40 works better than most switch-cleaners, as it adds a little lubricant to replace what has dried out.

It's a nice enough little machine (I used to repair them occasionally 'back in the day'), particularly as it has 7.5 inches per second.

Thank you Nigel, I'll try as soon as I can and I'll let you know! I don't have WD40 but I have a contact cleaner which specifies that has lubricant in it. I guess it'll work fine.

 

[Nigel Goodwin]

Thank you Nigel, I'll try as soon as I can and I'll let you know! I don't have WD40 but I have a contact cleaner which specifies that has lubricant in it. I guess it'll work fine.

In my experience contact cleaners never worked as well as WD40, but if you've got it give it a try - remember, just a small squirt.

 

[cipinthesky]

In my experience contact cleaners never worked as well as WD40, but if you've got it give it a try - remember, just a small squirt.

Yes, a small squirt, my mantra from now till I fix it. Jokes aside, since you're here and very helpful I wanna learn the more I can. When it rewinds, the right reel doesn't brake when I stop it, so it keeps loosing tape and I have to reset it manually, any idea about what to do?

Thank you very much Nigel

 

[Nigel Goodwin]

There should be a brake pad, have you downloaded the service manual?

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Pads, pulleys and belts all deteriorate with age - I used to get reel to reel machines for repair where the belts had just 'disappeared', if you were lucky a close examination showed a fine trace of dust where they used to run

From page 51 of the manual:

 

[cipinthesky]

There should be a brake pad, have you downloaded the service manual?

Elektrotanya for electronics experts

Electronics forum for electronics experts to repair defective appliance.

elektrotanya.com

Pads, pulleys and belts all deteriorate with age - I used to get reel to reel machines for repair where the belts had just 'disappeared', if you were lucky a close examination showed a fine trace of dust where they used to run

From page 51 of the manual:

View attachment 144293

So... I managed to go to the studio and work on the recorder. The brake pad is completely flat and there is a spring that looks like it lost strength. I somehow managed to make it work by stretching the spring. It won't last till Christmas, but I'm good for now. As per the recording problem that went a little odd. I cleaned the pots with just a squirt of lubricant, but then I found out that the problem I described happened just when monitoring the tape, so i figured it had to be something with the recording head. I gave it another round of cleaning and now it seems to work. Anyway the two pots for the aux input are not working at the same level, the left one sounds less then the right one. I fed some white noise in it and I matched the levels. Now the stereo works fine and both channels sounds almost the same. Would it be a good idea to change the pots?

 

[Nigel Goodwin]

So... I managed to go to the studio and work on the recorder. The brake pad is completely flat and there is a spring that looks like it lost strength. I somehow managed to make it work by stretching the spring. It won't last till Christmas, but I'm good for now. As per the recording problem that went a little odd. I cleaned the pots with just a squirt of lubricant, but then I found out that the problem I described happened just when monitoring the tape, so i figured it had to be something with the recording head. I gave it another round of cleaning and now it seems to work. Anyway the two pots for the aux input are not working at the same level, the left one sounds less then the right one. I fed some white noise in it and I matched the levels. Now the stereo works fine and both channels sounds almost the same. Would it be a good idea to change the pots?

No, they are very unlikely to be the cause of the problem - I would suggest giving the record/play switches a little squirt of switch cleaner, poor connections in old record/play switches are a very common fault.

As a matter of interest, what is the condition of the heads like? - if they are worn you can usually feel a 'ridge' across them when you slide your finger nail up them.

However, some Sony machines (I had an excellent Sony cassette recorder) used 'ferrite and ferrite' heads, and those are absolutely amazing and don't seem to wear at all - I also had an Akai reel to reel, and that used glass heads, and those are pretty immune from wear as well. However, both those types of heads are many times more expensive than the normal ferrite/steel ones, so weren't 'that' common.