Reel to reel slows after playing a long time

[csblue]

I posted the following on rec.audio.tech and rec.audio.misc:

I am trying to restore a Sony TC-630 reel-to-reel recorder. It records fine,
but after I play the recording for a period of time, say ten minutes, the
speed starts to slow down and gets worse with time. After turning the unit
off and letting it rest awhile, the speed is correct again for a time, then
slows down again. I have lubricated and cleaned everything that I should.
Any ideas???

I got several answers to my posts, including one that referred me here to homerecording.com.

One of the answers suggested that I may have a motor getting really warm from poor lubrication. I thought I oiled it, but I am a novice at this. I may not have done it properly. Can anyone tell me how to properly lubricate the motor? For example, do I have to completely take the whole chassis out of the case to access it? And anything else I may need to know.

Thank you so much,

Steven Schreiner

 

[The Ghost of FM]

There might be other factors here besides the motor which may have excessive dirt buildup on the brushes inside the housing or worn out bearings which might need replacement, there could also be issues with the capstan drive belt loosing its grip due to rubber fatigue all of which are mechanical issues only.

Electronic issues could also be at play with power supplies that are dropping in voltage due to thermal runaway on aging components.

Your best bet is to seek out a qualified and experienced shop and get an estimate to really see where you stand with this deck.

Cheers!

 

[csblue]

Thank you, Ghost.

I have a vintage audio repair shop near me that I am planning to take it to if I can't fix it myself. I always try to do what I can first, as I have some tech experience in several areas. But, it sounds like maybe I've done all I can with this one and need to take it in. If anyone has any other suggestions I would certainly appreciate them.

Thanks again,

Steven

 

[Blackdog.sn]

I have an old sony 2 track reel, and it does the same thing. I haven't fixed it because i don't know who to ask, but if you find out, please let me know.