Sony TTS 4000 duff speed control pot

[Anolsos_1974]

Hi all, I recently bought this stunning turntable but the speed control pot is shot. I think it’s a log scale with open or short at ‘zero’ as it were but my local electronics store doesn’t know. And suggestions will be much appreciated!

 

[eiraved]

Have you attempted spraying a shot of DeoxIT D5 inside the pitch control potentiometer? If not, spray a little and work the control back and forth fully about 10-20x, then allow to dry for a few minutes. Turn on, try again and see if that helps any.

 

[Anolsos_1974]

Howdy, thanks for your reply. I should have mentioned that I tried this and it didn’t help - at some points on the dial rotation the speed just goes crazy….

 

[eiraved]

Did you spray only once, or multiple times? It's possible you'll have to spray again and work the pot some more. Also, have you done the same operation to the push buttons?

 

[eiraved]

If that still doesn't solve your problem, you could follow the same fix as recommended on this post or the one below:

Thread 'Old Technics amp gain has gone mental after changing some parts'

Sep 28, 2026

Hi all, it’s a technics su c04. The volume pot was shot so I swapped it for the same spec pot. Stupidly I didn’t keep track and after replacing some bad caps (the two main caps, and the one in the power supply) I noticed the gain on the main volume knob has jumped - now it reaches full volume in about one quarter turn of the volume control. My limited experience is wondering if there is a mistake with the resistance of the VR as I had a similar experience replacing VRs in old speakers where I couldn’t find the exact spec VR so all the recognisable change in respective driver volume...

• Anolsos_1974
• Replies: 14
• Forum: General Audio Discussion

• 

 

[absolon]

B taper is linear, pot is 5Kohm. Log taper is for audio. There are two other pots that control the speed adjustment located on the circuit board as well and they should be cleaned too. I've had the same problem on the TTS2500 which is an almost identical circuit but different board layout. Try measuring across the pot output to see if it is working correctly or not. Replacement is a standard 5K B taper but you need one the fit's your configuration

 

[Anolsos_1974]

Did you spray only once, or multiple times? It's possible you'll have to spray again and work the pot some more. Also, have you done the same operation to the push buttons?

I’m pretty sure. I’ll do it again, and don’t forget deoxit in Europe doesn’t exist so I’m using contact spray…

The buttons are the next step but they seem fine. In fact the quality of the buttons is incredible!

 

[eiraved]

I’m pretty sure. I’ll do it again, and don’t forget deoxit in Europe doesn’t exist so I’m using contact spray…

That's ok, just ensure the contact spray you use is plastics-safe and you'll be fine.

 

[Anolsos_1974]

That's ok, just ensure the contact spray you use is plastics-safe and you'll be fine.

I don’t think this is the issue though because from looking at my records of the stuff I have done I think I have now cleaned it thoroughly twice. Do you think it is worth continuing - maybe desoldering and soaking the whole thing in contact fluid?

Incidentally I don’t need a speed control anyway so if I can’t fix or replace the VR then I could just bypass the circuit, to imitate the speed control being at 0 can’t I?

 

[eiraved]

I don’t think this is the issue though because from looking at my records of the stuff I have done I think I have now cleaned it thoroughly twice. Do you think it is worth continuing - maybe desoldering and soaking the whole thing in contact fluid?

Incidentally I don’t need a speed control anyway so if I can’t fix or replace the VR then I could just bypass the circuit, to imitate the speed control being at 0 can’t I?

If you cleaned and worked the controls twice, and haven't seen a difference, then it isn't the problem. Have you attempted to clean the two other pots located on the circuit board which control the speed adjustment? If still no changes, consider absolon's suggestion to "try measuring across the pot output to see if it is working correctly. Replacement is a standard 5K B taper but you need one the fit's your configuration."