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Why does a DD motor slow down after playing a while?

jleon92f

jleon92f

Addicted Member
Hi again,

I have a DD motor question: Why does the motor slow down and take longer to reach quartz lock after playing a while?

A good question for the TT Techs?

Thanks,
John.:music::D
 
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jleon92f said:
Hi again,

I have a DD motor question: Why does the motor slow down and take longer to reach quartz lock after playing a while?

A good question for the TT Techs?

Thanks,
John.:music::D
Click to expand...

Check that the magnetic strips under the platter are clean or maybe the spindle bearing needs to be cleaned & re-lubed. good luck!
 
jleon92f said:
Hi again,

I have a DD motor question: Why does the motor slow down and take longer to reach quartz lock after playing a while?

A good question for the TT Techs?

Thanks,
John.:music::D
Click to expand...

Heat and expansion of bearing surfaces contributes to what also may be power supply problems.
 
Some d/d units have occasional speed issues due to oxidation in the speed switch. Not sure if yours is subject to those kinds of fluctuations.
 
beej said:
Some d/d units have occasional speed issues due to oxidation in the speed switch. Not sure if yours is subject to those kinds of fluctuations.
Click to expand...

Thanks for your reply, the speed is steady once it gets quartz locked,little green light comes on. It just takes longer and longer each time as it gets warmer.

Thanks,
John.:music::D
 
If it is taking longer and longer each time you start it up, STOP using it until the problem is fixed. It sounds like a failing component, probably an electrolytic capacitor. You need to get the failing component replaced before it completely gives up the ghost and presents you with a "catastrophic" failure. A capacitor can either fail "open", which probably won't hurt anything, or "closed", which amounts to a short circuit, which will usually take out some nearby components. If it takes out a proprietary chip in your controller circuit, you may end up owning an interesting paperweight!

It is giving you warning signs that it is sick. Cure the patient before it dies, which it will if you continue ignoring the symptoms. [Just ask me how I learned this lesson... :yes: :tears: ] Try to find the service manual for that model, recap the board (replace all the electrolytic capacitors and while you are in there, check tolerances on everything else, re-flow solder joints and clean contacts), make any necessary adjustments (AFTER you get the service manual!) and then sit back smiling, knowing that you should be safe for another couple of decades.

DD TTs tend to be extremely long-lasting devices, but the first things to go will likely be electrolytics. The WORST things to go are the chips, but they can last a long, long time if they aren't ruined by other things failing around them (or by being abused, say by being run in hot, humid environments). Most of these TTs were built 20-30 years ago, so the electrolytics in them are due for replacement. Your TT is telling you that!
 
Last edited:
Arkay said:
If it is taking longer and longer each time you start it up, STOP using it until the problem is fixed. It sounds like a failing component, probably an electrolytic capacitor. You need to get the failing component replaced before it completely gives up the ghost and presents you with a "catastrophic" failure. A capacitor can either fail "open", which probably won't hurt anything, or "closed", which amounts to a short circuit, which will usually take out some nearby components. If it takes out a proprietary chip in your controller circuit, you may end up owning an interesting paperweight!

It is giving you warning signs that it is sick. Cure the patient before it dies, which it will if you continue ignoring the symptoms. [Just ask me how I learned this lesson... :yes: :tears: ] Try to find the service manual for that model, recap the board (replace all the electrolytic capacitors and while you are in there, check tolerances on everything else, re-flow solder joints and clean contacts), make any necessary adjustments (AFTER you get the service manual!) and then sit back smiling, knowing that you should be safe for another couple of decades.

DD TTs tend to be extremely long-lasting devices, but the first things to go will likely be electrolytics. The WORST things to go are the chips, but they can last a long, long time if they aren't ruined by other things failing around them (or by being abused, say by being run in hot, humid environments). Most of these TTs were built 20-30 years ago, so the electrolytics in them are due for replacement. Your TT is telling you that!
Click to expand...

Hi,
Thanks for the information, one question, which board? there are basically 2, one attached to the motor and another one in the front.
I have stopped using the TT.

UPDATE: I think I found the bad caps, see new pictures.

Thanks,
JOhn.:music::D
 
Last edited:
jleon92f said:
UPDATE: I think I found the bad caps, see new pictures.
Click to expand...

Looks like a shorted cap. It might have taken the regulator with it. It looks discolorer/burned as well.

I would be inclined to rebuild the whole power supply after a failure like that.
 
I'd agree on the failing caps. The Technics (and MCS clones) are the only ones that require lube on the spindle. Virtually all other DDs are sealed and don't require lubrication.
 
Arkay said:
If it is taking longer and longer each time you start it up, STOP using it until the problem is fixed. It sounds like a failing component, probably an electrolytic capacitor. You need to get the failing component replaced before it completely gives up the ghost and presents you with a "catastrophic" failure. A capacitor can either fail "open", which probably won't hurt anything, or "closed", which amounts to a short circuit, which will usually take out some nearby components. If it takes out a proprietary chip in your controller circuit, you may end up owning an interesting paperweight!

It is giving you warning signs that it is sick. Cure the patient before it dies, which it will if you continue ignoring the symptoms. [Just ask me how I learned this lesson... :yes: :tears: ] Try to find the service manual for that model, recap the board (replace all the electrolytic capacitors and while you are in there, check tolerances on everything else, re-flow solder joints and clean contacts), make any necessary adjustments (AFTER you get the service manual!) and then sit back smiling, knowing that you should be safe for another couple of decades.

DD TTs tend to be extremely long-lasting devices, but the first things to go will likely be electrolytics. The WORST things to go are the chips, but they can last a long, long time if they aren't ruined by other things failing around them (or by being abused, say by being run in hot, humid environments). Most of these TTs were built 20-30 years ago, so the electrolytics in them are due for replacement. Your TT is telling you that!
Click to expand...

Thanks for the information, I did replace the Caps on the PSB and now the controls do not function anymore?? The motor turns but still has no torque?

I am at a loss now, TT is spinning but cueing does not work anymore?:scratch2:

Thanks,
JOhn.:music::D
 
If your table performs worse after replacing the capacitors, make sure you did not install the new ones backwards.
 
I found the problem, broken PCB, repair the spot and I need (2 more caps)finished the recap, they were BP , different from the others.

It works again so far.

Thanks,
John.:music::D
 
Hi,
While replacing the caps I noticed there was a difference from the parts list.

C110 listed as 4.7uf 50v and what was on the pSB was 0.47uf 50v? I put back what I took out.. Was that correct?

Thanks,
John.:music::D
 
Hi, After all the electronics have been taken care of , it looks like all it is was a binding platter bearing. I am still testing.:scratch2:

Thanks,
John.:music::D
 
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