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Direct drive servo recordplayer issues.

T

TrevorBarten

Well-Known Member
For reference the record player is a yamaha yp d4

I have this record player that works but has a few issues. The two main ones being that it spins at the correct speeds but it slowly speeds up over time. And also that unless I turn the internal potentio meter all the way up for 33 rpm it just doesn't start spinning at 33 at all. I replaced all elektrolytic caps aswell as some others that I find to usually be defective. I also replaced all the pot meters and lubed the motor but no dice. Any clue what I should try now? I was thinking to just replace all the parts I still haven't touched yet. Might aswell at this point but that's fairly aimless and I would like to know what the exact issue could be here.
 
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TrevorBarten said:
For reference the record player is a yamaha yp d4

I have this record player that works but has a few issues. The two main ones being that it spins at the correct speeds but it slowly speeds up over time. And also that unless I turn the internal potentio meter all the way up for 33 rpm it just doesn't start spinning at 33 at all. I replaced all elektrolytic caps aswell as some others that I find to usually be defective. I also replaced all the pot meters and lubed the motor but no dice. Any clue what I should try now? I was thinking to just replace all the parts I still haven't touched yet. Might aswell at this point but that's fairly aimless and I would like to know what the exact issue could be here.
Click to expand...

I’d have sprayed them clean prior to replacing them. that’s just me tho.

1. Have you downloaded the service manual?

https://www.vinylengine.com/library/yamaha/yp-d4.shtml

2. Are the pots you replaced the same resistance values?

I don’t know this deck, but I know some speed issues with servo controlled motors tend to have issues with someone of the board mounted ICs.

Download the manual and start probing for proper voltages at the test points. This will at least give you some direction of where to look.
 
jobrewer1983 said:
I’d have sprayed them clean prior to replacing them. that’s just me tho.

1. Have you downloaded the service manual?

https://www.vinylengine.com/library/yamaha/yp-d4.shtml

2. Are the pots you replaced the same resistance values?

I don’t know this deck, but I know some speed issues with servo controlled motors tend to have issues with someone of the board mounted ICs.

Download the manual and start probing for proper voltages at the test points. This will at least give you some direction of where to look.
Click to expand...

I did clean them I went over them with a multimeter but some of the legs had cracks so I had to replace them regardless. Yes I am sure the pots are the same values. This deck doesn't have any ic's. I did measure some voltages and mostly everything seemed fine. Considering it's a speeding up issue rather than just not working at all I doubt that will do much either. The only thing that I could maybe try figuring out is if, when the pot meter isn't at full blast, there is still a voltage going to the motor. I tried this before but only when I hadn't replaced the potentio meters yet. If there is can I assume that the motor is damaged? Seems like with how it's designed that that would be hard but maybe some of the contacts/wires are oxidized and only work properly with a big enough signal?
 
TrevorBarten said:
I did clean them I went over them with a multimeter but some of the legs had cracks so I had to replace them regardless. Yes I am sure the pots are the same values. This deck doesn't have any ic's. I did measure some voltages and mostly everything seemed fine. Considering it's a speeding up issue rather than just not working at all I doubt that will do much either. The only thing that I could maybe try figuring out is if, when the pot meter isn't at full blast, there is still a voltage going to the motor. I tried this before but only when I hadn't replaced the potentio meters yet. If there is can I assume that the motor is damaged? Seems like with how it's designed that that would be hard but maybe some of the contacts/wires are oxidized and only work properly with a big enough signal?
Click to expand...

That I don’t know, as I don’t know this deck. I doubt the motor would be bad tho.

did you happen to check under the motor to see if there are any filter caps under it? I’ve seen some DD motors that have a small board under it, usually housed behind black plastic or some sort of casing.

You did download the manual correct?
 
I just looked at the manual, yea there are IC and semiconductor chips. They can fail over time and you may need to find a replacement.
 
It looks like a nice deck, I don’t know it or haven’t played with one but the service manual has some good info
 
Much like the higher end Denon's there's a handful of IC's and sensors throughout. GL, keep us updated if you find something.
 
I had a bad platter switch make a turntable go slow. The dirty connection made it have a voltage drop. I took it apart and cleaned the contacts and was back in business.
 
kirkendoll said:
I had a bad platter switch make a turntable go slow. The dirty connection made it have a voltage drop. I took it apart and cleaned the contacts and was back in business.
Click to expand...

Also cleaned those. Even bypassed them to see if they where just beyond repair but no sadly.
 
Are the waveforms on pins 7 & 12 of the Control PCB correct? You need to start here and work backwards.

This PCB has only transistors and OPamps so should be relatively easy to fault find.
 
I have just fixed a Denon DD with a similar problem, I replaced caps, checked and replaced transistors, checked psu even replaced the timing IC all to no avail, it turned out to be the darn switch. It would gradually increase speed as it warmed up and also stutter sometimes. I pressed the 33 hard in frustration and it fixed the speed issue so you may have a similar problem.
Chris
 
cafe latte said:
I have just fixed a Denon DD with a similar problem, I replaced caps, checked and replaced transistors, checked psu even replaced the timing IC all to no avail, it turned out to be the darn switch. It would gradually increase speed as it warmed up and also stutter sometimes. I pressed the 33 hard in frustration and it fixed the speed issue so you may have a similar problem.
Chris
Click to expand...

Ohh Man good info! One more thing to check!
 
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