Picked up a Denon DP-80. It ran fine for a little while then started making noise. It's not a bearing, it's the motor control 'jerking' on the motor. I replaced the electrolytic caps. I also replaced some diodes on the motor control board because there was noticable corrision on the leads along with a couple of transistors on the quartz servo board because the leads were black and they looked rough overall. Did the speed adjustent with a scope.
Runs great at 45 but occasionally stutters on 33.
Here is how it sounded initially
https://drive.google.com/file/d/1LQUzwEly-sIBxaW-U55pbDstA6bEyhF3/view?usp=sharing
These 2 videos are of 33 after doing the work. Much improved but stutters (turn the sound up, it's not nearly as noisy). The scope traces jump when the noise occurs and the strobe display does too.
https://drive.google.com/file/d/1itKhF_dauQXwIodlL1Oz-82OCIjfrppY/view?usp=sharing
https://drive.google.com/file/d/1_Pc-AP2z49s9yn5m7XSSJbhTaAYmxHuo/view?usp=sharing
Any ideas? Thanks
Edit - it now does it on 45 also. Initially it didn't or maybe I just didn't run it long enough to act up.
Kevin Looker
Runs great at 45 but occasionally stutters on 33.
Here is how it sounded initially
https://drive.google.com/file/d/1LQUzwEly-sIBxaW-U55pbDstA6bEyhF3/view?usp=sharing
These 2 videos are of 33 after doing the work. Much improved but stutters (turn the sound up, it's not nearly as noisy). The scope traces jump when the noise occurs and the strobe display does too.
https://drive.google.com/file/d/1itKhF_dauQXwIodlL1Oz-82OCIjfrppY/view?usp=sharing
https://drive.google.com/file/d/1_Pc-AP2z49s9yn5m7XSSJbhTaAYmxHuo/view?usp=sharing
Any ideas? Thanks
Edit - it now does it on 45 also. Initially it didn't or maybe I just didn't run it long enough to act up.
Kevin Looker
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Hey Kevin,
Many possibility and I am still struggling a bit with mine but since capacitors had been replaced and having scope to see that you are certainly much more capable and equipped then me, please try these 2 quick trials:
1. Deoxid the switches especially the normal/variable one if you noted difference in respective mode
2. This is especially if 45 rpm is ok or better and 33.3 rpm gives most issue ... replace the 10kohm semi-fixes VR1 and VR2 and rescope
Please keep us informed of the progress and fingercrossed.
Cheers.
Richard
Many possibility and I am still struggling a bit with mine but since capacitors had been replaced and having scope to see that you are certainly much more capable and equipped then me, please try these 2 quick trials:
1. Deoxid the switches especially the normal/variable one if you noted difference in respective mode
2. This is especially if 45 rpm is ok or better and 33.3 rpm gives most issue ... replace the 10kohm semi-fixes VR1 and VR2 and rescope
Please keep us informed of the progress and fingercrossed.
Cheers.
Richard
While at it, pls also consider doing solder touchup especially of the various small pcba of switches. Cheers.
http://amp8.com/amp-etc/record/denon/dp-80-3.htm
http://amp8.com/amp-etc/record/denon/dp-80-3.htm
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Congras on fixing yours !
Mine is still NG with 33.3 rpm at 0.8% wow via android rpm app while 45 rpm is fine at 0.02%.
Next replace photosensor ICs 613 and 614 that I see typically replaced and reportedly deteriorates .. and also replacing more transistors that I can get to attempt again.
Groping in the dark a bit without capability to troubleshoot circuitry nor using scope ... fingercrossed 🤞🤞
Cheers.
Mine is still NG with 33.3 rpm at 0.8% wow via android rpm app while 45 rpm is fine at 0.02%.
Next replace photosensor ICs 613 and 614 that I see typically replaced and reportedly deteriorates .. and also replacing more transistors that I can get to attempt again.
Groping in the dark a bit without capability to troubleshoot circuitry nor using scope ... fingercrossed 🤞🤞
Cheers.