Hello,
I have bought this well used SP-15 some time ago from the famous auction site. It was in a non-working condition, with almost all electrolytic capacitors being either leaky or out-of-spec. There was a extension cord coming out of it (never a good sign) which was connected to the Start/Stop button. The reason behind it was revealed when I replaced all the capacitors and got the voltages right and the turntable spinning. As long as the Start/Stop button was pressed down the turntable was spinning and when you leave the button it was stopping. It turned out to be a simple logic issue due to a faulty transistor. After these repairs, I used this turntable for almost 8 months without any problems.
The turntable stopped spinning in between a record change. One second everything was normal, next second it was not spinning anymore. I opened it up again and started checking. The Trouble Shooting section in the service manual starts with the voltages and moves on to the brake logic and ends up with blaming IC301 to IC3014 for the possible cause. This is where I got confused.
As far as I can see, my voltages are correct. The brake mechanism is working, but when it comes to pin-9 on DN860, I see no change between Start and Stop voltage readings. On the scope screen the only state I can observe belongs to the Stop case, although all other voltage readings follow the status changes as indicated in the service manual between Start and Stop conditions.
Observing the Start/Stop changes in other pins but not observing any changes on pins 8 & 9 tells me that this DN860 is faulty. Is my logic correct or is there something else which may cause this IC to malfunction? Anybody experienced with the caprices of SP-15s?
Best,
Dirk
I have bought this well used SP-15 some time ago from the famous auction site. It was in a non-working condition, with almost all electrolytic capacitors being either leaky or out-of-spec. There was a extension cord coming out of it (never a good sign) which was connected to the Start/Stop button. The reason behind it was revealed when I replaced all the capacitors and got the voltages right and the turntable spinning. As long as the Start/Stop button was pressed down the turntable was spinning and when you leave the button it was stopping. It turned out to be a simple logic issue due to a faulty transistor. After these repairs, I used this turntable for almost 8 months without any problems.
The turntable stopped spinning in between a record change. One second everything was normal, next second it was not spinning anymore. I opened it up again and started checking. The Trouble Shooting section in the service manual starts with the voltages and moves on to the brake logic and ends up with blaming IC301 to IC3014 for the possible cause. This is where I got confused.
As far as I can see, my voltages are correct. The brake mechanism is working, but when it comes to pin-9 on DN860, I see no change between Start and Stop voltage readings. On the scope screen the only state I can observe belongs to the Stop case, although all other voltage readings follow the status changes as indicated in the service manual between Start and Stop conditions.
Observing the Start/Stop changes in other pins but not observing any changes on pins 8 & 9 tells me that this DN860 is faulty. Is my logic correct or is there something else which may cause this IC to malfunction? Anybody experienced with the caprices of SP-15s?
Best,
Dirk
Attachments
If start/stop signal transitions are correct then yes, seems likely the issue is the DN860, though it's rare for it to fail.
Start/Stop SP-15
I recently bought a SDP-15 with some issues. Speed is pretty good. About 0,5% off. I measured it with an app on my phone. Someone already resoldered the 3 points on power supply board doing a horrible job at it but it seems to have done the job.
It too has the Start/Stop button not working. It is equipped with fader start. If I connect the 2 fader start wires the table spins. If I take them apart the table stops. If I press the Start/Stop button it turns, as soon as I let go of the button it stops. Everything is clean. You mentioned a transistor being faulty in yours. Would you please state which one and if it is a part that is easily available? I am not an electronic expert by far.
Also most of the time my '-' function does not work. The reset and '+' functions always work. If I press the '-' it will do either nothing or it will show '+0.1' and stay there. Sometimes if I hold the '-' button down and toggle the 'On-Off' swith several times all of a sudden the function '-' works correctly again. Untill I switch off the unit. If I then turn it on again the issue returns. Any ideas other then to replace the MN6042? All help is greatly appreciated.
I recently bought a SDP-15 with some issues. Speed is pretty good. About 0,5% off. I measured it with an app on my phone. Someone already resoldered the 3 points on power supply board doing a horrible job at it but it seems to have done the job.
It too has the Start/Stop button not working. It is equipped with fader start. If I connect the 2 fader start wires the table spins. If I take them apart the table stops. If I press the Start/Stop button it turns, as soon as I let go of the button it stops. Everything is clean. You mentioned a transistor being faulty in yours. Would you please state which one and if it is a part that is easily available? I am not an electronic expert by far.
Also most of the time my '-' function does not work. The reset and '+' functions always work. If I press the '-' it will do either nothing or it will show '+0.1' and stay there. Sometimes if I hold the '-' button down and toggle the 'On-Off' swith several times all of a sudden the function '-' works correctly again. Untill I switch off the unit. If I then turn it on again the issue returns. Any ideas other then to replace the MN6042? All help is greatly appreciated.
Thank you JP. As soon as I have solved the Start/Stop issue I guess I need to purchase the upgraded 6042 then. I hope Fidelis ships to Europe.
I do. You can also bypass it if you don’t need/want variable pitch. Maybe should do that as part of troubleshooting your speed issue.