xtifan gives step by step:
Now my step by step:
Power On/light On
sometimes the platter get running automatically
press Start,it is running, the tonearm lift down on the record (30) but
stay at the same groove No forward/backward movement possible
Appears that the tonearm advance / offset angle detection is not working.
What happens when you lift / cue the tonearm and use "Start" and "Stop" buttons to move the tonearm?
It does appear as AMOS says, that the switch(s) may have a problem.
From the service manual it appears the front (top) panel control switches are directly attached to the board
Both the "Start" and the "Stop" are 2 step buttons, when you push the "Start" 1/2 way down does it only light 1 left pointing arrow? All the way down lights 2 left pointing arrows? Same for the "Stop"?
ATHERMOS wrote:Hello xactifan,
To check the functionality of the switch first determine what are the PCB foils it is connected to , then manually while running the table make and break (i.e. short and release) that circuit as if you are duplicating the switch. If you are confirmed about switch's fault , (it is a tactile switch) try cleaning with the same fluid you have used before, if a replacement is required, try to source a similar switch from an electronics part shop, or, you might choose to source it from a junk TV or other similar device.
Cheer up again.
EXACTLY...... what AMOS ? /\ said.
Refer to pages 24 of 33 of the pcb for the switch(s) in question and foils where they are connected (soldered?) to.
As the unit starts automatically when you push the "Power" on button, I'd first concentrate on the "Start" switch. Remove (desolder) and install 2 wires as jumpers in their place. Cut the wires and strip the ends. and pull them out the front / top of the tt.
1. Push the "Power" button on. Hopefully nothing will happen only the tonearm LED and the strobe light comes on.
2. Touch one pair together and release and see if she starts and tonearm tracking works and plays;
3. Touch the same one pair together and hold and see if she lifts and starts slow advance;
4. Press "Cue" then touch both pair together and hold and see if she lifts and advances quickly.
These pairs of wires are simulating what is being done with the "Start" switch. So use your other SL-7 as a guide for proper operations.
You can identify which pair is 1/2 and 1/1 using a continuity tester on the switch and make sure to use / touch the correct pair together.
Hopefully it's a faulty "Start" button that's causing all of the problems. If there is any continuity in the "dirty" "Start / Stop" buttons, the circuit is not released and the rest of the logic programmed into the chip cannot proceed.
From your descriptions, I'd concentrate on the "Start" button first as it statistically gets used more. If pushing "Stop" has the desired / correct effect in any of 1-4 above, then you've isolated the problem with your other SL-7.
Fred and then you can try sourcing a replacement button and you'll have 2 working SL-7s.
Music is Everything....Except Predictable....WFUV Fan.