Hi guys, I have owned this turntable for a long time and it has always worked well; For some months now, the touch keys have only been working if I slightly moisten my fingers, but if I have dry skin, the controls are not responsive or respond after many insistences.
I have seen the service manual but I do not understand where to intervene to solve this silly problem.
Anyone have a solution?
Thank you very much.
I have seen the service manual but I do not understand where to intervene to solve this silly problem.
Anyone have a solution?
Thank you very much.
Try to touch not the buttons but the wires that connect to them. Does it work ? If so, I would look at the paint, perhaps it has worn out and is no longer conducting well.
You could disassemble the buttons and try to clean them, there could be some sweat contamination making permanent contact interfering.
You could disassemble the buttons and try to clean them, there could be some sweat contamination making permanent contact interfering.
Hallo, thanks for the solution, I overhauled and performed an excellent cleaning of the whole turntable including the keys taking advantage of a complete recap; so I feel that the keys are clean; I can try to touch the wires and see how the keys react.
Is it possible to replace some resistance of different ohmic value on the circuit to make the keys more sensitive to the touch of the fingers?
Hi Pitrus,
Possibly, but you probably don't want to do that. It took a lot of work for them to get the sensitivity right with those.
Two main methods for a touch button.
1.) Sensing induced voltage from your body
2.) Detuning an oscillator or reducing the amount of RF another circuit picks up
In either case, you can easily mess things up. I would concentrate on what may have changed rather than modifying something that used to work quite well.
When you cleaned the turntable, did you increase any capacitor values? Did you unplug the harness from the buttons and plug it back in? That would break any oxide formation on the pins.
-Chris
Possibly, but you probably don't want to do that. It took a lot of work for them to get the sensitivity right with those.
Two main methods for a touch button.
1.) Sensing induced voltage from your body
2.) Detuning an oscillator or reducing the amount of RF another circuit picks up
In either case, you can easily mess things up. I would concentrate on what may have changed rather than modifying something that used to work quite well.
When you cleaned the turntable, did you increase any capacitor values? Did you unplug the harness from the buttons and plug it back in? That would break any oxide formation on the pins.
-Chris
@anatech tThanks for the reply
I purchased electrolytic capacitors with the same capacity but some with increased voltage to obtain the same distance as the pins to be plugged into the pcb.
Several original electrolytic capacitors had impaired capacities.
I only removed the fastons that can be seen from the photo but I have not unsoldered any wire ... I wanted to have the frame devoid of everything to carry out a thorough cleaning.
https://i.postimg.cc/cCb2s9SG/P1010246.jpg
https://i.postimg.cc/8PfnRbGs/P1010263.jpg
I purchased electrolytic capacitors with the same capacity but some with increased voltage to obtain the same distance as the pins to be plugged into the pcb.
Several original electrolytic capacitors had impaired capacities.
I only removed the fastons that can be seen from the photo but I have not unsoldered any wire ... I wanted to have the frame devoid of everything to carry out a thorough cleaning.
https://i.postimg.cc/cCb2s9SG/P1010246.jpg
https://i.postimg.cc/8PfnRbGs/P1010263.jpg
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Hi Pitrus,
Work the push on connectors on and off to clean them, hopefully that will get you going again. makes sure the grounding screws on the back are making good contact!
-Chris
Excellent! That's the way to do that.
Work the push on connectors on and off to clean them, hopefully that will get you going again. makes sure the grounding screws on the back are making good contact!
-Chris
Well, I hope to get some free time this weekend to try the indicated solutions.
I will keep the 3ad updated as soon as there is news.
I have the same table and I find that they are almost to sensitive, sometimes when I'm placing a record on the platter I touch the buttons, it seems to always be the 45 button, don't even own any 45's.
I think it's a fantastic table, a real under rated masterpiece from JVC.
BillWojo
I think it's a fantastic table, a real under rated masterpiece from JVC.
BillWojo
Hi guys, not very positive news, in these days I picked up the engine again, I verified that the problem still exists after many months of stop and it has been confirmed; I started to check the conductivity of the ground of the contacts and everything was ok clean and screwed the 45 rpm button back on. and tried again.
Now I don't know for what mystery 33 rpm and stop are quite reactive and yet I have not disassembled the buttons, but the 45 rpm speed is not activated after the disassembly of the button ..... I'm going crazy!
Now I don't know for what mystery 33 rpm and stop are quite reactive and yet I have not disassembled the buttons, but the 45 rpm speed is not activated after the disassembly of the button ..... I'm going crazy!