Faulty power switch Yamaha YP-511

[sssboa]

Hi

Just bought Yamaha YP-511. Still waiting for delivery. Seller said power switch does not turn the machine off.

Is it any common problem? Is it repairable or the switch replaceable?

Thx
Andy

 

[sssboa]

This is a long shot but if the snubber cap on the switch is too high value, it can bridge the switch and by pass it. If it was an amateur recap, that's one option.

Oh. Is there a snubber? Will know soon. It's a rotating switch, I kind of doubt there's gonna be a snubber at all.

 

[sssboa]

OK, will see, tho I doubt as it's not serviced at all.

 

[sssboa]

There is a snubber in schematics, 0.033uF 120R. Maybe it's shorted if original?

 

[willyrover]

The switch is actually a microswitch. Same with the speed selector. The lever on top of the deck operates a cog which presses the microswitch.

My YP511 had a bad speed selector switch. After a lot of cleaning (I think I even took the switch apart), it works fine on 33rpm but occasionally acts up still on 45.

 

[sssboa]

The switch is actually a microswitch. Same with the speed selector. The lever on top of the deck operates a cog which presses the microswitch.

My YP511 had a bad speed selector switch. After a lot of cleaning (I think I even took the switch apart), it works fine on 33rpm but occasionally acts up still on 45.

So they are discontinued those microswitches?

Just found a post on another forum. Guy with the same problem in YP-511 replaced the on/off microswitch with new and didn't fix the issue.

I have a funny feeling that it's the guy that just sold me that turntable.

I had similar problem with Sony receiver that had Omron microswitch for power on/off. New microswitch still kind of leaked current, just less, strangely the microswitches tested ok.

 

[willyrover]

I think the original part is discontinued but there are probably substitutes that will fit.

Looking at the power supply schematic, there is not much too it. If the switch isn't cutting power to the table, either the switch is shorted (or someone jumpered it), or as mentioned earlier, the snubber network is shorted.

Snubber is C106 on the board layout at the bottom.

 

[sssboa]

I think the original part is discontinued but there are probably substitutes that will fit.

Looking at the power supply schematic, there is not much too it. If the switch isn't cutting power to the table, either the switch is shorted (or someone jumpered it), or as mentioned earlier, the snubber network is shorted.

Snubber is C106 on the board layout at the bottom.

View attachment 1199612

View attachment 1199611

So turntable arrived, I didn't bother to test it. Straight to business. The Riffa safety cap was cracked, still measured as a cap, with 10% leakage 8ohm esr and capacitance 0.088uF. The resistor is separate on the board, not integrated into the cap like in snubbers of most receivers/amps. The power switch measured good, the other microswitch for speed not that good. They seem to be quite standard where it matters, I ordered the Omron switches as seen in Yamaha CA-1000 or Sony STR-6065, hope will fit. I ordered a safety cap, though I was tempted to use my 0.033uF snubber with built-in 120ohm (really 100ohm) resistor and remove the 100ohm resistor from the board.

PCB is of poor quality, traces come off and components got legs crimped for soldering which does not help. Will have to link components with wires.

 

[sssboa]

Interesting safety cap trivia:
X rated fail to short, Y (or XY) rated fail to open.
There is an X rated safety cap in this turntable so chances are that this was the cause of not turning off.
Y rated are in most if not all snubbers with a resistor included.

 

[sssboa]

The switch is actually a microswitch. Same with the speed selector. The lever on top of the deck operates a cog which presses the microswitch.

My YP511 had a bad speed selector switch. After a lot of cleaning (I think I even took the switch apart), it works fine on 33rpm but occasionally acts up still on 45.

BTW. What kind of light is the strobo light? Is it a bulb which require replacing or LED? It's my first turntable after 30 years.

 

[willyrover]

BTW. What kind of light is the strobo light? Is it a bulb which require replacing or LED? It's my first turntable after 30 years.

It's a neon bulb. 120v with a resistor (R103) in series.

Probably this shape but I've never looked.

 

[willyrover]

Interesting safety cap trivia:
X rated fail to short, Y (or XY) rated fail to open.
There is an X rated safety cap in this turntable so chances are that this was the cause of not turning off.
Y rated are in most if not all snubbers with a resistor included.

In most cases, where having the device not shut down isn't a safety issue, it's better for a snubber placed across a switch (i.e., in SERIES with the transformer primary) to fail to short. This way your switch, while not working, is still protected. If it failed open, you likely wouldn't know there was a problem until your switch failed.

 

[sssboa]

It's a neon bulb. 120v with a resistor (R103) in series.

Probably this shape but I've never looked.

View attachment 1203086

OK, thx, I suppose it has long life span.

 

[sssboa]

In most cases, where having the device not shut down isn't a safety issue, it's better for a snubber placed across a switch (i.e., in SERIES with the transformer primary) to fail to short. This way your switch, while not working, is still protected. If it failed open, you likely wouldn't know there was a problem until your switch failed.

Yeah, but somehow all receivers I know have it to open on failure. I will try to install 440VAC X safety cap by Kemet. Those Rifa seethrough caps have bad reputation.

 

[sssboa]

So the turntable has been refurbished. The cheap $1 standard 16A/250VAC Omron switches fitted well. The original 33/45 speed switch was heavily worn down. I suppose it shouldn't be used while the turntable is on as it has no protection.

On closer examination there are 2 alternative traces on pcb for power switch protection.

 

[Anorak]

First post here

I have just acquired one of these turntables with the same problem. i.e. turntable still rotates (to a lesser degree), and strobe light glows stronger, even when switched off.
Now, I have almost zero knowledge of electronics, but have replaced the 'snubber' capacitor, and it makes no difference. If I remove the capacitor completely, the problem is resolved - is there any harm doing this? Also, the 18 volts measurement between the 'B' and 'E' terminals is about the same with it switched on or off.

Any suggestions?

 

[sssboa]

First post here

I have just acquired one of these turntables with the same problem. i.e. turntable still rotates (to a lesser degree), and strobe light glows stronger, even when switched off.
Now, I have almost zero knowledge of electronics, but have replaced the 'snubber' capacitor, and it makes no difference. If I remove the capacitor completely, the problem is resolved - is there any harm doing this? Also, the 18 volts measurement between the 'B' and 'E' terminals is about the same with it switched on or off.

Any suggestions?

It must be the snubber or power switch or both. I replaced both and problem disappeared. Was the original snubber cracked? Mine was.
If you say you remove the snubber and problem disappears, it must be the snubber that closes the circuit. Buy something rated for your ac voltage and install in exactly same place. I installed Kemet rated for 400VAC.

 

[WaynerN]

250 volt on the cap is not high enough. It should be at least 600 volt, 1000 volt is better. The value of the cap might be a bit too high as well. Should be around .01mfd. This cap is in the circuit to eliminate make/break noise from going thru the system (and then thru your speakers).

 

[sssboa]

250 volt on the cap is not high enough. It should be at least 600 volt, 1000 volt is better. The value of the cap might be a bit too high as well. Should be around .01mfd. This cap is in the circuit to eliminate make/break noise from going thru the system (and then thru your speakers).

The original from the era are rated 250VAC/600VDC.

 

[Anorak]

250 volt on the cap is not high enough. It should be at least 600 volt, 1000 volt is better. The value of the cap might be a bit too high as well. Should be around .01mfd. This cap is in the circuit to eliminate make/break noise from going thru the system (and then thru your speakers).

Thanks for your comments. So are you basically saying that the specification of the original component was wrong, and not fit for purpose?