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Is your unobtainium power switch worth $5 and an hour or so of your time?

Just finished performing this mod on my Realistic STA-85. Attached the Triac to an existing hole in heat sink. Luckily I was able to remove the alps portion of the switch and clean and reassemble it without to much difficulty. Running it through it paces now but seems to be fixed with no more flickering lights on power-up. Used Triac Q4025J6TP and 100 ohm gate resistor.
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EngineerNate said:
Is Euro 240V like US 240V where it's two hots 180* out of phase?
Click to expand...
VERY OLD thread i know...but..this important.
NO - UK & Euro 220/240v is not generated from 2 x 110/120v.
It is either a single 'hot' 220/240 ..plus gnd.
Or...a live 240v..and a neutral from the transformer..with gnd being seperate again...ie. 3wires.
Which of these 2 methods are used between regions is pretty random ....urban areas tend to have the 3 wire option, with L,N & gnd .....and rural areas the 2 wire option..L & gnd...mainly because its cheaper and easier to run the wire over the greater distances involved
 
offshoredual said:
urban areas tend to have the 3 wire option, with L,N & gnd .....and rural areas the 2 wire option..L & gnd.
Click to expand...
In AU we have Active, Neutral and protective earth.
The Neutral being the return wire for the Active so should be considered as live.
The protective earth is typically connected to item chassis. The term GND can cause confusion with the circuit GND.
 
kwayde said:
I have a little time where I can finally get back to rebuilding my Pioneer SX-750. I just finished working on the tone board and since I had access to the power switch I thought now is the time to put a triac in (alternistor on my case).

I did a lot of searching in this thread and after comparing some diagrams I finally found what I needed to do. I made up a diagram for the SX-750.

If you're going to use a triac, keep the snubber cap. If using an alternistor, remove it.

I was able to mount the alternistor to the chassis just in front of the transformer.

View attachment 3265450

View attachment 3156145
Click to expand...
Shouldn't the power switch get power from the unswitched side instead of switched side ,the way it's drawn in your schematic ? Seems like it wouldn't work the way it's drawn.
 
audiomaniac2 said:
Shouldn't the power switch get power from the unswitched side instead of switched side ,the way it's drawn in your schematic ? Seems like it wouldn't work the way it's drawn.
Click to expand...
I was thinking that to, but went back to original post, and realized I was wrong, and the switch doesn't actually switch AC, but connects the gate of the triac to the M2 side with a resistor, and the triac sends the AC to the transformer.
1725115573382.png
 
sregor said:
I was thinking that to, but went back to original post, and realized I was wrong, and the switch doesn't actually switch AC, but connects the gate of the triac to the M2 side with a resistor, and the triac sends the AC to the transformer.
View attachment 3286596
Click to expand...
sregor said:
I was thinking that to, but went back to original post, and realized I was wrong, and the switch doesn't actually switch AC, but connects the gate of the triac to the M2 side with a resistor, and the triac sends the AC to the transformer.
View attachment 3286596
Click to expand...
I get it . He is pulling the neutral through the transformer and feeding it to the gate through the switch and resistor.
 
kwayde said:
I have a little time where I can finally get back to rebuilding my Pioneer SX-750. I just finished working on the tone board and since I had access to the power switch I thought now is the time to put a triac in (alternistor on my case).

I did a lot of searching in this thread and after comparing some diagrams I finally found what I needed to do. I made up a diagram for the SX-750.

If you're going to use a triac, keep the snubber cap. If using an alternistor, remove it.

I was able to mount the alternistor to the chassis just in front of the transformer.

View attachment 3265450

View attachment 3156145
Click to expand...
Rather difficult to see the mfg # on this photo.

 
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