Scott 380R triac mod help needed

[RundownRob]

I have a Scott 380R with a power switch that was dirty and caused the lights to flicker. I cleaned it and it is working fine, but I have read that it will not stay that way. I used the triac mod on a Kenwood KR2090 and it worked great. I want to do the same with the 380R, but I am having trouble determining which wires bring AC to the switch and which go out the the power supply.

The Kenwood was simple. I could trace the incoming wire and then follow the outgoing wire from the switch to the PS. The Scott has two red wires and two orange wires on the switch. The orange are on the top and red on the bottom. Both pair of wires seem to come from a bundle wires from the AC out on the back. Some of that bundle then goes to the power supply. There is a both red and an orange there among other colors.

How do I determine which wires are which? Thanks for helping a beginner.

Rob

 

[txturbo]

Your switch will need to be replaced.

See this

 

[RundownRob]

Thank you Txturbo. I had read through that tread before posting. The part numbers for the power switch between the 380R and 390R are different in the service manual. Mine does not look like the old one from your 390R in the photo you posted. Mine is a beige rectangle with tabs on top and bottom. If I were able to use the new switch you linked to, I would still like to know which wire are incoming to the switch and which go out to the PS.

 

[txturbo]

Do you have DVM? You could just measure Ohms from the plug to the switch.

 

[RundownRob]

I do have a meter, but I am not sure what I am doing. I would appreciate a little more direction. I assume this is with the unit plugged into AC and the switch turned off??? Where would I place the probes?

 

[txturbo]

You should have the unit unplugged with the power switch off. Put the meter on ohm mode and place one of the test probes on the plug. Put the other probe on the different wires on the power switch to see which one is matching the plug.

 

[RundownRob]

I have done the ohm test. Thank you for the help. One of the red wires comes from the hot side of the plug and the switch connects it to the other red wire going out. The orange comes from the neutral side of the plug and the switch connects it to the other orange wire. Is it common to have both the hot and neutral inside the switch? I was assuming only the hot would be switched. That is what I am used to with light switches in house wiring.

 

[RundownRob]

Here is a photo of the switch for future reference. This is with the unit upside down and the bottom cover removed. That is the only way to access the switch.

 

[montecarlossfan]

I have a 380R that has the same issue, I took the switch apart , cleaned it and used it a bit and haven't touched it, I haven't gotten around to restoring the unit yet but I've had it for at least 10 years...that's how you know you have too many units. I had a Solid state relay I bought for like 5 bucks used at the time..and was going to use it in this unit...but the triac mod is essentially the same thing with a much smaller footprint. I remember that they were switching the hot and neutral for whatever reason.

 

[montecarlossfan]

IEC cord (like your standard pc cord ) which is IIRC on the back of this, If you have a polarized cord, the smaller of the prongs is the "hot", continuity check a cord and match it to the connector and follow it through the unit, then you can essentially connect the neutral at the switch to be permanent(solder and wire nutted and taped to be safe or use a proper splice or pull said wire back and permanently tie it in according to schematic). Now you only have to worry about the hot .

In the schematic above it looks like hot is on the left(fuse) so look for a 1.5M ohm to ground and that is your neutral...safety just in case hot and neutral get flipped somehow.

 

[RundownRob]

I added the triac to the hot side and have been using it daily. I have had no issues to far. I will post back if I do.