richardojohnson Messages: 32 Registered: May 2015 Location: goodland kansas
Member
I want to build a circuit for led's to replace the ge bulbs .I have rewired the 250 with a great switch on the back that does polarity and off and on works super well.It was a chore rebuilding this amp start to finish.It has such sweet tone and the ability to make such different types of tone.I want to drill into the blue lens and insert led's my switches are non functional with the blue squares barely sticking out.I have a four 12 t,n,r.I have two of the 250 heads and a 250 bass head I want to led all three.If someone could shoot me a schematic parts list I'm sure it should be simple.Non of my electronic library covers any led stuff.Thanks everyone for all the help and contributions to this sight richardojohnson
Even if the original switches are dead, you could just keep the internal light bulbs hooked up and the amp would look original when the power was turned on.
Leds are current sensitive devices, so they need a resistor in series with the power supply line. The resistor value will depend on the power supply voltage and the current draw of the led.
They are also polarity sensitive, so they will only light up when hooked up with the correct polarity.
richardojohnson Messages: 32 Registered: May 2015 Location: goodland kansas
Member
when I bought these amps all of the switch parts were super glued together in the on position
That's why I configured polarity and off on in one switch on the back plate.I can drill a hole in the blue lens and mount an led to light the switch when on .Really simple for some people.I just need some ideas how too.Im so deep in repairing these amps now .Thank you for your reply
Well, like I said, if you leave the original switches in place and keep the original wiring to their internal pilot lamps as is, you can just remove the switch wiring and re-route it to the new back panel switch. That way the original switches will light up just like they did originally.
If you must use an led, all you need to do is to buy the led that you want to use and a resistor to reduce the power supply voltage going to it. The led will have two leads. One will be longer than the other. The positive voltage from the power supply will connect to the longer lead through the limiter resistor. The second lead will connect to the power supply ground.
As for the value of the resistor, just guessing here, I'd try a 4700 ohm 1/2 watt resistor.
richardojohnson Messages: 32 Registered: May 2015 Location: goodland kansas
Member
Thank you for your help .I got it pretty much figured out.My only issue is I still need one blue
lens and I think I can mold that out of some thin abs with heat etc.Looking forward to the next stage.I got all three working really well,effects all working.I am amazed. I have a Kustom coupe 72 with the coupe 4x12 slant .I have gigged this setup and I never thought I could find another amp I liked as well .The 250 is now my favorite. Thank you for all the help