PINTO CAR CLUB of AMERICA

Shiny is Good! => General Pinto Talk => Topic started by: oldford66 on September 23, 2011, 10:54:42 AM

Title: instrument cluster restore questions
Post by: oldford66 on September 23, 2011, 10:54:42 AM
 Hey everyone, starting to work on my 73 runabout. The first thing Im gonna tacke is the gauge cluster, I have already taken it out and polished the lens, but what I want to know is what are you all using for replacement bulbs [I want the brightest possible]. Also what about paint for your faded needles, or any other advice or tricks. Thanks, Mike
Title: Re: instrument cluster restore questions
Post by: popbumper on September 23, 2011, 01:30:57 PM
Paint for your faded needles - go to a hobby outlet and get yourself some Testor's model paint (orange), I believe the proper name would be "insignia orange". Very easy to do, I did the needles on my '57 Chevy gauges when I had it and they turned out very nice.
 
The bulbs used for stock application are spefically rated for the voltage and the socket type - not sure what would work better, but brighter = hotter, and that may not be a good idea inside ogf the housing. Alternatively, LEDS could be used, don't know if they have one that is properly voltage rated and has an appropriate socket.
 
Chris
Title: Re: instrument cluster restore questions
Post by: JohnW on September 23, 2011, 09:20:00 PM
And one issue with LEDs - if the car is expecting a certain amount of draw it won't get it with them.  I don't think this is an issue with dash lights, but I know it is with directionals. 
Title: Re: instrument cluster restore questions
Post by: oldford66 on September 24, 2011, 03:31:22 PM
Thanks for the input, im gonna check out that paint for sure and LEDs might be the way to go. I will let you know how it works out. By the way are all pinto clusters wired with a circuit board style or is it just a 73?                                   Thanks, Mike
Title: Re: instrument cluster restore questions
Post by: JohnW on September 24, 2011, 06:56:32 PM
One other thing, you can't use a dimmer with them.  There will only be one brightness setting.
Title: Re: instrument cluster restore questions
Post by: ToniJ1960 on September 24, 2011, 11:35:47 PM
 
 If you can get LED`s that come in that base.Otherwise you would have to wire them in somehow,dont forget current limiting resistors,and the polarity.

 Why wont the dimmer work with them? If theyre wired in to the circuit the same place as the bulbs,they should vary with the dimmer I would think,since its probably just a variable resistor for the dimmer on these old cars.

 For current limiting resistors use about 500 ohms (standard resistance values 510 or 560 ohm) should give about 20 ma per LED,if one resistor per LED.  Maybe 680 ohms if youre using 1/4 watt resistors. 10% tolerance is fine 5% if you have them anyway.
Title: Re: instrument cluster restore questions
Post by: JohnW on September 25, 2011, 11:43:21 AM

 If you can get LED`s that come in that base.Otherwise you would have to wire them in somehow,dont forget current limiting resistors,and the polarity.

 Why wont the dimmer work with them? If theyre wired in to the circuit the same place as the bulbs,they should vary with the dimmer I would think,since its probably just a variable resistor for the dimmer on these old cars.

 For current limiting resistors use about 500 ohms (standard resistance values 510 or 560 ohm) should give about 20 ma per LED,if one resistor per LED.  Maybe 680 ohms if youre using 1/4 watt resistors. 10% tolerance is fine 5% if you have them anyway.
I've read on a Camaro/Firebird site that when wiring them up you can no longer dim them.  Even if you do make it work, LEDs don't like to operate that way.
Title: Re: instrument cluster restore questions
Post by: ToniJ1960 on September 26, 2011, 12:29:47 AM
 It could be they were talking about some kind of system? LED`s in general will vary in brightness with change in current through them.

 I have about 40 years experience in electronics,and an LED is basically a semiconductor,similar to a diode so the name light emitting diode. They have a forward voltage of about 1.6 to 1.7 volts,so you subtract that voltage from your source voltage,and then just use ohms law to select the dropping resistance to get the current you want. Its basically I=e/r I is the symbol used for current. So 12 volts,and 1000 ohms would give you 12 milliamps. And since auto voltage is typically about 13.8 12 volts is a good starting point with the 1.7 volts of the LED figured in.

  Maybe those cars used a PWM dimmer? I know my Lincoln does.

 The main thing is,even with a handful of LED`s wired in,they wont draw enough current to drop much voltage across the dimmer resistance,so either you would have to keep one or two filament bulbs in the circuit, add a load resistance in the circuit,or change the dimmer potentiometer to a higher resistance one. It will do no harm to an LED to change its brightness by vrying the current through it,unless you allow to much current to it and burn it out.