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I am Getting ready to Do A bulb replacement on my century'* radio 4 bulbs has burned out so I am upgrading all bulbs to led I have searched the net for this radio for replacing the bulb to avail I found jack so I have done my own Investigating and tore my radio down to see what bulbs was needed to do this process now the bulbs are filtered as well as the climate control so since the bulb has the color filter we can choose to change back light color at this time I have already done the climate control and Gauge cluster with blue And used a color filter sheet to change the radio clock & odometer PRND321 indicator red instead of green these displays has the color either in the displays or the the lens like the clock on radio the easiest way to change them is a color filter sheet but being green it does not give a lot of good color combo'* when filtering but the red works great so red is what I set in on cause I did not want blue back light with green odometer so that is how I came upon this choice. The picture is of the radio face of course and the location of the bulbs there are 16 bulbs on this radio and they are smaller than the climate control so they will be a bit more difficult to do but I am going at it. I got new bulbs coming and will update as things unfold and with finished product NOTE the climate control match'* the dash but for some reason it will not show in pics right there is not hot cold spot like pic seems to show
I'll guess the reason you haven't found much on the retrofitting the radio bulbs is because of the difficulty in doing it correctly by electrical theory. They need to be grouped in clusters of 3 or 4 and wired in series. However, I did it in parallel like the bulbs anyway, but added a lot of resistance inline, prior to the radio.I replaced all 14 of of my 3mm bulbs (8 of 14 were burned out). This radio face has 2 voltage regulators that darken 6 of the bulbs (where 5 of the 6 still worked), which I jumpered out to make all the lighting the same brightness. I left them in parallel (bad idea, Kirchhoff'* law), with 660 ohms of resistance in the wiring harness to drop the 12 volts. They look good with even brightness, we'll see if and when they start to fail. I am running them considerably darker than with their intended full voltage because of the 660 ohms of resistance, so I may get quite a bit of life out of them (2.5 years now, no problems).
I used just cheap, 3mm LEDs I got from Ebay. I originally tried blue ones, but they were too blue. I went with clear ones and put the little blue/green bulb 'condoms' back on them. It is still more slightly blue than original, as the LEDs give a pure, white light compared to the incandescent.
I'll guess the reason you haven't found much on the retrofitting the radio bulbs is because of the difficulty in doing it correctly by electrical theory. They need to be grouped in clusters of 3 or 4 and wired in series. However, I did it in parallel like the bulbs anyway, but added a lot of resistance inline, prior to the radio.
I replaced all 14 of of my 3mm bulbs (8 of 14 were burned out). This radio face has 2 voltage regulators that darken 6 of the bulbs (where 5 of the 6 still worked), which I jumpered out to make all the lighting the same brightness. I left them in parallel (bad idea, Kirchhoff'* law), with 660 ohms of resistance in the wiring harness to drop the 12 volts. They look good with even brightness, we'll see if and when they start to fail. I am running them considerably darker than with their intended full voltage because of the 660 ohms of resistance, so I may get quite a bit of life out of them (2.5 years now, no problems).
Since you said you have 16 bulbs, I would try 600 ohms at 1/2 watt rating inline to dim and protect yours. Mine is still plenty bright in the car.
I used just cheap, 3mm LEDs I got from Ebay. I originally tried blue ones, but they were too blue. I went with clear ones and put the little blue/green bulb 'condoms' back on them. It is still more slightly blue than original, as the LEDs give a pure, white light compared to the incandescent. It is still a little more blue than the picture suggests.
That'* awesome then. When I was looking around, all I could find were ones with external resistors. I even bought some, not realizing the resistor was attached to the lead.
I knew it was easy enough for to have resistance in the die with the diode.
Yeah that was my first worry when I started looking into this cause I new the traces being on back side of the board I would have to use a dome type Led and the ones I found before and the ones I have they had to have a resistor in line which made that A problem space wise but I thought Well I would just use a buck converter on Illumination circuit coming into radio but run across the 12 v dc leds. I really wanted to use SMD Leds but again the traces are on wrong side of the board for that without doing a crap load of prep work to move a contact point to that side of the board so the dome 12 v dc leds for the win
Really nice work!
I would like a link to the LEDs that you are using. I'll use them in the future, if they perform well for you long term. Don't have any projects on the horizon at this time, but the 3mm incandescents are lousy, IMHO. Nothing but outdated technology now that is a commodity for the lowest bidder.
02-01-2019, 11:21 PM
2001 Buick Century Radio Bulb Replacement
