Radio illumination, need a little help from someone with a working SC80x radio please

Problem is that *all* the bulbs are out, in fact they've never been on since we have owned the car but I thought I'd finally get round to it whilst doing a few other illumination bulbs.

I've been round this with a meter and can confirm that none of the radio illumination bulbs have blown, continuity exists from the power board of the radio down to the bulbs themselves and I'm pretty confident that it's the voltage regulator on the power supply PCB that's at fault.

However without a working one, I'd like to confirm the component first.

It's the 3 pin TO220 package on the board behind the heatsink that also carries what appear to be the IC amps.

The component is marked as DI 764 and then beneath 246 with a logo that I can't locate, nor can I identify the part directly.

On the left pin is 12v, centre is ground and right pin goes to the DIM pin on the connector and that finds its way to the bulbs.

That's a pretty standard pin out for a regulator and certainly appears to match all suspects since on mine there's no output from the output pin.

Now I did come across a link that suggested that the bulbs were powered by some odd voltage, 6.5 or thereabouts. I can get a 6v regulator which won't make any difference but I'd really like to know the actual measured voltage or confirmation of the part if anyone feels like popping their radio out and measuring this for me?

Please? :)

David.

Reply to
David Taylor
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The voltage to the lights work a bit funny. The rheostat for the illumination of the instrumentpanel also controls how much light you have in the radio. On the large 14 pin connector on the back of the radio, pin 11 (black wire) is ground for the lights and pin 10 (pink) is the positive signal from the rheostat.

Check you have correct power on those pins.

Niels

Reply to
Niels Bengaard

Thanks, I'll check that. I was looking at this diagram

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and it seems that the belief that pink is -ve is possibly because the lights weren't on at the time of test?

David.

Reply to
David Taylor

I have been looking at a wiring diagram from Volvo from a 1995 Volvo 850. If you cant get it to work I can scan it, so you can have a look yourself.

Niels

Reply to
Niels Bengaard

Sorted with that info thanks. I have a car phone kit with telmute interface lead and that brings "illumination" out on the wrong pins and since I couldn't find anything on the pink wire didn't think to check that one.

I went so far into the radio by this time that all I was finding was power to the one side of the voltage regulator and assumed that it was faulty.

Cheers, have an eBeer!

David.

Reply to
David Taylor

Are you sure that doesn't say D1764? TO-220?

Industry Number : D1764 NTE Device Number: NTE2332 NPN,SI DARL W/INT ZENER&DAMPER,TO-220

Reply to
Myron Samila

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just in case this is the IC.

Reply to
Myron Samila

Further to this, the reason why I didn't think of this before is that we bought the car about 5 years ago in the summer (light evenings till about 10pm) and then had the car phone kit installed almost straight away. I don't think i've ever seen the radio illuminated until this evening.

:)

David.

Reply to
David Taylor

It does and I'm sure I tried D1764 but just couldn't find anything. Given that it's coupled to the dimmer circuit, I was wondering if it was an darlington output transistor.

Irrelevant now anyway but thanks. As of yesterday, I knew nothing about the Volvo radio illumination, amazing what you can find out within a day, I now know more about this than I intended to. :)

David.

Reply to
David Taylor

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