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1966 Dodge Charger Question about the dash-board lights Power supply


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I had a gentleman come by the shop with a small power supply that is used for lighting the dash-board lights. He is wanting me to try and repair it, but I really have no idea how it works. I see that there is a transistor, as well as a small transformer, and a capacitor. Does anyone know of these things? Is there any kind of a work-around for this circuit? He said that he has completely restored the entire car except for this part. He also told me that this was only used in the 1966 and 1967 Chrysler products.

I've got the mans number, so I'll be sure and let him know of any answers. Thank you for any insight you can give.

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its called eletroluminescent lighting they still use it today. I did see someone the computer that did repair these clusters, but for the life of me i cant find it.

we usually send them out to get repaired due to the complex nature of the system. My understanding is it works somewhat like a fluorescent lamp.

The new ones today use pulse width modulation output to light them using computers.

I will try to see if i can find any info for you.

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Thank you Melvin. The circuit actually looks pretty simple. There is a power transistor, 2 resistors, a transformer, as well as a 330VAC capacitor in this pack. My gut feeling is that it has a bad capacitor, so I am in the process of finding one now. The power transistor might be a different story. My profession is electronics repair, but so far, I couldn't find any cross or info on the part. I'm sure it has to be out there, I just haven't found it yet.

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Note: The following is a June-July, December 1999 and September 2004 of email messages on the IML on electroluminescent dash lighting problems and repairs:

Anyone know who replaces the luminescent coating on the instruments? What shop rebuilds them?

If you mean the coating on the once-red pointers, that can be done by the DIY'er. The tricky part is getting the gauges out of the dash (which you have to do to send them off to be rebuilt anyway....)

All you need is a can of electroluminescent spray paint (also called "safety paint"), available at most home-improvement, hardware or hobby shops. Use the red (or "red-orange" as some are labeled) for Imperials. Be sure to shake the can up REALLY well before spraying.

Slip a small piece of newspaper, doubled over, under the needle, and shoot it with a few, quick shots. DON'T spray too much on all at once! Just a quick whisk every ten minutes or so, slowly building up the paint layer until the needle is back to it's former, glorious red color.

I did this to a '63 Crown that I sold just this past summer, and after 13-years in the harsh Colorado sun (car was never garaged or covered), those needles still looked as good as new.

Actually, I've used this same paint to restore faded needles on many late-50s to early-70s dashes, E/L and non-E/L, though the orange (or orange-yellow) shade is more correct.

Mark

'52 Chrysler Imperial 2-door hardtop

How can I fix my Imperial's electroluminescent lighting power supply?

Subject: IML: Blew out my '63's dash. DUH!

Date: Fri, 18 Jun 1999 11:25:03 -0600

From: Mark Brauer, mark.brauer@lmco.com

Well, folks, it wasn't easy, but I managed to smoke my '63's E/L system. Stupid, STOOPID!

But we shall not dwell on the past....

At present, what I have is a power pack with a blown 2 ohm, 5- or 10-watt resistor, and a 3-way wire that used to be a transistor. The resistor's no problem, they're easy to find, and if I pay a dollar for it I've paid too much. But that transistor - does anyone know what to replace it with now? It's a Bendix number PS 26, and it's not in any of the semiconductor manuals I have (I'm sure it's germanium), so I don't know what the specifications for this little baby are. I don't even know if it's PNP or NPN!

Perhaps if someone out there knows the operating parameters in a properly working system I can see if I can come up with a silicon replacement. After all, it seems to be a simple switching circuit.

How about the power packs used in the '66-'67 Dodge Chargers? I've heard of people using these in '60 - '63 Chryslers and Imperials. (Heard it makes 'em brighter...!) I would think they'd have a silicon transistor by then, but maybe not....

I've read through the Tips and Resources page on this subject, and while it mentions replacing the capacitor (always a good idea to replace those waxy capacitors, where ever they're found....), it doesn't get into the real nuts 'n bolts 'n transistors 'n such.

Any help would be greatly appreciated. (Brain's thinkin' - "Maybe I could get a vibrator from an old car radio to work for this....")

Mark

'52 Chrysler Imperial 2-door hardtop

'63 Imperial Crown 4-door hardtop

Subject: Re: Transistor substitution for a '63's dash.

Date: Tue, 22 Jun 1999 10:20:00 -0700

From: Dick Benjamin, bondotmec@ez2.net

Hi Mark;

It looks to me that the best choice for a transistor would be an MJ2955, available at Radio Shack as their number 276-2043, $1.99 (!)

You'll have to change the bias resistor to 120 ohms (your "R2") in the circuit diagram, this should make it hammer pretty hard. I'd just fire it up and let it run for a few hours to make sure it is not dissipating too much heat, but it should be fine. If you think it is running a little hot, you could try reducing the forward bias resistor, maybe to 100 ohms or so, but if you go much lower, the chopper will have trouble starting in cold weather.

Dick Benjamin

bondotmec@dte.net

Subject: Re: [iML: Blew out my 63s dash. DUH!]

Date: 18 Jun 99 23:09:35 EDT

From: IMPERIAL1USA@netscape.net

To Mark Brauer,

I am an experienced electronics technician of 9 years. I have played with these power supplies for Chrysler dashboard lighting for over 7 years now. It started off MANY years ago with a friend who has a few 300 Letter cars (59, 50, 61) and the dashboard lights would fade to nothing after about 10 to 20 minutes.

With help from co-workers we learned how to correctly repair these devices. A paper capacitor MUST be used, not an electrolytic type. As far as we know, paper caps. are no longer made in this country. Must be imported, and are hard to find. The transistors are available, as well as most of the original electronic components from electronic component catalogs and manufacturing companies.

I no longer work directly in bench repair, I work in RF engineering; BUT we have successfully restored about a dozen of these units for $35.00 a piece. Have been put into Coronets, Imperials, Chargers, and 300's. Some repairs only lasted a few weeks and had to be repaired again at no additional cost. Eventually everyone's dash lights worked again and all were satisfied customers.

The device is a basic power inverter - converts 12VDC into 225-270 VAC with very low current. We never had one blow up or short out after being repaired OR do any damage to anyone's electrical system...Hope this helps

Dave Brown (TWO 66 LeBarons)

Subject: Re: [Re: IML: RE: Blew out my 63s dash. DUH!]

Date: 20 Jun 99 22:28:15 EDT

From: IMPERIAL1USA@netscape.net

The capacitor is usually the culprit in these power supplies for dash lighting...it does break down and wear out with age...the analogy I use is...How many 1960 to 1963 TV sets do you still see in use in peoples homes today? Hopefully none....

Moisture problems that were mentioned are definitely not a good thing for ANY electronics and the parts will change their tolerances with age and heat conditions. It has been my experience with the 12 units I have helped in repairing that all parts in it are obtainable NEW today...

As far as taking a power unit from a modern car...the voltage and current rating would have to be known and the connector would have to mate up OR it would have to be hard wired. One final note from my experience...ALL (and I do mean ALL) Chrysler cars that used electroluminescent dash lighting used the same interchangeable power supply (including Chargers, Coronets, Imperials, 300's and I have not seen them but heard some Chryslers did too).

At Carlisle and Hershey NOS units are being sold for $100 to $200!!! Restoration shops in Hemmings will charge from $50.00 & up to rebuild these things...all parts inside total less than $20.00 to $25.00...and all parts would never need to be changed...the most frequent problem I have encountered is that dash lights work and then fade away after a very short time of being turned on, due to failure of parts in power supply...

Good Luck to all from imperial1usa@netscape.net

Subject: IML: E/L Power Pack EPILOGUE

Date: Fri, 16 Jul 1999 13:05:26 -0600

From: Mark Brauer, mark.brauer@lmco.com

I know you've all been holding your collective breaths, waiting for the exciting conclusion to the tale of woe I begat when I blew out my '63 Imperial's electroluminescent lighting. If you'll recall from our last episode, Dick Benjamin had just suggested to me a modern replacement for the germanium transistor I had popped. He had also provided me with secret instructions on re-biasing the circuit to accommodate the new, silicon wonder. Now, start breathin' again 'cause here are the results:

Works good.

Derned good. In fact, that dash never looked so good, at least not as long as I've owned that car, which was just over 11 years. Output was 190 volts A.C. And the transistor and assembly stayed cool, baby, cool....

I went ahead and took some voltage measurements around the transistor while it was operating in the car, and have included them with the JPEG schematic I drew up, along with the new transistor's part number and re-biasing instructions. I'm going to send it along:

ImpDash.jpg

And on behalf of everyone who has or ever will have one of these beasts with E/L dash problems, and finds their solution at the IML website, I want to thank you, Dick Benjamin, for all your help in solving yet another MoPar restoration/repair mystery.

Mark

'52 Chrysler Imperial 2-door hardtop

Subject: IML: Re: '63 E/L dash capacitors - value, pls

Date: Wed, 23 Jun 1999 09:38:38 -0700

From: Dick Benjamin, bondotmec@ez2.net

It appears from a schematic I received from Mark Brauer that the original capacitor was a .068 mfd rated at 330 VAC. I would suggest a replacement be the same value (sets the frequency of oscillation) but of mylar or polystyrene construction, and rated at least 600V. The original transistor was a germanium PNP in a TO-3 case, which will be a bear to find. I have suggested to Mark that he try a MJ2955 as a replacement (Radio Shack part number 276-2043 at $1.99), but it will be necessary to adjust the bias resistor from 50 ohms to 120 ohms to accommodate the Silicon replacement.

I think it would be wise to let Mark try this substitution first, and let him see if everything still works properly with it before others flock to a less than optimum "repair".

Mark's schematic is reproduced above.

Dick Benjamin

try this might be some info in it for you

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A google search led me to www.thegaugedoc.com/Pricing_Information.html Rebuilt and "repair" services for the transformer. Also, in the "66-67 Charger" page, an explanation of the electroluminescent system. On the trip to that website, I stopped at www.66-67charger.com/forum/ubbthreads.php?ubb=showflat&Number=133538#Post133538 and at www.dodgecharger.com/forum/index.php?topic=64286.0

Also . . . www.jcauto.com/electro.html which is the page explaining things. There's also a page on how to remove the '66-'67 Charger cluster, plus other information.

Hope this might help . . .

NTX5467

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  • 9 months later...

Hey all,

I have a 66 Charger and have had it since I was 16. Many... MANY years ago, I spent a lot of time trying to figure out why my gauges were burning out. I purchased a surplus gauge every few months from junkyards around the greater Tacoma area. I put in a new power pack, Cleaned all contact, checked and double-checked connections... still burned out the glow in the gauges.

While tearing apart the gauge assembly yet again, I noticed something I had not seen the 20 times before. A brass grounding plate nested between the backside of the gauges. It turns out, this grounding plate corrodes over time. The corrosion increases the resistance for the hi AC voltage and back-feeds into the gauges. The back-feed caused the needles to first burn/smoke up... shortly followed by the gauge itself.

I mounted a bonding strap to the plate and ran it to ground. I has never had an issue since.

I post this for everyone's edification.

Cheers...

Well, I pulled and checked the .05 uf cap, and it was open. I replaced it with a .047 uf @ 630 volts capacitor, and now I have 330 volts AC output. Told the owner to hook it up and try it out.

Thanks guys!

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  • 3 weeks later...

Hi,

I just replaced the cap on the power pack for my dad's 66 Charger and am also reading 330V AC on the output. Did the gentleman you fixed this for happen to let you know if it worked?

I really don't want to damage the EL system by connecting a power supply whose output voltage is too high. I know it will drop once a load is applied but I'm worried it won't drop enough.

Thanks!

Well, I pulled and checked the .05 uf cap, and it was open. I replaced it with a .047 uf @ 630 volts capacitor, and now I have 330 volts AC output. Told the owner to hook it up and try it out.

Thanks guys!

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  • 6 years later...

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