Does anyone know what the value (probably micro-farads) of the red capacitor between pins 81a and 31b of the stock headlight relay? I have enough wire on the capacitor for one more cut and splice. I understand the reason it's there, and from posts on this Forum, the relay will change hi/lo beams without it, but maybe not reliably. There isn't any information on my capacitor and Google says I need an oscilloscope and maybe some other stuff that in not going to happen. S57 doesn't give the value.

If anyone out there has a Masters in electronics, or just lucky enough to have the answer, I would appreciate the help.

Dave

 

Not master of anything, just have a good light.
Mine is Blue and says 1 muF
(';')

 

or if it is a Red one, try the one at the Brake Pedal.

 

I tried all my good lights, no dice. Is your blue one a round blob with a wire out of each end?


It's been 10 months since I removed the brake booster assemble, I had forgotten about that one. Thanks for the tip.

Dave

 

I can't get a photo of the numbers by just a hair but it clearly says 1muF.
Of all the things they fooled with during Restoversion I don't think they touched this.
(';')

 

Thanks for the picture Elinor, yours is a little different shaped than mine but I don't imagine the value would have changed between S2 and S3. The numbers/letters "1muF" should probably stand for 1 micro-farad, which is written "1uF". If I end up having to replace mine, that's the size I'll look for.

Thanks again for your help.

Dave

 

AHA! I knew it was Greek for lower case 'm', didn't know how to transliterate it to Mercan.
(';')

 

1. Greek from the Greek letter fraternities and sororities on college campus??

2. Or "Greek to me". AkA, I just don't get it!

3. I almost get the function of a capacitor, A battery of sorts to store energy. To make a available a charge when needed. Seen in some electric motors and in old style point and condenser 4. ignition.

4. In this application, does it really matter? Red with one value or blue with another...

5. Capacitor and condensor are the same .

 

I think this one where size does matter. Way back, when I had a career, I was good friends with our head mechanic. There was a lengthy period of time when the group of "shop groupies" would play pranks on each other. It all ended when someone scotch taped a thumb tack to another's exterior car door push button. Blood was drawn and a truce was made. During the interim period, my mechanic friend had his tools super-glued together or covered with grease; fine solder wrapped between the contacts on a tool or light plug which would flash and scare the crap out of him when plugged in; and the one I'm finally getting to, which was a capacitor/condenser from something that had been charged and carefully placed in his tool box, ready to be grabbed when he went for a wrench.

Capacitors come in many values that are appropriate for the purpose intended. Some circuits need a little boost because they are little circuits and others need big boosts. I think of it as having a tea-cup full of water and a gallon jug full of water; they both are storing water (12vdc in our case), but one will release much more of that water when it is discharged.

I haven't been able to find anything online that is encapsulated with stranded wire pig-tails yet, but I'm still looking. I will probably try the hi/lo beam function without the capacitor and if that in not satisfactory, I'll deal with it then. Jose tipped me to the one on the brake pedal and it looks identical, but I haven't figured out why it's there; maybe something to do with the release of the cruise control? I'll leave that one until I know what it does.

The end.

Dave

 

are yours missing or known to be blown? Have you checked with David at www.everyday.com for replacements?

in the electric guitar amplifier world, those are known as "Orange Drops" and "Caps".

Replacement Caps for guitar amplifiers are available at eBay in sets or individually, they come in Lemon Yellow or Orange colors.

 

Dave:

Thanks. Explained a lot or me. Especialy the tea cupo vs gallon jug analogy.

But, are the blue and red close enough to be interchangeable?

Gonna check on my Jaguar on a while. Battery down from no use. Put it on the Schumacher smart charger at about noon yesterday. Oughta be 100% by now. Await a rain intrerlude to check on it.

Did errands in the jeep yesterday/ the auto head lights worked!!

Carl

 

No, mine is still there and seems to work fine. I'm ashamed to admit that I have moved the location of that headlight relay more than once as I've rearranged wiring on that wing. The pig-tail is now so short that I can't make another cut/connect if I have to. I'm just thinking ahead. I've had very good luck with David, contacting him would be a good idea if I end up needing one, thanks.

Dave

 

Neither of mine have any writing on them so I can't make a comparison with anything. The color might have something to do with different values, it quite often does in electronics, but I don't see why it would in this case between Elinor's and mine. Same relay, same function, same brand of car, maybe hers was made during Jag's blue years and mine during their red years. I would use either one if I find one.

Dave

 

the color of those chiclets does have to do with their ratings. Elinor's is a Series 2, yours is a Series 3. Maybe that is the difference.

 

It was explained to me once why our old farm truck, DOT (Damned Old Truck), had a capacitor in the distributor.

When the points broke contact to spark the plug, there was a momentary spark across them which the capacitor absorbed, preventing metal transfer from one point to the other, resulting in a pit on one side and a spur on the other side, eventually shorting them completely. When the points were again in proper contact with each other, the capacitor released its store of energy back into the system to start the process all over again; not unlike a surge tank.

(Any time after that I saw a capacitor attached to a mechanical relay I have jumped to the conclusion it's there for the same reason. Must have been a good idea as these relays seem to fail only infrequently if reports on this forum are any indication of conditions on the Real World.)

To demonstrate this point, when I was a kid, one of my brothers replicated an experiment he had seen done in his science class in high school. He took 2 lengths of wire, about 16g if I remember, stripped about 2 inches off one end and 1/2 inch off the other end, twisting the short strands to keep them under control but leaving the longer ones loose.

Then he cut a length of aluminum foil, about 12 inches long by 2 inches wide, and a corresponding length of waxed paper 2.5 inches wide. Very carefully he wrapped one wire, the longer of the 2 stripped sections, into each end of the foil making sure to have good contact; one wire pointing left, one right.

After that he just as carefully rolled the waxed paper and the foil, rather like a cinnamon roll, as centered as possible so the foil wraps didn't touch, tight as he could, being careful not to wrinkle the foil or dislodge the wires from the ends of the foil. Then he saturated the whole thing in melted paraffin (wax) and let it cool till next day.

It's witchcraft, magic and sorcery, but when he stuck the ends into the kitchen outlet for a time (to charge it he said), removed it and then approached the ends to each other, he got quite a juicy, healthy spark! The longer he charged it, the better the spark; until he left it charging long enough to begin melting the wax.

Lesson Learned!
(';')

 

I have heard of making a science-fair capacitor like you describe. Being of a certain age, I have replaced, set and filed the pits out of many sets of distributor points. Even with the condenser, they would eventually get pits and spurs-I just assumed that was normal. As I mentioned in my last post, my only brush with them, outside of the distributor, was having fun with my mechanic friend.

As you've noted, a large capacity unit would absorb enough energy to probably destroy a relay. I think finding one very close to the value we are currently using would be the best idea. I am still curious to try the relay without the capacitor. I'll post if I try that.

Thanks for the story, until the last couple of sentences I was sure your brother was going to toss the little jewel at you, thereby giving you the "healthy spark". Probably best that he didn't.

Dave

 

If our dad hadn't been there he probably would have tossed that fully charged bomb at me, they did stuff like that to me all the time. (There are several reasons I live so far away from them and see them so seldom!)
(';')

 

The capacitor is across the realy coil. This is usually done to delay the release of the relay a smudge when the power is removed , the capacitor discharges thru the coil until it runs out of energy. Maybe this is to do with the temporary latching nature of the relay to make sure its a positive action if it only gets a short flick from the hi/lo switch.

 

Thanks for the input, Steve. After taking the cover off mine to look at the contacts, I thought the latching mechanism was an engineering work of art and seems to work as designed. But it is definitely old school by todays standards. I agree with you that with all the mechanical movement, a little more "hang time" in the coil is probably good insurance. I'm going to leave it in place until it fails, I'll address a replacement then.
Dave