Anyone have information on this (rectifier)

richard5933 · April 03, 2018, 05:07:50 PM

Quote from: buswarrior on April 03, 2018, 04:24:52 PM
Back to the religious scribings?

Headlights, speedometer...

Third time's the charm?

Happy coaching?
Buswarior

I take it that you don't agree with any of the current theories on this. I wish I had more information, but after looking at the manual, supplement, and wiring diagrams I still don't have a clear picture. The only description of a rectifier is in connection with the speedo, and since it goes to the same terminal as the speedo I'm leaning that way. The headlight part is due to the fact that the other end of the rectifier connects (through a 6-amp fuse) to the terminal where the dimmer lo switch connects. It's also listed in the parts book as a headlight rectifier.

Bottom line - I don't know but hope to find out.

Gerry H · April 04, 2018, 03:09:45 AM

Richard: As long as we are taking guesses, I don't think it has to do with the speedo. To rectify a pulse, typically uses a signal diode (small in nature). The one you show, is a power diode, more likely to be the headlight low beams (I know you said they still work, but maybe they don't dim anymore with fuse blown. Check that function out. That sounds more likely, that it's a zener diode and pulls down the voltage when switched on to dim the lights. Thanks for additional info, you'll figure this out, just takes time. Gerry H

richard5933 · April 04, 2018, 04:18:44 AM

Quote from: Gerry H on April 04, 2018, 03:09:45 AM
...but maybe they don't dim anymore with fuse blown. Check that function out. That sounds more likely, that it's a zener diode and pulls down the voltage when switched on to dim the lights. ... Gerry H

Not sure exactly how the function of the headlights on the old coaches should be, but I've got quad headlight. When the high-beam indicator is on all four bulbs burn brightly. When the high-beam indicator is off, just two burn.

Should there be something else going on to further dim the two that are left? Seems odd that if this was supplying power to the headlights in any way they'd have only a 6-amp fuse, but then again lots of things done on the old coaches seems odd.

chessie4905 · April 04, 2018, 06:05:51 AM

I think youll find that it just draws off that circuit source.

Gerry H · April 05, 2018, 03:21:39 AM

Richard: thanks for clarifying the operation of your lights (bright/dim) I now am at a loss, cause it doesn't seem like this one is connected to your light system either. Are you certain that nothing else is not operating (dead) there should be something not working. You also said that you have one on order that may not be the same, if you install it, be sure to identify the cathode (-) band and install the same as the old one. Cathode on yellow wire as your picture shows.
Facts: 12 volt headlights typically draw about 2 amps each. Yellow wire color code usually denotes 12 volts DC. A silicon diode only drops .7 volts across it. They are sometimes used across a coil, which when current stops flowing through the coil, a high reverse polarity voltage spike is generated, the rectifier safely dumps the voltage spike to ground. Rectifiers are measured in values of current thru it (amps) a reverse voltage that it can safely handle across it, and power rating in watts (volts X amps). Food for thought. Gerry H

Bill Gerrie · April 05, 2018, 06:26:34 AM

Richard5933
Do you have the wiring diagrams on a CD or can they be copied? I have all the books but no wiring diagrams. I would pay you for copying them.

richard5933 · April 05, 2018, 06:29:35 AM

Quote from: Bill Gerrie on April 05, 2018, 06:26:34 AM
Richard5933
Do you have the wiring diagrams on a CD or can they be copied? I have all the books but no wiring diagrams. I would pay you for copying them.

I do have the wiring diagram book, but haven't digitized it yet. Let me see if I can figure out a way to get it on my scanner in the next few days.

richard5933 · April 05, 2018, 06:37:23 AM

Maybe these will help for now...

chessie4905 · April 05, 2018, 07:55:15 AM

I've looked at yours and my wiring diagrams. You have some numbered diagrams that arent in my pack, (x7461). But it looks to me that that circuit is for headlamp low beams to come on when coach is running. That's why connection to generator. It looks like they happen to pull voltage for speedometer head from #42, and that connection has a 4 amp fuse in line for it. The fluctuation of speedometer could be bad condenser at connection 17, probably in engine apparatus panel. If it is a metal can type with pigtail, quite common back then for many uses, particularly in points and condensers in cars. They have a habbit of drawing moisture over time. Cheap, so no biggie to replace.

richard5933 · April 06, 2018, 01:30:26 PM

Just noticed this... Looks like I'm supposed to have daytime running lights. Who knew?

Maybe this is what the mystery part does.

The one I got from Luke isn't going to work. I found a generic diode with a 15 amp rating. Since this circuit has a 6 amp fuse, I'm hoping it will work.

We'll see. Long as we keep the smoke inside the part all is good.

buswarrior · April 06, 2018, 02:07:22 PM

No matter the problem...

A return to the religious writings, finding interpreters for those writings...

Salvation may be found!

And it works for life too, apparently...

Well found!

happy coaching!
buswarrior

chessie4905 · April 06, 2018, 07:26:20 PM

This one or similiar that will handle the current from two low beams will do the job. Wire it in so band is at same end as old one.

https://www.ebay.com/itm/100x-R-6-1000V-10A-Axial-Rectifier-Diode-High-Surge-Current-Capacity-Low-leakage/131993420782?hash=item1ebb6bc3ee:g:XWgAAOSwlptaRlTi

richard5933 · April 06, 2018, 07:50:05 PM

I found some rated at 15 amps at 45v which were designed for solar array building. I think this will work - guess we'll find out soon. Still not sure exactly what this is doing...I'm guessing that it's cutting the voltage to the low beams to make them shine at half brightness.

richard5933 · April 12, 2018, 06:13:34 PM

Got a replacement for the diode/rectifier - I found one with a big enough capacity to give it a go.

Got everything hooked up and installed. Still don't see anything different. The headlights don't light on dim (DRL) and nothing else seemed to function that didn't before. Thought maybe I had the thing in backwards so I turned it around. Still nothing.

For now I've pulled the fuse out and will have to research more to figure out what's going on. Perhaps whatever the original part was connected to it that caused it to burn out has stopped functioning as well. If I knew what it was I'd take a look.

Thoughts?

Lee Bradley · April 12, 2018, 10:46:19 PM

Looking this I think they were pulling half voltage off the Y connection of the alternator to power the low beams any time the engine was running and the lights weren't switched on. The diode was in the circuit to prevent backfeeding the alternator when the lights switched on. The Y connection would supply half the alternator's output voltage and it would be unrectified that is AC but the head lights don't care if it is AC or DC current. If you want to use this system, I would start at the alternator and check for the Y connection and trace the voltage forward and make sure you have the correct headlight switch. Good Luck.