Testing relays at home, no 914 around |
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Testing relays at home, no 914 around |
VaccaRabite |
Apr 14 2015, 10:26 AM
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#1
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En Garde! Group: Admin Posts: 13,444 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
I have an old bag of used round relays.
I dont have a 914 handy to plug them into the headlight riser (my usual test). How can I test them with a multimeter and a small 12 volt battery? I guess I just need the pin out for these things and I should be able to test them pretty easy. |
r_towle |
Apr 14 2015, 10:34 AM
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#2
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Custom Member Group: Members Posts: 24,574 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
Power, ground and a trigger should do it.
Using a lightbulb might be easier to verify it works versus a multimeter. |
okieflyr |
Apr 14 2015, 10:35 AM
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#3
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9fauxteen Group: Members Posts: 816 Joined: 9-January 05 From: Phila PA Member No.: 3,426 Region Association: North East States |
A 9v battery MIGHT give enough juice to operate it. I'm sure someone can post the pinouts.
I'd have to look at a schematic again to figure it out... |
type47 |
Apr 14 2015, 11:35 AM
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#4
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Viermeister Group: Members Posts: 4,254 Joined: 7-August 03 From: Vienna, VA Member No.: 994 Region Association: MidAtlantic Region |
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era vulgaris |
Apr 14 2015, 11:42 AM
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#5
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J is for Genius Group: Members Posts: 982 Joined: 10-November 13 From: Raleigh, NC Member No.: 16,629 Region Association: South East States |
Pins 86 and 85 are the relay coil. One gets ground, the other 12VDC. Relays are usually non-polar, so it doesn't matter which gets which for testing. Relays can generally still switch with 75% of their required voltage. Less than that and maybe it'll work, maybe not.
Pin 30 is the pole. Pin 87a is normally connected, Pin 87 is normally open. |
stugray |
Apr 14 2015, 12:45 PM
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#6
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Advanced Member Group: Members Posts: 3,824 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None |
Put your DMM on Ohms and connect it across pins 30 & 87.
It should read Open or "OL" - Out of Range, etc. (but you should see continuity across 30 & 87a) Connect a 12V (9V should work, but no guarantee) across pins 85 & 86 and you should hear it click and the meter will now read less than 10 Ohms. Do that briefly! If it does not work try reversing the voltage polarity. As stated above, the coil should pull in regardless of the polarity, BUT many relays have a "reverse EMF diode" inside that will conduct if you apply the voltage backwards so that would prevent the coil from energizing, AND if left that way for too long, you coudl burn up that diode. Dont worry too much if it works, and the closed resistance does not get below 10 Ohms. There is not enough current from the meter to "wet" the contacts and make them conduct well. |
Tom |
Apr 14 2015, 02:58 PM
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#7
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Advanced Member Group: Members Posts: 2,139 Joined: 21-August 05 From: Port Orchard, WA 98367 Member No.: 4,626 Region Association: None |
I have tried the 9v battery and it will not power the coil enough to close the contacts. Not enough current capacity in the 9v battery.
Typical results from bench testing the round relays with a 12v battery applying power to 85 and having 86 to ground: 30 to 87 with no power to relay = open, no conductivity. 30 to 87 with power to relay = less than 1 ohm. Tom |
r_towle |
Apr 14 2015, 07:12 PM
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#8
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Custom Member Group: Members Posts: 24,574 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
Stick your tongue across the two prongs when you connect the battery.
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rhodyguy |
Apr 15 2015, 12:27 PM
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#9
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Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,080 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
mail your box of relays to a buddy with a running 914 for testing.
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malcolm2 |
Apr 15 2015, 12:39 PM
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#10
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Advanced Member Group: Members Posts: 2,745 Joined: 31-May 11 From: Nashville Member No.: 13,139 Region Association: South East States |
i use the batt from my drill. it is 12v. got one of those?
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GeorgeRud |
Apr 15 2015, 12:46 PM
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#11
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Advanced Member Group: Members Posts: 3,725 Joined: 27-July 05 From: Chicagoland Member No.: 4,482 Region Association: Upper MidWest |
Here's a schematic of the relay:
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stugray |
Apr 15 2015, 01:56 PM
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#12
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Advanced Member Group: Members Posts: 3,824 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None |
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VaccaRabite |
Apr 16 2015, 02:34 PM
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#13
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En Garde! Group: Admin Posts: 13,444 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
I actually have a 12 volt battery. :-)
But I cheated, visited my 914 today and started testing all my relays. Well, I should say that all the relays I pluged into the headlight motors worked. Zach |
McMark |
Apr 16 2015, 02:52 PM
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#14
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
Here's a more specific diagram.
Attached image(s) |
barefoot |
Apr 16 2015, 04:29 PM
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#15
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Senior Member Group: Members Posts: 1,274 Joined: 19-March 13 From: Charleston SC Member No.: 15,673 Region Association: South East States |
While I was going thru circuits individually, I made up a 12V lead using a cig lighter connector with about a 15' lead with alligator clips on both + & - wires, then clipped on at each fuze to test various circuits. 12V provided by my other car.
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