Protocouplers will not open...only coupler sounds

First test is to check the coil resistance. Should be less than ten ohms. If they are in range the you can apply voltage using your transformer to check for mechanical issues.

Pete

@Norton posted:

First test is to check the coil resistance. Should be less than ten ohms. If they are in range the you can apply voltage using your transformer to check for mechanical issues.

Pete

Thanks. I’ll try that.

@ToledoEd posted:

Like a bad penny, my F7 is back (20-21357-1) is back.  It now runs fine...except the powered A unit's couplers do not respond to commands.  I inspected the wires, no issues and as suggested in a post here, I specifically checked "the blue wire crimp" and the connectivity was OK. I  checked connectivity of the wires from the coupler to the plugs. OK  Also connectivity from  front to the rear coupler OK  I pulled and reseated the plugs on the PCB. Still nothing. Frankly I can't remember if they ever worked.  I suspect they did, but, I don't know.  Is there a test I can perform to be sure the couplers are actually working?  Like the test you can perform on a smoke motor?  Oh, the coupler sounds are OK.

You know Ed,  perhaps the time has come to park that F-7 in the bone yard'............ 😁 Give yourself and Nancy a break'...

Ted, I’m having too much fun.

@Norton posted:

First test is to check the coil resistance. Should be less than ten ohms. If they are in range the you can apply voltage using your transformer to check for mechanical issues.

Pete

FYI, PS/2 and PS/3 couplers should be no more than about 3 ohms, TMCC & PS/1 couplers are in the 6-8 ohm range.  The PS/1 & TMCC couplers are are not compatible with PS/2 or PS/3, they won't fire.

@gunrunnerjohn posted:

FYI, PS/2 and PS/3 couplers should be no more than about 3 ohms, TMCC & PS/1 couplers are in the 6-8 ohm range.  The PS/1 & TMCC couplers are are not compatible with PS/2 or PS/3, they won't fire.

One tested at 2.6 Ohms.  Not sure I understand how to correctly "apply voltage."  Should I disconnect the coupler leads from the PCB and just apply power across the coil?  AC or DC?  18v AC? Thanks.

Make sure the coupler resistance appears at the other end of the wire at the board connection.

@ToledoEd posted:

One tested at 2.6 Ohms.  Not sure I understand how to correctly "apply voltage."  Should I disconnect the coupler leads from the PCB and just apply power across the coil?  AC or DC?  18v AC? Thanks.

To apply power you do have to remove the connector from the board. I use non polarized capacitor leads in the connector but a resistor more than 100 ohms would work too. Then just touch the leads with power. 10-18 VAC is ok. You just have touch the lead momentarily. If you hear a hum and it doesn’t open then you have a mechanical problem. If it opens the problem is with the board.

Pete

For the DCS couplers, I'd go on the low side of that voltage range, 8-10 volts maximum.  The Lionel/PS/1 couplers require a minimum of around 15 volts to reliably open.

Thanks. I’ll give it a try.