GM500 wiring problem
- lickeyjunction
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GM500 wiring problem
I have gone around and checked all of them.
I think was affecting one set.
I have put a multimeter across the points and the frog is showing opposite power to the point setting. I swapped the opposing two frog wires to double check and same result, just opposite polarities.
I originally joined the positive track feed to the positive wire on the GM500, then onto the bus to save joiners. Should I separate these?
Should I reverse the +/- on the GM500 on one side?
Thanks
I think was affecting one set.
I have put a multimeter across the points and the frog is showing opposite power to the point setting. I swapped the opposing two frog wires to double check and same result, just opposite polarities.
I originally joined the positive track feed to the positive wire on the GM500, then onto the bus to save joiners. Should I separate these?
Should I reverse the +/- on the GM500 on one side?
Thanks
It doesn't matter what you do, someone always knew you would
GM500 wiring problem
lickeyjunction wrote:<snip>
I originally joined the positive track feed to the positive wire on the GM500, then onto the bus to save joiners. Should I separate these?
Should I reverse the +/- on the GM500 on one side?
Thanks
This is the part that I cant quite get to grips with? Please supply a detail wiring drawing showing feeds and connections, as I asked for on page 2 second from last post.

GM500 wiring problem
Does this help?
Only shows one point and two panel LEDs.
Note wire from GM500 tab 1 goes to both the point frog and the panel LEDs Cathode leads (Shorter LED leads) Would suggest R1 and R2 are 1K0 or 1K5 Ohm. Two Diodes (Not shown) can ideally be 1N4148 or you can use 1N4001 or 1N4002 which are connected directly across the LED in inverse to each LED. Whether you fit these Diodes is up to you.
Only shows one point and two panel LEDs.
Note wire from GM500 tab 1 goes to both the point frog and the panel LEDs Cathode leads (Shorter LED leads) Would suggest R1 and R2 are 1K0 or 1K5 Ohm. Two Diodes (Not shown) can ideally be 1N4148 or you can use 1N4001 or 1N4002 which are connected directly across the LED in inverse to each LED. Whether you fit these Diodes is up to you.

- lickeyjunction
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GM500 wiring problem
Hi
Ref to the joined wires, on your diagram i have joined terminal two wire with the feed down to the red bus bar just to save joints on the bus.
This is what i have managed. Apologies for the delay,my ignorance and crudity of the drawing, i think i have this in line with what i have down in practice.
I hope this helps you and me!!
Regards
Ref to the joined wires, on your diagram i have joined terminal two wire with the feed down to the red bus bar just to save joints on the bus.
This is what i have managed. Apologies for the delay,my ignorance and crudity of the drawing, i think i have this in line with what i have down in practice.
I hope this helps you and me!!
Regards
It doesn't matter what you do, someone always knew you would
GM500 wiring problem
Its very much wrong! The PL11 surface motors should be feed via the CDU output and the sprung to centre off switch or passing contact lever Not from the GM500 contacts..
Gaugemaster have produced a wiring diagram for their GM500 and a pair of cross-over points BUT their point motor wiring colours do not match the Peco PL11 wire colours As Peco use Red and Black as the two operations wires with Green as the return, while the GM wiring shows Red and Green are the two operation and Black is the return.
Its now too late for me to do a wiring drawing showing the CDU, Switch/lever and the two PL11s I can do one for tomorrow PM, but it will be late afternoon as I'm out most of tomorrow!
You should not allow the GM500 contacts to switch the PL11s so do not use the point motors as shown. Nor allow the PM11 operation wires to connect to the rails or the DCC system.
What switch or lever is being used? It SHOULD BE a sprung to centre off toggle (On)-Off-(On) or Passing contact lever, such as the Peco PL26.
Gaugemaster have produced a wiring diagram for their GM500 and a pair of cross-over points BUT their point motor wiring colours do not match the Peco PL11 wire colours As Peco use Red and Black as the two operations wires with Green as the return, while the GM wiring shows Red and Green are the two operation and Black is the return.
Its now too late for me to do a wiring drawing showing the CDU, Switch/lever and the two PL11s I can do one for tomorrow PM, but it will be late afternoon as I'm out most of tomorrow!
You should not allow the GM500 contacts to switch the PL11s so do not use the point motors as shown. Nor allow the PM11 operation wires to connect to the rails or the DCC system.
What switch or lever is being used? It SHOULD BE a sprung to centre off toggle (On)-Off-(On) or Passing contact lever, such as the Peco PL26.
- lickeyjunction
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GM500 wiring problem
Hi
Many thanks in advance. I can embarrass myself easily with electrics!!
I have trialled with a single point and removed the connection between the bus and GM500.
Point is switching fine.
Power to the points is now via the bus wire only.
I now have a dead frog and the red and black from the GM500 needing a new home.
I am using sprung off-on-off toggles
I'm confused as to where the power comes from to power the rails and how that doesn't connect with the main bus from this diagram.
I'll look forward to the diagram!!
Thanks
Many thanks in advance. I can embarrass myself easily with electrics!!
I have trialled with a single point and removed the connection between the bus and GM500.
Point is switching fine.
Power to the points is now via the bus wire only.
I now have a dead frog and the red and black from the GM500 needing a new home.
I am using sprung off-on-off toggles
I'm confused as to where the power comes from to power the rails and how that doesn't connect with the main bus from this diagram.
I'll look forward to the diagram!!
Thanks
It doesn't matter what you do, someone always knew you would
GM500 wiring problem
Hi
The modified wiring diagram above taken from the Gaugemaster web site placed above, is incorrect.
The point motor wiring is wrong and also the wire insulation colours change when using a Peco PL11 and the ones shown in the reproduced GM drawing are using Seep PM1 motors.
I have drawn my own and shown the Peco PL11 wiring colours. This once wired as shown will get the points working correctly on a DCC layout.
LED Indications are just a wire from each frog connection (1 and 4 tabs) and taken to the panel LED Anode via a series resistor as I have shown previously, plus of course the two DCC sub bus wires.
The modified wiring diagram above taken from the Gaugemaster web site placed above, is incorrect.

The point motor wiring is wrong and also the wire insulation colours change when using a Peco PL11 and the ones shown in the reproduced GM drawing are using Seep PM1 motors.
I have drawn my own and shown the Peco PL11 wiring colours. This once wired as shown will get the points working correctly on a DCC layout.
LED Indications are just a wire from each frog connection (1 and 4 tabs) and taken to the panel LED Anode via a series resistor as I have shown previously, plus of course the two DCC sub bus wires.
- lickeyjunction
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GM500 wiring problem
Hi
Many thanks
As it stands, that is exactly how I have done it aside from my query around 2 & 3, 5 & 6.
I had tied these together with the track feed to the bus wire, from the point rails.
I have now separated them and have the rails powered from the main bus, so only the frog remains dead.
I have the two wires from 2 & 3 or 5 & 6. Where should these take a feed from please? I think this is the route cause of the problem.
Thanks
LJ
Many thanks
As it stands, that is exactly how I have done it aside from my query around 2 & 3, 5 & 6.
I had tied these together with the track feed to the bus wire, from the point rails.
I have now separated them and have the rails powered from the main bus, so only the frog remains dead.
I have the two wires from 2 & 3 or 5 & 6. Where should these take a feed from please? I think this is the route cause of the problem.
Thanks
LJ
It doesn't matter what you do, someone always knew you would
GM500 wiring problem
2 & 3 and 5 & 6 connections... They need to be opposing in polarity 2 goes to 6 and 3 to 5. Or they have four separate wires on them, one on each, from the DCC Bus pair or rails.
Two wires on 2 & 3 and also 5 & 6?? Possibly one pair from the DCC bus pair or rails if no DCC Bus used, and the other pair from/to where????
IMO if you wire as 'Ive shown and remove anything else it will work correctly for frog polarity switching and point operation.
Two wires on 2 & 3 and also 5 & 6?? Possibly one pair from the DCC bus pair or rails if no DCC Bus used, and the other pair from/to where????
IMO if you wire as 'Ive shown and remove anything else it will work correctly for frog polarity switching and point operation.

- lickeyjunction
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Re: GM500 wiring problem
Hi
So.......i have a single point working fine. Feed from track on 2 & 3, frog on 1. Return on C and switch on A/B.
Spent two hours fighting with opposing points last night....
Opposing points, there must be an easy fix that i am missing.
Points switch, but i'm getting opposite polarity on the frogs which is where i started.
2/3 & 5/6 are reversed. 1 + 4 go to frogs for each set
A/B operating switch and C returning.
I have tried reversing feeds and frogs. All i seem to do is swap the problem from one side to the other.
Am i a jinx?!
LJ
One hour later
I have researched on the web and there is a lot of discussion about the GM500 resisters and bypassing them, by crossing over them. Apparently the PL10's which i am using in some locations with the PL11's, absorb too much power and don't leave enough to switch the frog.
So.......i have a single point working fine. Feed from track on 2 & 3, frog on 1. Return on C and switch on A/B.
Spent two hours fighting with opposing points last night....
Opposing points, there must be an easy fix that i am missing.
Points switch, but i'm getting opposite polarity on the frogs which is where i started.
2/3 & 5/6 are reversed. 1 + 4 go to frogs for each set
A/B operating switch and C returning.
I have tried reversing feeds and frogs. All i seem to do is swap the problem from one side to the other.
Am i a jinx?!
LJ
One hour later
I have researched on the web and there is a lot of discussion about the GM500 resisters and bypassing them, by crossing over them. Apparently the PL10's which i am using in some locations with the PL11's, absorb too much power and don't leave enough to switch the frog.
It doesn't matter what you do, someone always knew you would
Re: GM500 wiring problem
You can remove the two resistors on the GM500 and replace them with wire links as they are there to reduce power flow to the two relay coils.
Either unsolder them from the PCB and replace each with a wire link soldered back in the resistors place, or just link across each resistor with a piece of soldered on wire.
These are the two resistors...
What you need to ascertain is which way the relay is laying (energised or de-energised) and which pulse of the operation wires allows the relay to become energised and then remain mechanically latched and which pulse is releasing the mechanical latch and allowing the relay to return to its de-energised position. Then you will be able to determine which contact is making (or broken) to 1 or 4 which are the two common change over contacts of the relay. Remember the relay is a mechanically latched device. So even when power is removed from its coils if its been energised the internal mechanical latch will hold the relay in the energised position forever and until a pulse is received on the Unlatch coil.
You should also be using as a minimum 16/0.2mm equipment wire throughout all the solinoid point motor wiring. From CDU output to the switches and out to each motor and the return wire too and also consider increasing the return wires size to 24/0.2 or even 32/0.2mm where two or more solinoid motors move together. 80% or more of solinoid fail to move or partial moving is due to the wiring being too small, the remaining % are often due to poorly fitted motors.
Either unsolder them from the PCB and replace each with a wire link soldered back in the resistors place, or just link across each resistor with a piece of soldered on wire.
These are the two resistors...
What you need to ascertain is which way the relay is laying (energised or de-energised) and which pulse of the operation wires allows the relay to become energised and then remain mechanically latched and which pulse is releasing the mechanical latch and allowing the relay to return to its de-energised position. Then you will be able to determine which contact is making (or broken) to 1 or 4 which are the two common change over contacts of the relay. Remember the relay is a mechanically latched device. So even when power is removed from its coils if its been energised the internal mechanical latch will hold the relay in the energised position forever and until a pulse is received on the Unlatch coil.
You should also be using as a minimum 16/0.2mm equipment wire throughout all the solinoid point motor wiring. From CDU output to the switches and out to each motor and the return wire too and also consider increasing the return wires size to 24/0.2 or even 32/0.2mm where two or more solinoid motors move together. 80% or more of solinoid fail to move or partial moving is due to the wiring being too small, the remaining % are often due to poorly fitted motors.

- End2end
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Re: GM500 wiring problem
lickeyjunction wrote:I have researched on the web and there is a lot of discussion about the GM500 resisters and bypassing them, by crossing over them. Apparently the PL10's which i am using in some locations with the PL11's, absorb too much power and don't leave enough to switch the frog.
I want to use the GM500 with a PL11 for a lit Dapol semaphore signal and 2 control Panel LED's showing point position instead of powering a frog.
Did you find anything along those lines in your research about having to bypass the resistors in my scenario per chance?
I only ask as it's the first time I've heard this and it has intrigued me.
Thanks
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Re: GM500 wiring problem
The GM500 resistors can be removed and linked out if your GM500 doesn't operate correctly every time the CDU discharges and moves the point motor. If it works correctly then leave them in place.
Wiring for the Dapol semaphore signal using a GM500 was shown in an old topic on here. But you cannot use the same set of GM500 contacts for both the Dapol signal and LED feeding. They need to have electrically separate contacts.

Wiring for the Dapol semaphore signal using a GM500 was shown in an old topic on here. But you cannot use the same set of GM500 contacts for both the Dapol signal and LED feeding. They need to have electrically separate contacts.
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Re: GM500 wiring problem
Phew. One less electrickery thingymajig to worry about.
Thanks Flashbang
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Thanks Flashbang
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- lickeyjunction
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Re: GM500 wiring problem
Finally had a chance to go back through my points.
I jumped the resister on evry GM500 and success. I constantly checked the power with a multimeter prior and the points fired but not the frog switch.
I used 32 strand wires for the main switch wires to the GM500 and 16's for all contact wires. I must say, the wires from the PL-11's are so thin, however they have always fired, just the frog issue.
So apart from a couple of polarity swaps for opposing points, they all seem to be firing and functioning correctly.
Thanks for all the advice. I will read back and get my led's sorted next...
LJ
I jumped the resister on evry GM500 and success. I constantly checked the power with a multimeter prior and the points fired but not the frog switch.
I used 32 strand wires for the main switch wires to the GM500 and 16's for all contact wires. I must say, the wires from the PL-11's are so thin, however they have always fired, just the frog issue.
So apart from a couple of polarity swaps for opposing points, they all seem to be firing and functioning correctly.
Thanks for all the advice. I will read back and get my led's sorted next...
LJ
It doesn't matter what you do, someone always knew you would
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