Increase power on Cw40 lionel

It appears that the current limit is set with the value of R8, sub R8 from your CW and see if that works. You will need the fan as well, and any heat sinking.  Are Q1 & Q2 the same on both transformers?

Thanks Rob,

I'm not sure to understand on diagram the value of R8 (44Mohms?), and I substitute R8 by a biggest or a smallest?

I think R8 senses the total load on Q1 & Q2, so if you want 5 amps, it should be 0.044 ohms, guessing that R8 on the 2.5 amp PowerMax Plus is 0.022 ohms.

You might also need to change the value of the fuse coming off the secondary, I would think. OP still needs to answer if Q1 and Q2 are the same on both transformers to get the full picture.

OK  for the fuse.

There's no Q2 on the 40watt transformer. Because there is only track output.

On  the 80watt, Q1is a BTA24-600cw

On the 40 watt, Q1 is a BTA08-600cw.

But the it seems they are the same characteristics, not sure.

The R8 is a resistor wire. They have the same lengths approximately on both.

@Isaak570 posted:

There's no Q2 on the 40watt transformer. Because there is only track output. Good Point!

On  the 80watt, Q1is a BTA24-600cw Rated Non Repetitive On-State Current  260A. Rated Repetitive Off-State Voltage VDRM: 600V

On the 40 watt, Q1 is a BTA08-600cw. Rated Non Repetitive On-State Current  84A. Rated Repetitive Off-State Voltage VDRM: 600V

But the it seems they are the same characteristics, not sure.  So there does appear to be a significant difference in rated current handling capability. There are other minor differences as well

The R8 is a resistor wire. They have the same lengths approximately on both. The note at the bottom of the CW-80 schematic states that the wire used on the CW-80 is 0.184 ohms/ft. If they wires in each transformer have the same length, then the wire in the CW-40 would have be changed - an easy swap job.

One last topic not touched on is the PIC chip. Looking at the ratings on Q1, there's one other minor difference in Holding current (50ma in the CW-80 vs. 35ma in the CW-40.) I'm not smart enough to know if that actually needs to be addressed in terms of the PIC chip or any other related components. But if it were me, I would not let that alone stop me.

The big question regarding the PIC would be if there's any differences in the code written into the chip. I will leave that question to the EE's in our audience

George

Good news my friend, it's works!

I have soldered a shunt on 1/3 of the length of the wire resistor R8.

Now, the green led flickering for 4,5 amps.

Last thing to do, add a fuse and fuse holder on the side of the case.

Thanks a lot to all to have helped a French guy who likes American trains