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stephen_usher · Post by **stephen_usher** » Mon Oct 24, 2022 12:56 pm

Another thought I had was to put a resistor in series with the capacitor with the same resistance as the ESR of the capacitor at 100Hz, effectively reducing the voltage across the capacitor by half, but I have no way of testing the ESR.

stephen_usher · Post by **stephen_usher** » Mon Oct 24, 2022 4:44 pm

Oh well. No post at work today (not a Royal Mail strike day is it?), so no wires. I can still make up a couple of the boards but without the wires to the pick-ups.

stephen_usher · Post by **stephen_usher** » Mon Oct 24, 2022 5:50 pm

It seems that I had the wires sent to home rather than work... they're here I can do stuff!

stephen_usher · Post by **stephen_usher** » Mon Oct 24, 2022 10:03 pm

Well, the board works!

Put it all together and hooked it up to a loco motor and other bogie and was able to talk to it from the DCC controller.

: IMG_2826.jpg (68.73 KiB) Viewed 1401 times

: IMG_2827.jpg (59.19 KiB) Viewed 1401 times

The only problem is that the only spade connectors of the right size to fit the motor from RS are too long, stopping the power bogie from fitting into the body. :-/

: IMG_2828.jpg (56.01 KiB) Viewed 1401 times

Still, it does work!

stephen_usher · Post by **stephen_usher** » Mon Oct 24, 2022 10:29 pm

Does anyone know where I might be able to get bare (no insulator) crimp 2.58mm spade connectors? Both RS and Farnell just have the long ferrule-type connector ones which are way too long for what I need.

stephen_usher · Post by **stephen_usher** » Mon Oct 24, 2022 10:58 pm

Managed to cut enough of the insulation off and bend the connector over enough to get the bogie to fit. A bit of a struggle though.

stephen_usher · Post by **stephen_usher** » Tue Oct 25, 2022 6:28 pm

Hmm... Bit of a problem. Somehow the motor is trying to pull 3A and the DCC chip is only rated for 1A. This is very strange given that when I powered this loco using a bench power supply it only ever drew up to 800mA!

stephen_usher · Post by **stephen_usher** » Tue Oct 25, 2022 7:09 pm

Hmm... I think that it must be the PCM "voltage" control from the control chip confusing the ammeter as the controller is saying a very much smaller amount of current is flowing than could possibly be 3A. Anyway, I'll put a 10R resistor in-line anyway for extra protection and it makes the motor control better. 27R is too high and I don't have anything in between.

stephen_usher · Post by **stephen_usher** » Tue Oct 25, 2022 8:34 pm

Here's the board in situ, with the teeny-tiny DCC decoder sitting it its socket.

: IMG_2831.jpg (41.59 KiB) Viewed 1361 times

Post by **rubber_jonnie** » Tue Oct 25, 2022 10:15 pm

stephen_usher wrote: Tue Oct 25, 2022 8:34 pm Here's the board in situ, with the teeny-tiny DCC decoder sitting it its socket.

IMG_2831.jpg

Very neat

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