Digitrax N Decoders DN147 and others

[John]

I noticed that the DN147 series of decoders has pads for Cap+ and Cap- ..



https://www.digitrax.com/media/apps/products/mobile-decoders/dn147a0/documents/DN147A0.pdf

If I read this correctly, I should be able to just connect a capacitor across those leads and have a "keeper aliver" ?    Anyone try this yet?

[signalmaintainer]

I noticed that the DN147 series of decoders has pads for Cap+ and Cap- ..



https://www.digitrax.com/media/apps/products/mobile-decoders/dn147a0/documents/DN147A0.pdf

If I read this correctly, I should be able to just connect a capacitor across those leads and have a "keeper aliver" ?    Anyone try this yet?

I have, using a TCS KA-N1 in an older Atlas GP38. After some filing and fitting of the inside of the light shield, I tucked the KA into the niche the light shield creates.

What are your thoughts on the DN147A0? I'm not impressed. Maybe mine is bad, as the accel and decel performance is quite mediocre, even at max values, and there's a hum from the motor that no adjustment of the PWM frequency can eliminate. My older and now obsolete DN163A0s have worked quite well.

[John]

I've installed 4 of them on Atlas GP38, SD35 and GP40, 3 with KA and one with the Iowa Scaled Engineering -- I just drop them into the gap under the rear of the board .. and route decoder wire to the pads at the front ..

I've not had any problem with them on my test track (as I'm currently without an operating layour) -- the buzz may be from transponding being default on .. then again, I also haven't fiddled with them too much ..

[sizemore]

Transponding is default "On" for DN147, was baffled why the headlight was twinkling. Low and behold long arcane knowledge I had forgotten.

The S.

[signalmaintainer]

I've installed 4 of them on Atlas GP38, SD35 and GP40, 3 with KA and one with the Iowa Scaled Engineering -- I just drop them into the gap under the rear of the board .. and route decoder wire to the pads at the front ..

I've not had any problem with them on my test track (as I'm currently without an operating layour) -- the buzz may be from transponding being default on .. then again, I also haven't fiddled with them too much ..

Ah, I'll be checking CV61 then. If its value is 2, there's the issue. Thanks!

[sizemore]

One thing I forgot to add, I coat the spicy side (where "electronics" live opposite the cap) of the K-A with silicone conformal coating vice wrapping it in Kapton tape. Just a small level of assurance it wont let the magic smoke out if it rubs a frame or bottom of the DCC board.

HTH
The S.

[peteski]

Isn't silicone conformal coating soft and rubbery (like the silicone caulking from the hardware store)?  I would think that Kapton tape would be much more sturdy and resistant to mechanical damage.

[sizemore]

Isn't silicone conformal coating soft and rubbery (like the silicone caulking from the hardware store)?  I would think that Kapton tape would be much more sturdy and resistant to mechanical damage.

Its the same equivalent to silastic coatings used in larger electronics like power tools to insulate, protect from vibration and elements. The main driver for me was due to Kapton tape quality where it doesn't stick to small electronics well or lets go over time. Conformal coating, achieves the same result without a lot of worry since electronics aren't really subject to mechanical damage.

The S.

[peteski]

Fair enough.  When there are components on the bottom side (not common), or if the solder masked traces on the bottom of the decoder are very close to the chassis I put the Kapton tape on the loco's metal chassis areas under the decoder (which are usually flat where the tape sticks quite well).

[signalmaintainer]

Transponding is default "On" for DN147, was baffled why the headlight was twinkling. Low and behold long arcane knowledge I had forgotten.

The S.

Read the CVs on mine today. CV61 is off, so I'm thinking I have a bad decoder account not being able to dial out the PWM freq.