DCC query with Black 5 R2555 & TTS Decoder

[Simmo009]

OK folks, wrap your collective heads around this.

Hornby 5MT, loco drive, dcc ready, can't recall the catalogue number off the top of my head, Ayrshire Yeomanry. Running beautifully on DC.

Hornby Black 5 TTS decoder, tested and all OK on ESU Test board.

Speaker (YouChoos twin sugarcube) fitted in tender due to lack of space in the loco. 2 pin connector between loco and tender.

All wiring checked by 3 people for correctness.

Put it all together, and nothing happened. We tried without the tender just to see, and still nothing.

We are completely flummoxed, does anyone have any ideas?

[SteveM6]

Two things to check which come up regularly on here.

1) check the pins are making good contact with the socket by slightly splaying them out to increase the interference fit.

2) check the pins are not too long and sticking through the socket and possibly causing a short. A bit of insulating tape under the socket can help.

[Simmo009]

Thanks SteveM6, already checked out that area, no obvious issues. If this area was a problem, I would expect a problem with DC running, but it was fine. We even removed the decoder and went back to the blanking plug, and it worked fine. Change back to the decoder, nothing.

[LTSR_NSE]

@Simmo009 - what DCC controller are you using? (you haven’t mentioned this.)

If you are attempting to run a TTS decoder fitted loco on DC, please be aware of the following: (I believe)

• DC running is generally disabled by default.

• TTS decoders don’t produce sounds on DC.

[Fishmanoz]

Simmo, might the loco be drawing enough current to shut the decoder down?

You can check by doing a DC running and stall current test.

PS. Just on your title for future reference - personally, I don’t find it interesting, just uninformative. I’m far more likely to open and contribute to a post titled “Black 5 not operating with TTS Decoder”. But that’s just me.

[Simmo009]

A Digitrax was used. DC running was only attempted with the blanking plug fitted. The Digitrax reprogrammed the decoder from the standard 03 as supplied. Fresh out of the box decoder, not previously used.

[Simmo009]

Will do current checks and advise.

[96RAF]

Also lift the socket and check for cross trace tracking with a magnifier and meter. Fitting a blanking plug for DC running simply shorts track pickups to motor but does not prove the other pins on the socket are OK.

[Simmo009]

Socket checked, all correct. Current checks performed, nothing exceptional noted.

We are thinking the suppressor may be interfering with the DCC signal.

Incidentally, I had another TTS decoder doing odd things. Moved the decoder to a different locomotive and it worked perfectly.

[96RAF]

You can remove the motor capacitor, but also check, if your track is powered by way of a power track or power clip, that they don't have a capacitor installed, if so snip it out. If your power is soldered direct to rails or via a bus then it will be OK.

[Simmo009]

If testing at home, wires are soldered direct to track, if at the club, crocodile clips are used. Suppressor removed from loco, still nothing, still works fine with the blanking plug on DC. What was that Queen song, I'm going slightly mad!

[Brew Man]

I had something similar with a Prairie some time ago, turned out to be the socket. Check if yours has any suppressor components on it as mine did. Changing the socket did the trick for me.

[Simmo009]

Thanks Brewman. My DCC wizards have checked the socket and found no issues. As I understand things, the decoder itself has suppression, hence why the one fitted for DC is redundant. But I will look if there is anything on the socket itself.

[Brew Man]

Some do, some don't.

[96RAF]

Check there isn't another capacitor hidden under the motor. Some can be difficult to spot.

[LesXRN]

Have you changed the address?

Having just re-addressed a number of loco's, including a Black 5, I would check that it has had the address changed successfully. Try it on address 03 again just to be sure.

[Simmo009]

Will do 96. Tbh I was hoping to not have to take it all apart as it is such a faff, but needs must.

Les, I will check it out at the club session tomorrow night if the dcc system and decoder tester are there.

I tried a non sound chip to see if that would work, I think it fried immediately, will check that tomorrow too.

[Simmo009]

Mystery solved folks. There was an errant piece of solder shorting between pins 7 & 8 on the socket.

[ColinB]

I am surprised it didn't blow up the decoder. You obviously didn't do the continuity check between adjacent pins with a multimeter. Those old Hornby PCBs are terrible for that.