Crosti 9F TTS

[ColinB]

Has anyone else had issues with the Crosti 9F TTS chip. My one has just suddently stopped making any sounds. The DCC function still works as it goes backward and forward, but the chip seems a bit warm, but normally it is inside the tender so I don't know if that is normal. It has been a bit weird since I fitted it, occasionally losing sound, but soon as I do a power reset on the Elite it started working again. I have only had it a month so it is going to have to go back, but I wondered if anyone else has had a problem. It is also not because it might have got shorted out as I insulated everthing, I even covered the device with sellotape as it says, even so the device is surrounded by plastic (it is in the tender). As I say it was working last night, but not today. I have done several resets on the device, but still no change.

[RDS]

Are you sure it is just not overheating due to all the insulation, which if it is surrounded by Plastic as you say, may not be required at all.

 

If the other DCC functions continue to work, is there a problem with the wires to the speaker?

 

Does it work for a while each time from cold and then fail?

[Phil_Spiegel.]

If possible, before sending back a decoder - there are a number of tests you can try = both on the loco and on the decoder.

Obviously, if you suspect a loco is possibly destroying a decoder - it would not be sensible to try another deocder on the same loco !!

Do you have any of the essential tools ?   - A multimeter is the first essential and can cost less than a single silent decoder - but better models do cost a bit more - but here we are basically interested in open or short circuit connections - which even the cheapest multimeter is okay for.

(And INTHIS CASE: The first thing to test is for approximately 8 ohms across the speaker / decoder leads (measured either end, no matter).)

A 9V PP3 battery - is an ideal portable  power supply (but do not leave the terminals exposed in your pocket !!) that is fairly safe to test with. For this reason I am NOT one of those who advocate disabling DC running - because it is one of the most basic and useful diagnostic tests possible! And my controller does not seem to create the start-up runaway problem that some do or did.  Of course; with a TTS Decoder = no sound.

When Hornby launched Zero-1, they provided their dealers with bright yellow Zero-1 controllers with a motor monted on the top, to make a convenient test-bed for decoders !!!   A spare motor - of 12V and low current rating will do - or another loco ... but the best option is the (more expensive) ESU Decoder Tester - which now has many connector types, a built-in motor and speaker, as well as function LEDs.  I test each new TTS decoder on this before fitting to a new loco (which I also pre-test separately)

AS THE CROSTI has a decoder socket - your fitting was presumably 'plug and play' - therefore it can easily be removed and tried in another loco or the ESU Decoder tester if you have one.  There are no lights to test lighting outputs with on the Crosti - you might have a diesel with directional lamps and possibly a 3rd light output  ??? -  o/w the decoder tester will confirn these are all okay.

IF you have only a 'Select' prior to V1.6 ... this might be a good opportunity to send it back at the same time for an upgrade ?? (check with Hornby) - apparently the new software allows more CV programming options.  This might make other processes easier in future

Testing, Testing

With TTS decoders and SOUNDS - there is a note in the manual, about having accidentally left some of the functions on - eg one which plays once only - and their suggestion is to renumber the decoder to a new address (previously unused) that starts with all functions off.

Resetting CV8 to 5  will reset sound levels only.   

Setting the overall volume control to something other than 0 should help (write only- no readback)

A VISUAL CHECK of the loudspeaker wiring - particularly at the decoder end where they are close together, and the plastic sleeving may have been melted back during assembly - it is possible for the wires to short together here .... perhaps after installation if the wires are pulled, and therefore move together.   I have had my only TTS 'failure' caused by this - which meant going back to Hornby for a replacement.

IF YOU HAVE A METER - you can measure - either at the loudspeaker or decoder end, to see if you get approximately 8 ohms resisitance - if there is a short at either decoder or speaker, this will give a near-zero reading, and explain why you have no sound, and a potential cause of heat.  It iS possible that a connecting wire has broken internally - in which case expect an open-circuit indication at the decoder end, and 8 ohms at the speaker end.

IF you can plug the decoder into a loco with Lights - or the ESU Decoder tester - you can verify whether the lighting functions - directional and F18/25 (Aux 1, green wire) are working  - if they are, this suggests the software in the decoder is running properly.

You have already established that motor control - in both directions - is operating normally  (it can fail in 1 directon only)

If visual Checking of the speaker wirning appears to be okay, and the decoder works for both directions on the motor - anD a total reset does not clear the problem - try testng it 'on the becch with another loco or motor.

DO NOT WRAP the decoder - but iNSULATE ANY METAL - that is both the original advice from Bernd Lenz, and good advice to follow.

It has been warm in the UK these last few days - so it may be suffering from high ambient temperatures combining with high on board temperatures.

If you need to secure the wires with tape - no problem. If you need to secure the decoder with tape - a minimum to hold it - but no more.

 

 

 

 

[ColinB]

Amazingly, I used to design microprocessor based circuits before I retired, so yes, I did check virtually everything with a multimeter. I ran it in another loco, I checked the resistance of the speaker, I always check that track connections are isolated from motor connections after I had one loco that wasn't (that is what blows up the motor driver,so it only goes in one direction, the loco was brand new). It is in the tender, so I took the top off the tender so it had free air, anyway on this one the bottom of the tender is open. I just wondered if anyone else has had issues, just in case Hornby had a bad batch. I have sent it back now, I wondered if by chance the driver had a thermal fault, and I know from bitter experience that when a device fails, the time between failures gets shorter and shorter, so switching off the Elite and switching it back on would get the chip a chance to cool down. I didn't check the functions as it doesn't matter if they work, because it still isn't going to make the sound work, if the micro was blown nothing would work. I suspect the audio driver to the speaker had gone short circuit which would explain it getting a bit hot. The only thing that possibly could have happened, assuming there was not an initial fault with the chip, is that when Hornby soldered the wires to the chip there was a stray strand of wire that occasionally touches, but that seems a bit vague. It worked in the loco for about a week, the joke of it is, I just about to put it back in its box, before I thought I would give it one more test. It couldn't have been a short on the speaker as this tends to blow all the device.

[RDS]

OK, hope it works out well for you.  Please let us know.