Mallard R3959TTS speaker gone?

[ronbram]

Yesterday I experimented with the volume control of my Mallard..As I wanted to hear what it could do, I wrote a value of 8 to cv 161. After some nice load chuffs, the sound started to rattle, likestones blowing out of the chimney. I put cv 161 back to 4, but the rattle remained, Other sounds like the whistle sounded OK. After a few minutes al that remained was silence. I resetted the decoder, by writing 8 to cv 8, but no sound anymore. Have I blown the speaker (which is cheap and easy to replace) or has the sound part of the decoder died (other then no sound the decoder responds normally)?

[Chrissaf]

The rattle is usually a damaged speaker. The only way to know if the damaged speaker then subsequently strained and blew the decoder audio amplifier is to replace the speaker and see (8 ohm speaker ONLY). The motor part of TTS decoder has been known to operate normally with the audio part of it completely shot.

[96RAF]

For info Ronald...

CV178 is the master volume control for TTS steam (CV182 for diesel), then you can adjust individual noise CVs if desired.

Also just to reset the sound side of TTS decoders you can write value 5 to CV8 which then doesn’t mess up the address or any other motor related adjustments you have made like acel/decell, etc.

I agree with Chris the speaker has probably gone., especially if one of the very early 4Ω ones.

Rob

[ronbram]

Chris, thanks for the advice and hope. I'll order a Tams mini 1511 8 Ohm, 0.5 W speaker with enclosure.

[96RAF]

TTS amp is 1.68W and the speaker should be 1W Ronald.

 

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[Chrissaf]

Remember to disconnect the wires at the speaker end and reuse them on the new speaker. Trying to solder the wires at the decoder end takes skill. Many on here have owned up to making a complete hash of it trying to solder the decoder end of the wires.

.

And I agree with Rob about wattage. I would go further and treat the 1W rating as an absolute minimum and look to fit a 2W one instead. The 0.5W will not last long and quickly blow again. The factory fitted speaker is 1W and look what's happened to that.

[ronbram]

Thanks guys. I actually found another speaker at Conrad, cheaper, still 8 Ohm and higher wattage. Although I have a semi-professional soldering/desoldering station, one look at the wire connections on the decoder, taking my eyesight into consideration, made me decide to work on the speaker side. Now 3 days wait for the parts to arrive.

[sir john]

Hi I had the same problem with one of my A4s changed the speaker made no difference had to send the decoder back for replacement 

Jonn

[sir john]

As an addition to my post I have many locos fitted with tts either retro fitted or factory fitted The A4s are the only ones I've had any trouble with 

[ronbram]

After a lot os searching, I found that the speaker I have ordered is rated at 0.7W. Since I ordered to 2 (when I order parts I usually order more, to have spares on the shelf). Would it make sence to connect them both in series?

[ronbram]

Planning for defeat, I searched for a replacement decoder, which should be a R8107. Found one on stock at Hatton's. On pictures of that decoder I see a yellow 9 on the round circular "blob" of soundchip?? I am pretty sure (will check tonight) that on my decoder there is a 7. Would that mean that it is a different decoder?

[96RAF]

I would think that the blob marking is to do with the batch of decoder OR it maybe that one was batched for factory fit and the other as retro fit.

 

As regards the speaker(s) - yes you could wire them in series (given enough space) to add the impedence together for 1.4W power handling.

Rob

[Triumph speedtriple]

After ajusting my TTS FlyingScottsman loco to level 8 it ran round well for 15 mins then screeching told me the speakers ruined. Changed speaker reset level to 4 and alls well again. Only followed what instructions came with the loco. Hardest part of replaceing speaker was getting the tender body back together again.

Peter

[96RAF]

Ronald

Given that any of the pictures you see on any of the sellers’ sites are real pictures of the actual decoder that they are supposed to be then a 9 or is it a 6 marking on the embedded chip would likely either be a Class 9F (9) or a Class 47 (6). An A4 would probably be marked 17, which you can confirm when you lift the lid on your loco.

 

If you look on the Hornby TTS product page there are mostly just repeat pictures of one with a round speaker and one with an oblong speaker and I would guess other sellers just rip off the Hornby picture(s) for their own sites.

 

Note the use of ‘likely to be’ and ‘probably’ as I have no firm information only reasonably accurate observations as the decoders pass under my nose.

Rob

[ronbram]

Going through the pictures in the Hornby shop, I see eitherr 8 (diesel???) or 9 (steam???), not that familiar with UK engine classes.

[96RAF]

# 8 = Class 43  HST according to my notes.

# 9 = as previous Class 9F

[ronbram]

I remembered that somewhere in the stack of cardboard storage boxes that mmagically appear over many years of modelrailroading there should be some mini speakers that plug into the jack connector of a portable radio. And I found them and they are 8 Ohm, wattage unknown, but they could handle full volume of the radio.. Dismantled one, unfortunately bigger then the one fitted. Connected it anyway and, as we say on this side of the pond, the sweet smell (or should I say sound) of success. With some creative filing of the speaker housing, I was able to fit everything in the tender body. Very, very 😀 Ronald. The bigger speaker seems to give a little more depth to the sound also, although I admit, even I have would have a hard time fitting a subwoofer in a Mallard tender.

 

BTW the decoder is marked with a yellow 7.

[96RAF]

That proves it was a bad speaker Ronald. I did see a speaker installation once where the frame had been cut to fit, but I didn’t think that would be too good for the sound quality. As usual I cannot find the picture.

 

Yellow 7 or 17 no matter, it just lets us know there is a unique code for whatever sound is installed on a particular embedded chip. I will amend my notes from 17 to 7.

 

Rob. 

[ronbram]

The speaker I fitted has a metal frame, which is glued into a round plastic housing. I ground two flat sides on the plastic housing to fit it in the tender body. I Glued the speaker to the inside bottom of the coal bunker. That way I could place back the original speaker housing, which is also used to hold a bar over the wheels in place. I stuck the decoder with two sided tape on top of the orginal speaker housing.

[morairamike]

The TTS speakers are not very robust. All mine have been replaced with Sugar cube units. Much better sound. Hornby did replacement my A4 speaker when it failed. Sugar cubes also fit under the chimney so the sound comes from the loco not the tender, more realistic. 

[96RAF]

Folk may like to look at Richard Crofts sound page on RMWeb DCC Sound forum where he has posted details and videos of many sound projects using improved speakers. The difference between a properly fitted decent and a badly fitted basic speaker can be exceptional.

Rob