badgerV8 Posted November 21, 2018 Share Posted November 21, 2018 Hi folks, after 30-odd sound conversions done to date, I'm doing my first 21-pin one! (All the rest have been 8-pin or hard-wire). Naively, I assumed Heljan might have had a couple of solder pads on the circuit board for wiring a speaker in, but no, I can't see anything. For those who have fitted sound to a Heljan railbus, where do I connect the speaker? Do I have to solder to the decoder? (Hope not!!!) Cheers. Link to post Share on other sites More sharing options...
SRman Posted November 22, 2018 Share Posted November 22, 2018 Identify the correct pins and elder to the bases of those. Far safer than soldering to the decoder itself, although that does have the solder pads on it. Link to post Share on other sites More sharing options...
Suzie Posted November 22, 2018 Share Posted November 22, 2018 Heljan railbus should have a socket to just plug the speaker in. Just need to find the right plug to put on the speaker - or if you are in a hurry unsolder the speaker socket and wire to the pads. Link to post Share on other sites More sharing options...
RAF96 Posted November 22, 2018 Share Posted November 22, 2018 Maybe a picture of the loco main board would help folk to ID the connections. Link to post Share on other sites More sharing options...
badgerV8 Posted November 22, 2018 Author Share Posted November 22, 2018 (edited) So, after further searching...… Connector CN6 con-checks to the correct decoder pins, but I've drawn a blank trying to find the correct plug and I'm not sure I trust my soldering on something so small...… Really NOT inpressed at Heljan for making what is a really nice model so complex when a small 8-pin would have sufficed! At least give us solder pads please, or enclose a plug with the model!!!!! Edited November 22, 2018 by badgerV8 Link to post Share on other sites More sharing options...
Suzie Posted November 22, 2018 Share Posted November 22, 2018 How would an 8-pin have sufficed? Where would you connect the speaker? Where would you connect the stay alive? PluX 16 or 22 socket with defined decoder space would have been better than the MTC 21, but bulky old legacy sockets with no where to fit the decoder and miles of wires no way. It would help if Heljan would document these things properly and either factory fit a speaker or provide a wired connector. I think CN6 is a standard 2-way JST plug but could not tell you what size. Measure the pitch of the pins and we should be able to work it out and find a source. Link to post Share on other sites More sharing options...
RAF96 Posted November 23, 2018 Share Posted November 23, 2018 (edited) I seem to remember a very similar (if not exactly the same model) topic on the forums and CN6 was the connection. The plugs are JST from memory, but the size escapes me. Edit - I think we had a picture of both sides to work from and CN6 clearly tracked back to the speaker pins on the 21-interface. Rob Edited November 23, 2018 by RAFHAAA96 Link to post Share on other sites More sharing options...
John K Posted November 23, 2018 Share Posted November 23, 2018 These are they I think https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F301942513575 John K Link to post Share on other sites More sharing options...
RMweb Premium Izzy Posted November 23, 2018 RMweb Premium Share Posted November 23, 2018 As has been said this question has arisen before, and I think I posted the photos below, but it doesn't hurt to do so again, so here they are. This is the PCB from the Heljan W&M railbus but I believe they are the same for all the railbuses, can't see any reason for them to differ. The socket is CN6, and it's easy to just cut away the top of it with a scalpel and solder the speaker wires to the pins. Better/easier than trying to solder to the decoder pins I think. Hope it helps anyway. Izzy 2 Link to post Share on other sites More sharing options...
badgerV8 Posted December 1, 2018 Author Share Posted December 1, 2018 Thanks Izzy, that's exactly what I've ended up doing. Suzie, the 8-pin decoder could sit in the same location as the 21-pin one, the speaker wires would already be attached to the decoder, as would the stay-alive wires in the case of a Zimo MX645R. John, thanks for the link. Link to post Share on other sites More sharing options...
Philou Posted December 1, 2018 Share Posted December 1, 2018 (edited) Well! This is all new to me. I have had one of those railbuses for about 2 years and I never knew about CN6. I wired my speaker to the DCC chip. It's a sugar cube and is currently 'dangling' in the saloon area and the sound is truly awful - not the quality but the quantity as no sound can escape from inside the body as there are no holes for the sound to get out. Has anyone had luck in putting a speaker externally such as below the underframe? If so how did you do it as the motor lies below the floor and the underframe is metal. I have a similar issue with the Clayton (Class 17). The speaker is in full view in the cab and the chip is jammed between the motor and the cab door causing the cab to bulge on the one side - any ideas? I was going to drill through the cab floor and put a bigger speaker in the battery box - which I finally got unclipped. There's more space to work around the Clayton's motor than the railbus - which is why I asked the question regarding the railbus. Cheers, Philip Edited December 1, 2018 by Philou Link to post Share on other sites More sharing options...
pauliebanger Posted December 1, 2018 Share Posted December 1, 2018 Well! This is all new to me. I have had one of those railbuses for about 2 years and I never knew about CN6. I wired my speaker to the DCC chip. It's a sugar cube and is currently 'dangling' in the saloon area and the sound is truly awful - not the quality but the quantity as no sound can escape from inside the body as there are no holes for the sound to get out. Has anyone had luck in putting a speaker externally such as below the underframe? If so how did you do it as the motor lies below the floor and the underframe is metal. I have a similar issue with the Clayton (Class 17). The speaker is in full view in the cab and the chip is jammed between the motor and the cab door causing the cab to bulge on the one side - any ideas? I was going to drill through the cab floor and put a bigger speaker in the battery box - which I finally got unclipped. There's more space to work around the Clayton's motor than the railbus - which is why I asked the question regarding the railbus. Cheers, Philip Philip, Class 17 fitting. Full details in Hornby Magazine Issue 120. For the Clayton I used a ZIMO MX645 with the shrink wrap removed and insulated with Kapton tape. This fits snugly but easily between the motor and cab side without pushing the latter outwards. Make sure the decoder is positioned to avoid being against the door, as this will cause distortion (and may damage the decoder). I put a sugar cube speaker, 11 x 15 x 12, at each end under the fan moulding. No need to create holes, plenty loud enough without, though I did trim the foam strips to provide clearance for the speakers. As an alternative, I replaced one speaker with a 166,666 uF stay alive capacitor pack. Viewed from the outside, the cab is indistiguishable from a non-converted model. Best regards, Paul Link to post Share on other sites More sharing options...
RMweb Premium boxbrownie Posted December 2, 2018 RMweb Premium Share Posted December 2, 2018 Quick question Paul, did you put the foam in there or was it installed by the factory? First time I have seen something like that in our models. Link to post Share on other sites More sharing options...
Philou Posted December 2, 2018 Share Posted December 2, 2018 @Pauliebanger Good one! Thanks for that - I'll do some rearrangement. Not sure about the decoder though as mine is an ESU and it must be slightly deeper than your Zimo as there is a definite bulging of the cabside (I didn't do the soundchip - the loco was bought already done). Now that i can see the body removed, I shall have a good look and get my thinking cap on. Cheers, Philip PS: If anyone has any ideas regarding the railbus; they would be very much appreciated. Link to post Share on other sites More sharing options...
pauliebanger Posted December 2, 2018 Share Posted December 2, 2018 Quick question Paul, did you put the foam in there or was it installed by the factory? First time I have seen something like that in our models. That's in the model already. Not sure of it's function in the original configuration; perhaps it was to quieten the sound of the motor for those who prefer Silent Running. LOL Best regards, Paul Link to post Share on other sites More sharing options...
RMweb Premium boxbrownie Posted December 2, 2018 RMweb Premium Share Posted December 2, 2018 That's in the model already. Not sure of it's function in the original configuration; perhaps it was to quieten the sound of the motor for those who prefer Silent Running. LOL Best regards, Paul They didn’t want it like a real Clayton then? LOL Link to post Share on other sites More sharing options...
badgerV8 Posted December 2, 2018 Author Share Posted December 2, 2018 (edited) Philou, regarding the Railbus. I have used a single ESU sugar-cube speaker with the thinnest enclosure, mounted underneath the chassis at one end, hard back against an air tank. I drilled two holes through the chassis after removing the 4 screws holding the upper (roof) frame and lifting the plastic seating up to see where the wires are routed underneath it. Once the holes were in the chassis, I replaced the plastic seating and continued the drill holes through that, then superglued the speaker in place and ran the speaker wires neatly along the inner edges of the seating and up to the pcb, holding the wires in position with a dab of superglue as required. After painting the exposed wires and solder tabs on the speaker matt black, you can't tell it apart from the rest of the under-structure, unless you were intimate with the real thing on a daily basis! I fitted stay-alive (Zimo Supercap) inside the roof, painted matt black. It's visible if you look for it, but not really noticeable unless you go looking, an acceptable compromise in my opinion to get good slow-speed running over point formations with only 4 wheels and no compensation! Both my Clayton's have twin sugar-cubes, one each end, with all the foam removed to (theoretically!) allow better air circulation around the motors! Probably makes no odds in real terms. I used ESU Loksound V4 Micro decoders (C&PRR sounds - very good indeed) as these locos only draw a max of 1/4 amp, the decoders are mounted exactly as-per Pauliebanger's. I can crawl at the slowest of speeds across point/double slip formations with no issues - after dismantling the bogies and easing the pickups out a touch so they all contact their respective wheels at all times, unlike when they left the factory! No stay-alive with the Claytons, simply not needed, and they look (and sound) awesome running double-headed with a long rake of tankers behind them, just as they would have done "back in the day" up the hill from Grangemouth to Falkirk Grahamston Junction. Edited December 2, 2018 by badgerV8 Link to post Share on other sites More sharing options...
Philou Posted December 3, 2018 Share Posted December 3, 2018 @BadgerV8 That is simply such good news regarding the sound improvement to the railbus. I was a little hesitant in drilling through the metal chassis, but I see its not a problem. Regarding the Clayton I had thought of putting a speaker in the fuel tank under the cab but that meant drilling through too. Your, and pauliebanger's, method of speakers in the body seems the way forward. Annoyingly I spotted that there's a buffer already gone walkabout and it wasn't me guv wot dun it. Means I'll have one less to remove! I hope there are some spares available from Heljan . Can I ask if the speakers were put in series or parallel - I can never remember which way round they should be (it's an age thing ). Cheers, Philip Link to post Share on other sites More sharing options...
badgerV8 Posted December 3, 2018 Author Share Posted December 3, 2018 I used 8 ohm sugar cube speakers with a Loksound V4 Micro, which is rated for 4 Ohm speakers, so wire in parallel. Link to post Share on other sites More sharing options...
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