Fried TCS chip in Heljan 47!

Fried TCS chip in Heljan 47!

Postby psbboy » Sun Aug 23, 2009 9:01 am

Morning all!

Just thought I'd report that I've had my very first chip on fire, yes actually burning! Fitted a DP2X-UK into a Heljan 47 this morning. Worked ok to start with on a test run with the body still off but suddenly juddered to a halt then set off again, closely followed by a puff of smoke and a nice flame from the burning chip!

Investigations will commence once the bacon sandwich and cup of tea has been made, and the toxic fumes have dispersed. From the chip obviously, not the bacon sandwich!

Until then, any ideas anyone please? I have several other Heljan 47's with this chip in and they operate perfectly.

Phil.
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Re: Fried TCS chip in Heljan 47!

Postby Giz » Sun Aug 23, 2009 10:02 am

Check underneath the circuit board, its possible for the pins on the chip to push through and short out on the chassis casting beneath.
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Re: Fried TCS chip in Heljan 47!

Postby 50033 » Sun Aug 23, 2009 10:19 am

Good morning, could it have anything to do with the Heljan motors drawing a lot of power for the motor. I had standard Lenz decoders in my 47s and had lots of trouble with them not moving, not responding and then lights not working etc. I eventually replaced the standard 1.0amp decoders with Silvers which have a higher 1.8amp rating and they have been trouble free ever since. Just a thought!

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Re: Fried TCS chip in Heljan 47!

Postby steve fay » Sun Aug 23, 2009 10:26 am

Dont forget the goof proof warranty. Pack it up and send it back with a note where you bought it and usually in two to three weeks you will get a brand new one free.
Its a great service. :thup
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Re: Fried TCS chip in Heljan 47!

Postby psbboy » Sun Aug 23, 2009 10:50 am

Thanks all. Yes warranty in mind, I've used it once before and got a new one in return within a couple of weeks. Now thats service! Off to investigate further...

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Re: Fried TCS chip in Heljan 47!

Postby Giz » Sun Aug 23, 2009 11:02 am

50033 wrote:Good morning, could it have anything to do with the Heljan motors drawing a lot of power for the motor. I had standard Lenz decoders in my 47s and had lots of trouble with them not moving, not responding and then lights not working etc. I eventually replaced the standard 1.0amp decoders with Silvers which have a higher 1.8amp rating and they have been trouble free ever since. Just a thought!

Mark


The DP2X-UK is rated 1 amp continuous, 2 amps peak, which is higher than a Lenz Silver. They should be more than enough for a Heljan 47 and I've found they suit them very well.
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Re: Fried TCS chip in Heljan 47!

Postby peter m » Mon Aug 24, 2009 9:18 am

I think I'd be checking Giz's first reply. Unless you just scored a faulty chip of course.
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Re: Fried TCS chip in Heljan 47!

Postby psbboy » Mon Aug 24, 2009 11:49 am

Thanks for the replies so far guys. Yes I'd already insulated underneath as I've encountered this problem in the past so I don't think its that. It may just have been a dodgy chip yes, but I'm inclined to think not as this particular loco was already playing up by stopping and starting randomly for no apparent reason. Don't understand it really, I've checked everything else, wheels are clean, everythings lubed, can't see any exposed wires touching anything anywhere... Odd.

Have I read somewhere before about the resistors being a problem?

...Or perhaps its because back along I chose this particular loco to be my avatar on here!! :)

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Re: Fried TCS chip in Heljan 47!

Postby 50033 » Mon Aug 24, 2009 12:43 pm

Giz wrote:
50033 wrote:Good morning, could it have anything to do with the Heljan motors drawing a lot of power for the motor. I had standard Lenz decoders in my 47s and had lots of trouble with them not moving, not responding and then lights not working etc. I eventually replaced the standard 1.0amp decoders with Silvers which have a higher 1.8amp rating and they have been trouble free ever since. Just a thought!

Mark


The DP2X-UK is rated 1 amp continuous, 2 amps peak, which is higher than a Lenz Silver. They should be more than enough for a Heljan 47 and I've found they suit them very well.


Ah yes sorry thought it was 1.8A continuous but I see now its 1.0A continuous with 1.8A max. Sorry!
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Re: Fried TCS chip in Heljan 47!

Postby SRman » Mon Aug 24, 2009 12:50 pm

I suspect I have one with dodgy resistors. I blew a TCS T1 decoder in it. It checked out OK on the programming track and ran beautifully when put on to the main line. Then I turned the lights on. SMOKE!!!! The lights wouldn't turn off either even though the loco would run. So, the decoder was pulled and sent to TCS for replacement but I haven't been game to try another decoder just in case the same thing happens. Like Phill I knew about the potential short on the chassis so insulated that beforehand.

That makes three TCS decoders I have had destroyed or damaged; one was entirely my fault (wired back to front), one was the Heljan 47 just described (I won't take any blame for that one), and one was a partial blame situation where i fitted a Hornby class 56, snipped the capacitor off and insulated the bare wires with heat-shrink tubing - unfortunately, the heat-shrink fell off one wire which subsequently shorted on the underside of the circuit board.

Full credit to TCS who replaced them each time with no quibbles. I just don't want to keep taking advantage of that warranty.
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Re: Fried TCS chip in Heljan 47!

Postby psbboy » Tue Oct 06, 2009 3:39 pm

Well I'm still no nearer getting to the bottom of this problem. I've changed the PCB, changed the chip, checked there's nothing causing a short anywhere. But the fault is still there. I haven't fried anymore chips but I've tried 3 different types and all have got immensely hot within seconds of the loco moving. All of this would make more sense were it not for the fact that this loco with its previous chip in it gave hundreds of hours of faultless running. Whats changed?

Any ideas anyone?

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Re: Fried TCS chip in Heljan 47!

Postby mike knowles » Wed Oct 07, 2009 7:35 am

I recently had a sound decoder meltdown in a Heljan 47. Investigations showed that one of the wheelsets had been installed (by Heljan) the opposite way round to the others. As far as I can see one wheel is live to the axle, the other is insulated. The loco did run OK for some time but derailed on a point and the incorrectly fitted wheelset seems to have caused a short cicuit resulting in the fried chip. Since turning this axle around I have had no further problems, though as yet I've only fitted it with a basic Bachmann decoder - can't afford to lose another sound one.
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