Tamiya Leopard 2A6. No Sound.

[zooma]

My oldest Tamiya Leopard 2A6 was running nicely at our local Rossendale Club on Thursday evening when all of a sudden the sound stopped - but everything else continues to function correctly.

I checked to see that the white and yellow speaker lead (J-SP) was still connected correctly to the T-07 DMD Control Unit so I can only guess (hope) that when the turret has rotated it may have pulled the connection wire off of the speaker?

This tank was already built when I acquired it several years ago so I did not build it and I am not sure what parts to remove to be able to get inside to check the speaker wires are still soldered on.

I have removed the top deck from the hull, but this only revealed the underside of the black moulded speaker box that must be screwed together from the top through the turret base?

After lifting off the turret top I cannot easily see what screws I need to remove to release the bottom of the speaker box so I can see anything obvious (such as a broken wire or solder joint) ..........or the best way to get to it - preferably removing as few parts or assemblies as possible.

I fear that I am looking at a complete strip-out of the turret, and I would like to avoid this if there is any way of fixing the problem by gaining access to the speaker box without doing this.

I hope that if I can identify the screws that hold the moulded speaker box to the underside of the turret I can unscrew these and just drop the bottom half of the box away from the underside of the turret to reveal the speaker inside so that I can see if there is anything obvious that I can fix?

Any help or advice would be appreciated .

[zooma]

I thought I had better just get stuck-in and find out for myself how many layers I need to peel back to reach the well buried speaker and the wires that I suspect have been twisted that will (hopefully) reveal the cause of the silence.

The first thing I did was to remove the turret reinforcement baseplate (part M1 "mechanism deck!) and disconnected the servo arm to the gun barrel by "popping" the ball joint so I could lift it out - carefully threading this plate under all of the wires inside the turret to remove it. At this stage the extent of the twisted wires was not visible as most were tangled up inside the speaker box.

Once the "mechanism deck" had been removed, I could (almost) clearly see the 4 screws that hold the moulded speaker box onto the underside of the turret, and more importantly I could use a screwdriver to gently slide in-between the mass of wires to unscrew them.

Once the above 4 screws were removed the black speaker box could be dropped away from the underside of the deck enabling me to unscrew the 6 screws that held the two halves of the large black speaker box together .........and this revealed a tightly tangled and knotted length of several wires that had clearly been twisted together as the turret was rotated.

[zooma]

The speaker wires were tight enough to bend the mounting plate upwards

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The white and yellow wires are from the speaker

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Surprisingly the speaker wires were still attached - but I had to unsolder them to be able to un-thread the J-SP lead from inside the twisted wire mass.

After unwinding the tangle of wires I individually straightened them all and soldered the speaker wires back on again. At this stage I have not found any obvious reason for the sound to stop working, but the knotted and twisted wires were strangling each other, and the thin speaker wires had faired especially badly causing me to suspect that they may be fractured inside. I may need to replace the J-SP speaker wires.

Once I get everything back in place and connected-up again I will soon find out if untangling the wires has done anything to help regain the missing sound, but I am happy to have un-would this tightly twisted mass of wires as other problems would probably follow if they were not, and I suspect that the turret turning motor and gears had been working a lot harder than they should have been so maybe this falls into the "preventative maintenance" section of my Tamiya Leopard 2A6 ownership?

Come to think of it, this 2A6 displayed a "shudder" when the barrel was raised and lowered, but it now feels nice and free - so maybe the barrel movement was also being affected by this entailed mass of wires as it was not able to move completely freely?

I will try to remember and take note of just how many times the turret turns in each direction so that I can avoid another tangle like this in the future. As far as I can remember I have never turned the turret excessively in either direction, but maybe the first owner liked to continually turn the turret in one direction more than the other - maybe at least a hundred times more than in the reverse direction? I certainly "unwound" these wires more than 100 times in the same direction to free them from each other.

[zooma]

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Now that the wires are free, I will reconnect everything and power up the system to see if I have regained the sound

[Jofaur86]

Good evening, what bag of knots do you have access to the yellow / white wires of the HP easily? Is this a plug that connects them to the module? if so, try this, remove the plug from the board, and insert 2 small rigid wires into it, then with a battery (4.5 volt flat type) connect one of the wires to one of the terminals of the battery, direction indifferent, then do momentarily touch the second wire, you should hear a crackling sound in the HP, which will confirm that the connection and the HP are OK, there is no risk with this method of damaging anything!!!

[zooma]

Powering up the system had everything working OK - except for the sound!

There was a high pitch buzz coming from the speaker - but nothing else. I had already re-soldered the speaker wires so maybe the thin speaker wires have fractured due to the extreme twisting (inside where I cannot see). The speaker itself LOOKS like it is in perfect condition - but it is not working.

To isolate the speaker (or the speaker wires) as being the only things that are at fault, I took the new speaker from the kit that I am currently building and plugged that in......and the sound returned perfectly!

So now I have everything "sorted" and the tank is running well with sound again.......but I need to prepare or replace the speaker that I took out of the tank because I need one for the new Tamiya 2A6 kit that I am building.

[zooma]

Good evening, what bag of knots do you have access to the yellow / white wires of the HP easily? Is this a plug that connects them to the module? if so, try this, remove the plug from the board, and insert 2 small rigid wires into it, then with a battery (4.5 volt flat type) connect one of the wires to one of the terminals of the battery, direction indifferent, then do momentarily touch the second wire, you should hear a crackling sound in the HP, which will confirm that the connection and the HP are OK, there is no risk with this method of damaging anything!!!

Thanks Jofaur86.

I have fitted a new speaker and everything is working perfectly again now - but I have to repair or replace the speaker as I have "borrowed" one from a new Tamiya Leopard 2A6 kit!

Your testing method will be tried on the failed speaker. I think there is a possibility that the thin yellow and white speaker wires were fractured inside when they were so badly twisted and stretched.

These two wires were stretched so tightly on the speaker that they had bent-up the fixing plate on the speaker that they were soldered onto!......so they may be fractured inside.

The two small braided copper wires on the back of this plate (that fix onto the speaker cone) look like they are still attached to the back of this plate and the speaker cone OK, so unless there is an internal fault with the speaker, the wires look like they may have failed.

I will change the speaker wires and plug the unit into the tanks MFU unit to see if it comes back to life!

........failing that, I need to buy a new speaker !

[Jofaur86]

the two small wires from the solder on the support, go to a winding located inside the magnet, so using the principle of the direct battery on the two terminals, will confirm if the HP is HS? Personally I would lean more for a problem with yellow/white wires cut internally? but hey, to see, if you have a multimeter, you can also use it, in the Ohms position. Already good if it works with another HP, great

[zooma]

A secondhand speaker unit to fit my Tamiya leopard 2A6 that would replace my failed unit nicely was found on eBay today - but the price was £49.99 plus £6.99 postage.

I also found these TWO new speakers of similar size and specification on eBay for £5.23 plus £2.02 for delivery making them £3.63 each!

https://www.ebay.co.uk/itm/295397785463

A difficult decision to make (!) but I thought it would be worth going them a go ......

[Jofaur86]

Hello, have you not done the test with the battery? the HP is perhaps not HS? Well it's up to you to see!! any speaker of the right diameter will be suitable, but respect the 4 Ohms of impedance, or even 8 Ohms, will also be suitable, see on online sites, or get a PC speaker, old transistor post, transistor, etc., will also be suitable.
Hello, have you not done the test with the battery? the HP is perhaps not HS? Well it's up to you to see!! any speaker of the right diameter will be suitable, but respect the 4 Ohms of impedance, or even 8 Ohms, will also be suitable, see on online sites, or get a PC speaker, old transistor post, transistor, etc., will also be suitable.