Restoring smoke pulse effect

[strmnd54]

Yes , the BD440 has similar ratings for power and gain and is "pin compatible" ...
As for the resistance ; I measured 2 Ohms on my digital Ohmmeter ....
When you measure a low resistance value , don't forget the internal resistance induced by your ohmmeter ( switch , probes ; etc...)
Prior to measure the resistor , put the probes of your ohmmeter together and whatever value you read has to be subtracted from the reading of the resistor ....

[Gerula]

Just replaced the power transistor, was pretty much a hassle-free job. Now I'm getting 7.2V to the plug of the smoke unit, the motor is running, the piston is moving, the unit's case is heating in the area of the heater, but no smoke whatsoever. (the crispy R22 had 2 ohm so I let it be - didn't had a spare at hand anyway- will replace it when I do the occasional trip to the electronic components shop)

The heater's element resistance is 20.9 ohm (measured with a wire disconnected from the motor)

I opened the unit and the cotton mesh is wrapped around the bottom of the U formed by the heater element . I touched the oily cotton with the hot tip of the soldering station and smoke came off instantly. So it's obvious the heating element isn't getting hot enough, but why?

[strmnd54]

From the description I conclude that you're using a stock H.L. smoke unit ?
If you feel heat in the combustion chamber but have no smoke ; you may have overfilled the unit ; try to lower the level of fluid and see what happens ....

[Gerula]

Yes, the one I'm talking about now is the stock HL unit that came with the Panzer III. I even opened the cap and completelly drained the oil out, leaving just the cotton soaked, but still no smoke.

Isn't 20.9 ohm a bit too much for the heater element?

[Gerula]

Update: did a test with the cap off, lots of smoke were instantly produced. Olaced the cap on without positioning it well over the gasket, smoke was coming out from all sides. Placed the cap well on the gasket (without even screwing it) = no smoke.

My guess is that somehow the pump isn't pushing air inside the heater chamber. No air=no combustion= no smoke. I'll check tomottow,probably it's either a clogged hole or a bad gasket on the piston. In the meantime, if anyone has another idea, please share .

[MarkofZollo]

Hi Gerula. I went through the same things a few months back, you are correct without air flowing in no smoke will come out. The problem is the piston set up really isnt efficient enough to get a reasonable flow, if you replace it with a 5v mini-fan you will see a difference. Also try to make it a staight through assembly, ie air inlet at front and smoke outlet on back rather than top, this helped mine a bit.
Cheers, Dave

[strmnd54]

Just go on page 1 of this tread ; I've posted pics showing how to do it ....

[Gerula]

I saw them when I first read the topic.

However, at the moment I'm just trying to restore the unit's functionality, not to do any mods.

[Tankbear]

Hi,

I'm trying to make my own smoker. Tried a 15R carbon film resistor and candle wick which makes a decent amount of smoke but smells like buring electronics looking at the resistor and wick tied around it both are black.

So thinking of trying as suggested here a ceramic wirewound resistor and kevlar stren, but have a few questions.
First struggling to find 14 or 15ohm CWR but found 7.5ohm so thinking of putting two in series and linking by clamping with a small nut and bolt in stead of solder as this probably melt off.
Secondly kevlar stren? where do I get this from when I search closest I find is for tennis rackets is that the same stuff?

[KommandantX]

Hello!
Excellent system, i am looking forward to finding the time to build someting similar for my JagdTiger. Currently i use the standard HL smoker that we all know how disappointing it is.

Just one suggestion (probably already mentioned but i may have missed it) for standard non proportional units.

If the power supplies are separated for the heating element and the fan and pulse motors it is possible to do the following:

1. Heating element on a constant (or through a switch) power supply +7.2V
2. Fan and pump motor powered through the standard HL smoker circuit.

In this case while tank engine not ON (heating element on) there should be only a trace of non pressured smoke. When engine starts the fan and pumper start and a huge puff of smoke will be blown on start up! In theory at least