Electronic train 118/138 and 139, anyone have one or have seen one?

[aernschd]

Hi there! Anyone still interested in reverse-engineering the 138 cirquit? I've dismantled one that only works forward/stop. I've made a sketch of the cirquit. There are three transistors 0N114, which must be PNP type, and two 0N115, which should be NPN, all in TO-1 casings. I could not really identify these type numbers, but they might be something like AC114/AC115, these would be similar to ECG102A and ECG103A. The integrated cirquit is housed in a DIL-14 package and is marked 211 0M. No idea what it is...

Edited April 2, 2015 by aernschd

[LEGO Historian]

aernschld .... are you sure that is a 138 electronic train unit?

In 1968 the 118 Electronic Train was introduced in Europe and Australia, which only went forwards.... here's the box....

This particular box is sealed inside, and shows all the paperwork and cardboard imagery....

In 1969 the 138 Forward/Backward Electronic Train was introduced, as well as the 139 Control Unit (forward/backward) and the 139A Control Unit (forward only) for the earlier 118 train, as shown here....

[Brickthus]

I have a picture of the two units:

The 138 unit on the left shows the IC

I can't find any data for it online but it looks like it has these features:

- Ground pin 1, positive supply pin 11.

- Input pin 14.

- Input balance/filter pins 2&13. Maybe set the difference between the short and long whistle pulses.

- Intermediate balance pins 6, 7 & 12 (might be like a 748 op-amp balance function).

- Output smoothing pins 3&10.

- H-bridge drive command from pins 5&9 low side, 4&8 high side.

On a previous occasion I thought the transistors likely to be BC series, so BC114 and BC115. The earlier unit used BC113.

That means they may all be NPN types. Here's the other unit's diagram.

Thanks for the sketch.

No evidence of flywheel diodes from the circuit as you have deduced it. I may be able to draw it with CAD sometime.

If the unit you have only works in forward/stop then maybe a transistor has failed. I wonder if a motor inductive discharge voltage spike caused the failure!

Mark

[LEGO Historian]

Wow..... you guys are talking way over my head!

But here's the whistles involved with the 118/139A (Forward/Stop) and 138/139 (Forward/Stop/Backward) models.

[aernschd]

The IC in the 138/139 unit is an ASIC, so it is very probably not replaceable... So I do hope that only a transistor is gone. I'll try and check them using some standard transistors and add the missing flywheel diodes. Those missing diodes are surely a weak point of the original cirquit.

By the way - I wonder why the whistle for the 138/139 set is tunable, as the 138/139 control unit does not seem to distinguish between two different frequencies but between a short and a long signal. High tolerances within the cirquitry? Anyway, the older whistle does the trick, too (as well as clapping hands).

[Oliver77]

Hello,

just want to give some input to the 138 Electronic circuit. I already had one working 118 Train (but without whistle). Then I found on a marketplace one who offered the 138 Electronic Box, Microphone and the adjustable whistle for an really excaptable price .  When it arrived I tested of course the whistel and the Microphone first and it worked like charme with my 118 Train. Then I tested the 138 Electronic Box. It was working Forward and Stop. Backwards it was working, but only on very low speed or even not. I opened the Box (which is really easy compared to the 118 which is glued). Then I noticed that two Transistors got very hot in the Backwards mode. T2 and T4 got quite hot. If you look to the circuit diagram (many thanks for drawing it) it seemed that T2 is not working propperly. That is a problem with the old Germanium Transistors... Luckily I had some stock of old Germanium Transistors from my uncle. I put in an AC180 as replacement. That was the only PNP with high current rating I had. Another types which should work are AC128 or AC188. At the end now it is working like about 50 years ago .

[Siegfried]

On 31/10/2017 at 4:33 AM, Oliver77 said:

Hello,

just want to give some input to the 138 Electronic circuit. I already had one working 118 Train (but without whistle). Then I found on a marketplace one who offered the 138 Electronic Box, Microphone and the adjustable whistle for an really excaptable price .  When it arrived I tested of course the whistel and the Microphone first and it worked like charme with my 118 Train. Then I tested the 138 Electronic Box. It was working Forward and Stop. Backwards it was working, but only on very low speed or even not. I opened the Box (which is really easy compared to the 118 which is glued). Then I noticed that two Transistors got very hot in the Backwards mode. T2 and T4 got quite hot. If you look to the circuit diagram (many thanks for drawing it) it seemed that T2 is not working propperly. That is a problem with the old Germanium Transistors... Luckily I had some stock of old Germanium Transistors from my uncle. I put in an AC180 as replacement. That was the only PNP with high current rating I had. Another types which should work are AC128 or AC188. At the end now it is working like about 50 years ago .

Ha! This is an old topic. Thanks for the info! I still want to buy one...

[Paperinik77pk]

I have one without the little whistle...but clapping your hands works too 

I love this little train, it has a good "old toy fashion"!