TLU-01 control unit stppped working

[JezzaBB 1]

My TLU-01 control unit has stopped working.  A multimeter confirms current to the battery connector.  The switch is on, but there is no voltage reading on the output pins to the lights.  Am I doing something wrong or is this just a failed PCB?  I thought I would ask before ordering a replacement.  Any advice would be much appreciated.

[Tamiyastef 1967]

Have you measured the output while switching off to on and vice versa? Tamiya switches are quite fragile in my experience.  You could open the unit case and with a wire make a "bypass" for the switch and then measure again. Still no output? Check all the connections and parts on the board for damage. No obvious damage?  Then I would go for a replacement 🙂

[JezzaBB 1]

Thank you Tamiyastef for your rapid reply.  I am happy to bypass the switch on the board because there is alreay one on the supply circuit.  Looking at the picture below, which two locations do I need to wire across?

[Tamiyastef 1967]

I would try these two. 

[JezzaBB 1]

I have tried, but no change.  Could any of the components on the board, other than the switch have failed?  I guess I will have to go for a replacement.  Anyway, thanks for your help.

[Tamiyastef 1967]

You're welcome. If none of the other components show any damage I would go for a replacement.  I'm not into electronics to know what's the function of all those component. Sorry I couldn't help you better.

[WillyChang 1814]

On 8/16/2022 at 1:19 AM, JezzaBB said:

which two locations do I need to wire across?

umm, if that’s a typical Dual Pole Dual Throw switch ... i think you’ve soldered across the case mountings  nothing “electrical” 

The 6pins are 3 poles x2 

Centre pin of the 3 is common, switches to the left or right depending on the switch knob position

the pads of the PCB look like they’ve got 4 of the 6 pins all shorted together - this would be the “off” position

Short all 6 pins together to jam it On. 

[WillyChang 1814]

In any case, I’d doubt it’s the switch. 

Looks like there’s some component missing where it’s labeled 7XL (ish) on the PCB. 

Haven’t opened up a TLU-01 before but it’s a pretty involved circuit design imho. It seems to limit current to the LEDs by some fancy transistorised switching - i can some hum when it works. 

[Tamiyastef 1967]

Thanks @WillyChang Something new to learn every day. 

[JezzaBB 1]

Thanks for the advice.  I've taken the easy way out and ordered a replacement.  However, I will try shorting the pins as suggested.  As you say, always something new to learn.

[WillyChang 1814]

23 minutes ago, JezzaBB said:

As you say, always something new to learn.

I’d be curious if it’ll still work if slaved to the TLU-02  

When they first came out I got the 02 & 2x 01s to play with. Complex circuitry made it hard to DIY extra LEDs on a custom wiring loom. Otherwise if one fully loaded every LED slot with the Tamiya LEDs you’d have a rats nest of wiring weighing a kilo. 

[JezzaBB 1]

Stranger by the day.  I ordered a new unit and it also does not work.  My micrometer confirmed voltage to the red input plug at 7.45v.  no power to the lights but the unit got quite warm.  Tested the output the lights pins - no voltage.  This all with a vehicle whose light system has worked perfectly in the past.