Pwm repairs

[jock1092]

So last night after finishing my new build, I dropped it and in catching it I lobbed my pwm mod hard against the floor

Now it's dead
It's an ne555 on a breakout board

I've opened everything up and can't see any damage to connections or the board, but no luck getting it back up and running

While it's a Cheap lot to replace, how should I go about finding what broke rather than just swapping things at random?

My thoughts are it's either the 555timer or pot, but that's a guess
Any advice or ideas?

It needed some tidying up anyway and a new sled, but I'd rather not fork out for another complete build just yet

 

[Miss Pepper]

@mattvapes1976 any ideas or pointers?

 

[mattvapes1976]

Ah , wish I could help you there jock ! Maybe someone like @mosfetius would have more idea ?

 

[mosfetius]

What's the symptoms? Is it dead.... dead! Do you get a reading at the gate when switched?

 

[jock1092]

What's the symptoms? Is it dead.... dead! Do you get a reading at the gate when switched?

No it was really dead
Ripped off some heatshrink I'd missed and found the wiper legs had snapped off at the board

 

[jock1092]

I spoke too soon
Re-assembling the mod I decided to check I'd wired the legs on the pot right by using my multimeter against the 510, slipped, shorted and I now still have a working mod
But it's just a series mosfet now, no whine, no voltage change vs 0-100 on the pot
This time I'm sure it's the 555 though
Edit - and my above findings where crap I found, the negative lead had snapped under heatshrink and was making poor contact in certain positions

 

[mosfetius]

I'd check the diodes, if it's acting as a series

 

[Tubbyengineer]

I think you need to pull it apart and rebuild, look closely at the bits - any sign of wear or damage then replace the part...

 

[jock1092]

I think you need to pull it apart and rebuild, look closely at the bits - any sign of wear or damage then replace the part...

Yeah it's been due a tidying up for a while anyway, think this is my best option
Needed to replace the sled anyway as it's been recycled through a few builds

 

[jock1092]

Got it back up and running now
But it's left me a question
The diagram i used originally had no wire gauges on it, what should I be using for the 555s Vin and ground
Having nothing to go on I went for thick wire but would thin control wire be good instead?
While using heavier gauges for the mosfet and 510