[RikoRocket]

Good stuff Chris, but I've only got top end pulsing and do you reckon that adding a capacitor makes no difference at the top end

 

[chris99]

Riko, no difference at all to top end pulsing, so I'm guessing my problem is a flaky capacitor in my PB especially as it seems to come a go at the low end but the top end is always there and sounds different. At very low revs it's as if the power is intermittent.

Chris

 

[RichG]

Hi Chris

The Powerbase caps I am refering to are on the track piece, not in the Powerbase itself.

So we still have a top end pulsing problem?

Rich

 

[chris99]

QUOTE (RichG @ 10 May 2012, 20:47) <{POST_SNAPBACK}>Hi Chris

The Powerbase caps I am refering to are on the track piece, not in the Powerbase itself.

So we still have a top end pulsing problem?

Rich
Yes, I have capacitors on the track piece. Can I check them with a basic multimeter - if so, on what setting?

The top end pulsing is always there and my extra capacitor makes no difference to this. In fact, I only detect this pulsing when holding the wheels up and gunning it. As I don't have any very long straights I don't notice it when driving.

Does anyone actually notice it when racing?

Chris

 

[RichG]

If the caps are there and soldered in they will be fine, cannot be checked with a multimeter. They are usually 103, so I guess it just needs a bit more cap to get rid of the low end pulsing?

Rich

 

[chris99]

So attaching a 104M cap, taken from a broken SCX RX42 motor, to the rail makes all cars as smooth as butter & doesn't seem to interefere with digital.

A 103 cap is the same when the car is running on the track and you only notice the (reduced) low end pulsing (spiking rather) if you lift the car up.

So, in the short term, I've connected a 104M cap to a half straight via a powertap lead which I can remove easily and eventually I could solder it to the half straight & just put that in for analogue. Alternatively, I could just put 104 caps in all 21k+ rpm cars which is probably the most sensible.

Ebay has a few sites with cheap caps so I'll probably go for the 104 if there's no other downsides?

A couple of techie questions:
Does it matter what the letter is after 104 is (it's M in my SCX cars), and is the the volt no. important - I've seen 25,50 & 100?

Eg: this one is marked as 100nF / 0.1uF - Ceramic Disc Capacitor (104) - 25V?

Also do they need to be these brown ceramic ones as I see many different colours & materials?

Cheers
Chris

Edit: Just to clarify - this cap makes no difference to the max revs pulsing. It just seems to smooth over spiking in the low range power which is presumably from a faulty/out of tolerance component in my APB.

 

[RichG]

Most any cap will be fine for this purpose, dont go less than 25 Volts, the ebay one looks fine. M will be the tolerance, (20%) again not critical here. Only thing not to do in digital is to end up with too many of them in parallel as they add up and will eventually degrade the signal.

Rich

 

[GRUNZ]

Just read this topic as I got my first NSR porsches and I wanted to test them before chipping. My and Trevor's APB got the pulsing issue. I have also the slot.it SISP15 chips that I want to use for digitalizing these cars: am I right in saying that once the chip is in the pulsing issue is gone?

thanks.

 

[Gysse]

I run my nsr porsche 917 with the f1 chip without magnets, and they are exceptional runners. I got the pulsing in analog also, on my apb. I think you will be all good.