Store: Scalextric
Scalextric US English $
M Menu
b 0 Items s

Dr_C

All Posts

Dr_C

296 posts

Hi MichaelDrago,

I am sorry to report it does seem likely that the brake transistor Q1 or Q3 is damaged and giving a short circuit... which has the effect of holding the brake in the on condition. There is a small chance there is a short circuit elsewhere on the copper tracks but we cant see anything in a position that would cause this type of short circuit. The earlier identified curved marking,.. if it was a short between tracks would have the effect of presenting the brake from turning on... so cant be the problem.

The challenge in replacing Q1or Q3 is that they are surface mount conponents so quite difficult to handle. I could take a look at it for you... but the postage costs times 2 between uk and usa would I think exceed the value of the powerbase. I wonder if Scalextric customer service might be able to help with a replacement?

 

C

Dr_C

296 posts

First, the car needs track power to power up the IR LED... so fitting the SICH10 without electrical connection could never be expected to register laps in digital mode. For the test to be valid the car needs track power.

 

Next, if you are comparing with analog cars... sounds like you may have then switched the powerbase from digital to analog mode... for analog the track IR photosensor for ID is not used at all.

 

C

Dr_C

296 posts

Hi dd213, did you try loading the BLE v2.6 firmware onto the ARC PRO using nRF tools? If so, what happened?

 

C

Dr_C

296 posts

I still believe it would be useful to try the slot.it SICH10 guide blade as a potential interim solution... I agree that Scalextric should offer a solution if ultimately it is proven to be a design issue... but the SICH10 is little more than the cost of a good cup of coffee... so worth a try?

 

C

Dr_C

296 posts

Hi MichaelDrago,

What you have found may be significant... perhaps along the lines of a defect during manufacturing whereby the copper material has not been fully etched away between the tracks on the circuit board. Given these narrow tracks connect with the gate drive of the power MOSFETs... might be the problem... please leave as is for the present and I will get back to you with a test procedure to establish if these are indeed short circuits between the copper tracks... looks promising progress...

 

C

 

Dr_C

296 posts

The small switch on the side of the power base is moved towards the track for ANALOG and away from the track for DIGITAL.

C

Dr_C

296 posts

So we are looking at the possibility of a short somewhere between the pcb copper tracks or a failed Q3. This is the transistor which applies the brake function to one of the lanes when activated, i.e. when its gate electrode is driven positive by a signal from the main microcontroller. The transistor should normally be open circuit. This is a surface mount transistor so a little bit of a challenge to remove. Lets look at the photographs before considering next steps. How are your soldering skills and/or dremel skills?

 

C

Dr_C

296 posts

OK, I suggest the following next steps...

 

1/ please visually inspect the area where you removed the flek... is there any chance the copper track is visibly bridging between pin 3 and pin 4? Another photo would help ifpossible please?

 

2/ with the 15V power supply completed disconnected, and with the four pin track power plug also removed please take five measurements with the meter set to the lowest resistance measurement setting. Please measure resistance between pins 1 and 2 - then again with the probes reversed. The please measure resistance between pins 4 and 3 - then again with the probe pins reversed. Finally measure the resistance of the probe leads by touching the two probe tips together directly.

 

This data should help with final pin-pointing ofthe problem...

 

I still suspect the site of the flek of debris I am sure together we can get this powerbase back into full working order... which continent do you live in?

 

C

Dr_C

296 posts

Just to add clarity... the flek of debris is located precisely where, if the solder mask was missing... an electrical short would result between ground and the PWM track output.  This would lead to a current overload whenever the corresponding throttle controller is pressed... sound familar?

 

C

Dr_C

296 posts

Interesting... the photos do appear to show a small flek of shiney metallic debris between pins 3 and 4 of the track power socket. I am using the convention that the square pad is pin 1. Pin 3 is ground and pin 4 is PWM power for one of the lanes. This could be the problem... although normally the green solder mask would prevent a short circuit for this type of debris... but then perhaps the problem was caused by a pin hole in the masking material... maybe...

 

Would be useful to see if the flek can be removed using something insulating and soft such as a wooden cocktail stick. But dont press too hard as you could damage the electronic tracks underneath.

Two questions...

1/ do you have a digital test meter.

2/ if you trace the faulty lane back to this socket, does this lane correspond to pins 3 and 4?

 

C

 

Forum Rules

  • The Scalextric Forum is intended for discussion of slot-car racing. Primarily, a place for newcomers to ask questions and seek assistance from like-minded individuals, the Scalextric Forum offers users the chance to join an active and friendly community.
  • Discussion of other slot-car brands is allowed, however, active promotion or advertising of our competitors is not permitted.
  • Please keep in mind that the Scalextric Forum is a publicly viewable space and you should never post personal information (including email addresses).
  • While every effort is made to contact you before any censorship, we reserve the right to amend or remove any content without explanation.
  • All customer service enquiries should be directed to Scalextric Customer Services.

Useful Links

Forum Guidelines


Membership Restricted Product