issue with my vintage fox

[oldtimernola 5]

Seem to have an issue with the throttle.  I have 20 plus vintage cars I have restored.  Most have all original electronics and MSC.  What I do, so I can take them on light runs, is I leave all the electronics in the cars and use a modern radio(fly sky).  I just put in the new receiver which is tiny and it always has worked perfectly while allowing the car to be all correct.  Now to the issue.  Plugged it all in and throttle goes wild.  Steering is fine. I even switched the channel and both servos work fine.  Played with all ch. 2 trim adjustments but no resolve. I can half throttle to stop the motor but when I let up it screams.   I realize it does not matter that it is a Fox, but is a pain because of the way you disassemble the chassis to access electronics.   Maybe I should take out pinion.  Was hard to stop it and disconnect batter when it was going wild, wide open. Whats funny is I set spa and end point and thought I had it, but no. When switch is on it does it, and also when off. Any ideas?

thank you 

[Running Fox 70]

Hello oldtimernola

Do I understand it right that you run a modern receiver, but the vintage MSC of the FOX?

You tell us 'I even switched the channel and both servos work fine.' Was the throttle servo connected tot the MSC at that moment an d were the motor cables connected to the motor at that moment? If so did it go wild then?

My fox goes wild like this when the receiverswitch is malfunctioning. What also could be the issue is that the MSC is not working properly. How scratched is the plate? Is it lubricated ok?

 

Kind regards,

Walter

[oldtimernola 5]

2 hours ago, Running Fox said:

Hello oldtimernola

Do I understand it right that you run a modern receiver, but the vintage MSC of the FOX?

You tell us 'I even switched the channel and both servos work fine.' Was the throttle servo connected tot the MSC at that moment an d were the motor cables connected to the motor at that moment? If so did it go wild then?

My fox goes wild like this when the receiverswitch is malfunctioning. What also could be the issue is that the MSC is not working properly. How scratched is the plate? Is it lubricated ok?

 

Kind regards,

Walter

Correct, I run a modern receiver with the vintage msc. Yes,  that is how the servo ch 2 for throttle was connected as were motor cables. It would go crazy. If I pulled throttle trigger a bit it would move msc to neutral.  Tried to adjust trim of the servo but no help there.  The msc is perfect. when I move it manually it works as it should.  Wonder if I have some other issue. The switch seems to be of concern as it would turn off , but if it was on and throttle was going turning it off did not shut it off. I had to disconnect battery.

Thank you Walter for helping me out.  I've never had this issue with any other of my vintage rigs. 

[oldtimernola 5]

Adjusted the exponential on ch 2 to negative 41 and its in neutral now.  So it can work like that , but I don't have to set the others like that. Still confused.  Not a fun rig to work on with the chassis in 2 pieces. Very annoying.  Have mostly matched my vintage ones with their reissue counter parts.  Was looking at a Nova Fox to pair with this one, but having second thoughts because of this awkward chassis set up.  I'll probably do it anyway

[El Gecko 1343]

Since you are using an MSC, I would check the servo and servo horn that are connected to the MSC to see if something is wrong there. Could be that the gears in the servo have skipped out of position but not stripped out entirely, or it could be that the servo horn (if it's plastic) has cracked and allowed the splines to skip or strip. Was the MSC servo centered with the Tx trim at 0 when the servo horn was installed?

Also, are you using a 4AA battery box or a BEC line from the MSC? Have you checked all the wiring for any cuts, crushed or melted areas that could cause a short or disconnect? It could be a faulty or loose plug somewhere too.

[Running Fox 70]

1 hour ago, oldtimernola said:

Adjusted the exponential on ch 2 to negative 41 and its in neutral now.  So it can work like that , but I don't have to set the others like that. Still confused.  Not a fun rig to work on with the chassis in 2 pieces. Very annoying.  Have mostly matched my vintage ones with their reissue counter parts.  Was looking at a Nova Fox to pair with this one, but having second thoughts because of this awkward chassis set up.  I'll probably do it anyway

I have them both (Fox and Novafox) but run the original completely vintage (Futaba AttackR) and the rere with ESC and 2.4Ghz. As the Fox was my first RC car, I was used to dismantle it every time before I got other cars (so I don't mind).

Is your antenna sticking out of the Fox coffin? :). Can't imagine why the car misbehaves if your testing was ok. 

[oldtimernola 5]

2 hours ago, El Gecko said:

Since you are using an MSC, I would check the servo and servo horn that are connected to the MSC to see if something is wrong there. Could be that the gears in the servo have skipped out of position but not stripped out entirely, or it could be that the servo horn (if it's plastic) has cracked and allowed the splines to skip or strip. Was the MSC servo centered with the Tx trim at 0 when the servo horn was installed?

Also, are you using a 4AA battery box or a BEC line from the MSC? Have you checked all the wiring for any cuts, crushed or melted areas that could cause a short or disconnect? It could be a faulty or loose plug somewhere too.

BEC is being used. All the wiring is like new as are plugs. This car was all original and the car itself was run once or twice from the looks of it.  I did check servo horn, that is fine as well.  A servo with stripped gears; I never thought of that and I will check that out. To be honest I forgot to check servo center issue.  I hoped it would not be that off and slight trim adjustment would fix that. Did not want to disassemble it so I was hopeful it would've been fine.  That could be the issue.  Guess I'll strip it down again and check.  

thank you again

[oldtimernola 5]

1 hour ago, Running Fox said:

I have them both (Fox and Novafox) but run the original completely vintage (Futaba AttackR) and the rere with ESC and 2.4Ghz. As the Fox was my first RC car, I was used to dismantle it every time before I got other cars (so I don't mind).

Is your antenna sticking out of the Fox coffin? :). Can't imagine why the car misbehaves if your testing was ok. 

The antenna is all good.  I wish it were easier to work on it without having the two halves to deal with.  It is a pain to me to not be able to work on it like a normal chassis set up. Especially when adjusting anything with the running motor  while on the bench.  If you have any tips on how to make it easier I would be grateful.  

thank you so much

[mtbkym01 4008]

Sounds like the servo is not centred on the horn to me, so when the servo centres, it’s moving the contacts on the MSC creating acceleration 

[oldtimernola 5]

Thanks guys.  It was the servo not being centered at neutral trim.  I can't believe I did not check that. I assumed it was.  Did  a few light runs and all is good. 

[Running Fox 70]

Great it works now! As for the ease of work: I've seen bodies with cut outs to make work/life easier.

[slimleeroy 241]

Lol sometimes you don't think of the simple things. I remember helping my son build his nova fox and I assumed the servo would be neutral from new. One assembled car later and I had to nearly completely take it apart to re-centre. Lol

[El Gecko 1343]

14 hours ago, slimleeroy said:

Lol sometimes you don't think of the simple things. I remember helping my son build his nova fox and I assumed the servo would be neutral from new. One assembled car later and I had to nearly completely take it apart to re-centre. Lol

How many times I've overlooked the simple things... and had to completely rebuild a gearbox (again) or a whole frontend (again) we're only human after all