How do I test electornics?

[Graham 0]

Okay, this is the gist:

I bought a trashed Stadium Blitzer off eBay, but the truck had a relatively new radio system, which is what I wanted. Got it for a song.

The servos, receiver, and speed-control all look to be in excellent condition, as does the transmitter.

I hooked the servos to the receiver, as well as the speed control. I then attached a charged battery to the speed control.

Nothing! No movement in the servos. Did I do something wrong? (yes, I tuned the switch On . . . ).

I then attached the leads to the motor, and when I moved the speed control, the motor was dancing! So I know current was flowing . . .

Any tips? I'd like to make sure I didn't get screwed on this auction, and I really don't want to shell out a ton for new servos . . . .

[Jimmy_GT-R 5]

On the servos there is 3 wires, 2 of them are for carrying the frequency and 1 is for the power, or it may be the other way round, but anyways, check that no wires are loose from their connectors or any wires are fraid. Also check that the slots for the servos in the receiver still have their 3 prongs for the servos connectors to fit onto.

Thanx

Jimbo

[Graham 0]

Okay, thanks, Jimbo.

So it's safe to say I didn't do anything incorrectly? That's my other big concern . . .

[Jimmy_GT-R 5]

U didn't appear to do anything wrong. U can't really go wrong with attaching a battery and hooking the servos upto the receiver, so if there not working check them on someone elses receiver, etc, to see if they work. And slowly u will find out whats wrong.

Thanx

Jimbo

[BalmyBaldwin 0]

I know you would probably have thought of this, but its worth saying;

Are the Crystals in place securely?

Have you tried hooking up just a receiver battery pack rather than a racing pack via the speed control? - The BEC might be fried!

Are you testing it with a manual speed control, or a ESC?

[mr_lister999. 3]

rotate the servo wire plug 180 degrees so it fits the other way around. You may have it in backwards. I have always found the black wire goes to the outside of the reciever. hope this helps.

[WillyChang 1814]

If you have another RC system with compatible plugs, simple systematic substitution is the best troubleshooter.

RX should be powered from max 6V unless it has BEC, then it can take 7.2V direct. There should always be a "BEC" symbol on the RX.

If you've plugged the servos in correctly to the receiver, they should both twitch a little when power is connected. Do they?

If they don't twitch then chances are the servos aren't working. If they're not connected properly in correct polarity then they'll be fried by now.

If they do twitch then... check to see if you have matching pair of xtals! Sometimes 2nd hand radios don't even come with xtals... let alone matching pairs. Try other xtals too, for xtals can get damaged.

TXes don't get damaged easily, but you never know. Try another TX if you have one, swap in the correct xtals. All AM gear is interchangeable, don't worry about the brand.

All servos are interchangeable too, just match the 3 wires:

red = power +ve

black = power -ve, gnd

orange/white/blue/black = signal

If you're swapping plugs, double check everything before powering on. If they're plugged wrongly you'll have no second chance. It only takes an instant to fry the control electronics in a servo.

[DJTheo 2]

As far as I had heared back in the good ol' days [], there used to exist RCs with negative and RCs with positive signal, servos weren't interchangable... []

[c_a_r_t_e_r 0]

Hi there.

As previously mentioned it could be your xtals.. but just as a point of interest, I've noticed that all my Blue transmitter xtals seem to have turned green with age.. or is that green turning to blue - I can't remember anymore!

You'd have thought that the manufacturers would have used light-fast labels..[]

Check the frequency printed on the side just to be on the safe side - there's a chance the previous owner got confused like I have in the past..!

Tim.

[SteveH(2) 0]

What make are the servos and receiver?

If they are different makes, switch the red and black wires in the servo plugs.

It's very rare you will blow a servo by plugging it in the wrong way.

[WillyChang 1814]

quote:Originally posted by DJTheo

As far as I had heared back in the good ol' days [], there used to exist RCs with negative and RCs with positive signal, servos weren't interchangable... []

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id="quote">id="quote">

Think that was in the 1960s, Theo.

Then in the 1970s they standardised the signal's pulse frequency too.

And in the 1990s... some bright spark decided to standardise everything to either Futaba-J or the Sanwa blue plug.

Jeez we have it easy these days!! []

[DJTheo 2]

quote:Think that was in the 1960s, Theo.

id="quote">id="quote">

I am a vintage Tamiya fan WIlly but not like that!!! []

Nope, this happened to me in the end 80s where I got a servo which didnt work with my existing Futaba/Robbe RCs and the guy at the shop told me it wouldn't.

[WillyChang 1814]

quote:Nope, this happened to me in the end 80s where I got a servo which didnt work with my existing Futaba/Robbe RCs and the guy at the shop told me it wouldn't.

id="quote">id="quote">

Hmm... some of the old (ie 1960s) systems had proprietary communications between RX and their servo actuators. So anything is possible if its *that* old.

I only got dragged into RC later on, ~1970s... when Futaba sold "reverse" servos when the need arose - no such thing as a servo reverse switch!! (Heck, radio systems were extremely expensive back then too!!)

All these were already "modern" digitally proportionate systems. Thought the RX puts out a simple squarewave on the signal line... and being this style would make the signal go from 0V=gnd to +5V=+ve.