Author Topic: Before I Go Insane (Read 987 times)

soninja8 · « **on:** May 05, 2011, 06:49:57 PM »

Okay, I have a 75mhz Hitec HFS-30MM receiver. It was working fine, but then it just has stopped. The green light still is on when I plug the battery into the receiver, but it doesnt drive my servos. I first thought it was the crystal, so I replaced both, but it still is not working!!! Please help!!!

MikeK · « **Reply #1 on:** May 05, 2011, 07:35:18 PM »

Can you scope the output? Or does your DMM have a frequency counter?

soninja8 · « **Reply #2 on:** May 05, 2011, 07:47:35 PM »

Im new to robotics, so can you dumb it down...sorry!

MikeK · « **Reply #3 on:** May 05, 2011, 07:54:09 PM »

What test equipment do you have available?

soninja8 · « **Reply #4 on:** May 05, 2011, 07:57:28 PM »

Mulitimeter, lots of tools, soldering gun....i have a whole garage full, so if you name something i need to test it, tell me

corrado33 · « **Reply #5 on:** May 05, 2011, 08:09:50 PM »

Scope = oscilloscope DMM = digital multimeter.

soninja8 · « **Reply #6 on:** May 05, 2011, 08:13:19 PM »

I have a digital multimeter...but how would that help in this situation

MikeK · « **Reply #7 on:** May 06, 2011, 05:51:38 AM »

If the DMM has the ability to measure frequency you can use it to see if the servo controller is outputting anything. It should be between 500Hz and 1 kHz.

TrickyNekro · « **Reply #8 on:** May 06, 2011, 07:15:52 AM »

No no no.... It should be 50Hz... 20ms a pulse... That means somewhere around 50Hz...

And it depends on the multimeter... but most multimeters that have frequency metering using mean it's a square pulse,
like the one a servo receives.

If it has frequency metering, then it should also have duty cycle checking.
Should my assumption be correct then, you could see if the receiver "receives"...

How, get the multimeter on duty cycle and then play with the remote, if the value changes then you are good with
the receiver and problem may be on the power feed...

Regards, Lefteris

Admin · « **Reply #9 on:** May 06, 2011, 09:13:43 AM »

step 1: check the voltage on your batter(ies), the receiver and remote battery
step 2: plug everything in and see if anything is overheating
step 3: use your multimeter to check that ground is 0V and power is above 5V
step 4: check the PWM signal line

If your DMM doesn't have a frequency setting, set it to voltage. If the PWM is working, it'll give you a voltage slightly higher than 0V.

MikeK · « **Reply #10 on:** May 06, 2011, 03:16:29 PM »

Quote from: TrickyNekro on May 06, 2011, 07:15:52 AM

No no no.... It should be 50Hz... 20ms a pulse... That means somewhere around 50Hz...

Woops. I did the inverse of 1ms and 2ms for some stupid reason.

soninja8 · « **Reply #11 on:** May 06, 2011, 10:54:42 PM »

here is my digital multimeter...i got 56.3Hz when I checked the leads, but it doesnt go up or down when i play with the remote...any suggestions

Admin · « **Reply #12 on:** May 07, 2011, 07:05:20 AM »

Quote from: soninja8 on May 06, 2011, 10:54:42 PM

here is my digital multimeter...i got 56.3Hz when I checked the leads, but it doesnt go up or down when i play with the remote...any suggestions

What's the voltage going into your servos? (the other two wires)

Soeren · « **Reply #13 on:** May 07, 2011, 07:55:43 AM »

Hi,

Quote from: soninja8 on May 06, 2011, 10:54:42 PM

here is my digital multimeter...i got 56.3Hz when I checked the leads,

The meter shown in the photo cannot measure frequency, so how did you arrive at 56.3Hz?
(56.3Hz would be fine, I just don't see how you could measure that).

Quote from: soninja8 on May 06, 2011, 10:54:42 PM

but it doesnt go up or down when i play with the remote...any suggestions

The frequency is not supposed to change. The repetition rate of the servo pulses should be around 50Hz and only the width o the actual pulse changes (and the change is 1ms, which equates to 5% of the period).

soninja8 · « **Reply #14 on:** May 07, 2011, 12:58:50 PM »

I turned it to the one right below the off switch...the 200....in the manuel it says to switch it to that to measure fequency....

Quote from: Admin on May 07, 2011, 07:05:20 AM

What's the voltage going into your servos? (the other two wires)

5.63v

Admin · « **Reply #15 on:** May 07, 2011, 02:20:51 PM »

Quote from: soninja8 on May 07, 2011, 12:58:50 PM

Quote from: Admin on May 07, 2011, 07:05:20 AM
What's the voltage going into your servos? (the other two wires)

5.63v

Whats your battery type? If it's a 6V NiMH type, your problem is a dead battery

soninja8 · « **Reply #16 on:** May 07, 2011, 03:01:00 PM »

no, its 4 x AA, its a holder...i have already tried replacing batteries for everything

VegaObscura · « **Reply #17 on:** May 07, 2011, 03:49:19 PM »

Sounds like a problem with your remote.

Admin · « **Reply #18 on:** May 07, 2011, 03:58:10 PM »

4 AA of which type?

And you also checked the xmitter battery, right?

soninja8 · « **Reply #19 on:** May 07, 2011, 05:36:56 PM »

Quote from: Admin on May 07, 2011, 03:58:10 PM

4 AA of which type?

And you also checked the xmitter battery, right?

yes, i have replaced the transmitters batteries too, im pretty sure its not the tranmitter thats the problem

its just duracell alkaline betteries....they have always worked for me

Soeren · « **Reply #20 on:** May 07, 2011, 07:54:22 PM »

Hi,

Quote from: soninja8 on May 07, 2011, 12:58:50 PM

I turned it to the one right below the off switch...the 200....in the manuel it says to switch it to that to measure fequency....

It it the 200 Ohm range you're referring to? (This gets weirder every moment).
Your meter cannot measure frequency and measuring voltage on a resistance range may even damage the meter.
It's a cheap Chinese meter that is sold in several iterations with different colors and markings and with or without a protective cradle - I have 3 slightly different versions of that meter, all with the same basic functionality - all carry different manufacturers names (OEMs), but are identical inside and nearly so on the outside - and they can not measure frequency (none of the really cheap meters have that function).

Quote from: soninja8 on May 07, 2011, 12:58:50 PM

Quote from: Admin on May 07, 2011, 07:05:20 AM
What's the voltage going into your servos? (the other two wires)

5.63v

Quote from: soninja8 on May 06, 2011, 10:54:42 PM

here is my digital multimeter...i got 56.3Hz when I checked the leads, but it doesnt go up or down when i play with the remote...any suggestions

I think you need to read a good tutorial on using a DVM, because it seems like you mix up what you measure.

soninja8 · « **Reply #21 on:** May 07, 2011, 08:17:25 PM »

Well then, it seems like I'm going to just get a new receiver since it seems as though I need a new multimeter too, thanks for your help though guys!

P.S. if anyone knows a cheap single conversion hitec receiver that they can link before monday when I buy a new one that would be awesome

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Author Topic: Before I Go Insane (Read 987 times)

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