Problem with the Steve, XP-7A & HP05S combo

[dbennettya]

Hi all,

I've discovered a problem that the Steve converter exhibits when combined with the XP-7A ESC and HP05S. I've had this problem with two seperate setups so far and I troubleshot the problem using my O'scope and battery. The problem doesn't happen when I use my 5A bench power supply only with a battery. The problem is a latchup of either the Steve output or XP-7A input. Basically the signal gets clamped at about 1.5 volts and only has about 1 volt amplitude during the latchup so the ESC doesn't see a valid signal.

Both setups worked without mods with the same the Steve, XP-7A and C05M motors. All I did was swap in an HP05S motor and the latchup started occuring.

The fix is to put a 2 to 10 Ohm resistor in series with the red wire going to the Steve converter from the V+ connection. This resistor allows signal integrity and prevents the latchup from happening.

Good Luck, Don

[brianp6621]

Originally Posted by dbennettya

Hi all,

I've discovered a problem that the Steve converter exhibits when combined with the XP-7A ESC and HP05S. I've had this problem with two seperate setups so far and I troubleshot the problem using my O'scope and battery. The problem doesn't happen when I use my 5A bench power supply only with a battery. The problem is a latchup of either the Steve output or XP-7A input. Basically the signal gets clamped at about 1.5 volts and only has about 1 volt amplitude during the latchup so the ESC doesn't see a valid signal.

Both setups worked without mods with the same the Steve, XP-7A and C05M motors. All I did was swap in an HP05S motor and the latchup started occuring.

The fix is to put a 2 to 10 Ohm resistor in series with the red wire going to the Steve converter from the V+ connection. This resistor allows signal integrity and prevents the latchup from happening.

Good Luck, Don

Aren't others on here using this combo? Thesteve/XP7A/HP05s?

[zeeflyboy]

Ah balls... That's the exact setup I was going to end up with.... I'd need to solder a resistor on to the tiny red wire between the steve and ESC?!

maybe I'll just leave my C05M in then.... Has anyone else had an issue with this combo?

How is yours wired up? Where are you taking signal from for the steve?

[brianp6621]

Originally Posted by zeeflyboy

Ah balls... That's the exact setup I was going to end up with.... I'd need to solder a resistor on to the tiny red wire between the steve and ESC?!

maybe I'll just leave my C05M in then.... Has anyone else had an issue with this combo?

Yeah, I was thinking of the same thing, HP05s swap for C05m. Really with all the soldering this mod takes, is one small resistor going to stop you?

[Pigs dont fly]

Ive got an XP7A and HP05s..all ok here, no resistors required.

[zeeflyboy]

Just out of interest then, where are you taking the signal from for the steve? From the little point on the back of the board?

[Pigs dont fly]

Off the resistor on the back.

[RedOctobyr]

My XP-7A and thesteve just arrived today, my HP05S is hopefully in the mail Thank you for figuring this out, Don.

When you say "so the ESC doesn't see a valid signal", what is the symptom we're talking about? The ESC kind of shuts off, and therefore the motor does too?

At least soldering in a single small resistor, inline with a wire, ought not to be very hard, if that turns out to be required. I'm not questioning your find, Don, it's just curious that others haven't reported this as well, if the symptoms are obvious (eg- motor shuts off).

Edit: I forgot to ask, do you have anything "unusual" in your ESC programming?

[zeeflyboy]

Does seem like a fairly common combo in the "hunt for best outrunner" thread, but no one else seems to have had the same issue in there...

I guess the question don, is are you also taking the feed from the small resistor on the back or from the motor outputs with a resistor? That's the only point of variation that I can think of given the same convertor, esc and motors.

[liftbag]

Actually I have two mentioned combos and no problem.
But, in many experiments, sometimes I happened to have some communication problem between the esc and the converter.
Sometimes the motor starts and sometimes not. Changing the wiring it was resolved.
Don, is this what we are talking about?

[dbennettya]

In both my setups I take the power for the Steve from V+ on the big red wire on the ESC and ground from the normal output to the RX. Power to the ESC comes from the main board connections. Signal to the Steve comes from Jon's connect point.

The symptoms are that when power is applied the ESC initializes and gives the proper tones. Then when you give throttle nothing happens because the signal to the ESC is clamped and isn't a proper signal for the ESC to work.

I soldered a 2.2 Ohm resistor to the ESC power connection V+ and then connected the Steve red wire to the other side of the 2.2 Ohm resistor and the circuit works great with no more latchup.

While troubleshooting this issue I used my O'scope to look at the signals and you can clearly see that without the resistor the Steve output gets clamped to ~ 1.5V and has about 1V amplitude when powered from a battery. This doesn't happen if I use the series resistor or if I use a 5A bench power supply with the resistor. I noticed that the clamping of the signal occurs right after the ESC initializes but before that was the proper signal of about 0 to 4Vpp on the PPM output.

Trust me I know what I'm doing and this is a possible issue that may affect some setups and not others. It is most likely SCR latchup in one of the ICs due to fast rise times of the voltage or a race condition.

YMMV, Don

[brianp6621]

Originally Posted by dbennettya

In both my setups I take the power for the Steve from V+ on the big red wire on the ESC and ground from the normal output to the RX. Power to the ESC comes from the main board connections. Signal to the Steve comes from Jon's connect point.

The symptoms are that when power is applied the ESC initializes and gives the proper tones. Then when you give throttle nothing happens because the signal to the ESC is clamped and isn't a proper signal for the ESC to work.

I soldered a 2.2 Ohm resistor to the ESC power connection V+ and then connected the Steve red wire to the other side of the 2.2 Ohm resistor and the circuit works great with no more latchup.

While troubleshooting this issue I used my O'scope to look at the signals and you can clearly see that without the resistor the Steve output gets clamped to ~ 1.5V and has about 1V amplitude when powered from a battery. This doesn't happen if I use the series resistor or if I use a 5A bench power supply with the resistor. I noticed that the clamping of the signal occurs right after the ESC initializes but before that was the proper signal of about 0 to 4Vpp on the PPM output.

Trust me I know what I'm doing and this is a possible issue that may affect some setups and not others. It is most likely SCR latchup in one of the ICs due to fast rise times of the voltage or a race condition.

YMMV, Don

Any reason you didn't power thesteve from the small red wire on the ESC? are they electrically different? That's how I have mine wired (and I assume some others) but I don't have the HP05s

[Uncle Chop Chop]

Just received my HP05s/XP-7A/Program card about five minutes ago. Waiting on theSteve and haven't even ordered the pinion yet. In a way, I'm glad I haven't started with the conversion with issues such as this popping up. While the majority using the above-mentioned setup aren't having any issues, it's probably in my best interest to buy a bit of time so that most of the kinks are ironed out. Knowing my luck, I'll probably encounter each and every issue mentioned so far.

Think positive, Chop Chop!

EDIT: Must recommend Terence from ChineseJade. Great communication and 7 day shipping.

[dbennettya]

Yes, others have reported problems when powering from the small red wire to the ESC. This is probably due to the voltage drop from the LDO regulator that is on the XP-7A as it drops about 0.3V from the V+ which could affect margin when getting to lower voltages.

So I chose to run it directly to V+ which is the best way for a 1S setup.

YMMV, Don

Originally Posted by brianp6621

Any reason you didn't power thesteve from the small red wire on the ESC? are they electrically different? That's how I have mine wired (and I assume some others) but I don't have the HP05s

[fusionsx00]

My suggestion for all bl modders

Pull the motor wire and plug from the stock mcpx

At the end where the brushed motor was soldered
Solder the resistor there.

Then solder the yellow wire to the resistor.

Now the steve is plug and play.

Now for the red power lead

Just solder a extra wire from the mcpx power lead
attach the resistors to this lead. Then you can solder direct
or solder a small plug similar to the stock motor plug.

Im working on a plug and play convertor, for those who don't want to solder.

I hope I don't get side tracked, but I did order the plugs,wires,resistors

I just need a better price on the convertor.

I think my plug and play will work for alot of eflites all in 1s

Ultra micro planes, msr,mcpx ect

[liftbag]

Originally Posted by dbennettya

In both my setups I take the power for the Steve from V+ on the big red wire on the ESC and ground from the normal output to the RX. Power to the ESC comes from the main board connections. Signal to the Steve comes from Jon's connect point.

The symptoms are that when power is applied the ESC initializes and gives the proper tones. Then when you give throttle nothing happens because the signal to the ESC is clamped and isn't a proper signal for the ESC to work.

I soldered a 2.2 Ohm resistor to the ESC power connection V+ and then connected the Steve red wire to the other side of the 2.2 Ohm resistor and the circuit works great with no more latchup.

While troubleshooting this issue I used my O'scope to look at the signals and you can clearly see that without the resistor the Steve output gets clamped to ~ 1.5V and has about 1V amplitude when powered from a battery. This doesn't happen if I use the series resistor or if I use a 5A bench power supply with the resistor. I noticed that the clamping of the signal occurs right after the ESC initializes but before that was the proper signal of about 0 to 4Vpp on the PPM output.

Trust me I know what I'm doing and this is a possible issue that may affect some setups and not others. It is most likely SCR latchup in one of the ICs due to fast rise times of the voltage or a race condition.

YMMV, Don

Don, very interesting write up

I have long suspected some sort of interference to communication between esc and converter.
Three days ago I disassembled the HP08s /9T / XP12A combos to replace it again with the HP05s / 8T / XP-7A.
I connected the power cables of the converter with those of the ESC.
In a vain attempt to limit the interference I put two sheets of aluminum between the double-sided tape



As a result, the esc is initialized, but the motor would not start.

Then I moved the red and blue wires of the converter at the points shown in the picture.




The motor has been worked and I've had no more problems.
Once I worked with O'scope. These days I really miss it.

[dbennettya]

Liftbag,

It looks like those points may have enough impedance to provide the same function as a resistor does.

I thought about this a little more and it seems the motor is part of the problem because when the ESC initializes it beeps the motor which could give a little inductive kick and somehow cause the latchup. Remember just changing from C05M working to HP05S then not working unless series resistor or possibly your connect points for the Steve power. I haven't scoped the power on the board during startup / latchup, might be interesting but I'm having too much fun flying

Anyways, I hope this information will help others.

Don

[ValHeli]

This is STICKY MATERIAL! I hope one of the mods is looking at this.

BTw, Liftbag. Where is your steve white connected to? And the 3 copper wires?? Where are they connected?

Pictures are excellent!!! I just love that picture in picture effect

[RedOctobyr]

Don, thank you for sharing all this. I certainly couldn't figure this out, beyond maybe "My motor stops responding, I don't know why" Kudos to you, must be nice to be able to troubleshoot this kind of stuff!

Does the resistance you use make a big difference? I see that Radio Shack sells 10 ohm, 1/4W resistors. In looking through their site, I'm not noticing small resistors under 10 ohms. Does that one sound suitable?

What changes as a result of going to a higher resistance? As I understand it, this is just a signal wire, so you won't be reducing motor power or anything. But I don't know if this changes the signal going to the ESC at all?

[brianp6621]

Originally Posted by RedOctobyr

What changes as a result of going to a higher resistance? As I understand it, this is just a signal wire, so you won't be reducing motor power or anything. But I don't know if this changes the signal going to the ESC at all?

Actually the Red wire to thesteve is power for thesteve, i believe, so I would think you'd be dropping the power voltage delivered to thesteve. Maybe this is what is needed to fix this issue but you're right it shouldn't effect motor power as thesteve is just converting the signal and delivering it to the ESC.

But that raises a really good question, are the red and blue really just + / - for the power to thesteve. If so, why are there so many different places to connect them, to the 3in1 power leads, to the ESC red/black, to the 3in1 points in this thread, with a resistor etc...