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[298]

Hi All, this is my first posting here so sorry if it's a bit basic. I'm building a Lindberg Tug kit and am using a 2 channel Acoms RC.

I have fresh Alkaline batteries in the reciever battery compartment and fully charged NiCads in the Tx. All three lights on the Tx are on to show there is sufficient power there, and the servo's move slightly when the battery switch is turned on. However, that's about it. No response from the servo's when I move the sticks on the Tx, even at close range and with both aerials extended.

Am I missing something....? Can't say i'm too impressed with the quality of this kit, as I had to tweak some of the battery connections in the Tx. Everything appears to be connected OK, with the TX cells giving about 10.5v and the Rx about 6.2v. I'm sure the battery connector into the Rx is connected properly, as although there are 3 pins, it'll only connect with the right hand pair.

[Martin (Admin)]

Hi 298!

Don't tell anyone but I've always liked Accoms radio gear despite the opposition!

1. Is it new radio gear?

2. what are the No.s on the TWO crystals? (If it is 27 or 40MHz radio - could be 2.4Gig)

3. Any chance of pictures?

Martin - Admin

[andrewh]

Hi 298, or may I call you 2

Acoms gear works for me, too.
Anyway all the bits have to be functional for it to work - and we can check the obvious:

Your Tx seems to have power, and enough power
If the servos twitch when you plug in the battery it SUGGESTS that you also have power there
Do you have a meter that can read volts?
What Batteries?  is it a rechargable pack or disposables?  if you can measure voltage check that you have enough voltage - which means more than 4.5V approx.
Are your servos plugged in the right way?  The signal wire (lightest colour (yellow on a new Acoms servo) must be nearest to the electronics of the receiver - but we need a photo to be able to show this)
The Rx battery plugs in so its black and red wires are in the same receiver pins as the servo black and red wires
 In the pic , if your rX is a bit like this the servos are plugged in so the black wire is the furthest to the right (servos and power lead)
and the servo yellow wire to the left (nearest to the crystal on this receiver)

Two things which cause your symptoms exactly are crystals and low receiver battery power
Are the crystals the right frequency for the radio (27 for 27radio?)
Are they in the right bit of kit?  The Tx and Rx crystals are different (by the IF frequency(s) if you are interested) so the one labelled T or Tx must be in the Transmitter and (curiously) the one labelled R or Rx in the receiver
hope some of this may help
andrew

[andrewh]

btw,
Just realised you are doing a lindberg tug!
This is a lovely little beast, and many of them are powered by modified servos.

Don't want to spook you , especially if the radio gear is new, but it is not too  difficult to modify servos so that the motor can be used as the drive motor, and the electronics become a forward/reverse speed controller.

If you even THINK about this don't tell FLJ, who makes and sells the most perfect little micro speed controls and motors with no need to go diving into a servo.
andrew

[298]

Thankyou all for your quick replies. It's a brand new Acoms 40Mhz kit from Antics, and the crystals only have TX Band 90 and RX Band 90 on them (and no, I haven't mixed them up). I was planning to see how if the modified servo has enough power to tow a small Railroad Car Float, plan B would be to use a motor and speed controller. I wasn't planning to extend the Hull, so too much weight or power could be an problem...

Here are a few photos:

[catengineman]

I know you have posted pictures of your REC with a servo fitted and the power plug put into the BATT position one question I will ask is

are you sure that the power plug is the correct way round. then plug it into the spare channel socket to see if that makes a difference.
I do notice you are using a BEC REC and I think that there may be a problem with your power supply and the BEC in the unit. ? but I have been wrong several times in the past

R, I have a REC from ACOMS which now only works with power from an ESC?

[Roger in France]

Probably nothing to do with your problem, but.....

Your tiller linkage is working in two different plains. the servo is trying to turn in the vertical pain and the tiller arm in the horizontal. That maybe Ok for a small range of movement but I do not think it is ideal for the distances a rudder moves.

If you disconnect the linkage, does the servo turn OK?

Roger in France

[298]

I know you have posted pictures of your REC with a servo fitted and the power plug put into the BATT position one question I will ask is

are you sure that the power plug is the correct way round. then plug it into the spare channel socket to see if that makes a difference.
I do notice you are using a BEC REC and I think that there may be a problem with your power supply and the BEC in the unit. ? but I have been wrong several times in the past

R, I have a REC from ACOMS which now only works with power from an ESC?

I tried plugging the battery connector into the Reciever as you said, apart from a brief servo chatter there's no movement. I'm happy it's all connected properly.

[298]

Probably nothing to do with your problem, but.....

Your tiller linkage is working in two different plains. the servo is trying to turn in the vertical pain and the tiller arm in the horizontal. That maybe Ok for a small range of movement but I do not think it is ideal for the distances a rudder moves.

If you disconnect the linkage, does the servo turn OK?

Roger in France

The linkage is just a trial I copied from another Lindberg Tug on the internet, as there isn't space to stand the servo upright. If the range is insufficient i'll have to move the servo.

[andyn]

About 90% of the motor's power is going to be taken in turning that coupling. In my plastic kit conversions, I use 2/3 layers of heatshrink, put them all on beforehand, you'll need different sizes of heatshrink of course, and heat them up. Works perfectly, I've not had one slip yet

[FullLeatherJacket]

I reckon that set is more trouble than it's worth. I'd send it back and get a proper set if I were you.
 
Back when Tamiya introduced their first electric hedgehog Sand Buggy we used to know the whole phrase of which ACOMS appears to be an acronym. I can't remember all of it but the C alluded to the state of things brown and sticky. Seems like certain things in life don't change much.

Shame you've trashed the servo; as has been mentioned, there are less problematical solutions to powering small models.

Suit yourself.

FLJ

[catengineman]

That is very close to what my Acoms REC did and I can only use it with the like of a Mtronik ESC with that supplying the REC with power through the number 1 channel point  (mine is three chan) and a servo in the no's 2 point
If I remove the ESC red wire and fit a battery pack to the REC just a little twitch then nothing, tried the radio with a different REC (same Xtails) all was fine tried different Xtails in 3 chan Acoms fine with ESC power but nothing on battery pack?
so now use  that with the Mtronik 15 and servo in my springer thingy

R,

[malcolmfrary]

Having been using my Lindberg tug (look for GYTHA in the readers models section of the main Mayhem site) for mmnnff years, I would make the following points.
1.  I would worry about the rudder linkage below the deck, being a tug this is VERY near the water, and a potential leak risk.
2.  I would have no worries about the plane of operation of the servo and the tiller arm being at right angles to each other.  I do this on a regular basis (see the Tuna Clipper as above).  The steering servo can sit at the front, upright or otherwise.
3.  How does the UJ connect to the servo motor spindle?  These tend to be very short, not as far out as the coupler screw is in, so the coupler could be hard against the back face of the servo, giving friction.
4.  Do the electronic bits work outside the boat?  i.e. with no load and where you can get at them.
5.  What is the RX batt voltage under load?  I use rechargeables (four in a home made sausage string nder the after deck) as they can deliver much more current.  Also took the opportunity to hook up a recharging socket so that the battery could be left in situ.  Trim can be a bit critical in these small ones.  If the drive motor is stalled by friction, it might be robbing the rest of the setup of power.

Try plugging the power into one of the control channels, see if the remaining one bursts into life - if it does, theres a dud connection in the intended power position.  I first saw that on a Futaba set.

For a little work with a soldering iron, ACTion do some very nice small motors with spindles at a modest cost, and electrically identical with the servo motor.  The servo control card provides a fully proportion control, its just that the deadband is dead narrow, as is the proportional control, but you use the trim tab as an engine room telegraph rather than the stick.

Power.  It is quite happy pulling a Revell Corvette around.

Seaport tug?  Go for the Tuna Clipper, only make your own running gear, much more fun.  If the radio s a dud, it will be just as dud in anything else.

[sheerline]

Hi 298. I have read your post and some of the replies which are useful bits of information. If you know little or nothing about radio gear, having a fault like this can be a good learning curve. If desperate, you still have a warranty so can chuck it back if all else fails anyway.

Couple of things you could try here:
If possible, beg, borrow, steal another pair of known working crystals to try in the set.

Failing that and in desperation if you want to know if the transmitter is putting any signal out, try this:
Turn on your domestic radio , turn the volume up a bit put the transmitter right up close to the set (virtually touching) and switch it on. You should hear your domestic radio making a loud hiss and it will probably lose any signal it is receiving because the transmitter signal (if you have it) will swamp the radio. By tuning your radio up and down the band, you may actually be able to hear your transmitter signal buzzing and if you mobve the sticks, you will hear the buzzing sound change pitch slightly.

This will at least prove that the transmitter is putting some power out to the airwaves if nothing else. You can then to begin to suspect the receiver or it's crystal.
Worth a try.
Chris

[DickyD]

Last time this happened to me it was because I was having an old moment and plugged my servo and throttle connections into the wrong sockets on the receiver.

[FullLeatherJacket]

And who is it you are referring to as the novice?

Shipmate Member "298" 5 posts. Fairly obvious if you re-read the thread.

And not just say his stuff is rubbish should have gone to you!

Can't seem to find where I actually said this. We don't make radio sets in any case.

BTW I can probably name eight customers who have all suffered very similar problems with this make of radio - I shall know where to refer them in future.

FLJ

[Martin (Admin)]

Ah, we have here, the now well known "Mayhem Effect!"

                                    "One simple question, so many answers!"

Age old principal: KISS, Keep It Simple Stupid..... (no offence to anyone).

1. Did you try the radio new out of the box?
2. Did it work then? (Yes, something has failed or you've done. No send it back)
3. Does it work with just the rudder servo in either channel?
4. Try swapping the crystals around.
5. Go to the local lake and beg steel or borrow another set of 40Meg crystals!

Topic cleaned up .... a bit.

[298]

Ah, we have here, the now well known "Mayhem Effect!"

                                    "One simple question, so many answers!"

Age old principal: KISS, Keep It Simple Stupid..... (no offence to anyone).

1. Did you try the radio new out of the box?
2. Did it work then? (Yes, something has failed or you've done. No send it back)
3. Does it work with just the rudder servo in either channel?
4. Try swapping the crystals around.
5. Go to the local lake and beg steel or borrow another set of 40Meg crystals!

Topic cleaned up .... a bit.

Hi Martin,

To answer your questions:

1. This is the first time i've tried the Radio.
2. (see above).
3. Apart from the brief judder when the battery is plugged in, nothing works...!! Not the servo i've trashed, not the micro one for the rudder, or the other half of the pair.
4. Tried swapping the X'als, still nothing.
5. For "Lake", read "shop" (with receipt).

I think we've established something supplied in the bid Acoms box is dud, so it'll be the retailer's problem. And a line such as "Acoms gear can be unreliable, i've had 8 customers in with similar problems" would have been more constructive and more likely for me to go to a retailer when i've decided I want a motor & speed controller in the future.

BTW Malcolmfrary, there is 5.6v across the red & black servo terminals.

Chris (sheerline), i'll try the thing with the radio later...

[Martin (Admin)]

We'll be waiting for a full new update here on channel 298   

[malcolmfrary]

BTW Malcolmfrary, there is 5.6v across the red & black servo terminals

OK, so there is enough wuff there to work the gear if a signal is being a) received and resolved  b) transmitted in the first place.
Once the answer is known, it will all be very logical, until then........

[andrewh]

298

Sorry you are having the problems - hope we can guide you towards sorting them out
Not sure where you are in the Midlands, but you need someone to help with the bits to substitute to find the problem  - I'm in Leicester but have no 40Mhz bits to substitute
If you would like to PM me I'm happy to see if we can get you together with  someone with a pile of bits

The dealer you got it from has a pile of bits - and the obligation to replace anything duff!

Something MAY be non-working, but almost certainly nothing is blown
There is nothing wrong with BEC anything - neither the initials or the BEC are part of your problem
Sorry to contradict someone, but 5.6 V from 4 Ikea alkalines is a definite sign that one of more is unhappy (new or not) - they should be welll over 6V.

Suggestions - lose the switch harness - at least for trial purposes - plug the lead from the battery directly into the Rx  - as a fellow mayhemmer suggested try the battery in all the sockets (Always with the black at the outside - nearest the edge of the Rx) ( all the Receiver power pins are basically the same connections - only the signal pins are divided to each channel.

Good try with the crystals - they both seem to be inserted into little "carriers".  Even though you have tried swappping them it is not certain that ther are a pair all - it is what it written on the crystal, not the carrier, that matters - can you see the little writing on the crystal?
It should have Tx and Rx and the same channel frequency in small writing on the side of the oval aluminium crystal itself - please don't try to winkle them out of the carrier - they can lose pins easily.
Otherwise any reputable trader would be concerned if something they sold was faulty, or even believed to be faulty.  You might have a word with them, and a visit would identify the snagette in minutes

Your rudder lnkage is fine   There is quite sufficient "compliance" in the system to cope with the two planes of motion

PM on the way to you
andrew

[298]

Hi Andrew,

The 5.6v is across the servo terminals, the four cells without a load on them is about 6.5v so the Rx is obviously eating 0.9v. What is the minimum voltage the Rx and 2 servo's need...? Four NiCd's would give alot less than this.

I can't see any other writing on the X'tals and aren't going to start pulling the covers off, so it's back to the trader.

[malcolmfrary]

While dropping 0.9 volt under a small load is quite a drop, the system should be showing plenty of signs of life otherwise.  The initial servo twitch on power up indicates that at least the servos are taking power, so the finger of suspicion is now pointing at the radio outfit, one end or t'other.  The best diagnosis is now substitution to find the broken bit, either at the dealer or, as suggested, with a mate with compatible gear.

[Circlip]

Hindsight is always a great teacher, but I'm surprised the dealer didn't make sure it was all working before you came out of the shop, or is that a memory of a time when even though they were serving ten customers at once they still had the ability to be building a model with the other hand??

   Regards  Ian.

[The long Build]

I to have recently bought one of these from my local Model Shop  to use in a sailing boat and found that it just did not work with the Futaba  tx.  So had to use the normal rx as I was in a rush and did not have time to test it.  But reading this thread will now have a closer look..  The rx is the same as the picture earlier on.

Larry