JollyPopper

My Feedback: (6)

I have a Sig 4*40 that ran fine late last summer. I intended to dust it off and fire it up along with several other airplanes a couple of days ago. However, the controls do not respond to commands from the transmitter at all. A little seven LED battery condition tester plugged in to any channel of the receiver shows the battery to be good, but the controls on the airplane do nothing. My question concerns how to go about determining whether the transmitter or the receiver has gone bad while sitting. I'm not sure how that can happen, but the airplane answers absolutely no input from the transmitter. This is an old Tower Hobbies system 3000 tx and rx. Any ideas on which to trash, the transmitter or receiver? Thanks

BuschBarber

My Feedback: (2)

I would check both the Tx and Rx batteries with an ESV like the H9 Loadmeter. I don't trust the LED circuit as much as an actual voltage reading.

I believe Tower radios are made by Futaba. You could try the Rx with a Futaba Tx, on the appropriate channel.

You can take the Rx out of the plane, set it on a table, plug the battery directly into the Rx and one servo into any channel and see if it works.

Make sure the Crystals in both the Tx and Rx are pushed in tightly. You could remove them, clean the connectors, and push them back in.

If the servos have been plugged in to the Rx for a long time, and they are not Gold connectors, there may be some corrosion.

Make sure the Tx antenna is screwed in tightly.

Campgems

You have voltage at the receiver, so that isn't your problem. Does the TX show it's transmitting, meeter on the face, or RF light? Are both the tx and reciver on the same channel?? If you can't easilly pin it down by these items, then it time to figure which is takeing an extened nap.

You mentioned you have other planes, are any of them on the same frequency? Same modulation, IE PPM( FM) or PCM? If you have a match, it just a matter of using another TX, or a different plane with the TX in question. If you have different frequencys, you can swap the RX crystal between receivers (easier than unpluging everything and pulling the antenna for a test). Just make sure that both receivers use the same type Xtal. IE single conversion or dual conversion. If you have two receivers of the same brand and model, then the receiver Xtals are swappable between them.

I gues it would be easier for us to give you a better swap plan if you told us which recevers and transmitters you have and on what frequencys.

Campgems

Woops, hit the send to quickly.

Assuming you have two tx/rx combos that are compatable other than frequency, you would swap the RX Xtals and see which ones worked now. If the RX in question still doesn't work with the new xtal and corsponding TX, the your RX is bad. If the known good one doesn't work after the swap, then your TX is bad.

One more question, did you store the equipment in an unheated garage over the winter?? Did things get wet over the winter? A slight amount of moisture hitting a very cold condition could cause circuit board failure. Not very likely, but possible.

Don

BuschBarber

My Feedback: (2)

Having voltage at the Rx does not necessarily mean that there is enough voltage. He needs to verify that he actually has enough voltage while under load.

I would not trust the Voltwatch type device he has without some more accurate ESV readings, once again, under load.

I would check the continuity of the Rx antenna, as well.

I don't believe this Tx comes in a version that is PPM/PCM selectable, but if it does, that could cause this problem if it was set to the wrong mode.

JustPlaneSweet

Given that you can buy a Spektrum DX5e transmitter/receiver for $100, I would throw both away.

Stan

Campgems

The voltwatch controversity has been on going for as long as I've been a member of RCUniverse. We are not trying to determine if the battery has enough voltage for another two flights today, only that there is enough voltage to at least make the servos jitter a bit. The volt watch is more than capable of indicting that the receiver has enough voltage to latch onto a signal as most Futaba receivers only require about 3.8 volts or less. Lets get the volt watch out of the conversation on this problem. It is not pertanant to the discussion.

The antenna may be a problem at range, but for a bench check, it doesn't enter into the picture.

Your comment about the PPM/PCM is accurate. The TX being set to the wrong mode would give the indications he is seeing. I've tested this on the bench and the receiver just doesn't decode the signal enough to drive the servos.

Let's see what JollyPopper has to say about his follow up testing. We'll fight the voltwatch later, again.

Don

BuschBarber

My Feedback: (2)

I have read about the Voltwatch controversy. Even if his Voltwatch appears to be working properly, it is still important to obtain more accurate readings, with an ESV

JohnBuckner

My Feedback: (1)

The old Tower 3000 is the most basic of PPM only Tx's. PPM/PCM miss selection is not an issue. You know the original poster nowhere said he recharged the flight pack only that a LED thingy said it was OK, Hmm

John

JollyPopper

My Feedback: (6)

I agree with you guys that the voltwatch is not very accurate, but when the seventh LCD is solidly lighted, I believe it is telling me that the battery has enough voltage to operate the servos long enough to test. I have also used a second known good battery pack to power the receiver, still to no avail. This system is a dual conversion FM system on channel 12. Tomorrow, I will pull a crystal from an operating receiver and send signals to it using the corresponding operating transmitter. If the receiver responds then, it will tell me that the channel 12 transmitter is not operating. If it doesn't operate, then I will assume the receiver has gone south, but I still will now know whether the transmitter has gone with it.

JollyPopper

My Feedback: (6)

ooops. In the previous post I said LCD. I meant LED. Two entirely different animals

BuschBarber

My Feedback: (2)

Yes!! That is why I suggested he use an ESV, with the proper Load, and verify that the Voltwatch, or whatever it is, is working properly.

An ESV should be the first thing you buy after the Radio.

Check the Rx pack Before and After each flight, Religiously.

pilotpete2

I'm with campgems here, it ain't the receiver battery
Tx problem or loose crystal in the receiver or transmitter probably.
I'm no fan of voltwatches, but with all seven led's on, there should be some response from the servos, if there is an RF link.
My suggestion to Jolly Popper would be to reseat the crystal in the receiver and the transmitter. The transmitter crystal is in the lower left side on the front, just above the Logo.
Also are the power lights on the Tx showing good battery voltage? Isolating the problem in the absence of another transmitter or receiver setup on the same channel is tough.
One other thing to do. turn on the receiver (transmitter off) only in the house, near fluorescent lights, if the receiver is working there should be noticeable servo glitching, try running any tool or appliance with a 120V brushed motor nearby, that'll get the receivers attention
Good luck,
Pete

JollyPopper

My Feedback: (6)

No, it ain't the batter pack. Or battery packs. I tried a known good battery pack directly in to the receiver to eliminate the possibility that the LED thingy was lying. The known good battery pack made no difference. Just moments ago, I went outside and fired up an airplane that is on channel 24, also using Futaba radio components. The control surfaces responded perfectly to the commands from the transmitter. I then removed the crystal from that receiver, took it inside the house, and plugged it in to the receiver in question. Using the channel 24 transmitter, I sent signals to the receiver that had a servo plugged in to the aileron slot in the receiver. So at this point, I was using a known good battery plugged directly in to the receiver, a known good transmitter, a known good receiver crystal, and a known good servo. The servo did nothing. Anyone wanna buy a good looking Tower Hobbies (Futaba) receiver?[>:] Might even throw a transmitter in the deal.

JollyPopper

My Feedback: (6)

Pete, I wasn't aware that running a brushed motor near a receiver would excite the receiver/servos. I ran a dremel tool right next to my receiver. It didn't get excited. My offer for a cheap transmitter and receiver still stands.

Campgems

A couple last things to consider. Are both receivers PPM? Are both receivers Dual Conversion, or both single conversion. If the ansewer to any of these questions is no, then the Xtal swap between receivers isn't going to show you much. A quick check would be to use the orginal rx Xtal in the know good receiver and check the questionable TX. Chances are nill that both the receiver and Tx died over the winter. If the suspect TX doesn't work with the good receiver, you might, if you can, swap TX Xtals just for the test to zero things down a bit further.

Rodney

I have to strongly disagree as to the comments on the Voltwatch. It is far superior to a loaded or expanded scale voltmeter in giving pertinent information. It is almost as good as an ocilloscope as it will not only tell you if you have an adequate signal at the receiver/receiver output, it gives you an excellent reading of the status of the battery, switch and wiring between the receiver and battery. If you see the LEDs dancing more than two down as you rapidly throw the stick positions from one extreme to the other, it tells you that you have a power problem. To isolate the problem to battery or wiring, plug the battery directly into the receiver (bypassing the switch and switch wiring). If the LEDs still dance, you have a battery problem otherwise a switch or switch wiring problem. If you do not have all LEDs at the top after a proper charge, you have a battery problem. The Voltwatch is almost as good as having an oscilloscope connected to the receiver power bus. A loaded voltmeter checks only the internal impedance and charge on the battery, a valuable tool but not nearly as informative as a Voltwatch.

BuschBarber

My Feedback: (2)

I am not disputing the usefulness and accuracy of the Voltwatch. The aircraft has been sitting around for a long period of time without use. Who knows what gremlins have worked their way into the connections on all the electrical components.

For God Sakes take an ESV and check the voltage of the batteries instead of debating about how good the Voltwatch is!!!

How hard is that to do?

I know many people who use the Voltwatch and I have heard few complaints.

The Tx batteries should be checked every so often. Do not rely solely on the voltage shown on the LCD display or some Needle.

JohnBuckner

My Feedback: (1)

The question remains (its a good question) has the original poster ever put a loaded meter on the flight battery?

JollyPopper

My Feedback: (6)

It isn't important in this instance to know exactly how many volts are in the battery pack or how it will hold up under load. I checked the receiver in question with a fully charged battery from another airplane that I KNOW will fly several flights. I only need it to operate for a few seconds and I am confident that the battery is capable of doing that. We have moved here from determining whether the receiver is any good or not to how my battery holds up under load. It just ain't important in this case.

I am satisfied that the receiver in question is not operable and it isn't due to an uncharged or undercharged battery or a loose/faulty crystal.

But, for you folks who are really interested in numbers, I checked the battery pack with a Tower Hobbies ESV. I kept the voltwatch plugged in to channel 7 and checked receiver voltage at channel 6. With the voltwatch holding steady on the 7th LED, the ESV was showing 4.9 volts. I ran the battery down with a small light bulb and when the voltwatch was glowing steady on the 5th LED, the ESV was showing just over 4.6 volts. I didn't run the battery any further down than that. During that time, a good servo was plugged in to the aileron slot and never moved or growled. Same condition as before. I am not sure what good knowing those precise numbers does for me. By the way, the transmitter was on during this time showing full output on the meter and I was constantly bumping the aileron stick.

Knowing that all of the channel slots have full battery voltage but the servo doesn't move, I suppose, means that the receiver is not accepting any signal or it is accepting a signal but not processing it and sending information to the servo. That would probably mean something to someone who is familiar with the internal workings of the receiver, but to me it means nothing. I did take the receiver case apart and the antenna wire is still solidly connected to the board and the entire interior is bright and clean.