stevefixit

Hi all, i have recently purcased a remote bait boat second hand (microcat mk2 and futaba t4yf transmitter 40mhz fm 4 channel).
my prob is i droppedthe transmitter in the lake i know lol.
to cut the story short it no longer worked!!
so i purchased the exact same model transmitter off ebay, futaba t4yf transmitter 40mhz fm 4 channel no batts or crystal.
so i put brand new nimh batts in and the 40 mhz crystal out my old transmitter all works fine until i took it to the lake and now the range is about 20 yards instead of about 400 yards ?
everything works ok until it goes past 20 yards then the boat has a mind of its own, thought prob interferance so tried it on a large field still the same ? when i go past about 20 yards the boat just acts erratic ?
is there a way to make them communicate better ie.. tweek the transmitter for better output? remove any parts from my old one??? really stuck guys having shelled out £60 quid thinking it would be the same has it was before.
please would like some advice...
kind regards steve....

mfr02

I am wondering if the aerial on the new transmitter is as connected as it should be.  It must be doing something, since you get some response, so either the TX is not doing a proper job, or the RX isn't receiving as well as it should.  Since the crystal had a bath, cleaning the pins might help.

stevefixit

Thankyou for your reply, tried cleaning pins still no luck going to try a new crystal tomorrow thx..
if you have any other thoughts please let me know.
kind regards steve.

stevefixit

no luck with the crystal must be the transmitter?
I ve found out that the transmitter i brought was identical to the one i dropped in the lake except it had a 35 mhz sticker on the bottom of the controller, and my original said 40mhz
so changing the crystal from my old unit is not good enough. I thought that the frequency was only to do with the crystal ???? so now it looks like i ve wasted my time and money.
Unless you guys know of anything else i could do i.e. tweek the caps inside, change the microchip ( if its still ok from the sinking)? both boards look identical. should be ok.
i know i could possibly change the rx chip in the boat but i really dont want to take the boat apart and cause more probs... any advice guys please...
kind regards steve.

Apismelifera

Try cleaning it like this, you may get lucky.

The transmitter that got dunked. Take it apart. Make diagrams, take pictures, so you can reassemble it again. Remove the battery if you have one in there, Open the case, and remove everything electrical. No need to cut wires, if something is plugged in and would be easy to reconnect later then go ahead and unplug it. Again document where stuff goes so you can reassemble it later.

Place all removed parts in a plastic container. Rinse them off under a cold water faucet, you're trying to flush out any dirt, bugs, mud, and so on that might have gotten in there. Remove from container and pat dry. You don't need to get it 100% dry, just remove most of the water. You can also let it sit in the dish drainer for a while to drip. Do not blow on it with compressed air, you'll get it too dry.

While the electronics are drying, rinse out the case too. It helps if you have a small one inch or so cheap paint brush to brush around in there with during the cleaning operation. When you finish with the case and have mostly dried it, dry the container and the brush.

Put the electronics back into the container and refill it with rubbing alcohol. You only need a couple of bottles of this stuff. Get the kind with the highest alcohol content they have. Tilt the container slightly and brush the alcohol onto every surface of the electronics you can get to. This further removes dirt, and mineral deposits from the water, and absorbs any remaining water too. When you're satisfied that you have brushed everything several times, you can take the stuff out and dry it again.

If the alcohol in the container looks really dirty then you need to repeat the alcohol cleaning step again with some fresh alcohol. You can reuse the dirty alcohol and clean the case with it too. Let everything air dry for a couple of days. If you have a small fan you can use to blow on it, this will speed the drying process. Don't forget to alcohol clean the crystal and reinstall it. Clean the transmitter battery. Alcohol only.

Before you reassemble the transmitter, get an aerosol spray can of TV Tuner cleaner, or relay contact cleaner. Spray any open switches, spray the throttle and rudder controls. Try and keep the runoff from spraying from getting onto the electronics you just cleaned. The tuner spray get inside those components that are impossible to clean with the brush.

Now put it back together and try it.

Hopefully you will be able to report back here that it worked. If not then your best option is to go out and get the correct receiver for your new transmitter and toss the old one.

In the past I have used this method to bring equipment back to life that quit when it got flooded in a basement, booze and beer spilled on, and people getting sick on it.

I wish you the best of luck.

mfr02

Everything John said - in the UK, get methylated spirit from the decorating section of the home improvement store.

Umi_Ryuzuki

If your OLD transmitter is 40mhz, and the NEW transmitter is 35mhz, then
there is really no way it should talk to your bait boat at all..

It is like putting AAA batteries in to an AA battery holder, it doesn't fit.

There are typically 3O channels for each Frequency.
You didn't change the channel, you changed the frequency.
It would require a complete retuning of the 35mhz radio to make work properly.

You should be able to dry out and clean up your old 40mhz transmitter.
The instructions given above are a good guide.

If the transmitter does not come back to life, you need to buy another 40mhz transmitter.

stevefixit

thx for all your help guys, tried cleaning the one i dropped in the lake with switch cleaner/ elec cleanerbut the board looks corroded i e. the elec tracks? i can get it to work plugged into the mains but soon has i put the batts in it kills the batts. The batts are brand new nimh and i checked that theyare fully charged, I put a multimeter on the batts and watched them drain in seconds, ie. they started at about 10, 11 volts when fully charged and counted down like seconds on the multimeter when i switched the unit on. 10.4 10.3 10.2 10.1 and so on until2 or3 mins later the light on the transmitter came on saying low batt and stopped working.
i thinkmfr02 is rightthe transmitter is wrong you cant just change the crystal you have to have a 40 mhz transmitter and the right crystal?
so if any of you guys have a 40 mhz transmitter laying around that will work with a 40 mhz crystal channel 58 and want to sell it cheap pm me.
kind regards steve...

mfr02

The switch cleaner itself will do little for the board or the components on it.  As said before, it needs a good soak in clean water, followed by a gentle scrub with a toothbrush (preferably somebody elses) to remove the surface corrosion, and, hopefully, any lumps hiding under components.