Arakon

The original voltage regulator is a 500 mAh one too, so I don't see why it shouldn't be enough.

Firefox

iTrader: (2)

Thought the .5 would be enough myself. Can't see it pulling more than that or even close to it.

Thanks for the good work, everybody involved with this radio...

skree

back in the pages of this thread, someone measured the ma drain of the radio with the LM7805 regulator, and it was 110-140ma. The 7805 at our voltages is less than 50% efficient so i'm expecting around 70-90ma with a switching regulator, as a pessimistic guesstimate

meaning these .5a regulators are more than enough for what we need plus added electronics. I might have to rethink my plan to use the TX as a portable 5v power station though as the drains are getting too close to the 500ma max

Speedy1980

Hey guys... after testing the SMT8S i got often theese error message:



everytime i put out the USB wire and try to connect it again... the window will open were i can read the links which are saved on the boar, but nothing more happens.

who can help me?

Arakon

How to replace the hot-running voltage regulator:

Take apart the top of the transmitter, turn around the board, and locate the 78M05 voltage regulator. Snip off the pins close to the regulator using sidecutters.

img225.imageshack.us/img225/537/cutwvf.jpg

Carefully bend the legs of the dc/dc converter down a bit. Add a bit of solder to the legs as well as the pins you cut to get a good connection quicker and easier. Stick it in position with a bit of double sided tape (just needed to prevent it from slipping off). Make sure the orientation is right, writing up, the dot marks the input voltage pin (If you use a different brand, check the pinout first!).
Then just solder the pins together. Check that you don't have any accidental connections to the pins next to each other. That's all there is to it.

img844.imageshack.us/img844/2767/recom.jpg

Don't mind the brown wire on the bottom pin, it's for a power LED and not needed for the replacement.

For the power LED, all you need is a 5mm (or 3mm) LED and an LED mounting ring. I used a blue one. drill a 6mm hole (5mm if you don't want to use a ring and hold the LED in place with hotglue or similar) where you want to mount it, put the mounting ring through from the front, and push the LED into it from the back until it clicks into place. This will lock the mounting ring too. From the short leg of the LED, run a wire to a ground point (i.e. the center pin of the voltage regulator). Solder a resistor to the longer leg (100 ohm 1/4W will work for blue ones) and run a wire from that to any 5V point (i.e. the right pin of the voltage regulator). Make sure you shorten the legs so they don't move around too much, and stick the wires to the case of the TX with hot glue or at least tape so they don't move around. I also suggest using shrink tubing on the pins and resistor to ensure no short circuits can happen. Sorry, no internal pics of that.

img641.imageshack.us/img641/1223/pledp.jpg

QuangVuong

iTrader: (16)

Original Author - Arakon. I only added links for the images.

How to replace the hot-running voltage regulator:

Take apart the top of the transmitter, turn around the board, and locate the 78M05 voltage regulator. Snip off the pins close to the regulator using sidecutters.



Carefully bend the legs of the dc/dc converter down a bit. Add a bit of solder to the legs as well as the pins you cut to get a good connection quicker and easier. Stick it in position with a bit of double sided tape (just needed to prevent it from slipping off). Make sure the orientation is right, writing up, the dot marks the input voltage pin (If you use a different brand, check the pinout first!).
Then just solder the pins together. Check that you don't have any accidental connections to the pins next to each other. That's all there is to it.



Don't mind the brown wire on the bottom pin, it's for a power LED and not needed for the replacement.

For the power LED, all you need is a 5mm (or 3mm) LED and an LED mounting ring. I used a blue one. drill a 6mm hole (5mm if you don't want to use a ring and hold the LED in place with hotglue or similar) where you want to mount it, put the mounting ring through from the front, and push the LED into it from the back until it clicks into place. This will lock the mounting ring too. From the short leg of the LED, run a wire to a ground point (i.e. the center pin of the voltage regulator). Solder a resistor to the longer leg (100 ohm 1/4W will work for blue ones) and run a wire from that to any 5V point (i.e. the right pin of the voltage regulator). Make sure you shorten the legs so they don't move around too much, and stick the wires to the case of the TX with hot glue or at least tape so they don't move around. I also suggest using shrink tubing on the pins and resistor to ensure no short circuits can happen. Sorry, no internal pics of that.



Original Author - Arakon. I only added links for the images.

j_blaze14

iTrader: (34)

and people make fun of these radios. at $300-$500 who would do all these mods to a radio? i'm still running stock but all these new cool things you guys are doing are making me curious. keep up the good work.

Yagya

I just bought this about a week ago and just put the receiver into an old RTR Bandit. I'm trying to get it all working, but there's all sorts of throttle glitching and the steering is screwed. The manual was hard to read because of some serious Engrish, but I think I got the gist of the "bind" cable and tried to do that, but I'm seeing no different results.

Tried messing with the trims, but steering caps at 30, and that's not enough to compensate for the "neutral" position of the wheels still facing to the right. The throttle trim seems like it needs to be set after every battery connection.

I had these same problems with the transmitter that came with the RTR, resulting in many uncontrolled instances that resulted in crashes. I bought this new transmitter due to price and positive reception, but I'm thinking perhaps the transmitter wasn't to blame now. Could the stock servos that came with the Bandit be that shoddy?

Arakon

May be the servo or the ESC, it may not supply enough power or interrupt power at times, leading to glitches.
As for the trimming, set the steering trim to 0, turn on TX and the bandit, take off the servo saver and place it as straight on the servo as you can.. that way, it should be close to centered and only need little trimming to be straight.

Yagya

Yeah, I just manually tried setting the servo to center and that fixed the centering as I only need to adjust the trim a little to be really center.

Now, the other problems. Realized the Steering is reversed, but putting reverse for the channel on the tx causes the centering to get screwed again. Also, sometimes it won't turn a certain direction, but after a bit it will. Could that be jamming since this has been left in the closet for about 7 years? The whole car is pretty dirty and was never cleaned. The throttle seems all messed up as well. Not going as fast forward as I remember. Reverse seems to go as fast as forward; which isn't fast.

Arakon

It's quite possible that the servo bearing has seized or that there's too much dirt in the bushings etc.

Speedy1980

IŽam a little bit afraid, that i destroy my radio because of my shown error... does anyone have some save answer for that problem?

losikid67

Did you set it up correctly

did you reboot cpu after install

Speedy1980

I think the setup was correctly. CPU from my computer or have i reeboot the CPU from the SMT8S board?

If i had to reeboot the board, waht i have to do for reebooting?

skree

For all of us looking for parts: consider your little local cb radio/electronic components independant store. Been looking high and low for that little recom regulator and have only found it in places charging mad shipping. Went to a little local family run shop and they're ordering me one in at trade price, no shipping.. so i'm also getting some more desoldering braid on order in while im at it.

Picked up a low current 3mm superbright red LED. This LED's brightness remains consistently linear down to powers of 2ma. Bit of nostalgia for me the red LED and a 1600 ohm 0.25w resistor will keep its current drain low - making it an indicator rather than a light. Got the resistor, the led, and a 3 way DIL switch for controlling my mods for 0.50 UKP - bargain modification imo

my stm8 and new soldering gear arrived today, can't wait to get tweaking a gt3b