Peter Nir

Hello guys,

This past weekend my starter stopped working while starting my Jetcat P-120SE. i flew all weekend with a friend's ECU and all was fine, so it has to be the ECU.

I took it apart together with my friend (he is an electrician) but couldnt find anything wrong, so took a photo of the transistor board. everything seems fine, so i would like to ask you which transistor is the one for the starter ? i would like to change it on my own and repair this rather than send the unit back to Germany for such a minot repair.

Please advise if you know where we should check.

thanks,
Peter.

voaferro

Hi Peter ! pls tell me the ref on those transistors
Just had a similar unit here from a modeler friend. They should be some MosFet good for about 30 ormore amps But logic level. Also there may be a diode that has given up the ghost

I could help u more but i dont see the module here, not anymore with me

Cumprimentos fr Porto Portugal
A. Ferreira

Peter Nir

This is the transistor:

http://www.datasheetcatalog.org/data...shay/70263.pdf

basimpsn

My Feedback: (5)

The only way to identify this transistor is to reconnect your starter wire to the ECU then do a (Continuity) check from the starter wire to each transistor until you find 0 ohms.

basimpsn

My Feedback: (5)

Double post [:@]

Peter Nir

Whats strange is that all transistors and traces look good, not burned.

basimpsn

My Feedback: (5)

Open circuit inside the transistor are common and will not show any sign of burn. Did you try a different motor or bulb on the starter wire?

modtron

Send it to Udo at JetCat in Germany otherwise you may loose a lot more than just flying time !

modtron
Oxford UK

voaferro

Hey Modtron: some of us have to make do... he is in Israel, and me i´m in portugal... mail, and time and effort may be saved by doing it yourself...

but u are also right in that iy may be the pcb (circuit board) itself that has failed under high current( there are a few vias that seem a bit small for the high current involved)

-Anyway :Here goes Peter- Just use a tramsistor from an old PC Board they are there beside the CPU , they are logic level, cheap, and are quite adequate I USED an 60N06L takem from a socket360 motherboard from a few years back.

-P.S. and u should use your multimeter to check continuity in those transistors. the usual fail mode is short between gate source or drain but if didnt have capacitors in ur started or the brushes are used it may have cause the failure and re- fail

My 20cents worth - Antonio Ferreira -
and i try to help my mate with what i Know

Peter Nir

I can order the transistor online i guess, but im trying to figure out whats wrong first.

I dont see anything wrong with the PCB.

Peter Nir

I did manage to find something.

Bottom left transistor has a resisteance of 1000k Ohm when measured gate to source, while the other 2 are disconnected G-S completely.

Peter Nir

I mapped some continuity checks and marked them in colors. i can see there is a common ground (yellow) and Drain for the fuel pump (red) and for the glow plug (blue) but the pins marked with green arrows have no continuity so its probably a burned trace between them somewhere ?

Peter Nir

Lifted the bottom right transistor - it is fine and everything under it is fine as well.

found out that the Starter +voltage wire goes to the component in the upper left (as marked) and it is glued to the PCB - does anyone know what that is ? its labeled BYW20E.

Im still not sure how the bottom right transistor (missing in pic #2) switches the starter. perhaps its a multy layer PCB and the trace is inside.

Peter Nir

Checked my second ECU and all of the continuity \ resistance checks i made are the same. i am puzzled. [:@]

basimpsn

My Feedback: (5)

Some of these circuit board can be positive Grn, That part with only two leg could be a diode or a zener diode. Recheck your starter wire. One of the wire should go to + or - grn and the other should go to the center pin of one of the transistor. Just like in the digram.

voaferro

Peter: the byw20e is a fast power diode that i referred to in my post ~ it serves to cath spikes that might damage the Mosfets. It is usual practice with switching power coils (motor, solenoids) u should see conduction in one sense but not the reverse.
- I dont think the 1000k u see is anything to bother : it may be due to circuit itself and not the transistor...
- That pcb is only 2 faced. theres holes that conduct from one side to the other. U should see full 0 ohm from one side to the other...
especialy in those that have larger traces (big current) in case u have any doubt u may pass a small wire tru the hole and solder both sides (after scraping the green resist, Slightly around the hole)

~~~~~~
found out that the Starter +voltage wire goes to the component in the upper left (as marked) and it is glued to the PCB - does anyone know what that is ? its labeled BYW20E.
~~~~~~~~~~~~~~~~
Have a good look with a magnifier and also try to check the pins that connect the various boards. Also the wires, plugs, etc
even ur starter motor

Cheers - Antonio F.

Kelly Rohrbach

My Feedback: (1)

You guys are brave if nothing else
I think modtron has the fix.

Peter Nir

First, its not anything outside of the ECU causing the problem as it was confirmed with a different ECU which worked perfect. its also only the starter acting up (pump, kero start, valves all work well).

basimpson, the + voltage starter wire is the one on the bottom right (MPX connector) and it goes to that big diode, not to any of the transistors.

Whizbang

basimpsn,

Thank you for sharing the schematic!
Do you have and would you share the schematics for the other boards in the ECU?
They would be a great resource.

Peter,

I tried to find a cross for the BYW20E and all I could come up with was a bridge rectifier in a rather large package.
Are you sure about the number?

Thanks, Whizbang

basimpsn

My Feedback: (5)

Well check if there is a (Continuity) between the second pin of the diode and the center pin to the FET. There must be a electronic switch (FET), transistor or relay (which I doubt ) to turn on and off the starter. Keep looking

modtron

I find your response very confusing.

So you have already spent out a small fortune to get your turbine and now your going to have a go at fixing something you know nothing about ?

If you ever had any circuitry problems with your transmitter or receiver, would you have a go at that also !

Do you not think that if it were that easy, then they would include a circuit diagram with avery engine ?

Good luck with your efforts, I know when you eventually send it to JetCat, your going to be charged big time now.

I'm out of here.

modtron
Oxford UK

basimpsn

My Feedback: (5)

Humm good point , So why don't they, Does guns comes with diagram?

JP-1

Humm good point , So why don't they, Does guns comes with diagram?

voaferro

Hi modtron!
- WRONG atitude, yours... If u know Nothing about it dont comment like u did. I KNOW WHAT I´m TALKING.

- 30 years in electronics and some 15 in modeling and HELPING me mates with electronics does gime some say....
- And YES, i did open and REPAIREd my transmiter also a few old receivers and i´m in the proccess of building a new one...
- DONT just think we´re all like u (in America) spoiled buy choice and hi living standard... SOME of us just consider all this a HOBBY in wich we strive to have fun, LEARN something and feel free from all those ifs and whats and such-
SO: YES I DO KNOW ENOUGH to help Petr and even yourself or JP1...HERE GOES:

The gun is ALways loaded and the horse always kicks back- STICK in here for a bit longewr , u migjht even learn a bit of electronics... BASIMPSON already gave us a partial schematic...QUITE adequate even for gunslinger to remedy is ECU

- PLEASURE to have been of help ... Just dont have the patience for this.,. U SHOULD live up to your own talk..

-Antonio Ferreira - Porto - Portugal

p.s. Peter, u can always ring me on my email (back channel) if u need to ... maybe i can help further...(like i did want to)

modtron

Antonio,

I'm not looking for any arguments, but just like you, only trying to help.

I to have been in electronics and software for some 25 years, but I still would not bother to try to repair this item myself - the reason being that if it was sent to JetCat directly, it would most likely have been repaired or exchanged "due to fairness" - which is the JetCat way of doing things.

The time it takes to do this is not always long and in the end, the customer ends up with a replacement and gets back in the air as soon as is possible.

Yes of coarse the ECU can be repaired by anyone who knows what they are doing, but not everyone does !
And then to expect someone who possibly has no knowledge of what they are doing, to go into the heart of the engine control system, to me seams like asking for more trouble.

Just my opinion and by the way, I'm not in America !

modtron
Oxford UK