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Greddy profec B spec II circuit diagram / PCB pics


Guest loren
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Guest loren

So, I'm trying to fix my boost controller... so far I have what appears to be a missing diode.

It's very weird, but that's the only conclusion I have been able to come up with based on

looking at the PCB and testing resistances with a multimeter.

I doubt anyone has access to an actual circuit diagram, but if someone was able to open

up their greddy profec b spec 2 and snap a picture of each side of the circuit board, it

will tell me whether I'm supposed to have the mysteriously missing diode or not and

I'd be very grateful.

Thanks

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Guest loren
 Koom said:

Hamsters gotten loose under the dash again? I have issues keeping the wee buggers under control at times.

Does it look like someone has de-soldered your diode? Seems weird.

it doesn't look like there's ever been one there, but it's marked on the PCB and I can't see any possible

way for it to work without one. The output is electrically isolated from everything on the board, apart

from the diode. The only explanation is that when the output was shorted, the solder points at both

ends of the diode melted... then when I open the unit the diode fell out without my noticing. It all

seems a little unlikely. It seems more likely that you are a twisted bastard that has photoshoped

a diode in the right place to screw me up :) you didn't do that eh? (just joking.)

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Guest loren
 kamineko said:

+1 for weird. if it got that hot for it to fall out you would notice other heat damage, and far less likely on a leaded component anyway.

is it 2nd hand? or did it just stop working. very very weird

I bought it from new. had it in the car for about a year... I was at Manfield a few weeks back,

was no problem at all day. As soon as I left the track and was driving home, I noticed the

car was running on wastegate pressure. Opened up the bonnet and noticed that the wires leading

from the controller to the solenoid had come loose and was sitting on the down pipe melted.

It wasn't until a few weeks later that I got round to fixing the wires, but then there was still no boost control. I tested the solenoid which was working correctly, and double checked the wires had been fixed properly. Then I open the controller itself, but couldn't see anything wrong. Was looking for a blown fuse or diode, but nothing jumped out as being wrong.

Then when closely inspecting the circuit, noticed that there was a missing diode... just though maybe it

was an option or something, but then couldn't figure out how the circuit would run without it at all.

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I vote it was a poos soldering job on the line and they were all off to the Mangatainoka pub/brewery for the Miss TUI contest so they can have "salad with their combo bro..."

EDIT forgot the IIIIItalics

Is it possible to hunt down the Diode from Jaycar?

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Guest loren
 kamineko said:

koom, does it have any numbers on it? otherwise you will have to reverse engineer it somewhat to figure the type of diode required. the green band only tells me the polarity

Is the diode type that critical? I think it's only there to protect the rest of the circuit from a short.

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At a guess it looks like it's a EMI supression diode. You usually need them to save the life of the rest of the circuitry after the solenoids magnetic field collapses and sends voltage surges through the system. Have a peek here http://www.suregripcontrols.com/install_suppress.htm .. a 1N4004 should do the trick, I can't imagine it'd go over 1A or 1000V

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Guest loren

Someone at work suggested that I needed my head examining if I thought a diode could just vanish into thin air.

I already thought that was the case, people have been asking what medication I'm on for years.

So went home at lunch and had another look... found that the output is connected to another diode (that does exists)

via tracks on the underside of the PCB... no idea how I missed that :-[

That diode works fine... but the very first component in the circuit, connected to the output, is a 50 ohm resistor

that is open circuit... I discovered this days ago, but somehow got completely side tracked when noticing the missing diode.

The most logical explanation is that the 50 ohm resistor is dead, and that's all that's wrong.

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Guest loren
 kamineko said:

that black smd thing with 50 on it is probably a capacitor

oh really? but it shouldn't be open circuit eh :-\

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Guest loren
 kamineko said:

;p if a capacitor isn't open, its broken :P

hmm yeah but it still has to conduct right... so should measure some resistance?

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if it's a capacitor it will measure an open circuit, you'll have to remove from the cct to test if it's a cap. There could be a cap in series with the output to block DC voltages going to the solenoid which makes sense. What do the two sides of mr 50 connect to? One is the diode?

my money is still on it being a precision resistor for now.. :)

Also that stripe on the diode means it's either a zener or a schottky. But not a power diode, so you will need to replace it with the correct part, not something generic.

Being a zener diode would make sense, in combination with the precision resistor would make a constant current source to prevent the solenoid overheating etc.

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Guest loren

It's denoted with an 'f' on the board, and the other more obvious capacitors are denoted with a 'c'.

I had though 'f' stood for farads possibly, so maybe a special capacitor... it is open circuit which

indicates a capacitor, but what does 50 mean in that case? 50 farads is very very large, and this thing

is not.

Interestingly there is another component marked with an f (and in the picture of koom's unit

it also has a 50 on it), and it reads closed circuit. On my board the two components are not identical,

but one is marked f1 and the other f2... one is open circuit and the other closed... so possibly one is

broken... but what they are and which one is broken, if any, is still a mystery.

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