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https://cajinnovations.com/yabb0/YaBB.pl MyECU >> MyECU Kit Construction >> Testing of Board https://cajinnovations.com/yabb0/YaBB.pl?num=1330901850 Message started by sign216 on 03/05/12 at 09:57:30

Title: Testing of Board
Post by sign216 on 03/05/12 at 09:57:30

I finished the board (except for Q5) and did the testing. All were good, except for these discrepancies.

4. How can I see the square wave on T5? Do I need an oscilloscope?

5. Left pins of the FETs were 0, except for Q1 and Q2, which were 0.02 volt.

The voltage at R28 was 0, and never went to 5V.

How serious are these differences?

Title: Re: Testing of Board
Post by YaBB Administrator on 03/05/12 at 17:11:47

Its a bit hard to see the square wave without an oscilloscope but its not too important. It's the tacho signal.

0.02 volts is ok

There could be an error in the notes. How about R28B. This is the fuel pump FET drive.

Title: Re: Testing of Board
Post by sign216 on 03/05/12 at 22:41:36

Ok, thanks for the tip. I'm just getting into work now (I'm in Boston, Massachusetts, USA). Tonight when I get home I'll try it out.

Title: Re: Testing of Board
Post by sign216 on 03/06/12 at 11:30:10

Yes, at R28b it goes to 5V after applying power, and then drops to 0.

I installed Q5, and did test 6. What is meant by the phrase - "...should see the voltage regulator (bottom of D1) input above the battery voltage"?

When I checked there, I got a voltage of 7.8V, and falling. Battery voltage was 8.5V.

Title: Re: Testing of Board
Post by sign216 on 03/06/12 at 23:28:50

Test 6 -D1 at bottom (stripe end) should give higher than battery voltage, right? I'm getting less, 7.8v, and it falls quickly.

Top end of D1 is 5V, and steady. If that helps.

Any ideas on what the issue is?

Title: Re: Testing of Board
Post by YaBB Administrator on 03/07/12 at 07:05:22

That voltage should not fall. It is the battery voltage minus the drop of the Polyswitch and the inductor so it should be close to battery.
If it is dropping perhaps the battery is dead. Alternatively the ECU is drawing too much current and the Polyswitch is kicking in. Does the poly get warm? Current draw should be less than 100mA. Check your draw.

Q5 is the element that creates the voltage boost. With 12V in you should see 14-15.

Title: Re: Testing of Board
Post by sign216 on 03/07/12 at 09:37:03

The battery gives 8.9V and tests as 75% full on a battery meter.
The polyswitch does not heat up.
Circuit draws 78 mA.

Below is a photo of my MOV and Polyswitch. Are they connected to the correct terminals?

http://www.flickr.com/photos/sign216/6813995830/lightbox/

Title: Re: Testing of Board
Post by sign216 on 03/07/12 at 12:01:22

sign216 wrote on 03/07/12 at 09:37:03:

I'm testing it with a small 9V battery, per the instructions.

Title: Re: Testing of Board
Post by YaBB Administrator on 03/07/12 at 12:37:41

75mA is ok and the photo looks ok.
I think your battery is struggling with the load. You don't mention what its voltage is when doing the test so i assume you are just measure the battery at no load.

75mA is a high load for a 9V battery. I suggest using it because the potential to turn the ECU into a molten mess is low.

Title: Re: Testing of Board
Post by sign216 on 03/07/12 at 13:11:05

Any ideas why I'm not getting a voltage boost at D1, but a 1V voltage loss.

Title: Re: Testing of Board
Post by sign216 on 03/12/12 at 12:41:21

I'm not getting a voltage boost when I test at D1.

I'm going to order a new transistor at Q5 (2N7000) from a supply store, and hope that's the problem.

Any other ideas? Any other parts I should replace, while I'm making a parts order?

Title: Re: Testing of Board
Post by YaBB Administrator on 03/12/12 at 14:32:33

What battery did you test with.

Q5 is not reversed is it?

So long as nothing is frying you should ignore this for the moment. Just make sure your bike battery is charged and warm the bike on your existing ECU.

Title: Re: Testing of Board
Post by sign216 on 03/13/12 at 04:35:09

Testing with a standard 9v battery, the kind used in common transistor radios.

I'll check to make sure Q5 isn't reversed, but I'm pretty sure I put it down just like the diagram on the board.

Work sent for away for two weeks (aargh). When I get back I'll ignore this issue for now, and see if the unit will run a warm bike.

Title: Re: Testing of Board
Post by sign216 on 03/29/12 at 01:19:30

I purchased a new transistor for Q5 (2N7000), installed it, and tested again.

Same results; only 7.6 to 7.8 volts. There must be a different error in the voltage boost circuit.

Title: Re: Testing of Board
Post by YaBB Administrator on 03/29/12 at 07:09:15

What voltage do you see on the gate ( check 10K next to it )
Lets skip if for the moment. We can see later what it does with a 12V battery.

Title: Re: Testing of Board
Post by sign216 on 03/29/12 at 09:54:11

At the 10k resistor, R37, I've got 0 volt on the left side, and 1.07 volt at the right side.

I'll go forward and try the unit out on the bike, but I'd also like to fix the voltage booster.

Title: Re: Testing of Board
Post by YaBB Administrator on 03/29/12 at 10:51:25

That seems correct.

I think the problem is that the voltage booster doesn't work well with a 9V battery. The voltage booster works by pulsing current from the battery and relies on the battery having a low impedance.