needing some help

[fidamohd82]

hi
this is my second attempt to make the HH option 1
but my problem is?
when r10 is open
tp1 -0.81 to -1.38 volt
tp3 0.0 volt
tp4 1.05 to -2.74 volt


with r10 in place (with out coil)
tp4 -4.5 volts
tp3 -0.7 volt

when i connect the coil in this setuation
1- no detect at all
2- r10 get hot and burn at last


so can you help me
fidamohd82

[habitbraker]

You are sure its R10? (1 ohm resisitor)

[silverdog]

You must mean something other than R10 ?

rev C or D ?

double check jumpers are in place

post a picture of your board if you can

[fidamohd82]

it is rev c
and i am sure it is r10 (1 ohm ) resistor

[habitbraker]

Looks like Q3 is opened all the time. Is IC5 working?

Have you tried shorting R7, R8 and connecting gate of Q3 between Q2s emitter and R9?

[fidamohd82]

IC 5 is working
r7 and r8 are shorted

[habitbraker]

Have you cheched Q3? It should be closed if you disconnect its gate or remove r5 or r15. If its ok then check Q1 and Q2 - with r5 removed you should measure full battery voltage between both transistors C - E

[fidamohd82]

could you explane more please

fida alawneh

[habitbraker]

OK. I think if you have R10 (1 ohm) burning all the time that means that Q3 is opened all the time - like closed switch, so that you have only 1 ohm+coils little resistance between batteries voltage. So large current is flowing. Q3 isnt hot?

It could happen if Q3, Q2, Q1 or IC5 is broken. First Pull out R5. If it stops(burning) - IC5 is bad or wired wrong.

Then pull out R15. If it stops - Q1 is bad. If not then disconnect gate of Q3 (You should know which lead is gate for your used MOSFET transistor. For IRF740 refer to http://www.datasheetcatalog.org/data...qhw2h4ek3y.pdf)
I it stops - Q2 is bad. If not Q3 is bad.

And there are more experienced members in this forum - I dont know why they are silent...

[Reg]

Hi,

If you open the gate circuit, you will most likely cause Q3 to fail. Do not remove R 10, or anything associated with the gate either.

If you want to check without Q3, then remove Q3 altogether

I suspect Q3 is bad now.

Reg.

[fidamohd82]

i have try several irf740
all same resulte

thank you
and thanks for carl.....!

[Carl-NC]

Q3 is turned on all the time. Check to make sure you have connected Q3-G to Q2-E and not Q2-C.

Do you have an oscope?

- Carl

[fidamohd82]

no effect

[Qiaozhi]

no effect

Try reducing the frequency (R2) and the pulsewidth (R3).

I know the article says, "while an oscilloscope is useful, it is not necessary", but you really do need one when you run into a problem.

[fidamohd82]

i have playing from a week ago