CHANCE Pcb's Finally Here

[Legaucho]

Q3 on Chance

I need your help, because I finished assembling the various components of the detector Chance, when I turn it on with the coil connected, Q3 becomes hot. As soon as I remove the coil, Q3 becomes cold.
Thank you in advance for your sugestions

[silverdog]

Can you post some pictures of your board ? what components are you using for Q1, Q2, Q3 ?

[Legaucho]

Hello Silverdog

Please find the attached pictures, I think Q2 is wrong.

Best regards

[silverdog]

Q2 is wrong on the pcb, S is ground, G goes to R3, D goes to Q1 For 2sc945 see pins in picture - Emitter to ground, Collector to Q1, base to R3

[Tepco]

And interestingly, new software version work perfectly good without any hardware change. It is unclear to me why these changes are needed at first place, nothing fundamental is changed in circuit operation, except creating problems like this. Lovely thing, just like Micro$oft, get ready to update software to V.1.1.1.

[Legaucho]

Q2 is wrong on the pcb, S is ground, G goes to R3, D goes to Q1 For 2sc945 see pins in picture - Emitter to ground, Collector to Q1, base to R3

Hey Silverdog

Silverdog thank you, I would make the correction as soon as I get a free moment. Again thank you for your help. PCBs that you provide is truly professional quality.

Best regards

[okantex]

dear friends
excuse for late photo attachment
sizes are same as original andy_f 's coil.I got drawing form his site and made mould.

all wiring is in clockwise direction.

when I use mono coil my delay starts at 8 us ,
but with this coil it starts at 22us

btw I calculate and got result as 8 us but It may be wrong.
on the other hand whatever the timing unit is not important.
my op finishes saturation 3 time late than mono coil assembly.

regards
Okantex

[Tepco]

This "original" coil is not especially fast, built and measured to specifications, will provide ca. 13uS when amp goes out of saturation. And detector samples after 17uS. Most probable cause of problem whit your coil is that it is not built "stiff" enough, you should flatten and tighten windings on coil former. This way, you probably have more wire length and more inductance, and this will slow down the coil. If you use other (faster) monocoil, try to adjust (decrease in value) R13, to "overdump" the coil, so detector can see exactly right part of waveform when expected.

[okantex]

dear tepco
my coil is tight.
first you need to know, my circuit is not exact chance circuit,it is a mod.
software is my own , on the otherhand right now R13 is 1K , ıf I use 390 R it gets our of saturation much more later.

with 390R at R13 monocoil construction , decay starats around 8us
but with this coil starts at 22us with 1k damping.

[Tepco]

I was completely unaware that your circuit is modified. Also, i'm not sure what you refer as a "monocoil", some other coil design perhaps? This on picture looks like original Russian monocoil. Still, whit this coil 22uS is way too slow and 1K to high, but still looks like good value (if time is increased when changed to 390R). It seems to me that something in the circuit increase total capacitance. If your power stage is similar to original, first check D4 and D6, using slow "ordinary" diodes (like 1N400x) instead of HER or FUF types can produce similar effect.

[okantex]

dear friend,
yes this russian monocoil is a kind of monocoil , I call it basket coil,
because generally round pi coils are called mono,like used in delta pulse and other.

with 390 R damping resistor,
mono 8us
basket 29us
with 1k damping
basket 21us are my end out saturation , btw I do not have scope, just get this reading with LCD and software.
do you have scope
can you show me scope pictures of different metal with this coils.
does the curve change when considered by mono coils.

[Tepco]

I have scope pics, will send it to you

[joop]

I have built the default search coil today. I have used 0.4mm wire, did not have any 0.8 lying around. The coil has an inductance of 360 microHenry and a resistance of about 3 Ohms. Will be testing Silverdog's kit later this week.

[selim]

change software 1.20 test video

http://www.youtube.com/watch?v=THM6_DXe9Ww

[smity]

question

dear tepco
my coil is tight.
first you need to know, my circuit is not exact chance circuit,it is a mod.
software is my own , on the otherhand right now R13 is 1K , ıf I use 390 R it gets our of saturation much more later.

with 390R at R13 monocoil construction , decay starats around 8us
but with this coil starts at 22us with 1k damping.

Please write more detail about their firmware and a modified scheme. Thank you in advance.