'KROT2-XM' (mole), new project Xmega32

[Tepco]

You probably messed up things with coil balance routine. Check for presence of sinewave signal at DAC1 (R14), also you will get high RX voltage reading or RX error even without coil. Disconnect both coils, enter Coil bal routine and wait to complete. RX voltage should drop and this signal disappear. Then make ADC zero to get ten's of mV or less. Only then connect coil and adjust balance manually. DO NOT use Coil bal routine unless coil itself is adjusted and balanced as close as possible. Repeat this if you change coil type.

[Geo]

You probably messed up things with coil balance routine. Check for presence of sinewave signal at DAC1 (R14), also you will get high RX voltage reading or RX error even without coil. Disconnect both coils, enter Coil bal routine and wait to complete. RX voltage should drop and this signal disappear. Then make ADC zero to get ten's of mV or less. Only then connect coil and adjust balance manually. DO NOT use Coil bal routine unless coil itself is adjusted and balanced as close as possible. Repeat this if you change coil type.

Thank you.
Sure i messed the rutine about coil balance.
I never disconnected the coils before mke coil balance, i will try it .
Also today i start to make a DD coil with details as Andrew wrote. I hope for better results.

[Tepco]

Coil obviously must be connected to perform Coil bal. Routine. Purpose of this, running Coil bal. without coil is to clear previously stored value, not to interfere with coil adjustment. Then balance coil manually, only when everything is finished and you have less than 1V RX signal, run Coil bal. to optimize.

[Geo]

I afraid that i has any other problem.
Rx signal = 20 mv (pin3 of D2).
Out at pin6 =`45mv, signal at R14=45...50mv, signal at C19,C20=20...25mv.
When i do coil balance then the display writes Rx = 1500+ mv
And when i press menu button and go to menu it starts from last rutine (volume, contrast etc...), why?? is this normal???

Regards

[Tepco]

This with menu is normal, volume, contrast etc are first adjustments, not last About what voltages you talking about, DC or AC-pp, with or without coil. Try without coil, DC voltage at D2 pins 2,3,6 must be around half Vcc, some 1.6V. If not, something is wrong in hardware (check if D2 gets Vcc at pin 7, something shorted or misplaced component etc) So if your voltages are DC, you have problem. If this is good, AC voltage at pin 3 is 0 without coil, and after Coil bal. Signal at DAC1 and output, pin6 must dissapear and RX voltage indicate some ten's of mV or so. As I understood, you have scope?

[Geo]

This with menu is normal, volume, contrast etc are first adjustments, not last About what voltages you talking about, DC or AC-pp, with or without coil. Try without coil, DC voltage at D2 pins 2,3,6 must be around half Vcc, some 1.6V. If not, something is wrong in hardware (check if D2 gets Vcc at pin 7, something shorted or misplaced component etc) So if your voltages are DC, you have problem. If this is good, AC voltage at pin 3 is 0 without coil, and after Coil bal. Signal at DAC1 and output, pin6 must dissapear and RX voltage indicate some ten's of mV or so. As I understood, you have scope?

Voltages that i wrote before are with coil connected... so a "medium balanced" coil gives at input of D2 a signal 25mv ac p_p (7854Hz) and the out of D2 is about 45mv.
Yes i have a 2 channel scope.....
I start to wrap the new coil. If i"ll finish today, i will write the new measurments.

Regards

[Tepco]

Hardware problem again. With 20mVpp input and x100 gain, output at pin 6 must be 2V, nearly saturating level, not 45mV! Do you get correct DC voltages?

[Geo]

Hi.
I finished the new DD coil but i have the same problem.....
It looks like hardware problem near to MCP601 (maybe this is fault). With 20mv signal at (very good sine) input i take about 20mv from output (something between sine and triangle). Without coil connected the voltage at pin7 = 3.3V, pin2 = 1.87, pin3 = 1.65 and pin6 = 1.87. Values of components are ok. Any idea?????

Another problem is that i have not second MCP601 so i must ordered it from ebay and waiting 2..3 weeks...

[Tepco]

Voltages are, well, nearly OK, no obvious sign of failure. Maybe chip is good too, it looks like it works with unity gain. Check physical connection from pin 2 to R10, R10 to C15, C15 to GND, for possible broken trace, check components too. Eventually check C18 for correct value (not inserted one with much higher value by mistake) or just remove it.

[WM6]

For additional info: All passive parts was checked and measured before inserted and soldered, I never believe in value markings.
C18 is of about 47pF instead of 51pF per schematic, this should not be problem. Except possible overheating on soldering, despite I am working at minimal soldering temperature, but some plastic C are very sensitive to overheating. As I remember I put there ceramic C18.
All IC was carefully inserted in HQ sockets after all other parts are soldered to prevent static damage, so I doubt that there is something wrong with MCP601.

Geo, can you explain, step by step, how you perform initial settings and coil balancing of your KROT-2 and what power supply voltage you used?

[Geo]

Voltages are, well, nearly OK, no obvious sign of failure. Maybe chip is good too, it looks like it works with unity gain. Check physical connection from pin 2 to R10, R10 to C15, C15 to GND, for possible broken trace, check components too. Eventually check C18 for correct value (not inserted one with much higher value by mistake) or just remove it.

I put MCP601 to a op.amp tester and it seems to works ok. Also i checked for the resistors and the traces... all good. I disconnected the coils and the R13 and i saw that at pin6 i have the same signal (20...25 mv, no good sine), so this signal is from inner oscillator. Later i"ll disconnect the R14 so to see what is happening!!!!. Also i will remove capacitors to measure them.

Thanks...

[Geo]

For additional info: All passive parts was checked and measured before inserted and soldered, I never believe in value markings.
C18 is of about 47pF instead of 51pF per schematic, this should not be problem. Except possible overheating on soldering, despite I am working at minimal soldering temperature, but some plastic C are very sensitive to overheating. As I remember I put there ceramic C18.
All IC was carefully inserted in HQ sockets after all other parts are soldered to prevent static damage, so I doubt that there is something wrong with MCP601.

Geo, can you explain, step by step, how you perform initial settings and coil balancing of your KROT-2 and what power supply voltage you used?

WM6,
Thanks that you make for me the "dirty" work so no need for capacitor checking.
So.... (ohhh my english)
1. Battery = 5.1V (4xAA Nimg)
2. Disconect both coils
3. run menu ... coil balance ... press O and wait. Rx c(if i write it OK) stop near to 1400.... 1500 mv. Then i press menu and go to ADC and i press zero. Again it gives me a voltage near to 1400mv and sometimes 2400 mv. I go out from menu and close the supply.
4. i connect coils and open power supply. Display says Fr..7850 hz or so.... and Rx 10..100... 500....1500.....ERROR.
5. I press menu. and make again coil balance (autometic with O). After it i go to Zero ADC and press O.
Sometimes i run frequency ... and ferrite balance.
But problem remains the same. Where i do mistake????
Last time the Rx signal from coil was only 5mv p_p but no results....

Regards

[Wiltran]

Krot3

Thank you Andrew K2 for sharing Krot2 detector! I built it and Universal RC Meter "AB0 2006 RC meter" and both work! On Krot3 detector is S1 a DPDT toggle switch where you mount the capacitors to select different frequencies?

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[WM6]

WM6,
Thanks that you make for me the "dirty" work so no need for capacitor checking.
So.... (ohhh my english)
1. Battery = 5.1V (4xAA Nimg)
2. Disconect both coils
3. run menu ... coil balance ... press O and wait. Rx c(if i write it OK) stop near to 1400.... 1500 mv. Then i press menu and go to ADC and i press zero. Again it gives me a voltage near to 1400mv and sometimes 2400 mv. I go out from menu and close the supply.
4. i connect coils and open power supply. Display says Fr..7850 hz or so.... and Rx 10..100... 500....1500.....ERROR.
5. I press menu. and make again coil balance (autometic with O). After it i go to Zero ADC and press O.
Sometimes i run frequency ... and ferrite balance.
But problem remains the same. Where i do mistake????
Last time the Rx signal from coil was only 5mv p_p but no results....

Regards

Pretty similar behavior with my MD-3030 coil on Andrew board.

Andrew explain that: "Error RX says that there is no balance". Geo, did you try to lower Gain to 1 according Andrew suggestion here:
http://www.geotech1.com/forums/showt...533#post182533

Another Andrew suggestion is to put "A" in coil balance settings to value 0, by simultaneous pressing "+" and "-" buttons.

Did you connect shielded coil cable direct to board or over connectors and flexible unshielded wire? At least RX line should be connected to board using shielded cable.

Maybe Tepco will give us another useful idea.

[Geo]

Pretty similar behavior with my MD-3030 coil on Andrew board.

Andrew explain that: "Error RX says that there is no balance". Geo, did you try to lower Gain to 1 according Andrew suggestion here:
http://www.geotech1.com/forums/showt...533#post182533

Another Andrew suggestion is to put "A" in coil balance settings to value 0, by simultaneous pressing "+" and "-" buttons.

Did you connect shielded coil cable direct to board or over connectors and flexible unshielded wire? At least RX line should be connected to board using shielded cable.

Maybe Tepco will give us another useful idea.

There is problem with D2 (99%).
I disconnected R13, R14, C19 and gave signal to input from signal generator. With 100mv signal it gives at output only 30..40 mv. It goes to saturation only with 1.5 v input signal....

What you say????