TGSL Tuning & troubleshooting

[sdesic]

two more for Simon
TX and pin 7 on 353


TX and pin7 393

[simonbaker]

Thanks, those graphs are better for comparing phase -- although we cannot trust the scope too much because of bandwith limitations. I'll try to compare them to some graphs of a working TGSL -- there are photos on this web site that should help if we can locate them. I have been busy lately and forget where they are.

We will continue to think about what may be wrong. Sometimes making a different set of coils solves such problems, although these coils should be capable of working.

We will continue to think about other tests to perform. If you can somehow get a real oscilloscope, it would help greatly.

Regards,

-SB

[sdesic]

tx and gate TR4 and TR5 in disc mode

[sdesic]

Simon,

I will try to get full scope... but can't promise that I will get it soon.

I was going to try without mylar shielding ... do you recommend that ?

[simonbaker]

Simon,

I will try to get full scope... but can't promise that I will get it soon.

I was going to try without mylar shielding ... do you recommend that ?

Yes, I do recommend trying without shielding. And of course checking your shielding to make sure nothing has accidentally shorted the gap you leave.

This is a test also to try:

1. Set the coil overlap so there is beeping.

2. Increase the resistor in each of your oscilloscope probes so that when you measure the gate of TR4 and TR5, the beeping does not stop. Use the highest resistor you can where you still get a good signal on your oscilloscope. Use the same value resistance for each probe.

3. In one channel, display the TX signal for comparison. Use the same voltage range and "amplitude" in each channel.

4. In the other channel, measure the gate of TR4 while the beeping is happening. Capture the photo for us.

5. Now touch the gate of TR4 with your finger (while taking the same measurements). I assume this will stop the beeping and increase the detection depth. Capture the photo for us.

Regards,

-SB

[sdesic]

arranged probe like this and still doesn't stop beeps from MD...


maybe 1M should be between GND and signal ?

[sdesic]

new configuration stops beeping (it doesn't start with more resistance)


EDIT - tried one more combination - one channel scope 4 M + 100k ...
stops it and until it is disconnected it don't start beeping again

[sdesic]

Simon,

it took 9M ohm resistors to stop it and it continues to beep after that connection... slower rate of beeps

[Davor]

But you did not identify problem yet. You could try to beef up some of the 220uF capacitors and expect some improvement.

[sdesic]

Simon asked to do this test.
Detector stops beeping after I touch or connect scope to gate of TR4 in all metal mode (only TR4)
later I will post some screenshots if I understand his request right

[sdesic]

what do you mean by beefing ... replacing with new or replacing with higher value capacitor ?

[Davor]

beefing up = nabacat više mesa

You could try replacing these with larger capacitors. When choosing these it is a good idea to find out their ESR and pick those with smallest possible ESR available. Those glitches you noted on a scope are not quite expected with large enough capacitors, and could be related with high ESR.

[sdesic]

Will do some changes ... 220uF ... is 1000 uF OK ? but no space for them ...
I don't know their resistance ... Made in China probably
we are making something for NASA ? KIT from Silverdog contains parts ... they are installed here

If I knew it would be like this ...
If I buy kit that means that I don't have enough knowledge to buy parts or produce my own PCB or experience to experiment

EDIT - here is manufacturers page http://www.jianghaius.com/Pe/CD263.htm

[sdesic]

"oscilloscope" is connected with tx and gate of tr4
all metal mode - beeping - probe has 8 M Ohm + 200k resitors (both channels)

with finger on tr4 gate and without

[sdesic]

Davor,

I replaced all 220uF capacitors with 3x 470uF 16V and two new 220uF 25 V
Changed also ... my battery ... now it is 12V 1-2Ah lead acid battery showing 12.8V when loaded with TGSL EDU
Changed original C6 15nF

unsoldering two sided PCB is a mess ... placed them on other side of PCB
same beeps on normal overlap... same delay 50s ...