TGSL Tuning & troubleshooting

[sdesic]

>Are you measuring the TX or RX signal as reference (your scope screen says RX)?
>Most useful to start with is measurements vs the TX signal.
that is TX graph sorry ... it was early in the morning typo in photoshop...

>Have you tried moving the cable in different configurations, touching it with your hand, etc. to see effect on beeping?
tried varius combination of wires in USB cable... it is not responsive to touch

>Do you have some RCA audio cables you can try as a substitute?
to separate TX from RX... OK will try that also
STP - UTP ?

>Probably not easy to help you troubleshoot without good equipment. Obvious ideas are to double-check your solder joints; make sure >no solder across traces; clean resin off PCB.
cleaned few times... MD works with more overlap ... no disc. mode

>I would still want to see all signals I mentioned compared to TX, to get phase relationships,
>although the PC scope may be interfering somewhat.
will post rest of them today...

[sdesic]

Replaced USB cable with RCA high grade audio cable (two coaxial cables connected)
nothing changed... tried GND in head of coil and tried connecting shielding wires to one of TX and then to one of TX wires ...
same thing happens... it is stable when overlap of coils is over 3.5 cm

moving on

[sdesic]

captured few more
TX and pin 7 393 close to GB (I am thinking that lower one is noise only - even if not connected there is similar signal)
TX and gate of TR4 and TR5
all metal mode

[sdesic]

Switched to disc. mode
tx and pin 1 353
tx and pin 7 353
tx and pin 7 393

[sdesic]

small signal GATE TR4 and GATE TR5 is from TX coil
when it is not connected there is no signal - this scope can't read TR4&5 ?
GB trimmer on middle

[Davor]

What FETs do you use?

[sdesic]

input to LM393 U102a pin 2 while rotating the DISC pot
and TX graph




Davor,

I am using KIT from Silverdog ... he has supplied me with BF245B

[sdesic]

LM393 pin 7 while rotating the GB pot




I made a mistake by connecting pins 7 and 8 of LM393 and detector stoped working
then it responded to ferrite and I was able to noch it with GB trimmer
(or just lower sensitivity to all)
I shocked it with 8V to pin 7 ... after minute it was beeping again ...
it is not fried...

[sdesic]

I don't understand why delay of 50s when powering up ... detector is getting power ... there is no tubes inside to warm up
if I move coils it detects on fist second from powering detects other coil or cable
other things is detecting after 50s

OK, that's it from me and "scope" for today

[Davor]

It appears as if you used up all the space for your attachments. You may want to politely ask Carl to do something about it. Those scope shots were all jpg. Unfortunately. For all screenshots you get 10 times smaller files, and in incredibly better quality if you save them as gif.

Anyway...

There might be a logical explanation after all. Guess you have some decent ohm meter at hand. I want you to switch off your device, and measure resistance between LM393 pin 7 and ground. With device switched off, of course.

Edit ... you can find ground at pin 5 of LM393.

[simonbaker]

Switched to disc. mode
tx and pin 1 353
tx and pin 7 353
tx and pin 7 393

Unfortunately we cannot see phase easily because time scale is too long -- can you "zoom in" by using faster sweep or magnifying the time scale?

I would like to see details of signal at Gate of TR4, TR5, but I think maybe your scope bandwidth is too small. The signals should be square wave for GB sync pulse (at gate TR5) and DISC sync pulse (at gate TR4). Sometimes the DISC signal has spikes which usually don't cause a problem. ALL METAL (gate of TR4 also) signal usually looks like a triangle wave.

Any distortions to these signals, or level problems would be interesting to know. Usually the max value of the sync pulses is approximately 0 V (ground).

Anyway, I'm hopeful you can find the problem because it is not sensitive to cables -- something more definite is wrong. Because it was a kit, it would seem you are using all the right parts.

What did you use to measure the inductance of your coils?

-SB

[sdesic]

Davor,
resistance is 14,94k ohm

Simon,
I bought LRC meter few months ago
VICHY DM4070
I will try to measure those graphs again...

Thank you all for your patience!

[Qiaozhi]

It appears as if you used up all the space for your attachments. You may want to politely ask Carl to do something about it.

That's not the problem.
I suspect he just took too long to upload the files before attaching them. There's a one hour limit, after which any unused attachments are automatically deleted.

[sdesic]

Thank you Qiaozhi

I was writing in this envelope and testing with scope and uploading then... no problem must hurry

Let's try another one... this time it is PNG and smaller

This is graph for pin1 LF353 ... without TX and with TX



this "scope" is not very accurate in this kind of scale...

[sdesic]

is this OK for view ?
tx and pin 1 LF353
disc. mode now