Analysis this schematic

[mohandes]

Hi my dear gurus and best friend
mr porkluver ,mr georgi,mr davor,....
you can see my adjustment for pin6 ne5534( by nulling : i connect pin3 ne5534 to gnd by wire and coil not connected)IN MY MULTIMETER PICTURE this value is -0.192volt
second picture for U1-3 and U4-6 but all of you attention this level coil not connection(it is additional for myself)AND wire disconnect of U4-3 to gnd
and the finall PICTURES U1-3 and U4-6 WHEN coil onnection,i put three picture for 3 kind different of Time/Div.Alos wire disconnect of U4-3 to gnd

look and tell me it is good or no.
thanks

[Davor]

You have some nasty oscillation in Rx

Is it possible that there is some strong transmitter running nearby? There is also a possibility that you are picking up some flux of a switching power supply. Is it possible for you to use batteries instead? And try to connect your coil with a meter or so of a cable and place a coil away from other devices on the bench.

[mohandes]

You have some nasty oscillation in Rx

Is it possible that there is some strong transmitter running nearby? There is also a possibility that you are picking up some flux of a switching power supply. Is it possible for you to use batteries instead? And try to connect your coil with a meter or so of a cable and place a coil away from other devices on the bench.

I tell my self every time when you have not scope why work?
maybe all davor, because i work in lab and i put the coil under the Worktable, and i use the power supply in lab because i think it is good,

or so of a cable and place a coil away from other devices on the bench, I think your means Distance coil of worktable.ok

[mohandes]

If that last scope shot was indeed U1-3 and U4-6, then there is something wrong. It might be as Golfnut said - so much gain that the amplifier is oscillating. Soldering a low pf capacitor across the 1.5M resistor (R20 on Georgi's schematic) might clear that up. I think 10pf might be a good value but it's hard to say what would be best without experimenting. If 10pF works, then that should be good enough.

That noisy display does not mean that U4 is bad, only that U4 does not like its environment.

After that noise gets cleaned up, that signal needs to be looked at up close, (with the coil attached). That is where you look to determine if your damping resistor R6 is a good match for your coil.

edit: I saw that nastiness and wondered about what to make of it, but I was under the impression that those two signals were on U5; the Z1 and INH inputs. The U5 outputs X, Y, and Z looked OK so I said nothing about it.

ok you think good ne5534?
and incredible things : imeasure all waves on oscillogram and say to you( dont take picture)
but when i measure U5-6,U5-9,U5-11 i angry,i set pin 10 second 4538 on 100mks but when look these pins and meaure not good , and WHAT DO YOU THINK?thanks,where i am mistake or ....
thanks

[porkluvr]

Don't panic, I think I found the problem. Alex's schematic and the PCB left out the 10pF compensation capacitor C13 between pins 5 and 1. Mohandes, get you a small 10pF ceramic disk, find a way to kludge it into the circuit, and then you can probably move forward.

Georgi, I'm sorry I 'blew you off' when you mentioned that the preamp signal looked wrong. I was looking at a different signal that I thought was U4-6, and I saw nothing wrong.

edit: Georgi's schematic shows C13 between 5 and 1, not 5 and 7 like I originally stated.

re-edits: (yeah, this is a mess.) I may be re-editing this post until my time expires.

The NE5534 datasheet shows that compensation should be applied between pins 5 and 8, but go ahead and see what happens by going between 5 and 1. Maybe that is a mistake in the original schematic - maybe or maybe not.

[mohandes]

Don't panic, I think I found the problem. Alex's schematic and the PCB left out the 10pF compensation capacitor C13 between pins 5 and 1. Mohandes, get you a small 10pF ceramic disk, find a way to kludge it into the circuit, and then you can probably move forward.

Georgi, I'm sorry I 'blew you off' when you mentioned that the preamp signal looked wrong. I was looking at a different signal that I thought was U4-6, and I saw nothing wrong.

edit: Georgi's schematic shows C13 between 5 and 1, not 5 and 7 like I originally stated.

re-edits: (yeah, this is a mess.) I may be re-editing this post until my time expires.

The NE5534 datasheet shows that compensation should be applied between pins 5 and 8, but go ahead and see what happens by going between 5 and 1. Maybe that is a mistake in the original schematic - maybe or maybe not.

please read it
http://www.geotech1.com/forums/showt...ry-one)/page20

#478 my means
disagree

[georgi.g.zhelev]

FOR ALLS : SHEMATIC IS CORRECT! NE 5534 .... pin 6 : See # 95 PHOTO 2 , waveform is correct !

FOR FINAL TEST : Powered only by battery (accumulator), NO FROM THE LAB. POWER SUPLY ! ( 50 Hz )

[porkluvr]

yeay team let's go home

edit: That's so bad it's scary.

[mohandes]

yeay team let's go home

edit: That's so bad it's scary.

Yeah lets go(!!!!!!!!!!!!!!!)
my friend i will change my supply and add C13(10pf){pin1,pin5}

any think remind for me?if you have it tell me complete

and you think if i change them my input in U5 ar correct(Sa<Sb<Sc)

so thanks

[mohandes]

Hi all
i come back, first i say dont laughing to my speaking.
see this videos:
http://www.uplooder.net/cgi-bin/dl.c...89edfd0c330cb1
and the next video i speak Farsi with English together ,sorry me
http://www.uplooder.net/cgi-bin/dl.c...64dbf39353b5a3

ok see them,again sorry me i forgot should speak just english

[Davor]

You'll learn much more when you use 2 channels simultaneously. All your measurements are single channel, and it will be great if you can see at least the 555 output for time reference. Also you can use 555 output to sync your measurements.

Right now it looks good, and I see you use batteries.

[mohandes]

hi davor i think mr porkluvr want that(or i dont understand that)
thanks for attention
mr porkluvr says :one of the scope set on 500Us an one of them on 50Us , so digital scope on 500Us and analog on 50Us

but my problem is that
when i connect c13 can not set pin6 ne5534 on -0,2v ,i check all and true.

WHat happen?

[Davor]

Could it be possible that the capacitor is somehow broken?

[porkluvr]

hi davor i think mr porkluvr want that(or i dont understand that)
thanks for attention
mr porkluvr says :one of the scope set on 500Us an one of them on 50Us , so digital scope on 500Us and analog on 50Us

but my problem is that
when i connect c13 can not set pin6 ne5534 on -0,2v ,i check all and true.

WHat happen?

You seem to have forgot the part where I said that the scope must be set on DC coupling or else DC information will be lost.

But, you have totally misunderstood what I wanted to see. You twisted my words, yet again.

[mohandes]

hi all
it is important question for me.
when i adjust the pin6 ne 5534 on -0.2volts,i cannot adjust TP points(TP3=-5.83 and TP5=7.7volts and arenot change)

tomorrow i measure again

Please interduce me sites for find equivalent for Ics and Trs