Surf PI Pro

[joop]

The offset is not used to set the output to zero, which you would normally do. I noticed the offset should be close to the positive rail voltage for the SURF-PI to become the most sensitive. Did not test it with different coils though.

[bernte_one]

hello

i finished two boards of surf xx (appies version)
and they work

did i have to set multimeter an AC or DC measurement when setting Offset trimmer and measure positive rail and pin6 on ne5534?
normally i have multimeter on DC but this time i can measure high voltage values up to 11V (range 2-11V) while measure and trimming the offset trimmer
what can be the reason if i cant set it to "0" volt
should i go outside far away from any metal? how is i done by the commercial builders do they go off their producing rooms to set the machines

so
how do i connect the multimeter right and how do i make the offset setup procedure

in the past i have seen that the best positon is not around zero volt (accordig to coil 2-4V)

seems that i have not fully understand the thing and i walk in the dark

so thanks for tips

[sdesic]

sorry CAT-5 network cable not CAT-T.

[sdesic]

How can I use CAT-T cable for coil for PI PRO?
I have seen some designs and solutions, has anyone tried on this model ?
Please post data - how much cable and how to interconnect them.
Thank you.

[porkluvr]

You might be right, but please, WHERE are you getting this from??

Like I said, you may be right but on the other hand, these are "nutshell" specifications you quoted. It could amount to (Newark, or Futurlec, maybe?) using personnel from their catalog division to convey electrical specifications that they know little about.

Could be the difference between one manufacturer listing "minimum" specs and another manufacturer stating "typical" specs which would amount to an unfair comparison!

[au1]

LM358N

20nA

2mV

700µA

60mA

[au1]

LM358P

20nA

3mV

1mA

30mA

[au1]

LM358N

LMx58 Datasheet

8-DIP

LM358 View All Specifications

50

Integrated Circuits (ICs)

Linear - Amplifiers - Instrumentation, OP Amps, Buffer Amps

-

General Purpose

2

-

0.6 V/µs

1.1MHz

[au1]

LM358P

LM158,258,358(A),2904(V) Datasheet

8-DIP

50

Integrated Circuits (ICs)

Linear - Amplifiers - Instrumentation, OP Amps, Buffer Amps

-

General Purpose

2

-

0.3 V/µs

700kHz

[ppodg]

Silence is golden (?) from metal detector band
Just finished my PCB 2 soldering and started device and nothing... same voltages as should be.
Must aquire few ICs.

Please, DO buy a scope, 2-channel if possible.

[porkluvr]

Silence is golden (?) from metal detector band
Just finished my PCB 2 soldering and started device and nothing... same voltages as should be.
Must aquire few ICs.

LM358P is going to recycle bin.
His friend NE555N also ...

If I am not mistaken, "N" and "P" regarding LM358, that is simply two different manufacturers' different methods of expressing the plastic DIP package, and those two letters imply NO electrical differences between them.

LM358N = plastic DIP (manufacturer "x")
LM358P = plastic DIP (manufacturer "y")

Each will be stamped with a different manufacturer's logo. (I am in a hurry or I would chase down more details).

Now perhaps one or the other of the manufacturers has a better process and thus produces better product, so if you want to believe that the LM358P is inferior, that is OK. Interesting possibility.

I will be a good thing to replace any NE555 with a CMOS version from one manufacturer or another. Which manufacturer (and which prefix they use) will make little or no difference so long as it is CMOS, and not old style bipolar technology (usually with either NE or LM prefix).

[sdesic]

Silence is golden (?) from metal detector band
Just finished my PCB 2 soldering and started device and nothing... same voltages as should be.
Must aquire few ICs.

LM358P is going to recycle bin.
His friend NE555N also ...

Rest of them ICs...
NE5534P
SMD one (7660) is working fine, giving out -4.0-4.5 V
HEF4066BP NXP and HEF4093BP NXP

[sdesic]

homefire, thank you, I didn't know that is in tollerance.
Resistors are mostly 5% tollerance

[homefire]

That is within the Tollance of 20%.

[sdesic]

Desoldering components from old detector I noticed that offset trimmer 100k is only 87k ... that is one of problems ?
Can it be used or I must search for new one ?

Assembled almost everything on new PCB, still need to connect pots and coil.