GOLDSCAN IV 4835 problem

[ashkelon]

Hello friends

i have a problem 4538 IC , GOLDSCAN IV , U7 input pin 5 only one pulse input but output pin 6-11 and pin10 has double pulses out. Is this my pcb error or there are right pulses at output ?

[ashkelon]

this is my board but not working properly

[ashkelon]

i have bought this transistor 2SK381 cross J113 , i could not find its datasheet , i use random pin connection

[porkluvr]

You should have a single output pulse at U7-6 for each input pulse on U7-5.

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I found your 2SK381datasheet but I can't read Japanese.
http://www.datasheetcatalog.com/data...3/2SK381.shtml

Use a digital multimeter to measure the FET. Two of the pins should read very high resistance between them either way you place the meter leads.
Those are S and D pins.

The other pin is G. If you place the black meter lead on the G you should read the same (low) resistance to the S and D pins.

If the 2SK381 is indeed a good replacement for the J113, the S and D pins will be interchangeable. Just make sure you get the G lead in the correct hole.

Other FETs that might work are TIS75, J107, 2N4393, BF245A, BF245B, but some or all of their pin-outs may be reversed. Use the multimeter to find the G pin like I told you. You can swap the S and D pins without any problem on these particular FETS.

edit: 2N5485, 2N5485 should also work OK. Although all the other FETS I mentioned should work reasonably well (watch the pin-outs!), I believe that J113 is your best choice, if you can find it.

[ashkelon]

thanks for replay porkluvr

2sk381 are working great with same position J113 at schema. No problem about it.

GS4 is begin the work 50% with these double pulses. first i have to solve this pulse problem. I read the Baracuda update and Geo problem was same about the pulses.

Sample pulse not begin after end of the main pulse then other 4538 make it double. connections all ok. i changed all 4538 in stead of new IC.

[ashkelon]

This picture U5 pin6 output pulse and 5534 pin6, sample pulse is not end of the main pulse.

[Altra]

J113 Data sheet, google, first hit
http://www.datasheetcatalog.org/data...o7zft3oopy.pdf

4538 try a different brand, I had some Harris CD4538's one time that did the same thing
brand new. A double pulse out when it should of been one.

Mark

[ashkelon]

J113 Data sheet, google, first hit
http://www.datasheetcatalog.org/data...o7zft3oopy.pdf

4538 try a different brand, I had some Harris CD4538's one time that did the same thing
brand new. A double pulse out when it should of been one.

Mark

i use 4538 everytime for GS4, GOLDSCAN IV 4835 problem, incorrectly type headline.

[ashkelon]

i prepared new pulse maker board with 4 CD4538 IC, this is better , i can adjust all pulse width and delay times.
Each sample pulse width 50µs adjusted. i don't know real what it was.
555 output main pulse width is 545µs minimum, current drain really much this MD.

Only working SEL1 and ALL metal mode. These modes are using gold channel (SW1-A GND pot).
SW1-A directly gold channel without GND pot (SEL2) not working, constant bip sound.

[Orbit]

lt spice unrelated to the original pattern of goldskan4

[ashkelon]

finished the super GS4 Disc. machine
i read many experiment about GS4. Thanks Max , Porkluvr , Reg , Alexismex and other friends

Certainly my GS4 is not adjusted like orginal one but i have little experiment about it
There is no great disc. but sens. is the similar with sniffer. If the metal is big, disc. is working. small and close metals can make disc. this was air test.
i am sure that it has better disc. on real ground area.

thanks Eric Foster

[sinko1]

please shematic and pcb

[didarpm]

+5 Volt FAULT IN GOLDSCAN IV

please shematic and pcb

Hello guys I need help because I'm not able to have the voltage of +5 volts, can someone help me ... thank you.

goldscan IV

[porkluvr]

Well, what do you have? You have not told us anything.

You should have about 10V going into the 78L05.

If you don't, then make sure the diodes D1 and D2 are good and properly oriented. Same goes for the transistors T1, T2.

The circuit looks funny around the transistors but it works good the way it is drawn.

Notice there are some recommendations for changing 10k resistors to 2k2 and changing 1N4148 to BAT84 but those are not important and if you have good parts
and everything is properly oriented the +5 power supply should work.

[Dr Vel]

If anyone still needs the pinout for the Fet.

2SK381 FET, N Channel ; cross to 2N3369. Looking at images, part number lettering is on top. The second PDF shows it's specs on the 4th page.