GOLDSCAN 5 SCHEMATIC QUESTION

[dbanner]

ok cap replaced with 22nf, now freq. is 2.7khz but pulse width is 275us. after connect coil power consumption is about 850mA.

Well, you're in the ballpark anyway. There is trimmer there to adjust pulse width, I think. Power supply 10V. Frequency Adjust potentiometer what value did you use? According to TDI PRO PROTO schematic, TX pulse width is 100uS
850mA , I don't know. What are youre coil parameters? Which schematic are you using?

[saba]

Sheamtic is on your post 317#
Trimmer adjust freq. from 2.4-2.7khz, power supply 14,4V,TX pulse width is bigger and cant adjust, coil is standart 20cm. mono coil for PI detectors, 2.4om 400uh.

[Jose]

In the TDI Pro Proto scheme, the pulse width setting is a 2K preset.
The TX width is set to 100 uS. It could not be greater because of the TX pulses, may overlap, with the second sample of the GB channel.
We are talking about a frequency of 3.3 Kc.
The current depends on several factors, the voltage used, the characteristic of the coil, the frequency and the pulse width TX.
500 mA or a little more, can be considered normal, if the parameters mentioned above are used.
Jose

[dbanner]

The supply voltage for 555 stage is shown as -10V. The -14.4V is only used to power the TX. The 2K trimmer preset adjusts the pulse width, the freq. adjust potentiometer varies the frequency. You haven't said what value potentiometer you used. Make sure you have correct power supply voltage, then everything else should fall into place.

[dbanner]

One other thing I noticed, not all 555 chips are the same internal architechture, there have been many, many changes made to them since they first came out, also there is CMOS 555 which is used here if I am not mistaken.

[saba]

couple of errors, now some is fixed to power and TX stage

[saba]

Hi please explain, timing on TDI proto shematic is correct?
And A,B,C.D are correct marked or have some mistake?
Thanks

[waltr]

Hi please explain, timing on TDI proto shematic is correct?
And A,B,C.D are correct marked or have some mistake?
Thanks

If I am looking at the same TDI proto schematic then the timing to analog switches are correct.
The Timing is C-D-A-B with C-D being the target sample-EFE samples and A-B the GEB-GEB+EFE samples.

There are many other errors on this schematic however. The common ones are Op-amp inputs swapped. This becomes obvious when looking at the op-amp gain resistor connections.

[saba]

Thanks my friend, im still on timing section, i see my timings is not correct like on TDI proto, First is ok about 10us but others is not good,
Second timing D start on 34us. this is from end of TX or end of first one C?

[scs]

Patience! You will soon see my easy to make Pi discriminator schema. It works great.There is no point in discover the hot water.

[scs]

Is not a complicated- amplifier of a proportion of two signals and you get ground balance and discrimination.

[dbanner]

Still waiting after many years, give us schema now.

[Davor]

Occasionally I browse through SD2000 and Goldscan topics only to see schematics brim full of errors. At this level of complexity it is not reassuring to simply boldly go and make yourself a detector using these schematics. I'm not sure why it is so.
Hopefully Sasho's schematic will be correct.

[dbanner]

True. How does one distinguish a good schematic among many that contain errors in the same thread? I start from the assumption that all contain errors, however minor. Even some published schematics from Companies, deliberately contain errors.

[dbanner]

Sacho has very good reputation on his designs. So I expect this will be no different. Thanks sacho for all your schematics through the years.