TGSL-Mini 100x70mm

[BKY1337]

Todays progress:




Im not sure with the 2N2222/2N2907 in the minus voltage generator. Should i change them with 2N3906/2N3904 for better Results?
I still need to wait for my china pots. :-(

[Nandor]

Looks nice!

[BKY1337]

Thanks! My Potentiometer are here. I have one question:

Is VD 14 (between Pin1 LM358 and 2k Resistor) a normal 1N4148 Diode?

I see an additional Zener Diode in the Schematic. I dont have it in my layout.

[blobber]

VD14 is an LED, but on pin 2 LM358 is a zener diode.
Both are for battery control.

[BKY1337]

I had -6 Volts without ICs. Now i have mounted all the ICs and i only have 0.7V. Even without the 1N4148 where the LED needs to be.

I have 7.5V where the led is. Which LED do i need to use there? Can the 1N4148 destroy anything in the minus voltage generator circuit?
I dont think so, the 1N4148 should work the same way or not?. And i don't think that the ICs cause the problem. I have used 2N3906 and 2N3904 as suggested in a russian forum because they work better. But i think they work the same but not better.

I had +8.1V and -6V before. OP07 instead of the LM308 and i removed the ceramic 100pf for it. LF412 and TL081, LM358 Audio.
I have also mounted the LM833.

I hope its not a circuit problem.

[waltr]

Hope you installed sockets for the ICs. Just pop the new Ic's out one at a time and test the Voltages.
The last one out that fixes the Voltages is either bad or has a different pin-out then what the circuit is wired for.

Also ensure didoes and LEDs are not back-wards.

[kt315]

Hope you installed sockets for the ICs.
---
no needs to install sockets in primitive simplest and visible device. that is first rule.

[Hyena]

Not only "not needs". I had unstable IGSL and become much more silent only by removing sockets (which is pain in the *ss). They add parasitic capacitance and op amps did not like it. Situation get much worse with their age. And espetially with these hobby cheap & crappy ones: http://www.sivava.com/image/cache/da...-1-500x500.jpg

Use them only when you intend to test different op amps and once you decide who is the winner, solder them directly into pcb.

[BKY1337]

I use sockets everywhere. I dont think that a bad ic could cause this problem because the minus voltage is generated indepentent from the other circuit parts.

I followed Nandors suggestions for ic replacements and used an LF353 instead of an LM358. I didnt knew that LF353 is a replacement for LM358 before.

I had the same problem with my other TGSL and it was one transistor in the -5 circuit.

[BKY1337]

I removed all ICs and i still have not the -5V only 0.3V. This means that something destroyed a part in the minus voltage circuit.

I will fix the problem in the minus cirucit and try it again one ic after the other from left to the right.

I have to say that i dont have the potentiometers and switches on my board.
Only one piezo buzzer and the battery.

[BKY1337]

Its -3.2 Volt now. I changed nothing.

[waltr]

Charge Pumps can get tricky and temperamental.

Check the Clock to this and the transistors are properly switching.
Diode and caps ok?

[BKY1337]

It was my bad. I dont have negative voltage without coil. :-D

[waltr]

It was my bad. I dont have negative voltage without coil. :-D

Ahhh... yes, of course, since the coil is part of the tank circuit oscillator which then produces the clock to the charge pump.

[BKY1337]

I had -7.3 Volts with my old coil attached yesterday. Then i plugged in my ICs today and connected my new coil which is not yet potted and nulled and now i have a steady sound and only 0.6 Volts again.

I see also that my selfmade coil has only 13.95 khz TX . Maybe thats why i had only 25cm. I had the same problem with my TGSL EDU and this coil , ive thought that its a problem at my EDU board but now i have the same problem with this coil.

I think it was a bad ideo to buy a LC Meter instead of measuring the frequency directly mit a Multimeter. 13,95khz with exactly 6.50 mH.

I think one Transistor is faulty in the minus voltage circuit but i dont want to desolder it because i have not touched anything and i used new parts.
I need to check the Potentiometer and disc swicht connections first.

Can someone tell me which connections are the right ones for the Pots?

I have connected the S1 hole from the disk switch to the middle pin of the potentiometer, AllM and Disc to the outter ones.

Thresh Pot - and Thresh pot + to the outter pins of the threshold pot and the other to the middle pin.

Sens Pot 1,2,3 from left to right with the potentiometer laying at the table.

Will i have steady sound without minus voltage?