Question about tgsl

[waleed]

Hi Waleed

The potetiometers you use must be linear not logarithmic.

B100k-linear and A100k-logarithmic.

Hi Nandor,you mean the black potentiometers I used is a logarithmic ones and how they would affect the circuit, but I don't think they cause the continues beeping because I used them on my old board and it worked but the performance wasn't good and that's why I changed to the EDU one.

[waltr]

Waltr, before the test part,can you take a deep look on my board and see if I did anything wrong, and also check if I did the mod by silverdog right or not, what I did is removing R33 and I put diodes at C20 and C23 reversed from D10 and D11, R29 and R31 was already 1meg on the board.

Mod seems ok. I played with that mod and found it didn't do much to improve performance.
There are a few things you can check using a DVM.
1- Is there -5V (-6.2V)?? A TX coil MUST be connected to have the TX Oscillator run which is used for the charge pump.
Without -5V the circuit will not work.
I would disconnect the speaker so the noise does not drive you crazy. Also some speakers may not work causing problems in the rest of the circuit.

2- Voltage at the outputs of U104 & U105 need to be very close to Zero. It is these outputs that trip the comparator, U106, to cause output to speaker.
3- Check Voltage at inverting inputs of U106. The Voltage here should change when you turn the Sens. pot.

Check the POTS as Nandor stated. Log pots will kinda work but they really should be linear pots.

[Nandor]

Hi Waleed

The potetiometers you use must be linear not logarithmic.

B100k-linear and A100k-logarithmic.

[waleed]

Waltr, before the test part,can you take a deep look on my board and see if I did anything wrong, and also check if I did the mod by silverdog right or not, what I did is removing R33 and I put diodes at C20 and C23 reversed from D10 and D11, R29 and R31 was already 1meg on the board.

https://i.ibb.co/xq4k2nL/IMG-20200214-WA0005.jpg

https://i.ibb.co/LhG98VW/IMG-20200214-WA0006.jpg

https://i.ibb.co/PGDtMHv/IMG-20200214-WA0007.jpg

https://i.ibb.co/MCVvyzz/IMG-20200214-WA0000.jpg

[waltr]

Thank you all for the support I appreciated it, and oki waltr I'll do these tests at sunday when I go to the uni because I don't have oscilloscope and I use the one at my uni, I'll be back when I'm done.

Good. I'll be watching for your results.

[waleed]

Thank you all for the support I appreciated it, and oki waltr I'll do these tests at sunday when I go to the uni because I don't have oscilloscope and I use the one at my uni, I'll be back when I'm done.

[waltr]

Unfortunately I didn't use sockets :/, maybe should I start removing them from right to left, like for example I'll remove first IC from the right and then turn on the device and see if the sound is gone?,because it is hard to remove them all together:/

Ok. Then before removing all the ICs, Just do the measurements I outlined in above post.
1- Oscillator running?
2- charge pump outputting -5?
3- etc.

[kt315]

checking each op amp and 393 on any stage being before soldering and being in a process of troubleshoting - tester board is helping you.
i ordered them much so they cover all your needs. sorry for reminder but i can not see on your long torments of creativity without tears .
recently i was checked easely 5218A in a board of 2+1 amplifier. just desoldered them and put in the tester.

[Qiaozhi]

Thats the main problem with Silverdog pcb's. The holes are metalized also, removing components is very hard.

Silverdog's PCBs are double-sided, and therefore they have plated-through holes, which is quite normal. You would not want a double-sided board without plated-through holes, as you would need to solder both sides of the board for every component.

Anyway, populating the whole board, on a design you've never built before, is a recipe for disaster. The correct method is to build in stages, checking each stage as you go along.

[Nandor]

Thats the main problem with Silverdog pcb's. The holes are metalized also, removing components is very hard.

[waleed]

Yes. I also assume you soldered in sockets so easy to pop out the ICs.
Without the IC's those sections of will not do anything.

Unfortunately I didn't use sockets :/, maybe should I start removing them from right to left, like for example I'll remove first IC from the right and then turn on the device and see if the sound is gone?,because it is hard to remove them all together:/

[waltr]

Thanks guys for the support I'll not give up, and waltr you mean that I remove all ICs only and keep the rest components and then install the ICs one by one and with testing as you mentioned?

Yes. I also assume you soldered in sockets so easy to pop out the ICs.
Without the IC's those sections of will not do anything.

[waleed]

Thanks guys for the support I'll not give up, and waltr you mean that I remove all ICs only and keep the rest components and then install the ICs one by one and with testing as you mentioned?

[waltr]

Not good to just go and stuff ALL parts.

Pull all the chips.
Connect coil and measure TX oscillator frequency and waveform with your O'scope.
If good install U100 with coil connected. Measure the -5V. Should be -5 to -6.2V for the charge pump..
If either not working then Re-check the Transistor's Pin-Out. Depending on where they were made there can be three different pin-outs.

Once Oscillator & charge pump work install U101 & connect RX coil. Measure with O'scope at U!) pins 7 & 1.
Pin 1 should look like TX, pin 7 should have very low amplitude IF coil is nulled.

Once they work add U102 and check GB and DISC at TR4 & TR5 gates. Then at TR4 &TR5 Source.
Keep adding stages and measure/test. If something doesn't work STOP and find out why, fix it before adding next stage.

[WM6]

I'm really disappointed because it's my second time making this device without success :/

Sorry this happen, but don't worry, electronic board can be repaired and fixed. Using scope of course.

You need to go step by step check, as already suggested by waltr and others in previous posts.