Wireless Lekato WS50, no sound but

[ricci]

I would like to try to fix a Lekato WS50 wireless system that after a few months suddenly no longer makes any sound.

https://lekatodeal.com/products/leka...r-system-ws-50

BUT....the good thing is that at least the transmitter and the receiver communicate with each other on all four frequencies but as I said before, no sound is heard anymore. I opened the two Tx and Rx in the hope of finding a disconnected wire from the jack but unfortunately the two jacks are ok, so the problem will be elsewhere. Can you help me ? I can upload photos if you want.

Thx

Edit: added photos

[Jon Snell]

The question is, is it a fault in the transmitter or the receiver section.
If you had a schematic, there would be a possibility of help but as it is very inexpensive Chinesium product, it is probably a throw away item.

[ricci]

I understand but unfortunately I don't have the schematic, however the seller sent me a new product even if in this category of cheap products (paid €60), it is one of the best, I was just hoping to recover it and be able to use it at home.

Anyway, the fault is only in the audio section because the battery charges and the wireless pairing also works.

What component is the 65b 130 that I can't find? Maybe a voltage regulator?

[g1]

Is the replacement unit the same model? They are supposed to be multi-channel units. Can you mix and match the new and old to see whether the fault is in the transmitter or receiver?
If you can at least do that, then you can compare the good with the bad for voltage checks, signal tracing, etc.

[ricci]

They work on 4 channels. Do you mean to try old Tx with new Rx on different channels and vice versa new Tx with old Rx ? Yes, I can do this, I'll try.

[ricci]

Is the replacement unit the same model? They are supposed to be multi-channel units. Can you mix and match the new and old to see whether the fault is in the transmitter or receiver?
If you can at least do that, then you can compare the good with the bad for voltage checks, signal tracing, etc.

Yes, same model.

[ricci]

Can you mix and match the new and old to see whether the fault is in the transmitter or receiver?

Done, unfortunately the mix does not work and the pairing does not take place.

[ricci]

I accidentally deleted the post while adding a photo. Anyway, I had written that the signal does not reach the antenna pole, which made me think that the faulty device was the transmitter.

[The Dude]

The signal at the antenna pole would be modulated RF- not audio. It would simply look like hash, if anything, on most o-scopes.

[ricci]

True, sorry I didn't think that the signal is still RF and still needs to be converted to audio. Instead, from the input jack, I find that the audio reaches the red marked pin of the 5-pin IC 21BLg (photo) which I couldn't find what it is. There is no signal on the other IC pins of the 21BLg. Actually, there are 4 ICs of that kind with 5 pins but they seem custom and I couldn't find them. The acronyms are:

LKNTH x 2
65b130
21BLg

[ricci]

Is the replacement unit the same model? They are supposed to be multi-channel units. Can you mix and match the new and old to see whether the fault is in the transmitter or receiver?
If you can at least do that, then you can compare the good with the bad for voltage checks, signal tracing, etc.

If you feel like it, could you tell me where to measure the voltage or trace some signals (the oscilloscope I have reaches 20Mhz) ? In summary, the pairing between TX and RX works and so does the charging of the batteries. The only thing wrong is the audio signal which is either not transmitted or not received.
thx

[x-pro]

here is the correct answer.

... but as it is very inexpensive Chinesium product, it is probably a throw away item.

I conclude from the questions that you are not up to the technical level of repair of this equipment.
This requires a good instrumentation laboratory. The carrier frequency in this unit is 5.8 GHz. This is not broadcast FM.
Having one oscilloscope and a tester, especially without a service manual for the product, without understanding the functioning of the components, is clearly not enough for troubleshooting.

[ricci]

here is the correct answer.


I conclude from the questions that you are not up to the technical level of repair of this equipment.
This requires a good instrumentation laboratory. The carrier frequency in this unit is 5.8 GHz. This is not broadcast FM.
Having one oscilloscope and a tester, especially without a service manual for the product, without understanding the functioning of the components, is clearly not enough for troubleshooting.

I'm not a technician but I know electronics at the level of university studies and DIY laboratories, allow me a few small errors even if they're distracting, on the other hand I wouldn't write here

[x-pro]

Let me put it another way. Can you repair a cell phone at the level of finding a small part?
You have a similar product.
For example, I have experience in repairing transceiver equipment at the parts level.
But it is definitely not worth repairing such a product without service documentation, without the ability to identify a faulty receiver or transmitter, without appropriate RF measurements, or even just a cheap tool. There is simply nothing to do there, unless you are lucky enough to guess the part.

[ricci]

Let me put it another way...

I know how every single component works, I repaired a Shure Diversity, there is a thread of mine in this forum, and also some cell phones and I also built some clone guitar pedals from online schematics, I have enough manual skills with smd components and I have a hot air soldering station with which I have repaired some laptops including my old Toshiba. Among other things, I know Arduino and I also know how to program it, because I've been a programmer for years, which helped me build a midi controller that I use in my pedalboard.
Here, the main problem is that I can't find the datasheets of some components, it would perhaps be easier.