Yes but we can forget the speaker now, I desoldered it (2 wires) for 2 devices, and the same. Same whistle in the headphones. The whistle frequency change a little when I push on buttons.
These devices are too small and simple to have ground issues, I assume the problem is more likely a frequency filtering component that has changed its value. Because both devices have the same problem and are the same age: 25 years.
I could try to replace yellows tentalum capacitors by black ones (if I have) ? Or better ones ?...
corrize
Badcaps Veteran
Last Activity: Today, 05:26 PM
Joined: 04-05-2021
Location: Paris
-
Yes I just saw that on picture : lower left under the card socket seems could be a solder bridge with wire, but it’s only flux and dust because I desoldered the card socket (plastic stuck inside).
I need to check one speaker state because it make a bad noise but I have 2 devices, twice make the same Whistle and it is electronic : I heard it in speakers and headphones (I restested, sorry). It is permanent, it is present in audio menus for navigate, when reading mp3 files, etc. This whistle in constant when I turn the volume up and down.
But the whistle frequency variate a little when...Leave a comment:
-
Voice recorder for blind persons Milestone 311 - Whistle in the speaker
Hello, I have 2 voice recorder to repair. Same issue : whistle in the speaker, but the sound is good with the headphones (via jack audio plug).
Built in year 2000, I guess that could be the (yellows) capacitors ? What do you thing about that please ?
(I found the specs : tantalum-polymer capacitors 100uF 10v 10%.)... -
To give an overview :
The input plug (220v) is at bottom right.
The brown round stuff beside is the main fuse.
The two rectangular black stuff close are capacitors.
The diodes bridge is under, on the other face : the black square stuff with 4 pins (cms)
Under the black plastic shield, there is another transformer.
The component screwed on heatsink (close orange capacitor) is MX0341B (or MX0341). I don’t know what it is, no datasheet. I found it on Aliexpress as ‘regulator’ ? But with 2x3pins, yes look like a dual transistor package. (It was burned on the...Leave a comment:
-
Yes I measured 4nF (I have another same charger, with another issue).
I don’t know what to do for next step to diagnose ? I measured all components at the high voltage part, and found no issue. But I don’t have ESR meter for check capacitors. I replaced the chemicals capacitors by news ones, I replaced fuses. Next step could be a test with voltage ?
I localized the diodes bridge, I could desolder the output for protect the secondary circuit, and mesure this output of diodes bridge for check if I have stable and continuous voltage or not ? (Edit : probably not the output of diodes ...Last edited by corrize; 09-11-2025, 05:29 PM.Leave a comment:
-
Hello, I received the resistors fuses and it is simple resistors (not fuses) and with bigger watt. So not good, but I tryed to power on very quickly under thermal camera for check if something became hot. And…
The big tentalum capacitor (orange) in center of the board instantly blow up. I saw nothing hot under camera (and it is a high refresh one : 50 fps). So I guess this capacitor coud be the guilty ? All other components look good (with meter). I replaced it, and now I want to test to power on.
But I’m not shure, I never saw tentalum capacitor blow up and I don’t know if it...Leave a comment:
No activity results to display
Leave a comment: