Zoom H4n Pro handheld recorder #
It’s a nifty device, but like the previous generation H4n, suffers from fragile side buttons, fragile SD card door, and a flimsy battery cover. I cover these repairs in a video here.
Repairs #
Side buttons #
I can’t be sure of the exact part number used in this recorder, but the dimensions and layout seem quite common across manufacturers. For example the E-switch TL3340 or Würth WS-TASU.
This type of side-actuated tactile switch is, in my opinion, asking for trouble. Especially when the only mechanical support comes from surface-mount pads:
Actuation force creates a twisting moment that translates into a force trying to pull the front pads up off the PCB.
On the H4n, Zoom chose to use the absolute smallest lands possible for these most critical front support pads. In addition, their plastic pushbutton linkage doesn’t have a hard stop that would’ve helped limit excessive actuation force.
I’m not the first to have to deal with this : https://www.youtube.com/watch?v=Hmzh0ejsJSQ
Ok, rant over
SD card door #
This is a type of rubberized or flexible plastic, held captive by two small wedges extending into the body of the recorder. These broke on mine; my fix was to drill the door, then thread and tie some braided fishing line through it and the case:
Internals #
photos #
components #
- D78F0536A 8bit mcu, 96k ROM . Manages display too
- TMS320VC5509AZ hidden under SD slot
- 29AL? 016J70TFI01 (Spansion), flash 16Mbit (2MB), also under SD
- em638165ts-7g SDRAM4Mx16 (8MB)
- AU6254 Alcor usb hub
- AU6336 USB-SD msc controller
- WM8750 stereo codec
- RT9971 - 7 CH Power Management IC
- MCP23017 io expander
- NJM2904 JFET-input high speed, low noise, and low distortion operational amplifier
- NJU7057 Low Noise, Low Offset Voltage Drift, Rail-to-Rail Output CMOS
- AK5357 24bit stereo ADC
- CDCE913 Programmable 1-PLL VCXO clock synth
- S35390A RTC
I wasn’t able to easily identify some of the smaller, ambiguously-marked ICs especially on the power PCB.