JYE Tech Forum

Assembled FG085. Checked all solder joint, twice. Checked polarity of bulk electrolytics. Everything appeared to be go. Fired it up with enclosed 15V wall wart, nothing. Measured voltages at test points, all hovering around 0.0 - 0.8V
Nothing was getting exceptionally warm, no smoke. Noticed that the display backlight was blinking, dark to maybe 10% at maybe 1 sec interval. Checked for solder bridges, extensively with a microscope, found none.
Given the negative voltage generator has a retry interval in that range, removed it (U1) and the processor side came right up.
Next step?

Please try a different power supply if you have. Voltage between 9--12V is okay.

replace the negative voltage generator, connected variable power supply. At 15V and 130ma, it functions correctly, extensive testing not done, yet
Send another power supply?

We will send you another MC34063 (U1). Please contact us at jyetech@163.com.