I had a main-board of a Hewlett-Packard HP C7280 all-in-one ink-jet printer for repair.

The client explained that the printer would work alright for some prints but later report error and freeze after running in stand-by for some time. The error code reported is 32 bit hex code 0xc19a0035. It looks specific but might actually be a catch-all general error code.

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Two of the capacitors on the main-board had a slightly bulged top. This indicate that the component is broken and it does no longer provide the capacitance. A case of bad capacitors.

Without knowing the details of the schematics, it appeared likely that these capacitors were for stabilising power lines. The negative side was connected to ground. Broken capacitors could cause noise on the power line for the connected components and that in turn may cause a logic error for signal lines and result in the system to reporting the error.

The failed capacitors are 680uF / 6.3V and 330 uF / 10 V, both rated for temp 105C, manufactured by Teapo. Two further capacitors to the right were same types both looked alright.

It turned out to be rather difficult to heat the solder points for the GND pins. The GND connections are made as a “ground-plane” and when heating it with solder iron rather than heating just the spot the heat dissipate quickly in ground-plane, so much that it never melt the solder tin. I needed to use a hot air solder and increase to 480 C to de-solder. At this heat level you risk collateral damage to neighbouring components if you are not careful.

For the PCB layout it is not good that Hewlett Packard connected the negative pins to the copper-pour of the ground plane. It would have been easy to de-solder / solder had they used a thermal relief for those component pin holes.

The Teapo capacitors were manufactured in week 04 in 2008, and the printer had been in use less than 5 years. It is bad quality that a capacitor last that short.