Guitar Dreamer: Yamaha PSR keys repair!

Guitar-dreamer is all about guitar and bass gear but we should not forget that there are many other electronic/electric musical instruments out there that need a bit of attention.

Keyboards, keys, synths, clavinovas and so on play a very important role in many bands and these keys have issues and need maintenance as any other musical instrument.

Two friends brought in their Yamaha keyboards that needed a bit of attention. The 1st keyboard was an early 2000's PSR model and the 2nd one was an 80's made in Japan PSR model.

Both keys had a few power supply(PSU) issues. Using the appropriate external power supply is very important for these keys. Unfortunately, Yamaha does not support old PSR keys and sometimes the new PSUs are just not right for the elder models.

Power Supply tips:

-First of all, one has to pay attention to get the right polarity and right Voltage supply.

-Don't use wrong polarity supplies, inverted voltage polarity could easily kill your equipment

-Always use STABILISED power supplies so that the Voltage remains stable no matter if the wall socket Ac voltage get a bit higher than the suggested (e.g. 246V instead of 230Vac).

- The current a power supply could provide is measured in mA (milli Amperes).

You should always buy a power supply that can provide a bit more mAs than what's written on your device. For example, should the device (keyboards) need 200mA, the PSU has to be able to provide the device with this current. A 50mA psu will burn up and maybe short circuit. A 1000mA psu is able of providing 1A current but the device will only use 200mA of it, so that's Okay.

-A psu cannot "force" extra current inside the device/load it is powering. The device consumption will determine just how much current it needs to operate properly. This amount of current is written on the back of the device or inside its manual.

-Always unplug the device and psu when not in use. That's very important as stand-by power consumption costs much more than we can imagine but it also wears out the psu and our devices. Many devices and PSUs have failed while being is stand-by/sleep mode...

These two PSR keyboards were opened up for a check and I found dust inside them that had to be cleaned. There's always dust inside these devices and it's the No1 cause of volume drops, pots and buttons acting funny, CPUs and DSP chips overheating and so on.

Once all dust was removed, I sprayed the pots and buttons with some contact cleaner and replaced a few leaky electrolytic capacitors(that's the No2 cause of issues...).

Now these vintage Yamaha PSR keys are ready to play again!

Here are a few pictures :