Roland HP100s 2 keys not working.

[nosaj]

`I have a roland hp1000s the low c key does not work. I have used the contact repairkit on it and no change. Also checked all diodes on the first board. Would anyone have any other suggestions? Roland no longer carries the replacement board.

Thanks,
Jason

[Jazz P Bass]

Not knowing how you tested the keypad, I would suggest finding the two terminal points that the 'contact' connects when the key is pressed.
Get on those two points & verify (power off) that the contact does close.

[nosaj]

Not knowing how you tested the keypad, I would suggest finding the two terminal points that the 'contact' connects when the key is pressed.
Get on those two points & verify (power off) that the contact does close.

Diodes were good but solder was not, reflowed and working properly now.

Thanks,

Jason

[nosaj]

after a few weeks same keys went bad. can anyone help identify which diodes these are on the bottom. They have a yellow stripe on them and most of the them measure .541 on the diode check in one direction. The ones not working measure .511.

Thanks,
Jason

Diodes were good but solder was not, reflowed and working properly now.

Thanks,

Jason

[Dave Mac Farlane]

4148 will be a good bet - any small signsl diodes - they only act as gates.
Dave

[doctor]

4148 will be a good bet - any small signsl diodes - they only act as gates.
Dave

Hi nosaj,

If only two keys do not work properly, the following reasons may be:

1. Rubber contact strip is out of order.

Swap strips from defect and intact octaves. If defect transferred to
another octave, the rubber strip is defective. If defect remained in the same place,
the keyboard print is out of order.
If the rubber strip is defective, try to repair it: take an eraser and gently scrub needed carbon pads of the rubber strip and clean these pads by alcohol. Check whether normal operation was restored. If repair was unsuccessful, you need to replace this strip. The Roland part number of this strip is 22185224. You need to take into account that this rubber strip may be obsolete.

2. Keyboard print is out of order.

Take an eraser and gently scrub the print’s carbon pads related to defective notes
and clean these pads by alcohol. Check whether normal operation was restored.
If no, check conductivity of related traces from these pads to diodes and from diodes to
related contacts of print connector. Trace may be out of order due to crack or rust
(small drop of water, coffee etc. is sufficient to mutilate a lot of traces). If trace is out
of order, solder wire jumper (30 AWG).

3. And only if all these measures have failed, replace diodes related to defective notes without
testing. It is impossible to distinguish genuine diodes type from the service manual,
but you can replace them with any small signal diodes (maximum reverse voltage more than 30V, DC forward current more than 100mA, power dissipation more than 200mW, reverse recovery time less than 10nsec), for example 1N4148.

Good luck