I was bored and found a HP-27S

[franz.b]

(11-09-2020 07:14 AM)jebem Wrote:  Just to eliminate that possibility, did you increase the LCD contrast to the maximum position?
Sometimes, specially when the power supply is running below the nominal value, the LCD appears to be blank when in fact what is required is to adjust its contrast.

If I remember correctly, on the Pioneer machines the LCD contrast is adjusted by pressing and holding the CLR key and then press the + key several times to increase it, and - key to decrease it.

Thanks Jebem! no, I haven't tried to increase the contrast, it's a good idea. But before this attempt I have to find a temporary way to fix the pcb to the keyboard without twisting the hooks.