Combintions P8055-1 with P2633 not working

Kits PC Related Projects
1

all,

I have connected the P8055-1 USB control board with a P2633 relay board. I connected output 1-4 of P8055 with relay input 1-4 from the P2633. I connecyed the relay GND to the USB baord GND. Releu board is poweren by P1823 set at 9V.
Problem is that the USB board works OK. The connections to the relay baord also seems to work (LEDs light up on relay board at same time as on USB board. However, the relays do not respond.
Any suggestions to solve this problem?
Thanks,
Jack

2

Check the value of the pull-up resistors on the transistor bases of the relay board.
If they are less than 1K, replace with at least 1K.
Check operation of relay board by grounding inputs.

3

Thanks for the reply.
I exchaned some of the RX pull up resistors to 1K. Problem remains.
I attached a simple conection diagram
Jack

See layout: descsite.nl/switch-box-layout-1.pdf

PS. Is it OK to power the p2633 with 9V since the relay seems 6V (SRU06VDC-SL-C)