wanted a schematic of the board A16B-1010-0150

[machinationus]

will to paypal
i need a schematic of the board A16B-1010-0150 for the RS-232 related
electronics parts ALL. board back number: A320-1010-T156/03 H468

I now have 2 of these boards semi-working, but no means of repair.
at this point repairs are around 4K which is more than newer faster
control.
I have all negative voltage on the rs-232 DB25 pin outs...UART replaced,MC1488-89 and LS157 all replaced, no change.

It shows the 086 alarm within 0.5 sec. on Input or Output
its not the PC or Cables.
This is on 1986 leadwell 0MA control.
appreciate any help

[cnc2149]

You won't need a schematic. I've never seen a problem with the USART but many problems with the drivers/receivers getting damaged. Replacing the 75188 and 75189 chips on the board should correct the problem. They are located very near the M5 and M74 Honda connectors on the board. Suggest replacing the bad chips with sockets so they can be replaced easier next time.

[machinationus]

Originally Posted by cnc2149 You won't need a schematic. I've never seen a problem with the USART but many problems with the drivers/receivers getting damaged. Replacing the 75188 and 75189 chips on the board should correct the problem. They are located very near the M5 and M74 Honda connectors on the board. Suggest replacing the bad chips with sockets so they can be replaced easier next time.

Yes they have been replaced, in fact 3 times with new ones. They had the sockets lucky for me. The 8251A uart also replace with zif socket and new chip(s). The USART was OK... The sn75188-89's also OK.

I been working on this thing for months. And call it quits, selling it.

Other than that it works real good. But needs a paint job real bad.
I got a small .avi (55mb) its 30 sec. maybe i'll try utube.
Has 48K memory, Drip feeding was working before the rs-232 blew up.

[greenery_fr]

Originally Posted by machinationus will to paypal i need a schematic of the board A16B-1010-0150 for the RS-232 related electronics parts ALL. board back number: A320-1010-T156/03 H468 I now have 2 of these boards semi-working, but no means of repair. at this point repairs are around 4K which is more than newer faster control. I have all negative voltage on the rs-232 DB25 pin outs...UART replaced,MC1488-89 and LS157 all replaced, no change. It shows the 086 alarm within 0.5 sec. on Input or Output its not the PC or Cables. This is on 1986 leadwell 0MA control. appreciate any help

Your PCB had M74 or not if your PCB had M74 you can change to this port for DNC

Regards

[machinationus]

Originally Posted by greenery_fr Your PCB had M74 or not if your PCB had M74 you can change to this port for DNC Regards

No can not find the M74 only a M27 plug is alone

[memoryman]

I have the diagrams. M5 is the rs233 connector. The chips to replace are 75189 and 75188, locations B22 and B24 respectively.
We have them, but you can buy them at Mouser and Digikey.