Hi there,

we (small 2 men metal shop in germany) have a problem with
our wire cut machine (Matra Tape Cut).

Control =fanuc 6mb
main pcb =A16B-1000-0030/06c

Following error's since last week:
Watchdog Alarm (920)
after few minutes of running.
Errors in the range from 910-960,
with different of the green error LED's going on after start.
Sometimes not booting at all.
Sometimes the whole control freezes with no error number, just no Input possible.


Saturday I did put a light pressure with my finger on one of the 3
chips (x,z/y,z/p) that are in the middle of the pcb,
made a restart, and the
machine did run the whole day with no problem at all.
Sunday, problems again, and my little "trick" did not work again.

I think there is a problem (bad solder point/trace possibly),maybe on the address lines, but
without a circuit drawing I am lost for the moment.

What I already did:
Test a different main pcb I borrowed today, machine runs fine, so the error is 100% on our master pcb.

Did re-solder points on:

CPU socket
socket of the 3 chips and surrounding area pins
connector to ROM board
connector to BMU board
result was negative

Clean and re-seat:
every chip sitting in a socket, including rom board.
result was negative.

Measured:
psu and voltages on the master pcb with a voltmeter, everything seems ok.

maybe there is noise on one of the power lines (I have to borrow an oscilloscope), although
all condensators on the pcb seemed fine.

Got a tip today to check the onboard ram (MB8128) chips, will do that
later today, but finding the board connections without a circuit drawing,
oh my... .
Can anyone help me please.

When you did that mobo-swap test, did you do put your chips into your friend's board, or did you just swapped the whole thing?

I have the 6mb manual in pdf format for free, it has a lot of nice information, drawings and schematics, if you need it, drop me a private message with your email address. NOTE: In order for you to get access to private messaging in this forum you will have to post several times, or you can upload pictures of your machine/control here, they count as well.

Hi, thanks for your reply.

I did swap the whole master pcb,not only chips.
Machine did run fine the whole day.
Old master pcb back into machine, same error again.


I try so send a pm

regards

My doubt still is...when you installed your friend's master board, did it (the board) have its own chips or did it have your master board's chips?

Here's why, you isolated the problem within your master board, ok, now try to diagnose if your master board's problem resides in the board itself or in its interchangeable chips. Do you notice the difference?

Chips can become damaged by time, specially those old 27256 Eproms or whatever you have in there.

Hi,
yes I understand what you mean.
No I did not swap any chip. since I might end up with 2 damaged boards
and a friend who is unhappy too (to put it mildly).
I can ask him tomorrow, but I doubt he will allow it.

I did send you mails via different channels, I hope you did get one.
Did not want to make 12 posts just to be able to PM you here.

I can get the cpu replaced that is 8086-2 and also the ram chips,
but what about those 3 (x,y/z,y/p) for example.
Are those rom's that can be copied, and so on.

So, what would help me a lot too would be a circuit drawing, info on rom/rom types, replacement types and so on.

regards

PM sent!

Keep us posted!

I mailed you and will keep you informed .
Big thanks

I read your problem. 920 watchdog alarm is one of big problem which we can not repair. you can change 2 IC mb6167 and some Sn74640 near slot. May be ok.
Try to!