Fanuc 6MB not starting after mothballed, mostly dead, no video
Hello
I'd appreciate any meaningful suggestions on troubleshooting, or where I can go to verify function of boards or ROMs. The couple places I've called don't actually seem able to test boards. Please excuse my terminology, I'm not hip with Fanuc jargon.
I have a Matsuura HMC with Fanuc 6MB control which has been in storage a while but is generally exceptionally clean (no mice, no filth). I think it is actually the 6MB2 rev.
I can get the control cabinet to power up, but have not seen a thing on the CRT.
* power unit shows green LED
* all supplies on main board are nominal, with reasonable noise/ripple
* CRT is scanning, if you unplug the cable the full display is lit
* no video signals on the test points on CRTC/Puncher board
* 6MHz clock is valid on main board
* reset pin is negated on 8086 chip
* watchdog LED never lights
I started removing cards, beginning with the PC-G card (I don't really get what that card does... I think interface to the other processor board... see below). For a little while I got the diagnostic LEDs on the main board to come on various ways at start up. I can't say they ever cycled, I think they just came on one way each time.
But after more goofing around, these don't come on any longer
I have generally tried starting with the 4th axis and PC-G cards removed, as it seems likely these are not needed to get some kind of response (i.e. error messages on the CRT). Yes? No? Whether or not the BMU is installed seems to make no difference.
I have reseated all socketed chips (8086, EPROMs, parity RAMs) and visually inspected all boards. I found a solder bridge on the PC-G shorting two pins of a 7404, but the gates are all still inverting after removing the short, so it is probably ok... amazingly.
The other 8086 board A20B-1000-057 (is this some kind of PLC board?) seems to be humming away happily, with lots of good data/address activity.The multiplexed data/address bus on the main 8086 seems to repeatedly go low with S0/1/2 and RD seemingly indicating it's trying a memory read. This makes me wonder if the EPROMs are corrupted (32 years old).
If I read these version M53 firmware ROMs using a burner, does anyone have files to compare them to so I could validate the code?
So, specific questions:
-which boards are really needed to see activity (e.g. crt error messages)?
-will system start if BMU or contents are toast? how would you enter BMU config if you can't boot or get display? Please don't say "tape"
-how can I validate M53 firmware? do I have to buy new ROMs from Fanuc? can I?
Re: Fanuc 6MB not starting after mothballed, mostly dead, no video
I recommend getting a Fanuc 6 Maintenance manual and operators manual to start with. The BMU will be fine as it's magnetic memory and not battery backed. All your parameters and part programmes are stored on this so it needs to be there for the control to work. The lights on the mother board should be off when it's running..they only light if you have a fault. My advice put all the boards back..they are all needed for it to boot up..then try getting the CRT checked over ..if that doesn't fix it could be your 24v power supply although I presume you have checked this already..maybe the crt puncher board but more likely a power supply fault on the crt or at the 24v supply.
The PC-B board is for i/o and controls all the parts of the machine that require sensors..switching solenoids etc for example the tool changer and pallet clamp are controlled by the PC-B board..it's just like a modern plc.The ROM board has the software eproms on it for the cnc control.
Hope this helps..remember if in doubt get an expert in, it's cheaper in the long run!!
Fanuc 6MB not starting after mothballed, mostly dead, no video
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