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Fanuc 21i-T RS- 232 Failure

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What is the most likely culprit of communication failure? There aren't any errors, just LSK blinking and blinking and blinking forever and ever like I failed to hit send from the PC feeding it. Everything to the machine is fine as the system works when plugged into other machines both for sending and receiving. I figure I would take the short cut of asking here first as I am getting too old and battered to enjoy crawling on the ground playing machine tech. Calling someone is out as service calls here are pricey and you also get incompetent tail chasers, tried that route years ago, never again.

Worse yet I need to figure out how to manually key in the next program as it is only 40 short lines. My off the top of the head attempts get "format error". There aren't any programs in the machine, I dumped them all or I would just alter one of those, I have no problem doing that. The machine also has a port next to the CRT that I think can be used to input programs with a hand held device, I believe the previous owner used that. I wonder if that would work, or if the RS-232 system was dead, that would be also. Looks like about 2 rows of 25 pins a side, no idea what you call that?
 
Have you had this machine receiving in the past? If it used to work and now does not you may have a bad chip on the control board. Once you get something keyed into the control, see if you can send it out.

To start a new program you should be able to key in O1234 then press insert. Note, no EOB at that time. Key that in next.

The slot beside the door is a PCMCIA card reader. If it is a 21iT it should read both FLASH cards as well as the much less common and more expensive SRAM cards.
 
There is nothing more comforting than a Vancbiker response to my troubles. I have had this machine for well over a dozen years sending and receiving without out any issues in two different locations with 3 different PCs and 3 different types of software.
 
I just tried the O1234 and it worked. That will get me by for the next job, thank you very much. You rock.
 
Older Fanucs used a 75189 chip for receiving RS232. I'm pretty sure the 21i is using something different, but I don't have any info for certain.

Connection JD36A and B are the RS232 ports 1 and 2 respectively. You probably have a cable connected to A and B is empty. If B is not used you could try swapping the cable to the JD36B connector and changing the communication parameters to use port 2 and see if it works.

The RS232 hardware is on the main board so you need to keep your fingers crossed that it's not a board problem. Sometimes one can figure out which chip(s) handle communication by googling the chip numbers near the connector and see if you find ones identified as RS232 or UART or similar.
 
Main board? Yikes, I figure it would be on a daughter card. I will probably just key in the next program and then when it runs out in a couple days start crawling on the ground and investigating.
 
Putting a program in the machine like a chicken pecking the ground sucked. A couple more days and I will try switching ports. I still haven't even opened the cabinet yet. I am not fond of crawling on the ground and getting up and down these days. For the life of me I cannot remember a communication failure with a machine once it was set-up. That includes all of them I worked on or around and I have ran machines that used tape readers. Just my luck.
 
Are you using a USB to serial adapter on your PC? I've had to replace a couple of those over the years for the same problem. They aren't super reliable.

Personally I'd opt for the PCM or flash card. It's nearly instantaneous compared to RS-232. And they're pretty cheap on ebay.
 
Are you using a USB to serial adapter on your PC? I've had to replace a couple of those over the years for the same problem. They aren't super reliable.......

The OP mentioned that he can send and receive on other machines so IME, that would rule out a bad USB-serial adapter. Have you seen a situation where a bad adapter worked on one machine but not another?
 
Are you using a USB to serial adapter on your PC? I've had to replace a couple of those over the years for the same problem. They aren't super reliable.

Personally I'd opt for the PCM or flash card. It's nearly instantaneous compared to RS-232. And they're pretty cheap on ebay.

Even though it works on other machines it is serial to serial.
 
The OP mentioned that he can send and receive on other machines so IME, that would rule out a bad USB-serial adapter. Have you seen a situation where a bad adapter worked on one machine but not another?

Everything to the machine is fine as the system works when plugged into other machines both for sending and receiving.

Apologies. I missed that in the original quote.
 
Once you get something keyed into the control, see if you can send it out.

I did that just now as after the previous job ran out I didn't get more work for the machine until a couple days ago. I was able to send my hand pecked program out without issue, but it still will not receive. I haven't crawled down and looked at the mother board or even flipped through the manual yet.
 
Now another machine has caught the disease, will send but not receive. It is a Fanuc OT, maybe they caught the Corona-virus. The thing was it happened about at least a week later. So freaking weird.
 
We had same problem on Hitachi Seiki vm50 from 98. It had fanuc 16 based control and Ic on motherboard failed. We could send out programs but not receive. They were placed right to rs232 connectors .
 
Got the OT going by switching channels, I found a solution posted by Vancbiker by Googling. The 21t I haven't tried anything on yet. I can work on the OT standing up or sitting on a stool, it does not require crawling on the ground.
 
Same idea as what I put in post 5 of this thread.

I poked my head in sitting on a stool and did not see connection JD36A and B yet on the 21T. I wasn't in the mood to crawl on the floor today. I will have to break down and do it.
 
I poked my head in sitting on a stool and did not see connection JD36A and B yet on the 21T. I wasn't in the mood to crawl on the floor today. I will have to break down and do it.

What's down on the floor you want to look at??? JD36A and B are on the main control board which is behind the display. I hope your display is not on the floor :eek: !
 
What's down on the floor you want to look at??? JD36A and B are on the main control board which is behind the display. I hope your display is not on the floor :eek: !

Heck I just assumed the main control board was in the bowels of the machine. It was in the other Swiss machine I owned that I ended up scrapping that was a 16T. On this machine electronically I have only replaced the VFD. I haven't poked around the circuit boards much at all. I have changed a few belts and bearings over the dozen or so years I have owned it.
 








 
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