Mirac PC connection issues

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dhop125
Posts: 12
Joined: Tue 17 Mar , 2020 10:59 am
Hardware/Software: Mirac PC with VR turning
Boxford Duo with Mach 3
Location: Aberdeen, Scotland
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Mirac PC connection issues

Post by dhop125 » Fri 19 Jun , 2020 21:17 pm

Hello, me again!
Needing some help trouble shooting some connections issues on my MIRAC PC.
Halfway through the day, the machine began slowing down, as in, the time between each movement got longer and longer. I decided to wait it out untill the programme had finished before I then restarted the system.
When the system restarted i got: "Machine error: could not connect to machine" after it goes through all the com ports trying to connect.
Things I have tried:

Machine is powered on - Control board shows 8 on the RED LCD. (eprom is v2.1)
I have updated to v1.51 from v1.49, running on a windows 7 desktop pc.
I have checked com port settings - 19200, 8, no parity, 2 stop bits, and no flow control. FIFO buffers disabled. And in VR turning i have Control type 0, 19200, com port 1, 2 stop bits, mirac mint file selected. hardware handshaking disabled.
Next i tried a new null modem cable, a fresh install on a new computer, and now I have tried the direct link cable db9-db9, as wired from a post on here. (i also double checked the cable I made)
Cant connect to the board via easy upgrader either... says it cant find rs232 link.

So im stuck! Not sure what else I should look at?
is it possible that I need a new control board?

Thanks in advance!

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Steve
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Re: Mirac PC connection issues

Post by Steve » Sat 20 Jun , 2020 7:33 am

Hi, The problem sounds to be with the communication as suggested. As you had the machine running with the original serial cable I would stick with that.

The seven segment display is lit so the controller is powered on correctly. Is there any chance the spindle motor had been overloaded? The gap between moves could have been related to the spindle getting to speed?

There are two possible causes. The control card could be faulty (this could be caused if the spindle motor had flashed over in a stall) or the RS232 card on the computer is faulty.

Have you tried connecting with a different PC?

A replacement control card would fix the problem and would offer either RS232 or USB communication. I think the cost is around £1100

dhop125
Posts: 12
Joined: Tue 17 Mar , 2020 10:59 am
Hardware/Software: Mirac PC with VR turning
Boxford Duo with Mach 3
Location: Aberdeen, Scotland
Contact:

Re: Mirac PC connection issues

Post by dhop125 » Sat 20 Jun , 2020 8:40 am

Thanks for your reply, that's very helpful!
Just wanted to rule out the cheapest fault first! as the cable is fairly vunerable in my workshop.
I wouldnt have thought the spindle was over loaded as I only cut plastic around 16mm dia, and not usually more than 0.5 depth of cut becauase of the long stick out.

I dont think it would have been waiting for spindle speed, the operations were all pretty much the same speed, 2000rpm, apart from the last which was threading at 200rpm - which worked fine just slow.
I did try connecting with a different PC, but couldn't rule out any settings or cabling issues at the time. I will give that another go.

Looking at the control card, the traces and solder around the com socket joins on the back are black, burned and crusty! As are some of the traces on the top around the com port chips. Basic continuity testing doesn't show up any breaks in the tracks though. But I dont know enough about the board to be certain it's not the issue.

£1100 would be a bitter pill to swallow considering how recently I bought the machine! I presume thats from denford?
Can these boards be repiared?

Thanks again steve!

DavidB
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Re: Mirac PC connection issues

Post by DavidB » Sat 20 Jun , 2020 18:55 pm

I think this may be a similar board to the Triac PC I have and there is a NiCd battery near the comms area which is prone to leak and the crud may be the result of that and effecting the signals in the area. Can you post a pic. Cleaning the area carefully with distilled or deoinised water may help remove any deposits, allow to dry and see if that improves things. Don't force the drying just place somewhere warm like an airing cupboard till dry.

dhop125
Posts: 12
Joined: Tue 17 Mar , 2020 10:59 am
Hardware/Software: Mirac PC with VR turning
Boxford Duo with Mach 3
Location: Aberdeen, Scotland
Contact:

Re: Mirac PC connection issues

Post by dhop125 » Mon 22 Jun , 2020 17:45 pm

Thanks for that top tip david, that was enough to get it talking again! I never would have thought of trying that!
I guess im still on borrowed time with that board though. But now I have a chance to put some cash aside for it!

DavidB
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Re: Mirac PC connection issues

Post by DavidB » Mon 22 Jun , 2020 18:47 pm

Good to hear it's working again. I need to replace the battery on my board as it is a little crusty but I'm not actually using it as I'm converting to LinuxCNC and a BOB. Better you spend on a new NiCd cell and replace the one on the board with a new one, I expect RS and others sell them. It may be possible to remove it entirely as some threads on the BB mention it isn't actually used for backing up information in some applications. Maybe someone will come along with more knowledge of its use.

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Re: Mirac PC connection issues

Post by TDIPower » Mon 22 Jun , 2020 22:10 pm

Steve or Martin would know best but I too believe the battery is not needed.

Pete

DavidB
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Re: Mirac PC connection issues

Post by DavidB » Tue 23 Jun , 2020 1:35 am

I think I was wrong to say it is a NiCd, it seems more likely to be a NiMH. The battery markings say 2.4V 150mAh but no battery type on mine visible and the only ones that I saw that matched the design were NiMH from a search. Wiki lists the common electrolyte as potassium hydroxide so fairly corrosive so good it has been cleaned off and keep it off your skin, although no indication of strength of solution given. Hopefully we will hear back soon as to whether the battery is needed in the Mirac PC application.

Martin
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Re: Mirac PC connection issues

Post by Martin » Tue 23 Jun , 2020 8:29 am

I can confirm the battery is not required & can be removed from the board.

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