Micromill is going to kill me!

[davejfowler]

... Through frustration!

Hello

I have micro-mill. It has been a fantastic tool, and enabled me to get on and produce some good prototype parts. The problem I have is that it developed a problem where the PC would not be able to see it. At first this was something that didn't happen very often, and only for a short time. Once the machine is up and running it is generally ok.
More recently though it is taking longer to get on line, and sometimes I am unable to use the mill at all.

The symptoms are that the error display on the control board shows .L or 0 or 8 (the display can show any of these when struggling to get on line). I should mention the LED display is red.

The machine does power up, and the lights come on. I can hear and see that the key activates the main relay. It just doesn't come on line.

... That is until (and this can take between 5 minutes and 5 hours) I hear a click (almost like a relay closing) and then a light humming noise from the controls at the back. at this point the machine is fine and works perfectly.

I see that there is an NiMh battery (2.4V) on the Denstep board... Could this be part of the issue?

Any help I can get on this will be much appreciated. As I state the machine is either off line, or on line. When it makes it on line it works just fine!

[Martin]

Hi Dave

Does your machine have a SmarStep Bottom board or a NextStep Bottom board?

Take a look at the on-board drive fuse (F1) on the control card. You could also look at the connections in to the board & make sure the plugs are fully in. I have seen it where the fuse holder legs can splay a bit & do not make full with the fuse. If you have a meter you can check that the voltage is present on the plug. I think it should be around 28 volts AC.

If you can supply a serial number I may be able to check what was fitted or you could attach a picture.

[davejfowler]

Hello Martin

Thank you so much for getting back to me. This is the card that I have, and its showing .L
The issue is weird and the unit will usually start up, but right now it can take a very long time, and may not start at all.

There seems some muck around where the battery is, I am not sure what the function of the battery is?

Really appreciate you getting back to me. I have a project I am working on now, and its really causing me some problems.

Regards

David.

[davejfowler]

Forgot to mention, I have a meter, and there is power on the bored. the legs on the fuse are pretty good and if I look for continuity across the holder I have it when the fuse is in place.

The issue is so annoying. it works sometimes but not is taking ages to come on line. When it does these a click and then I hear a faint buzzing from the boards. At that point it will be ok unit I next need to use the mill.

[Martin]

Ok, It is a full Denstep board.

If the power to the drives is present then it must be an issue with the board. You could try tapping it when it should be on with the back of a screwdriver to see if it is a dry joint otherwise you may need to have it looked at.

[davejfowler]

So, I tried attacking with a plastic screw drive, and manipulating a bit, then I tried heating with a hairdryer... Neither got the mill started last night.
I was about to pack up, when I heard the famous click and it wirred in to action. I was able to get some of parts made last night so that was good but doesnt help me make this reliable!!

I show a close up of around the battery, and also the back of the connections to the base board... Its seems to me both look corroded... Not sure why at the board end... Different solder?

Anyway, would really welcome your thoughts, and also your thoughts on what is the best way forwards? A repair, A second hand board? A different board all together?

If I can get this working reliably it will be fantastic.

[Martin]

It does look bad around the battery area.

Where are you located Dave??

[davejfowler]

Hello Martin

I am in Bexhill in East Sussex England. Not sure how close I am to support for this?

thanks for getting back.

[TDIPower]

Looking at that I would guess the battery has had a leak as it would appear that there could be corrosion It's that or it could be some form of water/moisture/condensation damage. They used to use those batteries in PC's 'back in the day' before moving onto coin cells. You could try some IPA (not beer) Isopropanol Alcohol and an old tooth brush to clean it up. It's what we did on PC's and Carphones (showing age) which showed these signs.
I don't know if you can just replace the battery and if you did if any setting would need redoing.

I have had issues with some of the Micromills which were down to dry joints on the connectors. Quick to fix once found.

Pete

[Steve]

I would try replacing the battery and see if its any better.

follow the attached post and remove the top card

viewtopic.php?f=54&t=2562

The battery is available from RS Stock No.422-371 Brand Varta Mfr. Part No.5561560294

You may need to use workbench to set up the card again but it may be OK.

[davejfowler]

Hello All

Could anyone help me and let me know if the card in the attached image could be used to replace the corroded card I am removing shown above????

[Steve]

Hi. When you say you are struggling to go online. Does the computer find the machine and download the flash? Or does it come up with the message to check the power and USB connection.
If this is the case it sounds like the machine is communicating but it may be an issue with the ratio.
Can you detail exactly what you men by hearing the click. Is this after connecting to the machine?

[Martin]

Yes the cards are the same however you will need to swap the eproms over.

[davejfowler]

Thanks both

The machine would always connect fine and then got temprimental, and then stopped all together. It's been a real pain but the card seems to be very very corroded now.

Thanks Martin. How do I change the Eprom? Does that involved switching the large chip over?

[davejfowler]

Also, just noticed the Jumpers look to be in different positions. I am assuming this should be the same for a same machine and so I should make the new match the old?

Thank you for your help, Very much appreciated!

[Martin]

Yes the jumpers should be the same.

The eprom is the big chip. You should be able to prize it out gently with a screwdriver. Make sure non of the legs are bent as you fit it.

[davejfowler]

Well have won auction on new board so wish me luck!

Thanks so much for the advice!

[davejfowler]

Have now recieved the replacement card. All looks well, but the battery seems to just have started to corrode. I have also noticed that the board does not seem to have any printed connecttions to the -ve side of the cell. I wonder, is it possible to cut and remove the battery terminals with no ill effects to the operations?