CNC Board Repair and Eeproms

[MaxHeadRoom78]

. I'm pretty sure I also have a ladder printout but I hope I never have to use it. I would assume a good repair shop would have these files if I had to send it in.

One problem with the A & B is the Ladder cannot be seen on screen as it can with the C & D, it is a great trouble shooting tool.
Max.

 

[JonesPrecision]

Ya I've read that...bummer.

 

[granddad]

Hi JP the 5 volt should be rock solid constant ... not 4.7 but 5 +- .1 scope not required just good DMM . also check for ripple on the 5v with DMM set to AC . Address / bus issues are more complex to diagnose, next step for me ...would be to eyeball the board with a good lens, looking for dry joints, especially where large components have been added. Has this unit been left unpowered for some time ? . then old electro capacitors can deform, if your error is UVEPROM data
data retention is not infinite Typically 10-40 years depends who you ask, but eventually they just start to forget their data. But a programmer may be able to read the device correctly ( bus loading and voltages better ), and then 'burn' some new chips with the old file.. (a long shot) ,

 

[JonesPrecision]

It's only been out of power for maybe a month. I got a lot of parts in today for my phase converter. Just need to order some run caps and I'm good to go. Hopefully have it powered up next week sometime.

 

[KeepItSimpleStupid]

First and foremost - reset the EPROMS. Extractors go from $1.95 to $20.00 **broken link removed** . The larger the chip, the harder it is to remove. The corner pins break when you remove at an angle.

5V was a typical logic supply. The tolerance is usually about +-10%. Usually, if the voltage is out of spec, the ripple is out of spec. You can sometimes try to measure the AC voltage. Ripple around 100 mV p-p should be tops.
5V logic gets very upset when the voltage gets above about 7 V or so.

A scope can confirm the ripple diagnosis. The power supply capacitors could be at the end of their life. DVM's with bar graph displays or peak hold can also help diagnose.

Getting a scope is not something to chose lightly on, Have a purpose.

This http://www.jestineyong.com/what-no-one-tells-you-about-data-recovery-from-broken-eeprom-ic/ points out the dangers of broken pins. Been there. Done that.

A worthwhile read: http://www.atmel.com/Images/doc0578.pdf


Aside:
Under that label is a quartz window where UV light is used to ERASE the EPROM. An erased EPROM reads FF, or the bits go to a 1.

 

[JonesPrecision]

KISS-Thanks for the help. I will look those over before I move forward. Everything is ordered for the phase converter. Hoping I can get most of it put together this weekend and have it running by next week. Will update once I'm there.

 

[MaxHeadRoom78]

So how have you been able to test it so far with no 3 phase?
Fanuc's are notoriously fussy about artificial 3 ph.
Max.

 

[KeepItSimpleStupid]

Max: The OP said it was bought cheaply with the problem known.

 

[JonesPrecision]

Yes just like KISS said. I knew the problem going in. Saw it powered up with the error.

I'm aware of the problems CNCs have with RPCs. This will be balanced and I don't think it will be a problem. Plenty of people running similar systems for years without issues on balanced RPCs. Worst case scenario the machine gets scrapped. I could make my money back in just the extra boards that came with the machine let alone whats actually in the machine. It also came with an extra spindle motor and axis servo all from a second machine they had. Either way I'm not losing money just time if it doesn't work out but I'm hoping it does.

 

[MaxHeadRoom78]

A last resort could be a retro fit, but the zero was a good little work horse and there must be quite a bit of used stuff out there on ebay etc to try and revive it.
Max.

 

[JonesPrecision]

I had thought about doing a retro as I have done them before but other than fancy graphics I don't think I will be gaining much. For as old as it is it has about everything I need and they seem to be rock solid controls. I'm not completely against it I just don't see it as too much of an upgrade. The other machine I did was a mill and that made a huge difference. Plus it's a lot of work.

 

[JonesPrecision]

If I end up taking the main board out of the machine to troubleshoot anything specific I should know about regarding protecting the electronics? I'm used to working on computers and wearing an antistatic strap but is there anything else? Maybe a special material to lay it on? I just don't know a lot about the 80's era electronics, not that they are much different, and I don't want to overlook something stupid I should have know about. Last thing I want to do is make it worse.

 

[KeepItSimpleStupid]

I never really used am anti-static strap, but I always made sure I discharged myself first. So, yep, the anti-static strap works and so does not wiping your feet on a nylon rug.

Laying it on aluminum foil also works. Just don't power up a board that way.

In a shop environment, you probably don;t have much to worry about except clothes that may generate static electricity.

Do remember the rule when working on high voltage. Keep one hand in your pocket.

 

[JonesPrecision]

Got it. I'm probably overthinking it but thought I would ask. These boards are expensive.

 

[granddad]

JP Be wary of charged capacitors... don't power up, switch off and remove immediately , give it a few mins to loose any charge. if unsure of connectors take a photo. look out for insulation washers etc length of screws may be different. plugs may have loose keyways on old equipment.

 

[MaxHeadRoom78]

A little OT, the first Fanuc 0 I was involved in was a retro-fit using a 0TT dual turret lathe version to a 30ft planer machine, (don't ask)!
But every so often I would get a call that the machine was down, turned out to be lost parameters, after a while it was discovered that the maintenance guy on night shift was swiping the batteries for his flash light when they died!
Max.

 

[JonesPrecision]

So I got sidetracked for a while with life. It happens. Hopefully some people are still interested in helping me on this journey.

To refresh the machine is a Hardinge Conquest 42 with Fanuc OT controls. I finally got power to the machine but before I fire anything up I wanted to make sure I wasn't using the manufactured third phase from my RPC on any of the electronics. Spent the better part of the day tracing wires. Still have a little more to do.

So far I've come up with most of it comes from R2 and S2 but the 110 transformer seems to have its input from S2 and T2. From what I can tell that means all 3 legs have some help in supplying power to the control. Thinking maybe I should keep everything R2 and S2 and wire it that way. Thoughts?

 

[MaxHeadRoom78]

I would have to check my 0 manuals, if i still have them, but the control is just single phase from two legs usually.
It is the drives and spindle you may have a problem with.
Max.