Author Topic: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)  (Read 11710 times)

Offline hermetic

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #25 on: June 12, 2018, 02:09:47 PM »
Look out for capacitor filter arrays that are centre tapped to ground, but if it has been stood in a damp shed for a few months, it may just be moisture, good luck with it Andrew. A new saga begins!

Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #26 on: June 12, 2018, 02:28:35 PM »
I'm rather hoping that the earth leakage is tied in with the controller not showing life - maybe it's internal PSU. Going over to have a gander shortly when my supper has settled  :thumbup:
Andrew Mawson
East Sussex

Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #27 on: June 12, 2018, 04:29:35 PM »
So back to it, objective being to get to the back of the controller. It's in a pretty well totally sealed box apart from the Operators Panel (below) and a filtered vent hole to the right.

I started by removing all the numerous screws retaining the Operators Panel, and noticing that one corner is broken but all bits there for later gluing. Having pulled the panel forward revealing the expected backs of switches, cables etc I noticed a small wet patch of brown liquid that obviously had come from above. There is only the control above and no way water falling on top of the machine could get to here as it is a solid box. Burst Capacitor or Battery I'm thinking at this point.

OK put the panel back and attack the Controller. Removing all it's screws there is no away it will pull out.
Andrew Mawson
East Sussex

Offline j1312v

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #28 on: June 12, 2018, 04:37:40 PM »
Sorry Andrew, because of the "ew" at the end all Matthews and Andrews are the same in my head   :doh: don't know why  :scratch:

Good luck finding that earthed bit on the machine, one think that helps is to disconnect, clean and reconnect... :dremel:


Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #29 on: June 12, 2018, 04:41:13 PM »
To get better visibility I removed the filter from the vent and shone a torch in revealing  a niffty bracket along the top of the controller stopping it sliding forward.

It was at this point I dropped the torch inside and no way could I get my fingers to it  :bang:

However feeling about inside as far as I could reach I discovered some Bakelite knurled headed screw knobs holding the surrounding panel in place. They were far too tight for hand unscrewing, and gripping them with pliers took some major contortions but they all came off in the end allowing me to unscrew the panel, get my hand in further to rescue the torch, and also see that the square holes under the controller were obviously intended to support a temporary shelf to pull the controller onto.

I cut some 3/4" square bar to make two supports for a bit  of surplus aluminium plate as a shelf, and reached in and was able to unscrew the retaining bracket
Andrew Mawson
East Sussex

Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #30 on: June 12, 2018, 04:47:40 PM »
So at last the rear of the Controller is revealed, but so is a lot more corrosion, and absolutely no sign of the back up battery  :scratch:

I'm sure the horrors MUST have been caused by a leaking battery, but I cannot at the moment see it, OR it's holder - very strange.

But that's enough for today - I'm wacked
Andrew Mawson
East Sussex

Offline vtsteam

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #31 on: June 12, 2018, 11:58:51 PM »
Nothing by halves, Andrew! The brown juice, not so nice.  :(  I'm sure you'll have this thing spinning, though.  :dremel:
I love it when a Plan B comes together!
Steve
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Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #32 on: June 13, 2018, 05:58:19 AM »
Progress report:

This mornings objective - get the controller out of the machine and find where the battery is / was.

I went round arbitrarily labelling cables and their associated sockets so that I stand some chance of getting it back as it was , then it was a case of unscrewing socket retainers pulling cables off and withdrawing the controller. Some of the badly corroded fixings on cable shell sheared off not surprisingly.

(many of these pictures are for record purposes so perhaps a bit boring - sorry :scratch:)
Andrew Mawson
East Sussex

Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #33 on: June 13, 2018, 06:02:25 AM »
So with the controller on the bench I attempted to remove all the cards from the card cage - again in places the corrosion defeated screwdrivers and some screws had to be drilled out.

But finally all cards were removed from the card cage - quite a bit of electronics here  :bugeye:
Andrew Mawson
East Sussex

Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #34 on: June 13, 2018, 06:15:21 AM »
Now Card-B would appear to be the root cause of all this corrosion.

It holds a plug in sub-module with the culprit battery backing up four 32k x 8 bit static rams. The battery has swollen, presumably burst, and dribbled it's contents down this card. Also on this card is the interface to the Probe, the MPG module and the I/O module

It is possible that this card and sub-module are recoverable, but it would be highly desirable to replace them . Apart from the 48 pin big i/c which I assume to be a custom LSI, all the other i/c's are standard LSTTL from the 7400 range
Andrew Mawson
East Sussex

Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #35 on: June 13, 2018, 06:28:32 AM »
I think my next task must be to see if the controller Power Supply works with all the cards out - and if it doesn't then fix it.

There is another plug in battery compartment suspended above the  CRT - not yet been able to withdraw it, and also there is another logic crate labelled up "MPG Module" and "I/O Module"  which interfaces to Card B via an umbilical cord with that very corroded plug.

 . . .oh joy  . . . off to google these cards . . .   :coffee:

"Card B" = 570 212 9202.10

Sub Module with the RAM & Battery = 570 342 9101.00
Andrew Mawson
East Sussex

Offline Spurry

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #36 on: June 13, 2018, 08:41:08 AM »
That's an incredible amount of damage from what looks like a puny little battery.
I wonder how long it took to get to that state...
Pete

Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #37 on: June 13, 2018, 10:15:54 AM »
Well Pete, the sticker says that the battery was changed  18/09/08 so best part of ten years ago . . but which battery are they referring to . . the other one mounted in a sliding drawer over the CRT unplugged reads  3.65 but drops to 0.15 volts when plugged in according to it's monitor points, but they don't seem to go directly to the battery - four wires leading away from the tray into the depths of the controller. To get that (good until 2007!) battery to drop to 0.15 volts I have to load it with 2.2 ohms so obviously those wires are going somewhere else !

Progress report - that badly corroded Card-B - I've manage to source one in Germany for a modest 50 including postage, but not the little sub module yet. I can find very similar ones that have some components missing from the board. I suspect that as the controller evolved they went away from battery back up and went to NV Ram, altering that little board to suit

I have powered up the Power Supply and the 5 volt line at least is working - it provides +5 volts and and +/- 15 volts but I can't find a convenient point to monitor the +/- 15. I took a chance and plugged all the cards back other than Card-B and the PSU held up , there was static on the monitor screen and the one LED on the cards illuminated
Andrew Mawson
East Sussex

Online nrml

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #38 on: June 13, 2018, 10:39:55 AM »
Pardon my ignorance. Are these cards made by Siemens for a number of different applications or are they custom built for the manufacturer and model?

Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #39 on: June 13, 2018, 11:12:58 AM »
Siemens made a range of industrial CNC controls under the Sinumerik name - dependant on the machine tool makers requirements a standard controller crate would be stuffed with more or less goodies.

Basically they are microprocessor driven computers with many custom algorithms for motion control, and I/O (input / output) to suit the application. So that horrid card that I'm calling 'Card-B' has on it battery backed RAM memory for machine parameters, an interface for the probe, and a bus highway driver to a remote set of I/O mainly hidden under the controller in the MPG and I/O crate (Shown in the picture above 'More Electronics') This seems to have got off lightly with just one corner affected. I will have to pull it out and clean it up, but I >THINK< it's recoverable :scratch:

The white deposits remind me of dry rot fungus  :bugeye:
Andrew Mawson
East Sussex

Offline NormanV

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #40 on: June 13, 2018, 11:20:53 AM »
"Basically they are microprocessor driven computers with many custom algorithms for motion control, and I/O (input / output) to suit the application. So that horrid card that I'm calling 'Card-B' has on it battery backed RAM memory for machine parameters, an interface for the probe, and a bus highway driver to a remote set of I/O mainly hidden under the controller in the MPG and I/O crate"

Is that English? I have no idea what you are talking about.
I was brought up making cardboard boxes, they're a lot easier for me to understand than electronics, but I am still enjoying the story. :beer:

Offline AdeV

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #41 on: June 13, 2018, 02:52:22 PM »
Is that English? I have no idea what you are talking about.

hehe, tech speak is a bit of a language all to itself...

I understand most of it, not sure what an MPG is (that was always Miles Per Gallon to me...), but I'm sure there's a perfectly rational alternative  :scratch:
Cheers!
Ade.
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Or: Zhengzhou, China. An even longer way from anywhere...
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Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #42 on: June 13, 2018, 03:03:33 PM »
Manual Pulse Generator. A twiddle knob with an encoder on the back to allow manual driving of the axis when not under CNC control

Andrew Mawson
East Sussex

Offline NormanV

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #43 on: June 13, 2018, 03:23:40 PM »
Manual Pulse Generator. A twiddle knob with an encoder on the back to allow manual driving of the axis when not under CNC control
Oh, that's ok then.

Online nrml

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #44 on: June 13, 2018, 03:24:12 PM »
With the boards appearing to use through hole components, wouldn't it be relatively straightforward (but tedious) job to replace the individual components that are damaged and salvage it if an identical replacement sub unit can't be found?

I presume the battery on the replacement board will be remotely mounted for safety and easier access.   

Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #45 on: June 13, 2018, 03:38:22 PM »
Yes quite feasible. The problem comes if the electrolyte from the battery has destroyed any of the copper traces.

I suspect if I were brave, a good wash in hot water might dissolve a lot of it, and where rust has been washed down a card, a light brushing of citric acid to remove the Fe2O3, but I'm not sure what effect it would have on the tinning on the ic's legs. It also rather depends what's been washed under a chip. Some of the devices are surface mount so no gap but stuff will have crept into the tiny space that must be there.

I've just made an offer to a chap in Germany for one of the battery backed memory cards - problem is it is mounted on a 'Card-B' (my notation) and he is asking rather a lot. My offer is for the sub-card. Fingers crossed - you never know he may accept.

Andrew Mawson
East Sussex

Online nrml

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #46 on: June 13, 2018, 03:42:54 PM »
How about ultrasonic cleaning with distilled water?

Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #47 on: June 13, 2018, 03:55:45 PM »
They might end up going through the domestic dishwasher  :lol:

Andrew Mawson
East Sussex

Offline Pete.

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #48 on: June 13, 2018, 04:21:33 PM »
Washing it might work, the trouble is you don't know how long for.

A few weeks ago a guy at work spilt a whole large cup of coffee onto his gaming laptop. He took it to a repair shop and they pronounced it non-repairable, all it had was a single red flashing led when you tried to power it. They couldn't even get it started to allow him to recover files plus the keyboard was integrated into the chassis so that was non-removable too and obviously full of dried-up sticky coffee.
I carefully pulled off all the keys and popped all the plastic moulding pins to get the coffee out of the keyboard, but the board still would not start. In desperation I washed it (the motherboard) in the kitchen sink by squeezing out a sponge wetted with very hot water and scrubbing the whole board off with the damp sponge, then I left it under a heat lamp to dry. After that it fired right up, and it is still running weeks later, though it does tend to get hotter than it did before.

Offline awemawson

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Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Reply #49 on: June 13, 2018, 04:33:59 PM »
Years ago we took on the support of all Eastern Electricity Board's white goods distribution system - loads of terminals in shops and offices.

We used to put their faulty keyboards through the dishwasher, taking them out after the rinse but before the dry cycle. They then went into the equivalent of an airing cupboard for a few days. The vast majority worked after this treatment  :thumbup:

(I learnt this trick during recruitment interviews - I'd placed a 'staff wanted' advert in the paper in the town where the previous maintainer was based, and of course attracted several of their employees. More than one of them revealed this trick, which we shamelessly copied  :clap: )

Andrew Mawson
East Sussex