The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)

[seadog]

I used to do the same with DEC VT220 keyboards. That, and repairing the silver track on mylar which, due to a design 'fault' used to rub through. RS silver loaded paint was an excellent product.

[PK]

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.

Isopropyl alcohol is the go to solvent for 'first go' cleaning of things in the electronics business. Toothbrushes and ultrasonic cleaners work about as well as each other. Anything that's going to chemically react with corroded metal is going to react with the tinned leads.

Glad to hear you found a replacement board.  If you get REALLY stuck, it is possible to re manufacture a board, we've done it before for a customer who just couldn't sort the problem out any other way.  If it's only a two layer board then that's a bit easier as you can trace the layout with a scanner after floating the parts off in a solder bath.  Anyhow, hopefully you won't need to go that far.

PK

[awemawson]

We have company for lunch today so no real play time having done the animals, but I did manage to draw up a sheet metal 'Shelf' in Autocad to replace that bit of aluminium that I'd previously balanced on the bars.

Drawn in Autocad, saved as a .DXF, imported to SheetCAM, ported to MACH3 and cut out of 2 mm Zintec steel on the CNC Plasma Table  then bent on the Edwards Box & Pan folder- the Plasma table certainly makes this sort of thing so much easier.

It sits nicely but some how I want to bolt it to the bars, so when they are withdrawn it stays as a single unit, but I want to preserve the undrilled top surface - might need to break out my stud welder and see how accurately I can place studs  - I can see it will be useful for paper work at the monitor when it's original purpose of removing and replacing the controller is done with 

[awemawson]

Glad to say after a bit of negotiating I've come to a settlement with the German Siemens Sinumerik Card Flogger, and Card-B (my name) and it's daughter memory card are on the way to me - cheeky chappie is charging two set of (expensive) carriage but I bet they arrive in the same box !

It wasn't cheap, but I reckon a better solution than trying to clean up the originals - however I will keep them and perhaps have a go in the future.

Still need to clean up the I/O crate (not got it out yet!) and also try and get the rust off the main controller crate. I may try masking it and using my 'spot sand blaster'

[awemawson]

So I got a little time this evening when guests had departed to fix the shelf and bars together. I drilled the bars 6 mm and counter-bored them 1/2" so that nothing sticks downwards under the bar to catch you out, and a hex socket will fit in the recess.

Then mounting the shelf and wiggling it into the centre of its movement latitude I marked though the holes with a Sharpie, and then gave the marks a decent sized centre pop.

Digging out my Stud Welder (*) I did a few test firings to prove my settings then  I located the pip in the M5 x 18 mm studs I was using in the centre pops and fixed four studs. Amazingly they fitted the bars, and being 18 mm they don't protrude below the 3/4" bars.

. . . so objective achieved - an unblemished upper surface and the bars and shelf now together as a unit 

The Stud Welder can go back to bed for another long sleep 



* https://madmodder.net/index.php/topic,10287.0.html

[awemawson]

Today's task: Get the Input / Output crate out and find how extensive the damage is.

Access a bit tricky - have to go through where the Manual Control Panel mounts - so that has to be removed first. I twisted the cable ident labels so hopefully I can see them in my pictures and get them back in the correct places 

I took many more pictures of the wiring but they are BORING !

[awemawson]

Now with the panel out of the way I can reach in and unscrew the four mounting screws for an L shaped mounting bracket obviously made by Beaver rather than Siemens - it's the white bit.

Usual thing - three screws no problem, but the fourth was rusted solid. A candidate for drilling as the bit it goes into won't take heavy hammering. Placing a rare earth magnet next to it to catch the swarf I drilled it out, constantly checking drill depth as if this blind hole were extended too far it would go into the tailstock end inners of the machine that will be awash with coolant (hopefully some time!)

[awemawson]

Then it was a case of disconnection of the cable forms but labelling them up first. All came off nicely except one that had a screen earth on a screw tag that was inaccessible without removing the top cover - time to drill a hole I think 

[awemawson]

So now I can put the I/O unit on the desk and dismantle it to see how extensive the damage is and identify the card part numbers.

Now actually the physical damage is not too bad to the inner IO card - I'm sure it could be recovered, but finding one on the ubiquitous eBay for only £35 including postage it seems silly not to replace rather than try a repair

[awemawson]

But the corrosion damage to the metal work was actually worse than I thought. No issue, it can all be  grit blasted and painted and will be fine . .


 . . .EXCEPT . . the fellow on ebay flogging the I/O card had another offering of the sheradised metal panel AND the umbilical cord with connectors both ends, that was so badly corroded at the controller end - so an excellent result (if all the cards work!)

I grit blasted the Beaver made white panel and have re-sprayed it to await the other bits to fix to it.

[vtsteam]

Excellent progress so far Andrew. Feels good seeing something being properly restored from an internal disaster.

[awemawson]

Thanks Steve.

Until the bits arrive there will be little more progress but this afternoon I've re-glued the corner of the Control Panel that was broken (not me gov!) and started sorting the corrosion on the card cage.

The rusty retainer with a sheared bolt in it I was able to remove by drilling out four pop rivets - then it could be grit blasted, the sheared screw drilled out and the hole re-tapped, and then the lot got a light coat of zinc spray before being re-rivetted. Note how I insert ALL the rivets before setting any to ensure that the location stays OK

The card guide bar, which is alloy, is more of a problem and I think I'll need to source a replacement. There are two sheared off screws in the square nuts that are supposed to slide in the extrusion - but they don't. The plastic of the guides themselves is very brittle and two have broken retainer pegs, and the bar itself is badly corroded.

Do any on you recognise the rack system to help sourcing a bit of extrusion and some guides - there is a logo in the molding of the guides, I recognize it but cannot recall who's  it is - can YOU help ??

[awemawson]

DOH - it's Siemens 

[awemawson]

On reflection, although I'd prefer to replace the extrusion, as a fall back , and if I can bully the current captive nuts out and down the extrusion, all I need do having cleaned it up, is make a length of tapped flat bar to slide in. 7.5 mm x  3 mm tapped every 20 mm  nine times. There are two unused card slots, so I can steal their guides to replace the ones with broken retainers.


. . . now where is my 7.5 mm x 3 mm flat bar stored 

[tom osselton]

On reflection, although I'd prefer to replace the extrusion, as a fall back , and if I can bully the current captive nuts out and down the extrusion, all I need do having cleaned it up, is make a length of tapped flat bar to slide in. 7.5 mm x  3 mm tapped every 20 mm  nine times. There are two unused card slots, so I can steal their guides to replace the ones with broken retainers.


. . . now where is my 7.5 mm x 3 mm flat bar stored 

you mean this guiderail?
https://www.partsfinder.com/parts/siemens-medical-solutions/1097492

[awemawson]

Interesting - I've registered and am awaiting a quote ! So how do I find the extrusion that the guides fit ?

[awemawson]

Had the reply and Parts Source are saying that they can't ship internationally 

[vintageandclassicrepairs]

Hi Andrew,
Maybe one of the forum members in the supplying country (is it USA?) would step up and
buy the parts and post them on to you??

John

[seadog]

Andrew, I will be in Seattle for three nights in July, the first to the fourth. Maybe something can be arranged.

[awemawson]

Seadog that is extremely kind, but I think I'm now sorted as the following paragraphs will show 

I was determined today to try and clean up the bar extrusion and see if I could remove the corroded nuts and make a tapped bar to slide in in  their place. It turns out that the orange plastic bit is one continuous bit rather than one per nut as I had thought. A bit of brutality got it and the nuts out, and I attacked the extrusion with a file followed by a wire wheel.

There is a big chunk dissolved away by the leaking battery, but it's not affecting the functionality and actually it cleaned up pretty well. I hunted around in my scrap brass box and the only suitable thickness that I had was one leg of a bit of angle that was barely long enough -but you use what you have. Being angle made holding it for drilling and tapping easier than had it been already a correct sized strip.

So this got  marked up, centre drilled, tapping drilled and tapped M4 under power

The hole spacing is 20 mm EXCEPT for the one at the far end which is 15 mm - this nearly tripped me up, but luckily I spotted it just at the last moment. Anyway - offer it up for a reality check - yes it looks about right 

[awemawson]

Then to slit it off the parent angle - I never like using slitting saws, but this went OK, but I made sure it was a very rigid set up. Setting the height of the saw blade I cheated and offered up one of the original square nuts - made life so much easier.

This was followed by a bit of a clean up, then I slid it into the extrusion and re-mounted the extrusion to the card cage.

PCB Guides:  Two were beyond use, their location pins having broken off when they came out, BUT three slots in the cage are not used, so the obvious solution is to steal their guides 

Popped the required guides into the relevant places, and did a trial insertion of the cards which went well and everything fits nicely.

(I couldn't bring myself to put the card with the leaking battery back !)

So now cosmetically it all looks a lot better than it did - look at the last picture to see how it was

[seadog]

Ok Andrew. Glad you sorted it.

[awemawson]

So in that frustrating time 'waiting for bits to arrive' I've been poking around familiarising myself with the various cabinets of contactors, relays, and axis drives - it all looks fairly sensibly laid out and even without drawings it doesn't look too bad to find my way around.

I've investigated the possibility of 'Powered Tooling' being mounted in the tool turret, and sure enough the facility is there - the selected tool gets lined up and has a simple 8 segment dog clutch on the rear of the VDI40 mounting spigot, that engages with it's opposite number on the tool drive

Pulling the monitor apart it turns out that it is a colour one - or at least the drive signals entering it are marked as 'H V R G B' and researching the controller, one of the memory cards is only fitted when a colour monitor is fitted. Seller thought it was green phosphor only so this is a bonus. Not that I'm much closer to seeing anything on the screen !

As well as the mechanical Tool Probe, it looks as though at one time it has been equipped with an optically coupled probe, presumably mounted in a tool port on the turret. The clue is that there is an optical sender / receiver mounted on the same plane as the Renishawe Tool Probe socket. No sign of the actual optical probe though.

[awemawson]

A little bit more progress today:

I wanted to prove the PSU was OK but only the +5 volt output had test points. I was fairly sure that it also was supposed to put out +15 v and -15 v.  Pulling the PSU apart it's only output connector is a three row  96 pin Eurocard type. I was surprised to find that mains for the 240 volt rack fans is routed via this connector. Inside I found a pair of 15 volt regulators confirming my suspicion, and also a Ferranti Uncommitted Logic Array - in a PSU for goodness sake WHY ?

Soldering a pair of 'wire wrap' square gold plated pins to my test probes I was able go along the crate back board and find the 15 volt lines powered up, so that's looking good.

Then I turned my attention to some of the card retaining screws that had sheared off. They are M4 but have an extended outer part with a hand grip, and a turned down section to retain them in the card. Drilling tapping and Loctiting replaced the sheered threads.

Then it was a case of 'hunt the battery' The one in the back of the monitor was easy - it's an SL2770 and RS Components carry it. However the one on the little RAM card proved more elusive. The original is in far too bad a shape to take reliable measurements from, but eventually I found an image on the web that revealed all - it's an SL886. There are two versions, one with pins and one with pads, and the original and the image I found don't help the diagnosis, so I will wait until the replacement card arrives to see which before I order.

Strangely the data sheet for the SL886 give it's weight as 21 grams, and my ruptured one weighs EXACTLY 21 grams despite all that death and destruction that it has oozed 

Apart from posting pleas for help on Practical Machinist and CNC Zone that's about it for today.

[PekkaNF]

.....
I wanted to prove the PSU was OK but only the +5 volt output had test points. I was fairly sure that it also was supposed to put out +15 v and -15 v.  Pulling the PSU apart it's only output connector is a three row  96 pin Eurocard type. I was surprised to find that mains for the 240 volt rack fans is routed via this connector. Inside I found a pair of 15 volt regulators confirming my suspicion, and also a Ferranti Uncommitted Logic Array - in a PSU for goodness sake WHY ?
....

If my memory serves right S5 135/150 series simens PLC rack had somewhat similar looking PSU module. I once had trouble with it. I was chasing non responsive CPU-card, when in fact the problem was "power good" sort of signal from PSU module. There were some handshake signals with busscontroller card/cpu/psu, it was not clear without consulting the technical manual, which we luckily had. If I remember right cpu had enough power to do post startup check and then fiqure out not to talk to bus, because status from PSU was not correct. It was all pretty odd to have some "logic" on the PSU, you might think that it just posts "power good" and that's it.

Not sure if this is relevant, but that was my personal encounter.

Pekka