The Craftmans Shop > New from Old
The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
awemawson:
A few minor developments:
My son in Houston, bless him, has bought that interface / memory card that I linked to and you encouraged me to get and will post it on to me I'm sure at a much lower price than the $192 the seller was quoting !
In addition to the two video cards, and the bare memory card (sans daughter cards) I have put in a half price offer for a CPU card which has been accepted :thumbup:
Incidentally it turns out that the memory card in this 820T is NOT populated with the extra 32K of RAM - presumably other models have it.
This >should< mean that I eventually will have spares of all the cards in the controller when international couriers do their bit - all of course are used items, sold as working, but I suspect that dealers probably have no way of testing them so we will see . . .
Meanwhile I have extracted the entire 820T controller from the rack for easier working on the bench. I seem to remember that when I first got the controller to come back from the dead when I got the machine, I was able to bring it up to 'Initial Clear' mode on the bench and only wired to mains - hopefully eventually I can repeat this :scratch:
Frustratingly I cannot find my 'Lab Book' covering that initial resurrection period (I try to keep notes on the more complex bits) - my current book only starts at 7th Sept 2018 yet the controller was up and talking to me by 21st June 2018. It's somewhere, it's A4 and blue - but WHERE :scratch:
Meanwhile some pictures I took really to make sure that I know where things go when / if I ever get it going again:
awemawson:
Pulling all the cards (except the two video cards) out of the card cage the screen is still blank, but with the ribbon cable from the video logic cable to screen unplugged the screen shows white scan lines.
(Screen is actually all white - the green bit is something to do with the camera and scanning)
According to the book of words the screen takes RGB TTL levels from the video-graphics card so I need to scope it and see whats what. No time at the moment as cottage guests due any moment.
However I HAVE managed to prove that the +5, and +/- 15 volt supplies are making their way along the back board - I actually found the original leads that I'd soldered wire wrap pins to back in June 2018 !
Pete.:
Do you think that the fault is definitely due to a lightning strike? I was talking to my mate about this very thing recently (long-time National Grid engineer) he said that most strikes hit the top wire on the pylons which is deliberately the earth wire, or it hits the pylon itself (being a metal frame and grounded). He said when it does hit a phase it causes loads of damage and (predictably) the closer you are to the strike the more things go bang.
awemawson:
Can't be sure Pete.
We lost power from 05:30 to 14:45 that day. But initially it was going on and off repeatedly (woken by iPhone that was on /off / on charge objecting !)
Many flashes of lightning, and we lost one battery backed timer program out of five installed around the farm - (fortunately only the pond pump!) and this lathe electronics. However the setting for the DNC controller that connects this lathe to my network (By RS232 cable) were also wiped out - I suspect that it was currents induced in this relatively long cable that caused the problem, but how do you prove it in the absence of a smoking gun?
The lathe WAS isolated at the time so it can only be induced currents.
I know it's proving a right royal pain to sort out !
awemawson:
Well, positive developments, but I don't know why !
I came over to the workshop this evening to set the scope up to look at the backboard bus. I have no diagrams but it's amazing what you can deduce of card activity if you are persistent.
But I thought, just because I could, I'd return the cards to the card cage and see what happened. Darn me it comes up talking to me! Now it's reporting a "Battery Alarm Power Supply" which isn't surprising as the battery is disconnected !
Plugging back the (modified and remote) battery it now comes up "Ord 1 PP-Memory wrongly Formatted" which is probably not surprising - be good if I knew what 'PP-Memory' was but never mind - I now have a means of diagnosis as I can SEE things on the screen.
. . . life is full of mysteries . . . :scratch:
Tomorrow I need to perform a rigorous and methodical re-run and see what does what when other cards are plugged in !
. . . fingers crossed . . .
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