Recent Posts

Pages: [1] 2 3 ... 10
1
Project Logs / Re: Building a 1 meter tall RGB LED tower
« Last post by spuddevans on July 30, 2021, 06:13:15 PM »
Here's the next episode in this 1 meter tall saga!!

This time I wire up all the LED PCB's (about 96 wires) to the Interconnect PCB, and also wire the speaker and the Tower-Top LED's to the main PCB.

Then it is time to hold my breath and power it up for the 1st time  :zap:



Next up will be a detailed check that every RGB LED is functioning properly (and then fixing those that are not!!), then tidying up the 98 wires that drop down the center of the Tower. Then a better capture of the various display modes including playing some music-type sounds through it and seeing how it responds to the audio.

Thanks for watching,
Tim
2
New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by Sea.dog on July 30, 2021, 04:22:14 PM »
Oxidation on some of the pins? Unlikely, I know, since most of your kit is tucked up in a nice, warm workshop  :)
3
New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by awemawson on July 30, 2021, 03:44:27 PM »
Apparently "Part Program Memory"

(Thanks Google  :wave:)
4
New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by awemawson on July 30, 2021, 03:29:04 PM »
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 . . .
5
New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by awemawson on July 30, 2021, 02:46:20 PM »
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 !
6
New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by Pete. on July 30, 2021, 02:26:34 PM »
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.
7
New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by awemawson on July 30, 2021, 09:44:15 AM »
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 !
8
New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by awemawson on July 30, 2021, 05:47:39 AM »
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:

9
New from Old / Re: The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
« Last post by awemawson on July 29, 2021, 12:48:17 PM »
You chaps are a bad influence !

Things have gone from bad to worse - I've ended up with a blank screen and no activity  :bang:

I had noticed an oddity. If I manually turned the spindle, even a degree, it immediately gave the spindle over speed error message. Now the spindle is monitored by a 'measuring card' that takes input from the optical disk - I had a spare so swapped it - no difference. Now this card talks to the CPU card - I had a spare (in fact the original that came with the machine - it's frame is slightly corroded but I'm sure that I've previously proved it OK. BUT swapping it into the machine - BLANK SCREEN. Putting back the one I took out but still BLANK SCREEN  :bang:

The video system is a pair of cards - a clever one and a bank of memory - no spares.  :( I reasoned that it was possible that the display itself may have died. Just putting in these two cards I got a random display, proving that at least the CRT was good (I'd tried to see the cathode filament glowing but couldn't)

The power supply is slightly suspect. it gives several rails none of which are accessible to monitor except the 5 volt rail which is good. I seem to remember having to inert pins into the backboard sockets to measure the +/- 12 volts but that entails the removaval of the entire controller and it's card compliment - not a job for today.

Meanwhile I have spares of the two video cards on order, and a memory card that has iirc 32 kByte of ram, and slots for three daughter boards that have the controller firmware on them. This card is minus the daughter boards but the chances are that mine are OK.

. . . .I didn't need this . . .  :med:

10
Gallery / Milling machine vfd
« Last post by russ57 on July 28, 2021, 06:37:37 PM »
Only took 3 years, but its working.
Drives a powtran p160 vfd. Which drives a top tech dm15 6x26 mill.
Ive also allowed for future x drive with separate forward reverse speeds and auto return.
Now to install the z axis dro scale.

Then fix the lathe drive which died.
Then the welder which died.


-russ

Pages: [1] 2 3 ... 10