On Wednesday 12 March 2008 20:29, Dennis Boone wrote: UART, I think. I know I've run into that number somewhere before. Baud rate generator. Look for a crystal somewhere close to that part. Bet you can trace some of the connections from that one to that MC14411 chip. Mostly the later UARTs are programmed to set things up. Likewise a bunch of the baud rate chips. This is earlier stuff you're dealing with here... Anybody know who made those parts with numbers like AY-n-nnnn? I don't think I have much data on those offhand. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin

"Roy J. Tellason" wrote: General Instrument. Often there's a "GI" logo on their chips. Dennis Boone wrote: (Yes, the AY-5-1013 is a hardware/switch/pin-configured UART. Can supply pinout if needed.)

There was the AY-3-1015, the AY-5-1013, the 6402, and the 1602, and possibly others. They are all much the same (some need a -12V supply line as well as +5V, others have that pin as N/C), the configuration signals and pinouts are the same in all cases. So finding a data sheet for one of them will help. -tony

That's a dumb UART. Dumb meaning it doesn't need a microprocessor to control it, there are seprarte sets of pins for the transmit and receive parallel chracters, pins ot set the word length, parity, etc. Baud rate generator. Receiver, actually, It'll take the RS232 input and turn it into TTL levels. TL probably means 'tape low'. This is detected by a reed swtich and magnet, and this jumper might bring that signal out to an RS232 pin or something. IIRC these Facit serial board have the festure that if they detect an error (parity, framing, etc) on the incoming character, they then punch a special 'error code character' in place of it. I susepct these switches set what that character is I really can't help with that one. I suspect you can only have one switch turned on at a time. It'll select the appropriate output from the baud rate generator. Note that 600 baud ~ 60 characters/second. Since the Facit 4070 is rated to punch 75cps, it'll keep up with a 600 baud data stream without needing any flow control. That's why there aren't settings for faster baud rates here. Maybe eneable parity checking on the incoming data stream Number of stop bits (1 or 2) Number of data bits (5..8) Maybe odd.even parity select for the incoming parity check. I usspect those 5 switchs go to pins on the UART, possibly with minimal logic in between, but most likely not. It'd be worth tracing them and getting a data sheet on any of the dumb 40 pin UARTs (there are all much the same!) and see what the switches control I suepct those are interrelated, and set what will be punched in track 8 of the tape. Either incoming it 8 (which is what you most likely want) or odd/even parity _generated_ from the other 7 its. Am I correct tyhat this board is in the lower slot of the 4070 and that there's the normal punch control board in the top slot? -tony

Very interesting. The older Facit 4070s (including all the ones I've every worked on) have a pounch cotnrol/PSU board in the top slot. It has a parallel interface. The interface connnections are wired to one side of the bottom edge connector, the other side of that connector is wired to the DB25 socket on the back of the machine. Normally there's a bridging board in that lower connector, so you get he parallel interfavce brought out there, but Facit also made an RS232 board (which is, of course, used along with the control/PSU board) that went in there, some other companies made custom boards for their own interfaces (HP was one such). If yuor RS23 board is the only one in the machine, then it must drive the punch solenoids and the stepper motor directly. That would explain all the power transistors on said board. And I've had another thought. With the units I'm familiar with, the 'Code Holes' button can be set to punch any character on the tape. 'Lace Holes' (0xFF) is the common one, but there are links on the cotnrol board to set it. I remember there being 8 unknown links on your comined interface/control board, maybe they have that function. -tony

I modified an old photographic enlarger into a copy stand. BAsically just removed the enlarger head (but hept the slider mecanism that goes up and down the column). The head was fastened to that by a handwheel bolt which turned out to have a 3/8" BSW thread. Took a it of brass bar, tapped a 3/8" BSW hole in one end and a 1/4" BSW hole in the other. Fixed a short length of 1/4" BSW studding ito that to screw into the tripod ush of my camera (Oh, and made a second one with a 3/8" BSW stud on the end for some of my larger cameras...). I already had a set of copying lights, which I rewired with a series/parallel switch so as to save the life of the bulbs when setting up and focussing. Thanks, I did take a look. I recognise some of the largeer compoennts as being similar to those used o nthe parallel-only boards in my 4070s. I am nor pretty sure that unmarked block of 8 jumpers near the middle of the board is to set what will bepunched y the Code Holes switch. I asusme the DB26 _on_ the PCB is for RS232 only, and that the parallel inteerface comes in on the DB25 on the main chassis, next to the mains connector. Is there a ridging board in the lower slot? I would think there should be (since the pins of the latter DB25 only go to the lower slot) I guess you could put any of the custom interface boards in that slot as well -tony

No, not those, the other set of 8 that you mentioned. 'Error Code' is what will be punched if there's a framing error (or parity error?) on the incoming serial character. It doesn't look to be impossible to trace out schematics :-) If the chassis wiring is stnadard, then the DB25 on the main chassis has many pins only conencted to the lower slot, with another set of pins on that slot going to the paralell interface on the control board. It's possible your machine has non-stnadard wiring and that the lower slot is not used (hence the metal bar to prevent a board being placed there, or that there are jumpers onthe back of the connector that you cut if you fit a special interface. I'd remove the bottom cover from the chassis (just 2 screws) and take a look. The supply reel should turn in juerks as you pull the tape off (or as the punch pulls it off), with the tension arn swining back and forth. The arm should nnever get right over, though (I think that causes and error condition). My guess is that eirther the linkage needs adjusting, or that the supply spool is stiff. I've never needed the tension gauge for this part. It's pretty crude and in general prolems like you're seeing are cuased by a fault rather than a misadjustment. Take the circlip off the centre spindle and remove the supply reel. Then take a look. -tony