RS-232 standard -- the most non-standard ever! Only (?) TI used that reverse channel. I spent a 3 hour WTF session attempting to determine the same issue early in my career, so I sorta knew where you were going. Nice to see it working!
I used to use one of those TI 810 printers 40 years ago in my first job. It was a beast. I recognised it immediately, before you even showed it close up. I also remember the joy of creating a serial cable that satisfies both ends to go from the serial port on a computer (pre PC compatible, CP/M usually) to a printer, often without a manual for the printer, and sometimes without a technical manual for the computer either.
Aside from the corrosion, this thing is an absolute tank! I didn't have to replace any parts, just fix bad connections is all. I was digging through a manual looking for any indication on pinout on the printer side, but turns out, I was looking in the wrong manual. I can't imagine the battle of trying to do it without a manual at all though!
Yikes! I supported one of these for years and years. It was fast and loud! As far as I know the reason they are hard to find is the airlines still use them.
Brings me back to my childhood with my Parent's Mac and Apple ImageWriter, the only thing better sounding from that time was the big honkin' Wang daisywheel printer that my Dad got with the old decommissioned Wang OIS that he got from work. That Wang system isn't something you see at all these days, the closest I've ever seen is the Wang setup on this channel.
I had a TI-810. Don't remember where I got it, but I used it for quite a while and was very happy with it. It was fast, but definitely not quiet. Nice printer. I *think* it had a parallel interface. I believe there were options for the interface. I gave it up when I no longer had a source of free tractor feed paper :-) Lots of businesses (and maybe airlines?) used it for multipart carbon or carbonless forms. Very heavy duty machine.
The TI810 was the very first dot matrix printer I worked with in 1979. I hooked the Centronics interface to our own Commodore IEEE to Centronics Parallel interface box and produced lots of output on it. I do remember how loud it was. Great to see it turn up at your place and restoring it! I always found it an awesome printer.
FYI - The Centurion printer type PRTQ is the nane of tbe Centurion print spooler program. The print spooler lets you send a print job to the PRTQ at full system speed and not be limited to the slow printer speed. Once the print spooler program receives the print job the printer starts printing the job, and the system user to do other jobs as the spooler prints the last job. In the case of this CPU5 system OPSYS gen. PRT0 is setup with the TI-810 printer driver.
My thoughts as well. I worked a different system/ OS that also used a spooler. You could send print job to 'prt' (printer) or 'slo' (spooler listing output). Standard practice was to send to 'slo' to have job run quick without waiting on printer. But if the spooler task dies, had to have sysop/ admin restart it. Wonder if there's some startup script that needs to start PRTQ spooler on Centurion?
Living in The Netherlands and owner of 23 pinball machines I sure loved your 2 in the background. Good to hear your brother will take good care of it (mayby them soon). Understandably you made a wise decision from your hobby's point of view. Love it. Keep up the good work! Cheers from Amsterdam
Hi David, great work again! I used to repair similar printers for Digital Equipment in the 80s and immediately thought of an encoder problem when the printhead did not move to its left margin at power up. A word of advice: if you ever come across a dot matrix printer from DEC, do NOT remove the encoder PCB from the carriage motor unless you have the manual describing the correct encoder adjustment procedure. On those printers, you must usually power the motor with some 5V or so, hook up your scope to the photo sensors, and then physically move the block housing the photo sensors only fractions of millimeters to produce the correctly timed pulses. You need a scope and very calm hands, it's a really fiddly task.
8 years ago i was sent to fix a printer at a logistics company. It was an epson dot matrix that printed all the slips for the drivers. When i got there there was 20 trucks backed up and two frustrated older IT guys. 26 year old me wsltzed in like nothing and was immediately turned around. They said the printer was older than me and there was no way i could fix it.
Well, they're 3x the age of the printer and they hadn't fixed it. I _HATE_ morons like that... there's no way anyone could ever know something they don't.
Honestly, I'm surprised the corrosion wasn't more of an issue. The fact that it only caused fatal damage to a socket and flex PCB is a testament to how well those boards were made. Great work getting it going again!
To stop battery leakage corrosion or even the standard oxidation, use white vinegar and baking soda, These will efficiently stop corrosion and neutralize the pH. Isopropyl Alcohol does not always achieve this result. Hope this helps!
9:41 The LM339 is a quad comparator with open collector outputs. It is not an op-amp. It works down to its minus rail. It takes about 1.5uS to react to its inputs It pulls down with about 6mA when the (+) is below the (-) It releases its output when (+) is above the (-)
What a great piece of nostalgia, love this sound! I never worked on these types of line printers, but was responsible for repairing and maintaining several dozen Okidata line printers, amongst lots of other tech, in a distribution center for a number of years.
Strange that when Centurion customised the printer they apparently left the badge recess empty and printed their logo on the centre of the panel instead of having a badge made, the empty space is very obvious - and I see you decided to put the TI badge back which looks much better.
Great work Dave and grats to the Discord crew for the assists. Ken Romaine comes in clutch again. I love a happy ending story involving the Centurion in any way.
This brought back memories. In the late 80's I worked with all sorts of dot matrix line (?) printers connected to mainframes. The sound is like music to my ears.
The magic! YUP! The magic of making old stuff working is so great! That printer is older than all my kids, Maybe older than me. And it still works. Can we say that planned obsolescence was not in the mind of the maker of that product, on the contrary, they made sure it would last for a lifetime! Yes some component did not lasted that long. But who knew that this type of chemical reaction would happen after decades... So happy that you have that system fully working. Congrats!!
Wow!! My first job was testing 810's for CADO Systems......back in 1979. We swapped out the character-generator ROM because CADO had a few custom characters. I definitely recognize the internal guts. Well-built machine.
Had not heard the CADO System computer name for over 40 years ago when I was working at Warrex / Centurion. We had a Centurion dealer in Atlanta, GA that also sold CADO system ( I think for Typesetting uses ).
@@kenromaine2387 It's possible you are referring to the CAT photo-typesetter, which was not associated with CADO. Most of the systems sold by CADO were for small business accounting, payroll, inventory, purchasing, and billing. The 810 was CADO's first-supported dot-matrix printer, and was replaced by a much cheaper (and lower-quality) unit from Dataroyal.
I was shouting at the screen when you were saying cabling issues. RS232 is easy when you understand the different layers of it. Each of the following are at opposite ends of the connector i.e. a end -> b end GND -> GND, since you always need a ground reference TXD -> RXD and RXD -> TXD so you have a data flow for the printed data, this is just data, no flow control, unless you use X-On / X-Off software flow control. The pins meanings are Transmit Data / Receive Data. This is the absolute minimum needed for communication. RTS -> CTS and CTS -> RTS, so you have hardware flow control. The pin meanings are Ready to Send and Cleared to Send. This is needed to slow down the sender at the right time. DTR -> DSR + DCD at one end and then and DCD + DSR -> DTR so you have modem flow control. The pin meanings are Data Terminal Ready, Data Set Ready, Data Carrier Detect. This is for modem control, so another layer of flow control for the modem, its only relevant if you have a modem in a link. If you need a full modem support for incoming call, then you also need Ring Indicator (RI), in this case, then connect RI -> Data Carrier Detect (DCD), since the receiving machine is being told its detecting a carrier signal. Do the opposite at the other end DCD -> RI Things will then work properly at all layers. When some of the other layers are missing (i.e. no modem / null modem), this is what's results in the mangled cabling that connects between the different lines above. Generally this is a bad thing, but sometimes its necessary to get the right levels on the right pins to make sure that each end thinks that the other bits of the RS232 protocol see the correct levels on the correct pins.
I spent years fighting the RS-232 interface. A patch box was my friend! Never saw a Pin 11 handshake, I thought it was going to be xon/xoff missing as no return transmit path. Still love the noise of a dot matrix. Another great video. Thanks.
Ahhh! To hear the sound of a dot matrix printer. Reminds me of being a kid and when I used to work at Foot Locker, printing the morning E-mail. Thursdays were always fun because that was the day we would receive the weekly in store stock report, so it would take several hours to print all the stock we had in the store. Eventually, I did stop printing them unless I needed one.
9:34 the LM339 is a quad comparator with open-collector outputs, note that it's used with positive feedback (for hysteresis) rather than negative feedback that you'd typically apply to an op-amp.
I fix modern computers.......... I don't have the love for the old ones....... BUT I totally appreciate and am motivated by your "don't give up" attitude with these projects.
I didn't actually get any runs until the fourth and fifth pass. I was getting lazy and my coverage was getting poor... Pays to be vigilant until the very end! Someday I'll sand it back for a smooth finish and recoat.
I once had a job calibrating and modifying these kind of printers before they were sold and that was in the nineties, so still then they were used. I also remember a cabinet below it to house the chain paper.
Oh, yea, even as late as ‘96 I had to maintain several that were used as report printers. Most had been replaced with high speed, quieter, ones capable of multi-part forms (some with automated stuffers), but these TI’s were the workhorses for general report printing.
There's something very satisfying about the sound of a dot-matrix printer doing its thing. 😄 For the too-light printout, I've heard that a tiny squirt of WD-40 on the ink ribbon and allowed to soak throughout the ribbon will help to both lubricate it and darken it. But I've also heard that there are ways to re-ink the ribbons even nowadays, so maybe you should look into that? And thanks for the bunnies... I mean... the fun video. 😃
Ahh, the sound of my electronic childhood. There is just something and the sound of dot matrix printers. They still use them at a lot of airports, so they aren't totally dead tech
With apologies to JFK: "We choose to go to the Moon in this decade and do the other things, not because they are easy, but because we _thought_ they would be easy." 🤣
As an old printer guy (think Dataproducts and Genicom and a few others), I did see a rotary dial but don't recall what it was called, but it functions like a soft carriage control tape. I don't know how it is programmed, but you might try to see if you can skip over the paper at the bottom of the sheets and not print over the perforation. I suspect one setting might do just that. It's just a thought. Sure miss the sound of a dot matrix printer. I used to be able to identify the manufacturer just by the sound it made! Keep up the great videos -- I look forward to them and learn so much. Regards...
Reverse channel. That really takes me back. I knew it existed but I never worked with it. You used to be able to get half duplex lines from the telephone company. If you were only using it for a printer or if you used polled Bisync, they worked great and they were cheaper than a full duplex line. You could used them for voice but if you didn't have control of the line, you would have a dropout. Reverse Channel was used to turn the line around so data could be sent the other way. By the 70s and 80s it was pretty well phased out but it appears that a few were still supporting it. I would have expected CTS/RTS flow control but the description for the printer clearly indicates that it's not supported.
I knew right away it wasn't working right, it needs to home. Even though It's been at least 30 years since I worked on it, I had one customer with one of those, and we supported it. I remember it being really easy to figure out and easy to service. When the power supply died, our sales team sold them an Okidata to replace it.
Paint it BLUE!!! We musts paints it blue! But seriously if it were me I would recreate it by painting it blue and then getting some vinyl printed Centurion logo recreation and have the whole system be classic and matching and everything. In any case thanks for all these great videos!
Love your vids, I'm a total computer geek with rack mounts etc in my house. I also love pinball and have 26 of them. Please don't get rid of your corner EM one.
That print head can't have too many characters on the clock, all the dots seem nicely aligned. I used to repair Oki printers and have replaced the pin guides (might be called a jewel by some) and pins too if the pattern was getting too rough for the owner.
Yes, I had a huge printer I got from a computer fair and the dot matrix head had probably run into a paper jam so some of the pins were bent. Fixing that was "fun".
I think 50% of my early IT career was fixing printer issues on some IBM/DEC Digital lash up 😳 Nothing ever “just worked”, it took hours of fiddling with settings and terminal hub programming
Those TO-220 transistors with the solid metal backs (the TIP150s at around 6:45)... when my company was still servicing intercom boards for a major brand, we were told to watch for these and replace when found. Never really found out why that directive.
Net time, use Wire-Wrap wire. Also, get yourself an old-time RS232 breakout box w/ the jumper wires. You will find that it can greatly help troubleshoot serial port issues.
There's a very strange compression artifact at 2:35. The "Texas Instruments" label jitters left and right. How could this have happened? I don't think it can be bug in UA-cam's video compression, because it's present in all resolutions and video formats.
I find it fascinating print spooling was a thing even back in that machines time, and yes even my vintage machines have to either pull up or print out an ascii "colander image" lol its like a right of passage of the old machines
I believe that some of the PCB manufacturers, now do "Flex" PCBs. You might be able to recreate that little flex PCB in KiCAD & get it re-manufactured! :)
The worst part of those printers was the 'paper out' error blocked the serial communications. This almost always had the effect of freezing any connected system that was running a print job - especially if the affected software hadn't been engineered to handle a print failure.
I worked at Texas Instruments in Cypress, Texas and my desk was about 20 feet from the 810 and 825 printhead lifecycle test room. 40 or 50 or maybe even more printheads running 24 seven. Try and imagine the racket.
I used two of these at work One was a KSR and one was an RO. The only thing that ever happened was the hub the carriage cable was connected to the motor cracked and I had to replace that. Otherwise never a problem. Stone reliable and they ran 24/7 as a administration terminal and a call detail recording logging printer on a Nortel SL1 VLE phone system.
Had a stand for a 800 series printer, which still has a printer on it, a laser printer, as the TI printer was not upgraded, and the newer Seikosha that replaced it was replaced (a few times, with the same model as the heads wore out) with an assortment of HP printers. 800 printer was scrapped, but I kept the print head rods, and used them as long drifts.
I actually adore dot matrix printers. The sound, the print quality (or lack thereof), and the simplicity of design. The printer did all the printing work, all the computer had to do was send ASCII, and maybe (later on) control code sequences. Yes, they are noisy. Yes they are slow. And i'd have kicked puppies and punched kittens for a cheap dot matrix printer back in the day.
I had an 810 Ro back in the day (1985 ish) when I was in college. I had it hooked up to a Commodore 64 originally and then a 10mhz AT clone. I could not figure out the handshaking and ran it at 1200. I only had the upper case roms. Used it mostly for printing computer listings when I dialed into college (I was a computer science major). Don't get your hand inside the machine when the carriage is moving... it will mess up your fingers. Ask me how I know 🙂
Oof. Dot matrix printers bring nightmares. Worst was printing my undergrad thesis on one back in the early 90s... had to nurse that printer day and night for a week to print 87 pages. Never again. :)
The quick brown fox says HELLORLD!
😆
So that's what the fox says...
@@JohnSmith-xq1pz and the bunny
@@SeekingTheLoveThatGodMeans7648And the strange man on the screen
RS-232 standard -- the most non-standard ever!
Only (?) TI used that reverse channel. I spent a 3 hour WTF session attempting to determine the same issue early in my career, so I sorta knew where you were going. Nice to see it working!
Your enthusiasm on getting this old tech working is why I continue to follow your channel.
Thank you so much!
Also, the bunnies.
Came here to say exactly the same thing. Your enthusiasm always makes me smile.
I used to use one of those TI 810 printers 40 years ago in my first job. It was a beast. I recognised it immediately, before you even showed it close up.
I also remember the joy of creating a serial cable that satisfies both ends to go from the serial port on a computer (pre PC compatible, CP/M usually) to a printer, often without a manual for the printer, and sometimes without a technical manual for the computer either.
Aside from the corrosion, this thing is an absolute tank! I didn't have to replace any parts, just fix bad connections is all.
I was digging through a manual looking for any indication on pinout on the printer side, but turns out, I was looking in the wrong manual. I can't imagine the battle of trying to do it without a manual at all though!
Yikes! I supported one of these for years and years. It was fast and loud! As far as I know the reason they are hard to find is the airlines still use them.
Ahhh... I love the sound of a busy dot-matrix printer.
I'm a bit partial to the rhythmic chunka chunka of the Data-100 chain printer, but the TI-810 at full chat is definitely a cool sound!
Brings me back to my childhood with my Parent's Mac and Apple ImageWriter, the only thing better sounding from that time was the big honkin' Wang daisywheel printer that my Dad got with the old decommissioned Wang OIS that he got from work.
That Wang system isn't something you see at all these days, the closest I've ever seen is the Wang setup on this channel.
Usagi never fails to make me happy. Congratulations on the win 🎉
Thank you!
There's something very satisfying about the sound of a dot matrix printer whirring away.
I had a TI-810. Don't remember where I got it, but I used it for quite a while and was very happy with it. It was fast, but definitely not quiet. Nice printer. I *think* it had a parallel interface. I believe there were options for the interface. I gave it up when I no longer had a source of free tractor feed paper :-) Lots of businesses (and maybe airlines?) used it for multipart carbon or carbonless forms. Very heavy duty machine.
The TI810 was the very first dot matrix printer I worked with in 1979. I hooked the Centronics interface to our own Commodore IEEE to Centronics Parallel interface box and produced lots of output on it. I do remember how loud it was. Great to see it turn up at your place and restoring it! I always found it an awesome printer.
FYI - The Centurion printer type PRTQ is the nane of tbe Centurion print spooler program. The print spooler lets you send a print job to the PRTQ at full system speed and not be limited to the slow printer speed. Once the print spooler program receives the print job the printer starts printing the job, and the system user to do other jobs as the spooler prints the last job. In the case of this CPU5 system OPSYS gen. PRT0 is setup with the TI-810 printer driver.
My thoughts as well. I worked a different system/ OS that also used a spooler. You could send print job to 'prt' (printer) or 'slo' (spooler listing output). Standard practice was to send to 'slo' to have job run quick without waiting on printer. But if the spooler task dies, had to have sysop/ admin restart it.
Wonder if there's some startup script that needs to start PRTQ spooler on Centurion?
@@mikefochtman7164 It should have a JCL file with a the JCL commands ( guess you could call it a script ) to start up the Centurion print spooler.
Living in The Netherlands and owner of 23 pinball machines I sure loved your 2 in the background. Good to hear your brother will take good care of it (mayby them soon). Understandably you made a wise decision from your hobby's point of view. Love it. Keep up the good work! Cheers from Amsterdam
Seeing the printer action at the end gives Tech Tangents vibes. You just need to get the bunny staring at the printer.
Hi David, great work again! I used to repair similar printers for Digital Equipment in the 80s and immediately thought of an encoder problem when the printhead did not move to its left margin at power up. A word of advice: if you ever come across a dot matrix printer from DEC, do NOT remove the encoder PCB from the carriage motor unless you have the manual describing the correct encoder adjustment procedure. On those printers, you must usually power the motor with some 5V or so, hook up your scope to the photo sensors, and then physically move the block housing the photo sensors only fractions of millimeters to produce the correctly timed pulses. You need a scope and very calm hands, it's a really fiddly task.
8 years ago i was sent to fix a printer at a logistics company. It was an epson dot matrix that printed all the slips for the drivers. When i got there there was 20 trucks backed up and two frustrated older IT guys. 26 year old me wsltzed in like nothing and was immediately turned around. They said the printer was older than me and there was no way i could fix it.
Well, they're 3x the age of the printer and they hadn't fixed it. I _HATE_ morons like that... there's no way anyone could ever know something they don't.
Honestly, I'm surprised the corrosion wasn't more of an issue. The fact that it only caused fatal damage to a socket and flex PCB is a testament to how well those boards were made. Great work getting it going again!
To stop battery leakage corrosion or even the standard oxidation, use white vinegar and baking soda, These will efficiently stop corrosion and neutralize the pH. Isopropyl Alcohol does not always achieve this result. Hope this helps!
9:41 The LM339 is a quad comparator with open collector outputs. It is not an op-amp.
It works down to its minus rail.
It takes about 1.5uS to react to its inputs
It pulls down with about 6mA when the (+) is below the (-)
It releases its output when (+) is above the (-)
What a great piece of nostalgia, love this sound! I never worked on these types of line printers, but was responsible for repairing and maintaining several dozen Okidata line printers, amongst lots of other tech, in a distribution center for a number of years.
Printers are just disobedient little robots, but it was a lot of fun watching you get this one to behave.
Strange that when Centurion customised the printer they apparently left the badge recess empty and printed their logo on the centre of the panel instead of having a badge made, the empty space is very obvious - and I see you decided to put the TI badge back which looks much better.
Great work Dave and grats to the Discord crew for the assists. Ken Romaine comes in clutch again. I love a happy ending story involving the Centurion in any way.
Oh WOW! That brings back memories. I remember fixing quite a few TI 810 & 820 printers back in the early '90s. They are workhorses!
You mentioned JCL and a shudder went through my soul from 30 years ago.
Different kind of JCL, Centurion uses it's own home spun Job Control Language, but still definitely shudder worthy, haha.
I still have boxes of green tractor feed paper that I printed at the university. That sound really takes me back.
4:34 holy hand grenade of a capacitor
its not a modern 'capacitor plague' afflicted thing
Yes, and at 8:20 he is really calling its bluff by counting to... gasp... 5!
Usagi Catchphrase: "Things Have Changed..."
This brought back memories. In the late 80's I worked with all sorts of dot matrix line (?) printers connected to mainframes. The sound is like music to my ears.
RS232 - the standard that isn't. 25 pins to do whatever with!
Well, there is a documented standard, but few actually follow it.
The magic! YUP! The magic of making old stuff working is so great! That printer is older than all my kids, Maybe older than me. And it still works. Can we say that planned obsolescence was not in the mind of the maker of that product, on the contrary, they made sure it would last for a lifetime! Yes some component did not lasted that long. But who knew that this type of chemical reaction would happen after decades... So happy that you have that system fully working. Congrats!!
Makes me nostalgic for my long departed dot matrix... Nice work
modern printers still print by a matrix of dots
Great job David! Another great fix for another old piece. I saw a lot of those used at work….😄
Now that was quite interesting.
I have forgotten mostly how serial comms operate.
And it was nice hearing the song of a dot matrix printerer...
Wow!! My first job was testing 810's for CADO Systems......back in 1979. We swapped out the character-generator ROM because CADO had a few custom characters. I definitely recognize the internal guts. Well-built machine.
Had not heard the CADO System computer name for over 40 years ago when I was working at Warrex / Centurion. We had a Centurion dealer in Atlanta, GA that also sold CADO system ( I think for Typesetting uses ).
@@kenromaine2387 It's possible you are referring to the CAT photo-typesetter, which was not associated with CADO. Most of the systems sold by CADO were for small business accounting, payroll, inventory, purchasing, and billing. The 810 was CADO's first-supported dot-matrix printer, and was replaced by a much cheaper (and lower-quality) unit from Dataroyal.
I was shouting at the screen when you were saying cabling issues. RS232 is easy when you understand the different layers of it.
Each of the following are at opposite ends of the connector i.e. a end -> b end
GND -> GND, since you always need a ground reference
TXD -> RXD and RXD -> TXD so you have a data flow for the printed data, this is just data, no flow control, unless you use X-On / X-Off software flow control.
The pins meanings are Transmit Data / Receive Data. This is the absolute minimum needed for communication.
RTS -> CTS and CTS -> RTS, so you have hardware flow control. The pin meanings are Ready to Send and Cleared to Send. This is needed to slow down the sender at the right time.
DTR -> DSR + DCD at one end and then and DCD + DSR -> DTR so you have modem flow control. The pin meanings are Data Terminal Ready, Data Set Ready, Data Carrier Detect. This is for modem control, so another layer of flow control for the modem, its only relevant if you have a modem in a link.
If you need a full modem support for incoming call, then you also need Ring Indicator (RI), in this case, then connect RI -> Data Carrier Detect (DCD), since the receiving machine is being told its detecting a carrier signal. Do the opposite at the other end DCD -> RI
Things will then work properly at all layers.
When some of the other layers are missing (i.e. no modem / null modem), this is what's results in the mangled cabling that connects between the different lines above. Generally this is a bad thing, but sometimes its necessary to get the right levels on the right pins to make sure that each end thinks that the other bits of the RS232 protocol see the correct levels on the correct pins.
I spent years fighting the RS-232 interface. A patch box was my friend! Never saw a Pin 11 handshake, I thought it was going to be xon/xoff missing as no return transmit path.
Still love the noise of a dot matrix.
Another great video. Thanks.
Great work! You are definitely persistent and determined. Great to see the old printer working again. This old stuff can really challenge us.
Back in the day, we restored ink ribbons by spraying with WD-40 and putting in a ziploc bag overnight. Works amazingly well.
I was just thinking that ribbon could use a little WD40. (modern WD40 is not the stuff to use, 'tho.)
Spanish Eyes are crying for the loss of that Spanish Eyes pinball, but what great detective work and repairs!
Ahhh! To hear the sound of a dot matrix printer. Reminds me of being a kid and when I used to work at Foot Locker, printing the morning E-mail. Thursdays were always fun because that was the day we would receive the weekly in store stock report, so it would take several hours to print all the stock we had in the store. Eventually, I did stop printing them unless I needed one.
I don't know, I find the "PHA HAZY @KS" hilarious :)
9:34 the LM339 is a quad comparator with open-collector outputs, note that it's used with positive feedback (for hysteresis) rather than negative feedback that you'd typically apply to an op-amp.
Also notice that they are using the forward drop of the LEDs to bias the (-) pin of the comparators. This is a bit clever as it saves some resistors.
Printing always was (and still is) and ADVENTURE
Carcinogens and Bad Decisions would be a good band name. Hilarious Collection Of would be their best of album title.
I fix modern computers.......... I don't have the love for the old ones....... BUT I totally appreciate and am motivated by your "don't give up" attitude with these projects.
That title sums up soooo many idea's I've hqd in my life lol
5:50 I reckon you were getting paint runs by changing direction in the middle of the cover. Just do full passes, then the coverage will be even 👍
I didn't actually get any runs until the fourth and fifth pass. I was getting lazy and my coverage was getting poor... Pays to be vigilant until the very end! Someday I'll sand it back for a smooth finish and recoat.
Can we talk a bit more about everything that's going on in the Captain Fantastic photo 0:17
That is one heck of a brochure, no doubt!
Some things are better left unknown…
That Jersey alone.. 72 Series would have been more badass, but still love it.. Sir Elton is Canadian now anyway. 🙃
Elton John is a gigantic pinball nerd. He cooperated with Bally...
I once had a job calibrating and modifying these kind of printers before they were sold and that was in the nineties, so still then they were used. I also remember a cabinet below it to house the chain paper.
Oh, yea, even as late as ‘96 I had to maintain several that were used as report printers. Most had been replaced with high speed, quieter, ones capable of multi-part forms (some with automated stuffers), but these TI’s were the workhorses for general report printing.
That printer looks very pretty in its new paint scheme. Like it belongs there.
There's something very satisfying about the sound of a dot-matrix printer doing its thing. 😄
For the too-light printout, I've heard that a tiny squirt of WD-40 on the ink ribbon and allowed to soak throughout the ribbon will help to both lubricate it and darken it. But I've also heard that there are ways to re-ink the ribbons even nowadays, so maybe you should look into that? And thanks for the bunnies... I mean... the fun video. 😃
modern ones still print by a matrix of dots
Avoid applying WD on it. Sometimes this breaks the plastics molecular linkage
@@VitorFM yep, i've had WD40 destroy some plastics....
@@andygozzo72 on rubber, it can even melt it ...
Mountains were climbed. Printers were conquered! Great video 🙂
Ahh, the sound of my electronic childhood. There is just something and the sound of dot matrix printers. They still use them at a lot of airports, so they aren't totally dead tech
For future reference, using white vinegar to neutralise the battery leakage helps.
Makes hooking up my ImageWriter II to my Power Macintosh G3 look like child's play. Love to see a community effort pay off!
With apologies to JFK: "We choose to go to the Moon in this decade and do the other things, not because they are easy, but because we _thought_ they would be easy." 🤣
Congrats! Not only is it working well it looks great also
As an old printer guy (think Dataproducts and Genicom and a few others), I did see a rotary dial but don't recall what it was called, but it functions like a soft carriage control tape. I don't know how it is programmed, but you might try to see if you can skip over the paper at the bottom of the sheets and not print over the perforation. I suspect one setting might do just that. It's just a thought. Sure miss the sound of a dot matrix printer. I used to be able to identify the manufacturer just by the sound it made! Keep up the great videos -- I look forward to them and learn so much. Regards...
Nice work. Nice to see it working!
Reverse channel. That really takes me back. I knew it existed but I never worked with it. You used to be able to get half duplex lines from the telephone company. If you were only using it for a printer or if you used polled Bisync, they worked great and they were cheaper than a full duplex line. You could used them for voice but if you didn't have control of the line, you would have a dropout. Reverse Channel was used to turn the line around so data could be sent the other way. By the 70s and 80s it was pretty well phased out but it appears that a few were still supporting it. I would have expected CTS/RTS flow control but the description for the printer clearly indicates that it's not supported.
I knew right away it wasn't working right, it needs to home. Even though It's been at least 30 years since I worked on it, I had one customer with one of those, and we supported it. I remember it being really easy to figure out and easy to service. When the power supply died, our sales team sold them an Okidata to replace it.
That's a sound I used to hear all the time in the 1980's & 90's when I would dump code to my trusty Epson MX-80 which is still up in the attic.
Wow Thanks for the way back!
Paint it BLUE!!! We musts paints it blue! But seriously if it were me I would recreate it by painting it blue and then getting some vinyl printed Centurion logo recreation and have the whole system be classic and matching and everything. In any case thanks for all these great videos!
Love your vids, I'm a total computer geek with rack mounts etc in my house. I also love pinball and have 26 of them. Please don't get rid of your corner EM one.
That print head can't have too many characters on the clock, all the dots seem nicely aligned. I used to repair Oki printers and have replaced the pin guides (might be called a jewel by some) and pins too if the pattern was getting too rough for the owner.
Yes, I had a huge printer I got from a computer fair and the dot matrix head had probably run into a paper jam so some of the pins were bent. Fixing that was "fun".
looked great by the time you were done!
27:04 Ah, the days of 7-pin half-descender output... I don't miss it at all.
I think 50% of my early IT career was fixing printer issues on some IBM/DEC Digital lash up 😳 Nothing ever “just worked”, it took hours of fiddling with settings and terminal hub programming
What a win! Great job!
Those TO-220 transistors with the solid metal backs (the TIP150s at around 6:45)... when my company was still servicing intercom boards for a major brand, we were told to watch for these and replace when found. Never really found out why that directive.
Well done, David!
LOVE your channel. Nice to know there are bigger geeks in the world than me!! (Mean that in the most respectful way)
Net time, use Wire-Wrap wire.
Also, get yourself an old-time RS232 breakout box w/ the jumper wires. You will find that it can greatly help troubleshoot serial port issues.
There's a very strange compression artifact at 2:35. The "Texas Instruments" label jitters left and right. How could this have happened? I don't think it can be bug in UA-cam's video compression, because it's present in all resolutions and video formats.
That reminds me of the 9 pin color printer I would use with my Commodore 64 and then with a 486.
17:00 looks like some kind of Caesar Cypher 🤣🤣🤣
Fantastic series. Well done. Would like to see how you would tackle re-inking the ribbon. 👍
I find it fascinating print spooling was a thing even back in that machines time, and yes even my vintage machines have to either pull up or print out an ascii "colander image" lol its like a right of passage of the old machines
I used to have an Epson Do-Matrix printer with my Apple II-E computer.
it was great hearing D.M printer running . I miss the way they sounded
I believe that some of the PCB manufacturers, now do "Flex" PCBs. You might be able to recreate that little flex PCB in KiCAD & get it re-manufactured! :)
I'm not a fan of dot matrix printers, but that one is GORGEOUS!
Great success! Congrats!
The worst part of those printers was the 'paper out' error blocked the serial communications. This almost always had the effect of freezing any connected system that was running a print job - especially if the affected software hadn't been engineered to handle a print failure.
I haven’t heard that angry buzzing printer sound for so long!
Well done the non standard rs232 usage was rampant in them thar days! 😊
That TI data terminal is downright sexy.
I like older stuff, it was meant to be fixed and setup rather than just thrown away. Very cool.
I worked at Texas Instruments in Cypress, Texas and my desk was about 20 feet from the 810 and 825 printhead lifecycle test room. 40 or 50 or maybe even more printheads running 24 seven. Try and imagine the racket.
That’s the stuff of nightmares! H3ll modernization that added a new circle for IT. 😱
@@ChrisSmith-tc4df I can still hear it. That was 1984.
I used two of these at work One was a KSR and one was an RO. The only thing that ever happened was the hub the carriage cable was connected to the motor cracked and I had to replace that. Otherwise never a problem. Stone reliable and they ran 24/7 as a administration terminal and a call detail recording logging printer on a Nortel SL1 VLE phone system.
Had a stand for a 800 series printer, which still has a printer on it, a laser printer, as the TI printer was not upgraded, and the newer Seikosha that replaced it was replaced (a few times, with the same model as the heads wore out) with an assortment of HP printers. 800 printer was scrapped, but I kept the print head rods, and used them as long drifts.
Oh my gosh! You absolute wonderful person doing all kinds of cool things like this I love it!
I actually adore dot matrix printers. The sound, the print quality (or lack thereof), and the simplicity of design. The printer did all the printing work, all the computer had to do was send ASCII, and maybe (later on) control code sequences.
Yes, they are noisy. Yes they are slow. And i'd have kicked puppies and punched kittens for a cheap dot matrix printer back in the day.
I had an 810 Ro back in the day (1985 ish) when I was in college. I had it hooked up to a Commodore 64 originally and then a 10mhz AT clone. I could not figure out the handshaking and ran it at 1200. I only had the upper case roms. Used it mostly for printing computer listings when I dialed into college (I was a computer science major). Don't get your hand inside the machine when the carriage is moving... it will mess up your fingers. Ask me how I know 🙂
2:34 "I don't think it will take too long to fix it up"
With that title, I bet you were too much optimistic there.
Nice!! now you can put a ribbon in it :p
Yep you definitely need a ribbon re-inker.
You said ‘unwind the cable’ and I groaned in sadness and empathy.
Wrap a rubberband around it before pulling it off the motor.
Oof. Dot matrix printers bring nightmares. Worst was printing my undergrad thesis on one back in the early 90s... had to nurse that printer day and night for a week to print 87 pages. Never again. :)
white vinegar neutralizes and eats up the white crusty crap really well, I use it on battery terminals all the time