The 1520 Plotter Survival GuideTHE COMMODORE 1520 PLOTTERThe 1520 was the only plotter Commodore ever made, and it was essentially a toy. You can see pictures and read a little bit about it here:
http://www.zimmers.net/cbmpics/peserial2.htmlIt came in at least three different versions: off-white with a black plastic paper roll cover, brown with a black plastic paper roll cover, and brown with an open paper roll holder with no cover.
Parts are hard to come by, and that was the inspiration for me to write this survival guide.
PAPERThe roll paper used by the 1520 is a fairly obtainable office supply item, so it's the only thing you're likely to be able to find relatively easily. It's just 4 1/2" wide x 3" diameter adding machine roll paper ('bond', not thermal!) with a cardboard center tube. (This just happens to be the same width as toilet paper - but don't be tempted to use THAT!) Problem is, it's not a standard off-the-shelf adding machine paper size. Staples and Office Depot don't carry it, and most business suppliers want to sell you a case of 50 or 100 rolls at a time. Nobody will sell you a single roll. About the most reasonable I've found is to buy a box of 10.
Here's a list of real-world machines that use the same paper. If a roll says it fits these, it will most likely fit your 1520, as well:
Hamilton-Test Micro T/TS 1000 & Petrosonic 111 Star 312 DP-8340 Hamilton Test System Data Saab 5808-3 Petrolsonic III printer Squirrel Squirrel POS systems Petrovend Petrolsonic Racal-Transcom RG Fast 2000 Squirrel Squirrel POS systems Westrex 4900, POS2000 80 column printer, S600, S610, S7000, S830 80 column printer Star Micronics DP-824 (40 column), DP8340 series, DP8340FM, DP8340SM Unisys EF4260 Westrex 4900, POS2000 80 column printer, S600, S610, S7000, S830 80 column printer (No, I couldn't figure out where the model number breaks should come, either!)
The following site has rolls for $22.98 per box of 10, plus shipping (disclaimer: I've never ordered from them personally):
http://ezpaysys.com/412inx1951pl.htmlBut this site has boxes of 25 rolls for $27.55. Of course, shipping will be at least 2 1/2 times more, and who can do that much plotting on a 1520? (I've never ordered from these guys, either):
http://www.paperrollsplus.com/thermal%20paper%20rolls.htmFor a supplier that will sell you two rolls at a time for $3.95, see B&C Computervisions, below.
PENSHere are images of the 1520 plotter pens. The first is a dimensioned drawing, to hep you figure out if other pens are close enough to work. The second is a photo of the package in which the pens were shipped.
The following plotters all use the ALPS mechanism. They are NOT identical in their controller or interface logic - they merely use the same cheap ALPS drop-in plotter unit. (Numbers which follow each entry are the manufacturer's original part numbers for replacement pens.) Hopefully this will aid you in your quest for pens.
Commodore 1520
Tandy CGP-115
26-1480a
26-1481
Sharp CE-150
EA-850B - 4 black pens
EA-850C - 4 color pens (black, blue, green, red)
Atari 1020
BX4206
Mattel Aquarius 4615
TI-99 HX-1000
1000BL
As of this writing, the following two vintage Atari dealers claim to have pens available for the prices shown. Be aware that these are NOS (New Old Stock) 20-year-old pens, and though they both claim to test first, customers have reported that it's a crap shoot as to whether you'll get pens that actually work. (B&C Computervisions also says they have replacement 'revolver' pen holders and paper.)
Best Electronics
http://www.best-electronics-ca.com/Page 148 of their catalog:
Atari 1020 BX4204 Color Pen Set (4 pens per set) $3.00 (Limit One set per customer)
Atari 1020 BX4206 Black Pen Set (4 pens per set) $3.00
B&C Computervisions
http://www.myatari.com/ PRA082 WHEEL 1020 PEN HOLDER $1.95
SUA001 PAPER 1020 - 2 ROLLS $3.95
SUG506 PENS 1020 BLACK (set of 4 pens) $3.00
SUG507 PENS 1020 COLOR (set of 4 pens) $5.00
It seems the same pens were used in some medical equipment, which is why a German firm still sells high-quality precision replacement pens. They're expensive, and probably overkill for the 1520, but at least they're available.
The Sharp User Group (
http://www.sharpmz.org/index.html) tracked them down, and here's what they say about them:
The times of searching for this very rare item are over! The sets of plotter ball-point pens EA850B and EA850C usable for the MZ-1P01 and MZ-1P16 are now again available. The German company "Christiane Lass" developed the equivalent set which is now waterproof (the original SHARP set is not). I got the following message from the company:
"The pens correspond actually accurately to the defaults of the models EA850C and EA850B including the crucial ball point. We worked at the project nearly 1 year; and first we experimented with a fiber tip, but this wasn't acceptable by the technical examination of international medical technology manufacturers. We now sell the current version to Scandinavia and into the USA with no objection. Our actual emphasis lies in the medical technology but the pens are also usable for computer plotters."
Really, they are! I could test a free set. See the result on the picture. The company sells the pen sets internationally and has 2,000 sets at its stock. Contact Christane Lass by email: Christiane.Lass@t-online.de if you want to get more info or if you want to order the set(s). Price: Euro 12.70 plus shipping costs Euro 5.00 for Germany. Please ask for the shipping costs outside of Germany.
There's even a picture:
This medical supplier in Switzerland also has them, but they want you to ask for a quote so I'm sure they're not cheap there, either:
http://www.diagramma.com/1520--Comodore-.13+QSoqMjc2M3xMKioy.0.html?L=2IMPORTANT TIP: As hard as these pens are to find, follow Commodore's advice - REMOVE the pens and cap them in between uses. It's stupid, and it's a hassle, but just DO IT!
PARTSThe ALPS plotter mechanisms are very fragile, and the cheap plastic gears have a tendency to break. As stated above, B&C Computersisions claims to have replacement pen holders (the 'revolver' mechanism) for $1.95 each.
But Electronic Goldmine (
http://www.goldmine-elec.com/) currently has the entire mechanism as a surplus part:
ALPS 4 Color Head Assembly - $1.49
http://www.goldmine-elec-products.com/prodinfo.asp?number=G158244 Color Pen Printhead by ALPS - $3.95
http://www.goldmine-elec-products.com/prodinfo.asp?number=G2092Electronic Firing Mechanism - $3.49
http://www.goldmine-elec-products.com/prodinfo.asp?number=G2093The first item is the chassis stripped of the revolving pen holder and pen-down solenoid. The second is the entire mechanism. The third is the pen-down solenoid only. (Note that they're selling the solenoid for almost as much as the entire mechanism - apparently they've decided it's a good part for robotics hobbyists.) I have no idea how hard it is to repair these. Considering how tiny and fragile they are, I'd go the route of replacing the entire mechanism if you can.
It's held in by two easily-accessed phillips screws from the top of the 1520. Take them out, disconnect the ground wire (another philllips screw), unplug the mechanism from its connector, and it's out. Reverse the process with your new mechanism and you're done.
Before you replace the mechanism, you might want to try a drop of sewing machine oil on the motor and gear hubs and on the pen holder slider. DO NOT get any oil on the platen roller or anywhere else!!! My 1520 was totally frozen up when I got it, so I figured I had nothing to lose by carefully applying a couple of drops of oil. I even bravely turned the gears a bit by hand to get things loosened up. I DO NOT recommend you do this with a working 1520 mechanism - the old adage "If it ain't broke, don't fix it" certainly applies here.
I have just ordered four of the entire replacement mechanisms from Electronic Goldmine. Why four? I've read online that as many as 3/4 of these may have bad gears. While my 1520 still works, sort of, it is flaky at best. I'm trying to make sure I have the parts to keep it running well into the future. I figure this will probably be my last chance to order replacement parts.
If you insist on trying to repair it yourself, here's an exploded view of the ALPS mechanism from a Tandy computing site:
http://support.radioshack.com/support_accessories/doc10/10508.pdf(If you back up a bit on this site to
http://support.radioshack.com/support_accessories/5632.htm you'll find the entire user's manual for the Tandy plotter.)
CONTROLLERThe MPU (not CPU) in the 1520 is a special 6502 (yes, another one) made by MOS which has 2K of mask-programmable ROM on board along with 64 bytes of RAM (in zero page, of course) and a UART. (Mask-programmable means the ROM is programmed when the chip is made, so it's not reprogrammable at all.) It's called the 6500/1 and its Commodore part number is 325340-03. Here is the 14-page PDF data sheet for the 6500/1 (make sure you back up a level and check out ALL the MOS chip data sheets this guy's got!):
http://highgate.comm.sfu.ca/~rcini/classiccmp/pdf/ds_6500.pdfWith all this going on, it's no wonder the 1520 board is so bare - no ROM, no 6522 or 6526, nada. Just a couple of interface chips for the stepper motors and some transistors to drive the pen solenoid. The 1520 schematic is available here:
http://www.zimmers.net/anonftp/pub/cbm/schematics/printers/1520009.gifAm I the only one thinking, 'Hey! The 1520 board's got all the logic, controllers, and interfacing to let it drive ANY TWO compatible stepper motors AND a solenoid!"?
SOFTWAREI'm still looking for a D64 image of the original disk that shipped with the 1520 (if any), Does anyone have this?
There is apparently not one but a suite of GEOS printer drivers for the 1520, though I haven't found a link to them: 1520 40 Black, 1520 40 Blue, 1520 40 Green, 1520 40 Red, 1520 10 Col., 1520 20 Col., 1520 80 Col.
You can buy them all (along with several other GEOS printer drivers) on a $4 public domain disk here:
http://oldsoftware.com/64pd.htmlI don't know if they're on the GEODRIVERS1 disk that Click Here Software sells for $8 here or not:
http://cmdrkey.com/cbm/pricelists/prices.htmlAnd they might be on the Shell printer driver disks that are available for free download here, though I don't know for sure:
http://www.filegate.net/cbm/g-disks/There are a dozen or so disks and individual BASIC programs for the 1520 at the GEnie Information Networks archive at:
http://cbmfiles.com/genie/C64SoftwareListing.htmlCOMAL has good support for the 1520, and there are several demos that use COMAL turtle graphics with the 1520 to good effect. The best COMAL download site I've found is the COMAL Archive (which includes a disk dedicated solely to the 1520) at:
http://users.macunlimited.net/kenross/INDEXC.HTMLOf course you'll probably stumble across the occasional program for the 1520 on other Internet archive sites now and again, but they are rare birds.
MANUALS & BOOKSProject64 doesn't have the 1520 Printer/Plotter User's Manual, and I can't find it anywhere else on the web for free either, though you can buy it here in PDF format for $15.99:
http://www.manuals-in-pdf.com/1520-p-225051.htmlI'll scan my paper copy (eventually) and put it online if I can't find it elsewhere.
1520 User's Manuals also come up for sale every once in awhile on eBay, as does the 1520 itself, of course.
Zimmers has a command summary:
http://www.zimmers.net/cbmpics/cbm/printers/1520.txtI haven't been able to find any indication that there was ever a 1520 Plotter technical manual, except for the fact that the schematic exists. If you know of one, let me know.
Issue 8 of Commodore Techtopics discussed how to change the device number of the 1520. I haven't been able to find a copy online, though the schematic (above) makes it clear that it's the standard CBM 'cut a jumper' method, with three jumpers. The 1520 ships with a default device number of '6'.
The only book I've found that talks about the 1520 is Abacus'
Commodore Peripherals: A User's Guide, which seems to have a chapter dedicated do it. I don't own this book, so I can't say if it actually provides any useful information over and above what's in CBM's 1520 Printer Plotter User's Manual.
THAT'S ITI hope you've found this helpful.
If you have any other 1520 information, please add it to this thread.
