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ALPS plotter pens, gears, paper

Brian K. White

ALPS Plotter Engine

The Tandy CGP-115 is based on the same ALPS DPG-1302 plotter engine as several other plotters.

Plotter Models:

Tandy CGP-115
Tandy 26-3605
Sharp CE-150
Commodore 1520
Atari 1020
Mattel Aquarius 4615
Texas Instruments HX-1000
Oric MCP40
Silver Reed EB50


Search box: "stifte" ("pen" in German)

  • US 016.01 - 4 black
  • US 017.01 - 4 color, black blue green red

Web shop does not handle US shipping address. Order by email to:

Peter at

Peter speaks English, you can write the email in English.

They will make a PayPal invoice / request for payment.
You have to manually check your PayPal in a desktop browser to see it and pay it.
Doesn't appear in the Android PayPal app or even in the Android browser, but does appear in FireFox in desktop mode.


The pinion/spindle gears on the X and Y motors are made of Nylon, which has shrunk over time, and essentially all of these gears are split by now, or soon will be. There is at least one good working replacement. The new gear is brass instead of nylon, which is not necessarily a great thing, but they are the right dimensions and teeth size and teeth count, modulus, bore hole, etc. It's practically a miracle to find these.


13 tooth
1.5mm bore
0.25 modulus


WOW! Now you can get brand new gears 3d-printed to order!

Bam! Done!

I have ordered and received a set of these, and they do look and feel good. I haven't installed them in a plotter yet.

Alternative, these gears are brass, and actually cheaper, but, as best I can tell they are not really in production any more, merely some resellers simply still have stock. I actually got several of these from 2 different resellers for about $1.90 per gear.

Manufacturer: Xtreme Production

Model: EA-055-13
Motor Pinion 13T (1.5mm hole, 0.25M)
Notes: "Suitable for Walkera CB100, 4#6, 4G6, V100, V120 series"

Many resellers list the part, but most don't actually have any in stock. I had success at and
There may be others still out there. Look for r/c hobby shops, particularly ones that sell helecopters, particularly Walkera.

I used a small hobbyist table top vise to press the gears onto the motor shafts. Panavise 301, with plastic jaws. You can remove a thin metal sheet that covers the motors on the back, and that exposes the motors enough to get the corners of the vise jaws on both ends of the motor shaft without having to remove the motors. The jaws on that model are plastic, so they don't harm the motor shaft on the back of the motors. If you use a steel jaw vice, be sure to protect the rear motor shaft from direct metal to metal contact with the vice jaw.



plain bond
4.5" wide
7/16" core
up to 3" diameter
160 feet

Original Radio Shack item was 180 feet but that's not a common size. The Original paper may have been a thinner bond too. 160 feet of plain bond does fit in the machine with room to spare. Often the selling sites will list the roll diameter which removes all guessing.

Typical search term: "4.5" bond roll"

Refilling Pens

The new pens from the German medical supplies company are pretty expensive considering that they are so small and don’t last very long.

The new pens can be refilled fairly easily with insulin syringes available from local drug stores. Example:

Walgreens item 677232
10-pack, 29 gauge, 0.3mL
super thin syringes for insulin

When looking for alternative inks, you need to know that the original ink is water-based.
Use water based drafting/plotter pen ink. Example:

Chartpak/Koh-I-Noor models
3080-F-BLA black
3080-F-BLU blue
3080-F-RED red
3080-F-GRE green

Clean up with a calligraphy pen cleaning solution, like:

or Koh-I-Noor Rapido-Eze.

It works to clean up old dried pens too if you soak the disassembled parts in a jar for a day or so.

Fill a syringe to about the 20 mark. (0.2ml)

Around the tip of the pen (the new plastic german ones) there are 3 vent holes. Insert the syringe into one of those. Angle towards the center a little to minimize how much the vent passage gets mushed open by the needle.

Slowly, giving the ink time to soak into the fiber filler inside, push the plunger from about 20 to about 10. When you see ink in the other vent holes, you’ve actually gone slightly too far, or too fast.

Remove the needle, wipe it down with a damp paper towel and cap it.

Wipe the pen tip with a dry or slightly damp paper towel to clean the excess ink and wick out a little from the vent holes too.

Repeat for all 4 colors.

Put the printer in 80 column mode ( jumper 2 = off ) and LLIST a basic program until the writing looks clean. It may splatter a little at first.

I have no idea how many times a pen can be refilled before the ball point wears out, but even once is worth it, considering how expensive they are and how quickly they run out. I have only refilled each color about twice so far.

For the old steel barrel pens:
You have to completely disassemble the pens and soak the parts in the cleaning solution for a few hours or days.
You may need to pass the metal ball point tip into a flame briefly, once, to free up the ball from being stuck. I think it melts the dried ink, or maybe it expands the brass nib that holds the steel ball? In any event, I had some pens that no amount of soaking in water, alcohol, ammonia, etc ever freed the ball, but just briefly passing into the blue flame from my stove got the ball rolling and the ink flowing.
You have to inject ink with the pen tip off. You can’t go in through a vent hole like you can for the new all plastic pens.
All in all, I’ve generally had less than 50% success rate refilling and reviving old pens. Even after completely disassembling and cleaning all parts and freeing the stuck ball points. But occasionally it does work, and a few pens are better than no pens.

Pics / Video

Manual, BASIC programs