Friday, July 31, 2015

"Made In The U.S.A" - Why American CoCo 3s Are Quality-Challenged

[Note: Back in 2000, I wrote a white paper on the differences between CoCo 3s made in Korea (from the 1986-1987 era) versus the ones manufactured later at Tandy's Fort Worth factory (from 1988 onwards). My conclusion then was that the CoCo 3s made in America were somewhat inferior in a number of respects, and I continue to stand by that. I thought I would revisit the topic and move the contents of the paper into this blog especially in light of some additional information I've come across recently. Most of the information here, including the photos, are from the original 2000 white paper.]

"Made In The U.S.A" - Why American CoCo 3s Are Quality-Challenged

It is well known that over the course of the Color Computer's production, Tandy manufactured Color Computers both overseas and in the United States. One of the more interesting comparisons can be made between the American and Korean models of the Tandy Color Computer 3.

The Korean model of the Color Computer 3 was manufactured in Korea between 1986 and 1987. Sometime in 1988 (see this link for info on Tandy's move), the switch was made to a factory in the United States. Although both models are virtually the same and functionally identical, there are some interesting differences, minor as they are, which may yield clues as to Tandy's decision to move production from overseas to home.

For this post, I'll compare two CoCo 3s:

  • An American made 128K Tandy Color Computer 3 SN#1299880
  • A Korean made 128K Tandy Color Computer 3 SN#1144677

Exterior Differences

Look carefully at a Korean and American CoCo 3 side by side; at first glance, it's not immediately noticeable that they are different. In fact, without the original packaging and box, they look identical. However, just examining the box will give away a CoCo 3's country of origin.


Korean CoCo 3's were shipped to Radio Shack stores in a predominately white box with red lettering and graphics. The picture on the front cover of the box shows the outline of a CoCo 3, and the sides of the box give a summary of features.

The later American CoCo 3 was packaged in a more attractive, sturdier white box with blue and red lettering and graphics. Featured on the front top of the box are two children sitting in front of a CoCo 3, while the sides depict graphics and lettering oriented towards younger computer users.

This more "kid friendly" packaging fit well with Tandy's promotion of the CoCo 3 as a game machine towards the end of its production run in 1988-1989.
The later American CoCo 3 box on the left compared to the original Korean CoCo 3 box on the right.

Outside Case

As mentioned earlier, the Korean and American CoCo 3 look virtually identical from the outside. However, there are a few minor clues which can tell the two apart without even opening them up.

The Nameplate - The word "TANDY" on the American CoCo 3's nameplate is slightly larger than it is on the Korean CoCo 3.

The Korean CoCo 3's badge has a smaller "TANDY" logo and no space between the "128" and "K".
This American CoCo 3 badge has a larger, fatter "TANDY" logo and a space between "128" and "K". Note that the red/green/blue color bars have shifted on the plate, indicating a bit of carelessness on the part of Tandy QC. 

The Power Button - On a Korean CoCo 3, the power button on the back protrudes out further in the "OFF" position. On an American CoCo 3, the power button is shorter.

On this American CoCo 3, the power button does not protrude out as far as it does on the Korean CoCo 3, pointing to a different parts supplier. Note the button is in the OFF position.

Here on this Korean CoCo 3, the power button (also in the OFF position) extends out of the case noticeably compared to its American counterpart.
The Bottom - The bottom of the CoCo 3 case reveals different warranty and identification stickers. Also, the grey rubber feet on the American CoCo 3 are glued onto the bottom of the case, whereas the Korean CoCo 3 uses interlocking, black rubber feet that are larger in size.

The American CoCo 3 bottom has a square beige, opaque identity/serial number sticker, as well as warranty seal sticker. Also note the round grey rubber feet (and one missing at the bottom right). Unlike the Korean CoCo 3, these feet are glued in place. Over time, the glue gets soft/tacky and the feet move around and even dislodge.
Here, the Korean CoCo 3 has a rectangular, transparent identity/serial number sticker, as well as several additional stickers and a smaller warranty seal. The plastic feet are also pinned against the case for durability and adhesion.

The Power Cord - The power cord is noticeably “cheaper” on the American CoCo 3. The blades are not as strong and thick as its Korean counterpart, and the shape of the plug is less fluid. The strain relief is not as long and the wire itself is not as robust.
The power cord of the American CoCo 3 on the left vs. the Korean CoCo 3 on the right. The blades are thinner on the American CoCo 3, and the plug body and wire are noticeably thinner and less "rubbery" than its Korean counterpart.

Interior Differences

Upon opening up both CoCo 3's, the differences are more striking internally.

The Motherboard

Upon opening up both CoCo 3s, the differences are more striking internally. On both models of the CoCo 3, the actual motherboards have identical identification numbers, and appear to be exactly the same.  The components, however, are slightly varied.

Capacitors and other Components - While the values of electrical components such as resistors and capacitors on both CoCo 3s appear to be the same, there are some noticable visual differences. The American CoCo 3 has smaller "blob" capacitors which are yellow in color, while the Korean CoCo 3 has slightly larger blue capacitors in the same locations. Likewise, certain ceramic disc capacitors on the American CoCo 3 are orange in color, and on the Korean CoCo 3 are green.

RAM - The Korean CoCo 3 has Korean-manufactured 120ns Samsung RAM chips, while the American CoCo 3 has U.S. made Micron Technology 120ns memory. I have seen American CoCo 3s with 150ns Micron Technology RAM chips as well.
This wide shot of the Korean CoCo 3 motherboard shows the assortment of chips. Specifically, the RAM chips are four Korean-made Samsung KM41464 at 120 nanoseconds.
This American CoCo 3 keyboard shows US-made RAM chips from Micron Technology with 120ns access times. Other American CoCo 3s have contained 150ns variants of the same chip (apologies for the blurry photo).

IC Markings - Most integrated circuit chips, particularly the GIME, have different markings and logos, probably due to newer runs of those chips. Even later American CoCo 3s have both GIME and ROM chips made in Mexico.

Other Internal Differences

One glaring difference internally has to do with the area where the keyboard rests on case. The Korean CoCo 3 has two small round black rubber washers on either side of the pegs where the keyboard rests, in addition to a rectangular black rubber "boot" at the bottom of the keyboard and a round rubber insert directly underneath for support. The American CoCo 3 has none of these.

This Korean CoCo 3 has the rubber cap on the post that the keyboard rests on, as well as a GIME chip made in Korea and  an NEC ROM chip from Japan.

Here, the American CoCo 3's rubber cap is missing. In addition, the rubber block (not pictured) that rests at the bottom of the keyboard is also gone. While the GIME chip here is made in Korea, later models have GIME chips made in Japan. The ROM chip is also made in Mexico.


So what conclusions can we draw from these differences?

The CoCo 3 was nearing its end of life as it moved from its home manufacturing base in Korea to the United States. It would appear that the overseas move gave manufacturing an opportunity to source parts state side with potentially new suppliers.

Without a doubt, quality slipped with the transition from Korean-made to American-made CoCo 3s. The Color Computer manufacturing plant manager, Kenji Nishikawa, was notorious for cutting costs, and it really shows on the later American CoCo 3s. The omission of rubber stoppers and washers, along with the replacement of the more durable pinned plastic black feet to the grey rubber ones which were glued on, shows compromises were made, more than likely for cost reasons. Even the fact that the above badge had a misprint reflects carelessness (this is the ONLY CoCo 3 that I've ever seen with such a badge defect, by the way).

Addendum (July 2015)

One interesting note to this, and which prompted my posting of this white paper as a blog post: I recently acquired a CoCo 3 that was most unusual. It was an American CoCo 3 with the opaque beige "PRODUCT OF U.S.A." sticker on the bottom. However, the feet were not the glued-on grey half spheres, but were instead the nicer black round plastic ones. In addition, the electrical plug was the more durable black wire and blades, along with a Korean style TANDY badge. The serial number of this particular CoCo 3 is 1277278, which is less than the 1299880 profiled here.

I suspect this was one of the early CoCo 3s made in the Fort Worth factory after the move, made with parts that were originally stocked for the Korean factory. There are probably other CoCo 3s that are assembled in the same manner, but this is the first one that I have personally run across, making it somewhat of an anomaly compared to its earlier and later brethren.


  1. Great article. If were not for it, I would have most likely never noticed any these differences on the CoCo 3 machines...

  2. Just now getting to read this. Wow those differences are more significant than I would have thought. I can see the IC vendors changing, but the font on the label and the stickers on the underside? Great information here, thank you for sharing it

  3. I purchased one of the Korean made ones by the description of the warranty label and round molded stand-offs for feet. Unlike my older Color 2 which had square adhesive feet. It came with a problem, the display was shifted about ¼" to the left concealing the 1st character of any text. I sent it back but the store I got it from told me they were met with some resistance getting support for any Color Computers. Not having featured monitors equipped with screen position adjustments I took it back and faced the screen restriction until I later retired it to the attic.