Commodore blog

There was recently this short post about the customized, unique-housed Plus/4. What happened was, I marveled at the ad for a day, and then... well... I bought it.

It wasn't that simple; in the first message, the seller got quite offended because I laughed at his beloved unique and rare Plus/4. He stated that he certainly didn't have to sell it to me. Especially since I bargained quite cheekily from the imagined price.

The original ad

It was quite difficult to come back from there, but I eventually suggested that I would also buy the faulty Commodore 16 he was advertising, without bargaining, plus for the Blue Menace (by then, for the sake of peace, I was calling it the Wonderfully Unique and Valuable Rarity or something similar) I was willing to pay around 30€ instead of the requested 100. Here, we finally found common ground, so for a total of 80€ + shipping cost, I got the C16, the Blue Menace, and as a bonus, the latter's (also non-original, but not as extreme) power supply.

A little interlude: the Commodore 16 is a fairly good condition machine, with a slightly yellowed keyboard, without a processor. I replaced the latter, and since then the machine has been working flawlessly.

So we struck a deal, then I tried to get more information about the origin of the strange machine. Unfortunately, the seller didn't have much information either - he bought it on eBay many years ago, and all he knew was that it was used in some industrial application. Whether the case was damaged and therefore replaced, or it was originally put into service like this, he didn't know. He bought it anyway because of its "uniqueness," and had kept it in a display case (!!!) ever since.

A few days later, the package arrived. Naturally, my first task was to thoroughly examine the details, and I took plenty of photos all around.

The first question that arose in me and others: what is the case made of? Well, it's made of some kind of dyed plastic sheet, feels like something like fiberglass plastics, minus the fiberglass itself. At least it turned out that it wasn't cut out of boiler plate, as it seemed at first glance :)

After the initial astonishment, I assessed (and photographed) the details, including the ingeniously poorly conceived hinge and the screw fastenings reminiscent of the finest Balkan solutions:

Notice the anatomically correct C264 inscription (which covers the C16-C116-Plus/4 series), and the extra-demanding flat-head screws, aren't they adorable? :D The hinge is lame in every aspect; if we open the machine along it, not only does it not lie properly on any surface, but the keyboard ribbon cable is also nerve-wrackingly tense from it. Fortunately, the rotation axis can be pulled out of the hinge (according to some professional opinions, it even falls out on its own!), making the structure somewhat easier to handle.

The motherboard's fixation on the bottom plate is definitely meticulous, I mean in the sense of the word as used on the Pakistan-India-Bangladesh axis. A screw from below, two nuts as spacers on it, and another nut on top, above the motherboard, for fixation.

The motherboard's fixation on the bottom plate

I changed this quite quickly so that the motherboard could be loosened with a screwdriver from above. It temporarily got motherboard standoffs from an old PC case, although I ordered slightly longer ones because, due to the thickness of the plastic sheet, the nuts could only be fastened just barely, and a washer was out of the question.

This is how it was

This is how it became

It's a bit less painful to look at now - I'll take care of the dust later.

The motherboard itself hasn't been tampered with, aside from the heat sinks glued (!!!) onto every larger surface. I don't know how much of a threat overheating is to the 3-PLUS-1 ROMs in normal operation, I think the creator wasn't really informed about this either, but clearly didn't leave it to chance. He had heat sinks and instant glue at home, so he didn't hesitate. Another question is how useful all this could have been, since dried cyanoacrylate is not famous for its high thermal conductivity.

The next step was obviously to examine the Blue Menace more thoroughly, especially regarding what might be wrong with it, since it was advertised as faulty.

Image from the original ad about the (non)functioning

Here's a little extra information: in the eighties and nineties, with the proliferation of electronic devices, filtering radio frequency interference became a huge problem. Such interference could be caused by practically any electrical device (even a simple light switch), but continuous operation devices, like computers, posed a real problem. Back then, besides radio broadcasts, many other systems operated with radio waves (railway, police, military, stock exchange systems), whose undisturbed operation was very important. Therefore, in Germany, strict regulations were already in effect in the eighties regarding the commercial distribution of such devices. Originally, the German Federal Post Office regulated this as an authority, which is why, for example, on the bottom of early C-64s, you can find the inscription Allg. Gen. n. DBP Vfg 529/70 - Allgemeine Genehmigung nach Deutsche Bundespost Verfügung 529/70, roughly meaning general approval according to the German Federal Post Office Regulation 529/70.

Allgemenie Genehmigung nach Deutsche Bundespost Verfügung 529/70
from a "breadbin" C-64

This approval, or rather its indication, roughly meant:

- The device is protected against radio interference emissions
- The manufacturer or importer reported the product's domestic (West German) distribution to the German Federal Post Office
- The Post Office was authorized to conduct subsequent inspections of the product during the distribution period

However, there was a later, stricter version of this, (Allg Gen, etc...) 1046/84. I'm not revealing a big secret that the previous one is dated 1970, the latter 1984, so it came into effect right during the not too long distribution period of the Commodore Plus/4. As a result of the tightened regulations, many Commodore computers received internal shielding plates for more definite shielding, so - aside from the fact that over the years since then, everyone has already tampered with these machines - in principle, a machine with a 529/70 inscription would have at most aluminum foil-coated cardboard under the motherboard, however, one with a 1046/84 inscription would have a proper metal plate under the motherboard, and in most cases, the motherboard would also be shielded from above. Of course, only if it was manufactured or distributed in West Germany. Originally, we see such inscriptions and shielding on every German-manufactured or distributed C128, Amiga, or C16, C64, Plus/4 manufactured from the end of 1984.

A late, cost-reduced Commodore 64C case with a baked-in "sticker," already with 1046/84 inscription

Well, our Blue Menace had some problem with this, as it seems it was made according to the stricter regulations. Without a sticker, we can't be sure, but into the brand new, streamlined, fancy case, the bottom shielding plate was inserted just as it was in the original case, along with the thin cardboard sheet serving insulation purposes. It looks something like this:

Shielding metal plate at the bottom of the motherboard on a 1046/84 marked Commodore Plus/4

Shielding metal plate at the bottom of the motherboard on a 1046/84 marked Commodore Plus/4

And here's where the problems come from. The component legs protruding from the bottom of the motherboard, left somewhat longer than factory, testify that some components had been replaced in the past. The longer legs, however, reached the insulating paper sheet belonging to the metal plate, and piercing through it, simply shorted the component legs to the shielding plate soldered to GND. After removing the plate, it turned out that I have huge luck: the short circuit didn't damage anything, in fact, it even worked to my advantage, radically reducing the potential selling price at the previous owner.

So the machine works, and it looks so crazy that I decided to keep it. Despite its bizarre appearance and the systematic banishment of ergonomics, its use is somewhat more uncomfortable than an original, "flat" Plus/4, but no worse than in the case of a breadbin C16 or C64.

Instead of the retro-pushing flat-head screws, I ordered relatively good-looking, lens-head, hex-key screws, found a handful of M3 flat washers, removed the labeling. If I can come up with a less glaringly makeshift solution for the hinge, and replace the square LED resting in a round hole with a round one plus a socket, it might not become prettier, but a kind of party atmosphere will still scream from it.

I've since cleaned the keyboard (from below, haven't done the caps yet), dusted the motherboard, and tested the machine through Datasette, 1541, 1551 lines, everything seems fine for now. I'm a bit wary of removing the heat sinks (the photographed IC fell off on its own), I'm not sure if at MOS they prepared for the selection of the IC material with cyanoacrylate in mind. Yet it would be good to at least remove it from the TED and put back the shielding-cooling cover.

Then, once the machine is assembled and has returned to civilization as much as possible starting from this point, I'll report back with it :)