Commodore 1084 monitor

Last Updated on April 26, 2023 by Dave Farquhar

The Commodore 1084 monitor was Commodore’s flagship monitor, a monitor that worked with everything they produced in the late 1980s, including the C-64, the C-128 in 40 and 80 column modes, the Amiga line, and Commodore’s CGA-equipped PC clones like the Commodore Colt. Its versatility makes it popular with retro computer enthusiasts today. Not only does it work with almost any Commodore computer, it also works with a lot of non-Commodore computers.

Commodore 1084 monitor history

Commodore was bad about playing musical chairs with its monitors. Usually it was due to someone offering a better price. Commodore introduced it in early 1988, fast on the heels of the Commodore 2002 monitor, which was the first monitor Commodore billed as a universal monitor. The Amiga 1080 monitor was just as universal, but Commodore didn’t tell anyone.

Although the pedigree of its predecessor is a bit unclear, the initial 1084 units were made by Philips. Philips sold identical-looking monitors under its own label in North America at the same time, just in colors that looked oddly VIC-like. Commodore flipped 1084 production from Philips to Daewoo and back multiple times. There are at least 13 variants of the 1084, varying just in case styling and which company made them.

The 1084 featured Analog RGB to match the Amiga’s output. However, it also worked with digital RGB like IBM CGA and the Commodore 128’s 80-column display, and composite video like the C-64. It was a universal monitor that worked with every computer Commodore made at the time. The 1084 works well with all Commodore computers, and even with many non-Commodore computers, including the Apple IIgs and Atari ST. It’s also a popular choice for the Tandy 1000. Its .42mm dot pitch gives a clearer display than the Tandy CM-5 monitor did.

The 1084 line was one of Commodore’s longer-lived, as monitors go. I think Commodore learned their lesson from the 2002 confusion. Even as Commodore changed suppliers, Commodore kept the name the same. The case styling and even the color changed, but the badge and the box still said 1084.

Pricing could vary, but Tenex Computer Express advertised the 1084S for $319 in its winter 1991 catalog. The non-S versions tended to sell for closer to $300.

Distinguishing between the Philips and Daewoo-built Commodore 1084 and 1084S

The Philips versions of the Commodore 1084 and 1084S monitor typically have the power LED in the power switch. Daewoo versions of the Commodore 1084 and 1084S monitor have the LED above the power switch. Early Daewoo 1084 and 1084S monitors look suspiciously like the earlier 1080 and 2002 monitors. Later Daewoo units took on a modernized appearance, but are still less boxy than the Philips versions.

Most of the later monitors have extra letters and numbers in the name on the label in the back. If there’s a P somewhere in the name, it’s a Philips. If there’s a D somewhere in the name, it’s a Daewoo.

Unfortunately, the differences aren’t just cosmetic. Functionally the monitors are equivalent, except for the very late cost-reduced models that omit digital/TTL RGB. But they have different RGB connectors, so a cable for a Philips monitor usually doesn’t work with a Daewoo. Generally, the Daewoo versions use a 9-pin connector while Philips versions use DIN connectors. Pinouts for both are at the end of this blog post.

The monitor doors can break off either unit but seem especially prone on the Philips units. I think part of it is because the composite/RGB switch was behind the door, so C-128 owners were opening and closing the door every time they switched between 40 and 80 column mode. 3D printed replacements turn up on Ebay fairly regularly. If you have the door but its hinges are broken, replacement hinges are also available. The replacements are usually whiter than the monitor’s original color, but I still think a mismatched door looks better than a missing one. If you want to paint it, an almond-colored spray paint is likely your best bet.

Compatibility

The composite connector on the 1084 works with the Commodore 64 and VIC-20 and the C-128 in 40-column mode. It will also work with non-Commodore computers with composite outputs, such as the Apple II and Atari 8-bits, with the appropriate cable. There’s a button to switch between composite and RGB. Depending on the model, it can be in the front next to the volume control, or in the back next to the monitor jacks. There’s also a switch on the back to switch between standard and separated composite. Separated composite is a boon for the 64/128 and Atari 8-bits.

In analog RGB mode, the 1084 works with the Amiga and other computers that use analog RGB with a 15 KHz signal, such as an Atari ST or Apple IIgs. It will not work with VGA, which I learned the hard way in the 90s.

The RGB connector will work with the Commodore 128 in 80-column mode, and IBM compatibles with CGA or Tandy graphics, when you put the monitor in digital mode using the switch on the back next to the video connector to pick digital or TTL RGB. It’s a nice match for a Tandy 1000, as most CGA-compatible monitors lack a speaker.

Caveats with the late-model Commodore 1084 and 1084S monitors

Some very late 1084s, made after Commodore had discontinued the 128 and the PC compatibles with CGA, omitted the digital RGB. These generally were made in 1992 or later and the design tends to look newer. The color matches the Amiga 600, 1200 and 4000 rather than the Amiga 500 and C-128, and the styling is more 90s-like than 80s-like.

If you intend to use these with a Commodore 128 or any kind of PC, examine it closely. It would be really unfortunate for you to spend hundreds of dollars on a monitor only to find out you can’t use it how you intended.

When digital doesn’t mean what you think it means

Also, despite the name, digital RGB isn’t compatible with modern digital connections like DVI or HDMI, so you can’t connect a DVD player to it using the digital RGB connector. They’re both digital, but that doesn’t mean they’re compatible. This has been a source of confusion on vintage computer forums from time to time. To use a DVD player or 21st-century game console with it, you have to use its composite connectors.

This is the same reason you can’t just plug a C-128 or Tandy 1000 into a cheap HDMI TV with a $6 cable.

Disadvantages of the Commodore 1084 monitor

From what I understand, the Philips-made 1084 is easy to fix. It’s the monitor I had growing up, and I can attest mine broke a lot. So how hard it is to fix ought to be pretty well known. And let’s be fair. These days, any RGB monitor is going to be prone to break down, so you might as well go with one that’s easy to fix.

The flyback transformer on the 1084 wasn’t very reliable, and tended to give out after 2-3 years. And the monitor seems especially prone to developing broken solder joints. The symptoms are snaps and pops, followed by the tube going dark. It comes back if you slap the left side of the monitor. As you can imagine, slapping the side of the monitor doesn’t improve those failing solder joints. It’s the Commodore equivalent of blowing into a Nintendo cartridge.

It’s no 1702.

Now that I’ve had a chance to compare a 1084 side by side with the 1080, the 1080’s picture quality is a bit sharper, and has better contrast than the 1084. The glossy display on the 1084 detracts from it a bit. The 1084 isn’t terrible, but I like the 1080 better.

The power switch is also prone to fail. Ultimately that was why I got rid of my original 1084. The switch broke and the remaining repair shops couldn’t get another one.

Commodore 1084S monitor

The 1084S is a version of the 1084 with stereo speakers. Over time the 1084 got harder to find, but it’s unclear whether Commodore sold the two side by side or intended to phase out the 1084 in favor of the 1084S. The only difference between them is the 1084S had two speakers, and therefore, two speaker inputs, to accommodate the Amiga’s stereo sound. This makes a 1084S a better match for an Amiga than any earlier Commodore monitor.

The extra speaker just added unnecessary cost for owners of 64s and 128s, which didn’t have stereo sound except for the couple thousand units that ended up with a stereo SID mod, and for Commodore PCs, which didn’t have sound outputs at all.

Both Philips and Daewoo manufactured 1084S monitors for Commodore. There are variants of each style, in both mono and stereo varieties. Near the very end of Commodore, it appears Commodore was also sourcing 1084s from Likom, using tubes from both Philips and Hitachi.

Commodore 1084 and 1084S monitor pinouts

RGB cables for the 1084 tend to be in short supply. Here are the pinouts if you need to make your own.

If you’re soldering up a cable like I did, reverse the connections. I cheated and marked the connections on my connector as I soldered them.

Daewoo version (same as Amiga 1080)

This is the view from the back of the monitor.

Philips version

The Philips version has separate digital and analog RGB connections. This is the view from the back of the monitor of the digital RGB connector. This connector, incidentally, is the same as on the Taxan RGB Vision III monitor. The analog RGB connector and pinout follow.

Here is the view of the analog RGB connector, from the back of the monitor.