Insignia IS-CM100751

I have a number of filters set up on eBay to alert me when deals on CRT screens show up. Most of these usually amount to nothing, but this Insignia monitor looked really promising. It's a 19" monitor supporting resolutions of up to 1600x1200 at 60Hz. Also, the monitor had a manufacture date of 2005, which is very recent for a CRT monitor. A newer build generally indicates better quality and a more robust feature set, along with less runtime (meaning I can get more use out of it before the inevitable cathode poisoning sets in).

The pictures looked good, the seller had very high positive feedback, so I went ahead with the order. However, when the monitor showed up, it didn't work! Now, keep in mind this monitor was listed as working, and shown as working in the pictures - I would have been within my rights to simply return the monitor. But that didn't feel fair to me, since the seller would have been stuck with $65+ in shipping and another $65 for return shipping (assuming they wanted the monitor back). So, I decided to reach out to the seller first. They were very responsive, and they did offer a refund after I explained the situation. Instead of taking that refund, I first offered to attempt a repair (with the understanding that I would still have the option to return the monitor if the repair was unsuccessful). The seller agreed, so I cracked open the monitor!

A partially disassembled Insignia monitor. The outer shell has been removed, and the internals are visible. The primary focus is the back of the picture tube and the numerous grounding wires and plates covering the electronics.

I removed the monitor's outer housing, and found it surprisingly clean inside. The monitor was obviously used in a pretty clean environment, likely an office or similar indoor space. The design is fairly typical for a CRT display: main board on the bottom, and a CRT tube with a smaller neck board suspended from the back. One feature I did find odd were the sheer number of grounding elements. This monitor has shields on the neck board, over the thin section of the tube, and around some of the major electronic components on the main board, along with what seemed like a hundred grounding wires connecting everything. Most displays I've worked on only have a few such grounding wires, and maybe a shield around the neck board.

A partially disassembled Insignia monitor, laying screen-down on a desk. From this angle the CRT neck is visible, along with the numerous windings used to control the image.

When I first turned the monitor on, I had a power LED and degauss, but no image, static feeling on the screen, or transformer whine (somehow my hearing is still good enough to pick that up). Based on those characteristics, I assumed the issue was with the flyback transfomer itself or the power supply to the flyback. I attempted to discharge the monitor, and there was no stored charge. This further confirmed the bad flyback transformer/power supply problem. From here, I removed the main board from the monitor. This was a hugely involved process due to the number of grounds and other connections; I spent about an hour on this step. Unfortunately manuals can be difficult to find for older hardware like this, so I took a lot of pictures and went slowly to ensure I didn't damage anything further.

Closeup of a CRT control board, with damage visible around a mounting hole. The board is cracked, although it's hard to tell from this angle how far the cracks run since components are in the way.

Ahh, but what's this? Looks like some damage to the main board. The hole in the center of the image is used for mounting, along with more holes along the periphery. My guess is that the board was already cracked, and (despite being well packaged) the stress of shipping, elevation/temperature changes, or all three finally caused the board to split badly enough to interrupt at least one trace and render the board only partially operable (remember, the power LED and degauss worked at this point). Unfortunately it was hard to tell exactly what areas were affected from this angle, because there are some large components in the way. To determine the extent of the damage and figure out if a repair was possible, I had to completely remove the board.

Closeup of a CRT control board, with damage visible around a mounting hole. The board is cracked in three directions radiating out from this mounting hole, with cracks through numerous traces.

Here we can see the underside of the board. The cracking was a lot worse than I expected, with numerous traces interrupted (I believe I counted 22 or 24 traces which were broken). The good news is that the board was otherwise intact; most of the damage was localized in this area. Also, the board is single layer with through-mount components, meaning it was possible to repair with my skills and the tools I have on hand. I originally contemplated grinding out each broken trace and reconnecting them, but a number of these traces were very fine. My hand-eye coordination is pretty good, but I was worried I might make things worse on the more delicate traces and trash the board altogether. So, I decided to find the start and end points of each trace and solder in wires between those components. Basically, forming a "bridge" between the components directly, completely removing the traces from the circuit.

And here's the final result! I used some 18ga stranded wire that I had laying around, and a standard soldering iron. The board was clean enough that I didn't need to do much prep; I just measured between each component and cut the wire to length. The results aren't super pretty, but this section of the board is completely hidden even with the monitor housing removed so I wasn't concerned about aesthetics much. This repair process took about two hours total, which I split up over multiple 30-40 minute sessions (whenever I noticed any fatigue in my hands/wrists/eyes, I put the tools down and took a break for awhile).

Reassembly was a bit faster, since I had a good sense for how the monitor fit together. I probably spent about 30 minutes putting everything back together with the exception of the outer housing. Moment of truth...

CRT monitor showing the display settings menu for Linux Mint running the Cinnamon Desktop environment. The monitor's current settings are for 1600x1200 at 60Hz, which is impressive for a CRT display.

It works! My first attempt at the repair yielded outstanding results. Note the image is a little fuzzy here; the flyback transformer's focus potentiometers were either out of adjustment or I bumped them during disassembly/reassembly. That's why I left the housing off; there are a few fine adjustments which are often necessary after servicing a display like this. I tweaked the potentiometers a bit, and the focus fell right into line. I also dialed the brightness down a bit, to help extend the life of the monitor (maximum brightness using the front controls is now about 85-90% of the previous maximum brightness).

CRT monitor alongside an older laptop and a drawing tablet. Each screen is displaying the same background image; the monitor at 1600x1200, the laptop and tablet at 1920x1080. Some color differences are noticeable, and the montior has a small black area at the bottom due to the refresh rate syncing up poorly with the camera

Here's the final result. It's always difficult to photograph a CRT display, and this one is no different; but believe me, it's extremely sharp for a CRT. There are some slight color differences between the laptop and tablet displays and the CRT monitor, but I'm not terribly concerned about that (I typically only use one at a time, and the monitor will be primarily for retro PC gaming). Still, I may try to make some color adjustments further down the road. The monitor geometry is spot-on after a few adjustments using the front controls, and I'm very happy with how this turned out. Oh, and the eBay seller is as well! I kept them updated on my progress, and they were fascinated by the repair process.