I had a stack of old CRTs taking up space, so I went through six of them to see which ones were worth keeping and which ones were headed to e-waste. The first one on the bench was a Sanyo VM 4509, the smaller companion to the VM 4512 I’d used before. Its power cord had been cut, so I opened it up, checked the fuse, found the power connections on the board, and soldered in a replacement cord after a quick visual inspection.
Once that was done, I cleaned the case up and tested it alongside the larger Sanyo by daisy chaining the video connections. The VM 4509 came right up and looked great with the Apple-1 output. Side by side, the two monitors matched nicely, and the smaller one looked like a better fit for sitting on top of the Apple-1 case.
The next composite monitor was a small generic CCTV unit with no useful manufacturer information on it, just a piece of tape marked “good.” I used an Apple IIc and a couple of monitor test programs to check it over. After adjusting the front panel brightness and contrast, the picture cleaned up well, and the diagnostic patterns showed a solid image with only a slight skew near the top.
I also tried 80-column output on that little black and white monitor, and it was still readable from a few feet away. It wasn’t something I’d want to stare at all day, but it worked well and displayed both text and graphics cleanly enough. That one stayed in the keep pile too.
The HP 35731A was a green phosphor terminal monitor with a swivel base and tilt mechanism, plus a keyboard port, speaker connection, and composite video input on the back. When I powered it up, the screen showed repeating patterns instead of a stable image. I pulled the case apart, found the internal adjustments, and was able to improve it by tweaking the horizontal hold, but I never got it fully locked in.
Inside, nothing obvious had failed, and the monitor still seemed close enough to working that I didn’t want to scrap it yet. I left that one unresolved for now. There was also a very short cutaway with the Penny Cam before I got into the next IBM display.
The IBM 15V, model 6325-001 from February 1994, looked promising at first, but the power light came on and immediately went back off. Getting the case open took far longer than expected because of hidden tabs along the top edge. Once inside, I checked the power section, removed a RIFA suppression capacitor that measured 57 ohms in circuit, and tested it out of circuit where it measured in the megaohm range, but removing it didn’t change the behavior and the monitor still shut right back down.
A generic RIC VGA monitor from May 2000 did much better. It powered up cleanly, accepted 1024×768 from the test laptop, and produced a usable image, though I noticed some flicker and a slightly dim picture. The big IBM G94 from April 1998 was the standout of the bunch. It weighed in at 55 pounds, came up with a healthy degauss thump, synced properly after a reset, and looked sharp and vivid on both a modern laptop and an HP OmniBook 800CT, with only some minor horizontal artifacts still visible on bright areas.
In the end, the Sanyo VM 4509, the generic CCTV monitor, the generic RIC VGA display, and the IBM G94 all worked well enough to keep. The IBM 15V went to e-waste, and the HP 35731A stayed on the maybe-fix-later pile.
— Aaron
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Timestamps
00:00 – Intro
00:59 – Sanyo VM 4509
03:41 – Generic CCTV
09:38 – HP 35731A
15:42 – PENNY CAM
16:09 – IBM 15V
23:02 – Generic VGA
25:16 – IBM G94
35:07 – Wrap Up