paul
Veteran Member
Andrew, as you would also expect the only difference at 230VAC would be the additional heat produced by the snubber circuit, the power resistors near the main switching transistor. Once you complete that testing, and furthermore decide to use it, my suggestion would be to reinstall the PS without the aluminium cover. I tried this and it did not affect the CRT image yet allows a lot better air flow. Still, the 5153 main enclosure is poorly vented itself at the underside.
You can just imagine that the PS designer at Tatung, assigned to the IBM contract, tested their masterpiece on the workbench, open to the air, and proudly dubbed it "job-done." Nek-min, handed over to the packaging engineer, it's in a metal box with almost no air flow. All these PS PCBs get burnt around the driver area, the 230VAC version twice as badly as the 120VAC. Considering it was produced near the same time as IBM's 5150 PS, it's not nearly as sophisticated.
You can just imagine that the PS designer at Tatung, assigned to the IBM contract, tested their masterpiece on the workbench, open to the air, and proudly dubbed it "job-done." Nek-min, handed over to the packaging engineer, it's in a metal box with almost no air flow. All these PS PCBs get burnt around the driver area, the 230VAC version twice as badly as the 120VAC. Considering it was produced near the same time as IBM's 5150 PS, it's not nearly as sophisticated.