Quote:
Originally Posted by Maarten
I'm not surprised the TDA8351 failed. They are run very near their maximum ratings (in some sets from Vestel and Grundig, they even failed routinely. .
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Many might not share my opinion on this whinge, but I think one of the worst things to happen to CRT based TV's and monitors was the incorporation of IC based vertical deflection systems. They were so much better when the output amplifier was based on discrete components. The heat was not localized in one place. They were easier to repair and adjust and often had better linearity control options.
One good example would be the design of IBM's 5153 color monitor, that had a beautiful vertical output system based on a discrete transistor amplifier. In the 5154 EGA monitor (the new superior dual standard CGA/EGA monitor) they changed that for a compact vertical deflection IC. This IC totally roasts the phenolic pcb around it to carbon and dries out the electrolytic caps that were placed near it.
I decided in the end that the only way to get the quality was to make the early and better CGA monitor scan convert from 15.75 Khz to 21.85Khz, so I managed that, there is an article here :
http://www.worldphaco.com/uploads/IN...OR_TO_AUTO.pdf
In NZ in the late 70's, color TV's were introduced using Philips IC's, including a vertical scan output IC, they were the leading cause of vertical scan failure at that time, it was always without exception a thermal/dissipation issue. So I guess that could be blamed on inadequate heat sinking.
I'm sure the audio enthusiasts felt the same when many audio amps went away from discrete transistors and became IC based with a similar set of issues.