Compact Mac & Heat

[Mac128]

I was just watching my 1985 10" Sony Trinitron TV, realizing it was going to be obsolete soon when the US goes digital. When I realized it is about the same size and shape as my Mac Plus. I felt the top of it and sure enough it was pretty darn warm. At least as warm as my Plus.

So that got me thinking. This little TV has been in constant use for almost 23 years, many more hours than my Mac Plus ever saw. And, it has never needed a single repair!

Does the Mac Plus run that much hotter than this little TV? Or was the original design so underpowered that it was not as robust as even my little TV? Why were the failure rates of the early compacts analogue boards so much higher than that of a similarly constructed TV? The venting scheme is about the same. A quick hand test confirms that after several hours the TV and Mac Plus feels about the same temperature from the top vent.

So did Apple really fail to design the compact up to the standards of television sets of the day, or does the logic-board add significantly to power consumption and heat production over a TV set, which could not be adequately compensated for in such a compact design?

 

[tomlee59]

All good questions. In my not-humble opinion, the components on the analog board were selected at the lower end of the "acceptable" range. The voltage, power and temperature ratings of critical capacitors and diodes were marginal (with the infamous C1 simply being "wrong" altogether), the original flyback was barely adequate, and the heatsinking of several components was also on the light side. It's all a judgment call, of course, and mine is predicated on the assumption that the goal is to design a long-lasting, reliable product. However, one could argue that it was only necessary for Apple to design a product that would generally last well past the warranty period. Given that criterion, Apple arguably succeeded, and your television was overdesigned.

De gustibus...

 

[porter]

your television was overdesigned

That's the difference between engineers and accountants, engineers have more tolerance.

 

[Scott Baret]

I have a Sony Solid State (pre-Trinitron) from 1972 that still works fine. I actually played a game of Madden on it last year, hooking my GameCube up via RF modulation. It's a 10" monochrome display unit that overall is about as large a Mac LC with a 12" monitor on top of it.

I think the older electronics were better designed and I do believe the TVs were designed with constant use in mind. When Macs first came out in 1984 they were more of a novelty item, not something that would be running from 8AM until 5PM.

 

[trag]

(with the infamous C1 simply being "wrong" altogether)De gustibus...

Tomlee, what do you recommend for C1? I think I saw something somewhere once about it, but I have no clear memory of where or in what format. Was it an arrangement of ceramic caps in parallel? That's what my really vague memory is trying to extrude into my consciousness.

 

[JDW]

your television was overdesigned

I myself would prefer to say, "designed well."

That's the difference between engineers and accountants, engineers have more tolerance.

As an engineer, I have zero tolerance for bad designs.

So the question now becomes, did Apple's engineers select low end parts, or did they try to use good parts but got the thumbs down from upper management?

 

[porter]

When Macs first came out in 1984 they were more of a novelty item, not something that would be running from 8AM until 5PM.

No, they were intended to be used, but designed to a price.

 

[Christopher]

Most CRT TV's have venting to the max, so it has better air circulation. I have this 1992 Sylvania 20" and it works just fine, however I think it's going soon since the sharpness seems to be loosing it, like it has a person showing, and while they are moving you see bars going horizontal around it. It's faint but it still annoys me.

 

[JDW]

Mac128 is certainly no fool. If there was excessive venting atop his Sony, he would have certainly noted that and logically deduced such would cool his TV more than a compact Mac. My guess here is that his TV has the same or less venting than a Mac Plus.