Expected behavior for Mac Classic when power applied?

It is a long time since I've actually used a _working_ Mac Classic (I'm a Plus/SE guy), but I'm trying to see if I can get one of mine operational. This one has no visible electrolyte leakage, solder joints look good, and the battery was deleted long before it could cause any problems. Very clean machine internally.

Can someone remind me what the expected behavior is when I plug in the power and turn on the physical power switch? My recollection is that it should start the fan (only), and that the HDD should spin up only at the same time as I hear the chime, when I press the power button on an attached ADB keyboard.

Right now this unit is spinning up both the fan and HDD as soon as I turn on the power switch. I see the CRT heater glowing also, but don't hear the h-sync (might just be my old ears, I can only JUST hear NTSC and the Classic is higher frequency ). Nothing happens when I press the power button on the keyboard. I've also tried pressing Cmd-Opt-PR immediately after the power button, and nothing happens there either even if I wait for a minute.

Haven't scoped the power lines for noise yet. Don't really want to recap this machine but if it's what I gotta do it's what I gotta do... but it really does look pristine inside. Sigh. Time to dig out the ol'd SMD electro kit I guess.

I have 2x Macintosh Classic II. Both of these units power on immediately via the rear switch. I flip the switch and hear the fan, HDD spin and chime within a couple of seconds. The power button on the keyboard seemingly has no effect on my machines. From my perspective, the Classic II operates like an SE in terms of power behavior. (I assume that the Classic would be similar as the Classic II).

funkytoad said:

I have 2x Macintosh Classic II. Both of these units power on immediately via the rear switch. I flip the switch and hear the fan, HDD spin and chime within a couple of seconds. The power button on the keyboard seemingly has no effect on my machines. From my perspective, the Classic II operates like an SE in terms of power behavior. (I assume that the Classic would be similar as the Classic II).

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Thanks! It's been a long time for me Sigh. Guess I need to really get into troubleshooting this machine rather than phoning it in.

why are you attempting to test a mac classic that has not been recapped?

the expected behaviour of a mac classic that has not been properly recap is for it NOT to behave.

finkmac said:

why are you attempting to test a mac classic that has not been recapped?

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Because I am lazy. I am well, well aware that every single Classic and Classic II I've powered up in the last several years has required at minimum digital board recapping. But I live in eternal hope. And, like I said, I'm lazy.

powering up known-bad power supplies and logic boards is a good way to end up with MORE work to do

finkmac said:

powering up known-bad power supplies and logic boards is a good way to end up with MORE work to do

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Given the sources of these machines, it has already been done by hopeful sellers before me. And I rarely experience issues with the SEs and Pluses apart from the usual solder joint issues.

yeah but this isn't an SE or Plus. it's a classic.

Yeah the classic AB and LB are both optimised for cost, it's much cheaper-and-nastier than the SE AB. It's not surprising that it doesn't work. In my experience the odds are middling-high that the LB is buggered if it hasn't been recapped and cleaned by this point, but it's worth a try...

finkmac said:

yeah but this isn't an SE or Plus. it's a classic.

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And when I bought it it already had notes on it about what it did on powerup, so after I cleaned the digital board with IPA and deoxit'd the sockets, I had very little, if anything, to lose by applying power.

HI All,
The classic is turned on only from the off/on button on the back of the case, the classic color model has soft power on the keyboard.

cheesestraws said:

Yeah the classic AB and LB are both optimised for cost, it's much cheaper-and-nastier than the SE AB. It's not surprising that it doesn't work. In my experience the odds are middling-high that the LB is buggered if it hasn't been recapped and cleaned by this point, but it's worth a try...

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Ah well, it's okay as a project machine (I probably have 10 such project machines - Classic/Classic II were never my thing - but this one is the cleanest). I'll nibble through it and see if I can get it working, especially since I have so many donors that could supply an organ or two. The analog board appears to be providing stable and sane voltages, at least. I am moderately optimistic that it's just capacitor plague - wish I had a working board to swap into it to verify that, but ALL my classic/ii boards are nonbooting.

Cost optimization (eyeroll). I've worked in consumer electronics and in the toy industry. I remember I was working for Little Tikes during the time of an oil price spike, so their big cost optimization project was to see how much sawdust they could mix into the resin and still have their outdoor toys strong enough to sit on. Reminded me of how my grandma (who was in Germany during the war) used to talk about how they made bread out of sawdust. Also at that job I learned that the main reason Walmart has toys in "exclusive" colors is that some of the pigment powders are much more expensive, so when Walmart says "We'll only pay $1 for that blue toy" they get it in orange because orange powder is cheaper than blue powder. And it's a fainter color because they put less pigment in per pound of resin beads, to save more money.

One of the specific optimizations I made while working in the toy industry was to take a capacitor out of a certain toy and replace it with a resistor [this wasn't simply swap a C for an R, I changed the circuit a little so the C wasn't needed]. That saved 0.0002 per unit. But we found out that it made the toy susceptible to getting triggered by static discharges while it was in its blister pack, which would have worn out the battery between factory and shelf. So we removed the blister pack and put it in plain cardboard packaging, which saved 0.03 or 0.04 per unit, something like that.

I also worked for Honeywell's security division for several years, and I spent about two years redoing a group of products that used COP8 micros to use the NEC 78K0 series. Absolutely goddamn horrible development systems and the chips were only really understood by five guys in Japan, so eventually we gave up on those and I designed in an Atmel ATmega. BOM cost reduced by $5 or more, and I got the code ported from COP to AVR in just a couple months. Love the AVR so much.

Well that was a diversion. Sorry. I'm trying to avoid going back to my work email, which I can see dinging at me

larwe said:

their big cost optimization project was to see how much sawdust they could mix into the resin and still have their outdoor toys strong enough to sit on.

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this same process may account for the classic PCBs, to be brutally honest: sawdust being a major component would account for a certain amount