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You seem to have sufficient horizontal deflection, but vertical deflection is wonky. I'm not sure I fully understand the history you provided -- are all the components from the Classic II, or is there now a hybrid of SE/30 and Classic II bits? The reason I ask is that the deflection yoke (the...

Some models will not start up if the PRAM battery isn't healthy, so you might want to check that first. In many cases, a completely dead battery will enable startup, but a kinda sorta dead one will prevent startup. If you don't have a voltmeter handy, just try removing the battery altogether and...

You may want to check out some of the troubleshooting hints in the doc found at http://68kmla.org/files. Before twiddling voltages, it's critically important to clean contacts and touch up some solder joints (see doc for details). If you don't do that first, you may permanently damage your Plus...

That sounds like a good thing to try, I agree. Thanks for the suggestion.

The symptoms are hard to reconcile with the "bad polarizing film" theory. The darkening worsens as the thing operates. But if you turn off the computer and let it sit, the LCD often looks fine the next time you turn it on, and then degrades again over a tens-of-minutes time frame (typically). In...

From what I understand, the "progressively darkening corners" problem is due to poor edge seals, allowing moisture to contaminate the liquid crystal. This phenomenon first showed up in the active-matrix 1xx Powerbook series. Allegedly, the damage is somewhat reversible by doing a long...

I have burned many discs with my SE/30 running Toast 3.5.x. I recall finding it difficult to get reliable burns at 2x, so my default was 1x. IIRC, Toast required an '020 or higher, so the first generation of compacts is unfortunately out of the running. But being able to burn with, say, an LC is...

See http://lowendmac.com/tech/crt_danger.html Short version: If the ac cord is unplugged, danger of lethal harm from a compact mac's crt is extremely low. It's not so much volts or amps, it's a function of the energy delivered to your delicate parts. And that energy is not high.

You earlier asked about whether you should use a dedicated 10Mb/s hub to act as a go-between. That might solve your problem; autosensing/autoswitching might not work so well with that old converter. Give it a shot and report back. Good luck!

If the screen is bright, has good contrast but is blurry, it generally means that there is either a simple focus problem, or the brightness is simply cranked up too high. If the blurriness is actually jitter, that's often a symptom of capacitor-related problems, or loose connections. Both of...

Well, I can invent scenarios that could explain the observations; whether they're correct is a different matter altogether. :) For example, suppose these DRAMs aren't truly hermetic. Over time, moisture could seep in and corrode things (say, a bond wire or bondpad). Or if gold bondwires were...

Very interesting about the Apple-branded DRAMs exhibiting unusually high incidence of bit rot. I've not seen that myself, but your data certainly trumps my non-data. :) I'm just trying to figure out how two could fail together (assuming that this is what happened), or what type of failure of...

First, carefully double-check your repair. Use plenty of light and a magnifying glass, as well as an ohmmeter as necessary. Also, what is pin 1 of the DRAMs connected to (I haven't looked at my 128K schematic and I don't remember the answer off the top of my head)? If it's floating, I...

Switchers can certainly be twitchy beasts, can't they? Congratulations on figuring out the Zenith problem -- that's some mighty fine troubleshootin', my friend. I once came across a problem that was the inverse of yours -- a prototype supply worked great with cheap caps, and the company went...

I don't know offhand what C6 is connected to, but if it's just a power supply bypass cap, it only needs a voltage rating "sufficiently beyond" the nominal supply voltage. A 50% buffer is fine. So, if it's across a 12V supply, a 20V rating is plenty. If there are spikes large enough to take out...

The suggestion by applefreak to move chips around is an excellent one. The power-on diagnostic routines are not comprehensive, so a "memory error" indication might actually be due to, say, a decoder failure. If the problem does not move with the chip, the memory chip is probably ok. If the...

Before plugging the thing into the wall again, perform a few simple checks with an ohmmeter first. It sounds as if you have a short circuit somewhere. Those are usually very easy to find (unless they're intermittent). If you do find that a short exists, you can narrow down the possibilities by...

It's best to keep the deflection yoke with its original analog board if one is unsure of compatibility. The only problem arises when transplanting between Classics and the compacts that preceded them. Within Classics or within the other compacts, the yoke can be kept on the crt and the pair...

;)

It depends very much on the skills of the operator. An unskilled tech is likely to cause more damage, so that's the basis for my recommendation. Btw, carbon is not the usual problem. It's a simple cleaving along grain boundaries in the solder, plus a bit of oxidation at the interfaces...