Originally Posted by unitron
If it's an old style monitor, with a picture tube that has to warm up that makes the back of the monitor stick out and makes the whole thing very heavy, then it's probably too old to have gotten any of the "capacitor plague" capacitors when they built it, and whatever's wrong will be much more difficult to figure out and fix.
But if it's a flat panel LCD monitor made from the mid '90s on, there's a very good chance that if it up and quits powering on, it's the same reason and solution as with your TiVo power supply.
I've found bulged caps on old CRT TVs and monitors. Often it's just one cap, in the power-on relay circuit, where the cheapest and least reliable cap was used, likely to save money.
I've also had monitors that refused to resume from standby, but would power-on if the power was pulled and restored. Same thing.
I've also had a variety of devices that could only be powered-on by a remote. Same thing, bad cap in the circuit that receives the signal, and triggers a relay.
Like I said, I could spend a day listing every scenario where one single cap was responsible for something being completely unable to power on, was hit-and-miss, or was otherwise not operating properly.
In many/most of these cases, it was the only cap of that brand in the whole TV, and/or the only cap in the circuit involved.
Big shock (sarcasm) that these brand caps I replaced were later the top offenders in more modern equipment as being "known to be suspect".
In power supplies, it's never a good idea to only replace the caps that have visible signs. The rest have to pick up the slack, and will be stressed by doing so. This includes caps on other voltage rails, and ones upstream and downstream, in the circuits. Usually, with power supplies, the only one I don't mess with, unless it's easy to source and reasonably priced, is the very high voltage one(s) on the voltage doubling/tripling switching transistor(s). If a switching transistor fails, then it's a good idea to replace the transistor and the very high voltage caps (while taking proper safety precautions).