I have an Apple II power supply with an early serial number that i'm looking to refurbish.. I know ReactiveMicro sells repair services ($90)..
1) Is it worth it?
2) Is this something I could generally do myself with a soldering iron and multimeter?
Diagnosing switching power supply issues can be challenging, because of two reasons. Firstly, if the PSU runs off line voltage, it has areas that are dangerous if touched, even after power is removed. Second, a switching supply relies on analog behavior of many parts that feed back into one another so that it can be hard to isolate which component is the cause of the problem.
A digital multimeter (DMM) would be usable for non-operating tests with capacitors discharged. In particular, the diode mode is very useful for finding failed transistors or diodes. But the tool is pretty limited for these types of problems, for instance, if you probe two points of the circuit while it is operating, a DMM can only give you a numeric measurement of voltage, it cannot show the waveshape which is often important. As for your soldering iron, there are components on PSUs that require a lot of heat to rework, which can be a special task in itself.
If you can use a soldering iron at all, your skills are good enough to install the ReActive replacement yourself. And personally, I say it's worth it. The kit fits into the original metal enclosusre in your system so I see little reason not to just replace the whole PCB. On some machines where it's hard to fit a modern replacement I'm more keen to recap and spend time servicing the stock PSU, but, the original Apple II power supplies aren't rated for a ton of current on the expansion slots anyway. Factor that in with hours spent, and IMHO, the reactive kit is a better use of your time and money and also more likely to reliably power your machine for a long time.
I have installed the ReActive kit myself into an IIgs and IIe and it's been working great. The IIe has a card in literally every slot, and the IIgs is close.
I believe ReActive Micro's "service" involves swapping out the circuit board inside the power supply with their new one. While this is a great repair for a non-collectible unit, I wouldn't recommend it for an early low serial # Apple II. You want to keep that as original as possible. That means replacing only the components that are actually bad. That's a lot more difficult and probaly more expensive due to labor costs even though it requires less parts. But it will preserve the value.
For machines that are cheap and plentiful like //e and IIgs I'd agree... But few people are going to load up an early ][ with cards and use it hard. As I said in my previous post... the ReActive Micro replacement is great for what it is... but unless you want to drop the value of a collectible machine down a lot... not good for that.
I suppose for something early/rare I can agree, but soley from a financial standpoint, which isn't really how I view the hobby. I'm not out here to devalue anything, when I do work I do it well. But I do not dictate my decision to install a proper power supply from a recent decade on someone else's view of the machines resale value.
I tend to use my machines, and many expansion cards are irreplaceable or valuable too, so a reliable power supply within the original enclosure raises the value of pretty much any machine I would buy. But that does fall mostly under the "common" ones mentioned (IIgs / IIe).
I must have skimmed the serial initially, I mainly made my post just saying that the ReActive replacement is easy if you want to do it. But for something like this I can certainly see preserving the PCB too and not gutting the PSU enclosure.
A good compromise would be to buy a totally other power supply and use that one and keep the original one unmolested or just restored to working oerder.
More expensive option -- but it preserves the value of the machine while letting it be used more fully.
I'd buy the ReActive Micro universal power supply kit and be happy that it is new, quiet and noise-free, and reliable.
Once you install that in place of your original power supply's circuit board you will never know that a modern power supply is inside the case.
My 2¢ worth ...
I've used the $10 capacitor kit from Console5 to replace all the electrolytics and the RIFA .... took several resolderings for everything to work right, but then you've still got all those older components.
The $70 replacement power supply kit is a piece of cake. They have made it quite easy now. Everything you need.
I've taken to getting the $36 basic power supply. It's an easy job, if your handy. I cut/drill a piece of plexiglass and mount the board with standoffs and a piece of flashing beneath so that all four corners of the PS are grounded together with the case. No extra wire needed; no soldering; all new parts. I posted my results on the Apple II Restoration and Preservation Facebook page.
My opinion is that if the power supply is working, then replacing the safety caps and the electrolytic caps is possibly a good idea. However, the problem with this will always be doubt. If something goes wrong with the computer, then the problem possibly coming from the power supply will always be nagging you.
The only power supplies that I found success with were NOS WMP-302 power supplies. They were marketed by Applied Engineering back in the day as being a heavy duty power supply. In actuality they were built in a foreign country and Applied Engineering simply put their name on them and sold them for a profit. While it may seem to be a shady business practice, the power supply is really good.
I also have a liking for the AE power supplies
A couple of years ago I wondered how close my power supplies were to +- 5 & 12 volt. I tested a number of Apple and aftermarket power supplies and the AE ones were closest to being dead on. I know it doesn't have to be but it's nice when it is
AE wasn't the only company that imported those same power supplies. I have one in my original //e from back in the day that I bought mail order. It is basically identical in virtually every marking to the ones AE sold except for it has a different brand name on the sticker.
And yes, it never struggled even with a very loaded machine... full RAMWorks II card, Transwarp, etc.
I have a 3 digit serial number original Apple ][. I chose to replace the guts of the power supply with a Reactive Micro because I wanted the best, most stable power for the rest of the system. It is fairly loaded with a true Apple Language Card with Applesoft ROMs in slot 0, If flakey power cost me that card or corrupted the Integer ROMS on the motherboard, I'd be really, really unhappy. Stable power is a good thing. Slot 1 contains a SilenType card, slot #2 has a serial card, Videx 80 column in slot 3 and a Disk ][ controller in slot #6. I had a Z-80 in slot 4 before it died. That was enough load to not trust the original PS. Even though we tend to think about the oldest Apples being relatively simple, we still tend to load them up a bit. But, I'm more of an "authentic use preservationist" so I also wanted to keep it original. So I rebuilt the original PS with a Console5 cap kit and keep it in a box. If I ever want to go back to pure original, I can do it in 10 minutes. Did I mention "Stable power is a good thing."