Yes and that's your problem mate! I forget the value, but it definitely needs to be in there. Fuses normally do not blow for just any old reason. My guess is that another component blew. Probably a transistor or diode. I haven't looked inside an A2000 power supply in quite some time, but if there are any tantalum caps inside those puppies - that'll do the trick every time. Those particular caps are very prone to failure and usually take out more than just a fuse when they go.

If you jumper the fuse clip (if you do not happen to have a small 1/2 amp, etc. fuse) and turn it on without it being connected to the Miggy, be prepared to turn it off quick. Another educated guess is that you'll see something else start burning if you were to jump it.

Not recommended, but...

Sorry to hijack this thread but seems appropiate place for my question.


I'm in the uk and have an a2000 that has the us 110v power supply...can this be converted to 220v?

@DoogUK
Some of the A2000 power supplies have an internal link which selects the supply voltage, though it depends on the model of the supply.  I recall the Pkihong PSM-2000 has this option, where the LiteOn PA-4201-5B doesn't??

A fuse seems to have fixed the power supply, but the A2000 appears to be dead. The drive lights come on and stay on, and there's no display.

Vhat voltages should be on what pics?

I found the A2000 power supply pin out online. My supply measures as follows (spec - my measurement)

+5 - +5.18
+12 - +11.83
-12 - -12.12
+5 USER - +5.17
-5 - -10.65

My +12 volts is a little low, at 11.83 volts. Abd my -5 volts is way off.... COuld that be a problem?

It's not stated if the power supply was measured under load or not.  It needs to be measured under load if you want to test load regulation.

The +5V outputs are only +3.5% which is fine considering the supply is probably rated at +/-5%.  This supply is well within the specification for both TTL and CMOS logic, how can this possibly cause damage??

Granted that the -5V supply is outside normal limits.  That may or may not indicate a problem, depending if this was measured under load or not.  As I recall, -5V is routed to a rarely used pin on the serial port.  It's not required to run any of the computer logic, which runs entirely from +5V.

Given the measured results, the power supply should not be the cause of the computer not booting.  Of course this needs to be measured under load to have any relevance.


@orb85750
Non-booting problems may be caused by the failure of a single IC anywhere on the board, a single bad connection in an IC socket, a single PCB track failure (corrosion), etc.  So while the non-booting symptoms are the same, there can be many different causes for it.


The best approach to booting problems is to check for visual problems first; physical damage you can see.  For example, if there has been battery corrosion, check PCB tracks and vias are not open circuit.  Check socket contacts for corrosion and replace accordingly.

Secondly, most people are limited to swapping out socketed devices for known good parts.  It can work well so long as ICs don't get damaged in the process.  I've seen many instances where people try this and end up causing more damage due to putting ICs in backwards, bent/broken pins.

Lastly, you can go a bit further with an oscilloscope or logic analyser.  Checking bus activity, clock sources, reset lines, etc.  It's time consuming and requires equipment and skill that many people won't have.