MrEWhite wrote:Well, the issue is still there sadly. How would I be able to tell if the PSU is bad or if a cap/caps are bad? I am also only using 128MB of RAM now btw.
There are some things you can do but you can't fully check either without soldering skills and some test equipment.
The PSU:
You can check the DC voltages with a basic multimeter.
- That is important but won't show you how much ripple is present, which is also important. For the latter you need an O'Scope.
- You generally don't need an O'Scope if you can fully check caps - although a scope can still come in handy.
The scope needs to be able to see millivolts at approximately 100kHz. (Say 10kHz to 500KHz.) That's not too tough a requirement.
Depending on how lucky you in shopping a used scope that will work would probably run $100-$400.
Back to the PSU: (With it disconnected from line power for 5 to 10 minutes at least.)
Beware a faulty PSU may have caps with residual charge up to 400VDC depending on the design. Not common but can happen..
Check for voltage on any caps you might fondle and also the exposed heatsinks before you start sticking things in there.
Now do a visual internal inspection.
- Look for bloated/leaking caps.
- Look for places/parts that show signs of overheating. (Darkened circuit board is one give-away.)
- Look for burned traces and/or melted insulation.
- Look for cracked IC chips or signs there has been melting inside. (Shinny spots. Pits.)
Anything you find suspect explore in greater detail.
Caps (no matter what they are in.)
To fully and correctly check caps you need to pull them (to bench test) and have some test equipment.
They need to be pulled because 'in circuit' there are usually parallel paths so measurements are not accurate.
The test equipment [And rough cost estimate.]
- An ESR meter with a test signal of 100kHz that is readable to +/- 0.01 ohms. Which means a digital one. [ $75-$125 ]
- A basic capacitance meter that covers the range from .01 uF to around 10,000uF. [Under $50. Sometimes much less.]
- A basic multimeter. [ A $10 cheapie from the department store is good enough for this.]
[[ An ESR meter does basically the same thing as a resistance meter except it does it with an AC test signal rather than with a DC voltage. ]]
You can with a multimeter do the 'old school' kind of tests but that is incomplete testing for low ESR caps (will only find some bad ones) and they still need to be pulled first.
That procedure is all over on-line so I'm not going to repeat it.
.
To fully test caps you need to.
- Check the ESR is within the range specified in the datasheet.
- Check the Capacitance is within the range specified in the datasheet. (This is almost always +/-20% of the marking.)
- Check with the multimeter set to resistance that the cap is not a dead-open or a dead-short.
(A shorted cap may appear to be good if you only check ESR.)
(Any one of those parameters can be out of spec while the other two test fine. Depends on what the cap's problem is.)
.
.
.
People on Vogons seem to have trouble wrapping their head around the idea that as retro gear gets older bad caps ARE going to become part of their life.
(The 15 year age is according to Nichicon.)
At about 15 years old caps enter what is called the "Wear-out" phase of their lifetime.
Once into the wear-out phase the failure rate of caps goes up exponentially with time in years. (It's the famous "Bathtub Curve".)
Example. If 1% fail at 15 years old - then: 2% fail at 16 years old, 4% fail at 17 years old, 8% fail at 18 years old ... and so on.
(That 1% was picked out of thin air in aid of discussion. I dunno what the actual rate is at 15 years.)
It (the 15 years) applies to ALL Aluminum Electrolytic caps. Nothing at all to do with good vs bad brands or the Capacitor Plague.
-
So, IMHO, if you are going to be into any kind of retro electronics for the long haul it would be in your best interest to learn how to test and replace caps.
And please note that socket 370 faded away about 15 years ago. The last ones built are 'officially' entering the wear-out phase this year.
80486 faded away about 20 years ago.
Fortunately 486s did not stress caps all that much so they are lasting longer than expected but they are still going to wear-out eventually.
.
GRUMPY OLD FART - On Hiatus, sort'a
Mann-Made Global Warming. - We should be more concerned about the Intellectual Climate.
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
