Blown STE power supply, how bad is it?

[KLund1]

I turned my STE with my Cosmos EX installed today.

POP, SPARKS, SMOKE!!! Saw a white screen just before I was able to pull out the cord from the PSU.

VERY NOT GOOD!!

How bad do you think it is?

See the pictures. The round orange guy on the left is blown!

But look closer at the RF shield, on the left is also a lighter burn mark. I am not sure what if any component may have also blown.

One thing that is not good is the fuse is not blown!

I have only been using the CosmoEX for a couple weeks!

I do not have another STE PSU to replace it. I do have a STF PSU, but is it strong enough to run a STE/CosmosEX? At least for a few minutes to see if the STE was killed.

Exxos' store is down for his house move, SO I will have to wait for a good replacement.

 

 

[Justin Payne]

Looks like you blew a ceramic capacitor. Just replace it with a similar high quality one. You might want to also think about replacing the electrolytic caps just cuz those are the most prone to blowing.
Ideally, you want to then power it up, with a load, and just make sure it's working before putting it back in the system. You know, test the voltage (rails) with a multimeter but someone with more electronics background could probably give you a more experienced opinion.

Oh, and the fuse won't blow if current doesn't blow it. Since it's not blown, I'd say signs are that it didn't get out of the power supply and into the computer's components. That's good.

Edited April 6, 2017 by Justin Payne

[KLund1]

Thanks, That make me feel a bit better.

I think I will wait to buy a new unit.

If one component is bad, who knows what other parts got damaged, and might fail worse in the future. I am unfamiliar with how to check circuits, or what a multi meter is telling me if I happen to test the right ends of part. I'm no E.E. person, more of a 'put tab A in to slot B' type. I could do it after I'm show how a couple times, but there is no one here the CA/SF Bay Area that I know of to help out.

[Justin Payne]

Thanks, That make me feel a bit better.

I think I will wait to buy a new unit.

If one component is bad, who knows what other parts got damaged, and might fail worse in the future. I am unfamiliar with how to check circuits, or what a multi meter is telling me if I happen to test the right ends of part. I'm no E.E. person, more of a 'put tab A in to slot B' type. I could do it after I'm show how a couple times, but there is no one here the CA/SF Bay Area that I know of to help out.

Well, I understand your fear, especially since you're not an EE guy but neither am I. What I know is what I've had people show and explain to me. That's a ceramic cap. Those are pretty solid but like anything, age could have gotten it one of those electrolytic caps (Those ones that look like cans) could be leaking voltage. That's why I suggested replacing those as well. Of course, if you had an ESR meter, that could tell you for sure but with the cost of one of those and the fact that you're not testing caps on a regular basis, just replacing is a much cheaper solution. I know with electrolytic, if one blows, you tend to replace the ones right around that one since it's possible one before the circuit is going bad or the one after it got damaged.

 

The process of replacing them is pretty simple but you'd need some supplies, such as...

• A soldering iron. You might be able to get away with a inexpensive one.
• Solder. lead based
• Solder sucker (or braid) to remove the old solder and get the components out. A vacuum desoldering station is what one has who does LOTS of repairs like this. They are slick!
• Replacement component(s). Pretty cheap.

So, to sum it up, it's completely fixable by someone with the basic knowledge of troubleshooting stuff like that but it sounds like you're not that guy so save that for when you can find someone to repair it so you'll have a backup.

[+poobah]

So definitely check the voltages with it loaded down before you hook it back up to the ST. Often times when you lose a component like that, it can take other stuff with it.

[Justin Payne]

So definitely check the voltages with it loaded down before you hook it back up to the ST. Often times when you lose a component like that, it can take other stuff with it.

Yep. My suggestion is to find the 5V+ and put a DC fan on it. There is your load (AKA: The thing that is drawing current)

Unfortunately, these retro devices sometimes need some tender loving care. Some people are willing to pay for it while others want to get to know their machines a bit better. As long as you get some satisfaction out them, I think that's what is important. We can offer you suggestions on how to fix things but sometimes just giving you that, "You're system is good. Here are my suggestions. Get it resolved in the way that works for you" is sometimes all someone needs.