Power supply low current?

[mickcris]

I bought a roller controller and it came with a power supply. It does not power on my system (no video output) for some reason though. The led that I installed on the 5v line is working fine, but the blue led on my atarimax cart only flashes for a second and then turns off. The led should flash and then flash for a bit longer when its reading the SD card. I also tried a real Donkey Kong cartridge and had no video output either.

 

I measured the power supply and all 3 voltages are present so I'm thinking it must not be putting out enough current. Has anyone had this happen before and know what component needs replacing in the power supply?

 

thanks

[mightywiz]

replace the electrolytic capacitors in the power supply.

 

this will fix low current issues, it will also fix low voltage issues.

 

and if you want to do an accurate test for testing voltages then measure the voltages with it plugged

in to the colecovision and powered on.

 

you need a load on the power supply to get the correct readings.

[mickcris]

Thanks for the reply. Yeah, I should have done it under load, but I really dont want to have to take the console apart again as I had a hard time getting it back together last time. I will take a look at the caps. I dont really need the supply, but it would be nice to have a backup.

 

edit:

pulled it apart and c1 and c2 had leaked. Did not check the smaller ones yet but they look ok at 1st glance.

Edited August 15, 2014 by mickcris

[mickcris]

Actually it looks like all of them had leaked with c1 being the worst. Will look at finding some replacements.

[mightywiz]

mouser.com

and replace with 105 degree temperature caps, they will last longer then the 85 degree.

[mickcris]

the ones that were in there were 105deg already. checking for replacements now. thanks.

[Osgeld]

there's different ratings than just temp

 

105c for 1000 hours or 105c for 10,000 hours is a big difference

 

(that's how long its supposta last IF the temperature is indeed 100ish degrees throughout the entire in use time)

[mickcris]

I made sure to select ones that are at least 5000 hours when i was searching. going to cost $11 for the caps from mouser with shipping. just debating on whether its worth it or not to try and fix it.

 

edit:

after I pulled them all out i measured them. Only the 3 largest ones were bad (4700uf and the 2 1000uf). The 3 small 22uf and the 220uf were ok, but im going to replace them anyway if I replace the others.

Edited August 15, 2014 by mickcris

[iscout62]

Are you using a capacatince meter or just ohm-ing them?

It would be a good idea to swap over all of the wet caps, they are all far beyond their service life.

[mickcris]

capacitance setting on my multimeter.

Edited August 15, 2014 by mickcris

[mightywiz]

unfortunately the capacitance test on a volt ohm meter only tests value.

 

to get a true test you need an esr meter or an expensive sencore lc meter (which I have).

 

esr meters will measure the low resistance value of the cap and give you a value, some esr meters

will give you a good/bad reading others have a chart you have to look at to determine if it's within tolerance

or not.

 

you can have a good value reading and still have a bad capacitor with leakage. and leakage is what your

trying to avoid.

[Osgeld]

caps are cheap, go with your plan and replace them all, for smoothing and decoupling applications getting identical replacements (like ESR, ripple, impedance), is not critical

 

it only took me one experience to just bite the bullet, when I replaced a cap on my video card, and the next week another one blew and it took out more than the cap when it did

Edited August 16, 2014 by Osgeld

[iscout62]

rubycon or matsushita caps are very good. panasonic av caps are good if you can find them.

[mickcris]

I decided to replace the caps. Just installed them and it still will not power on the console. Still reading all the correct voltages with it just plugged into the wall. I did not measure it under load. I assume now that one one the voltage regulators is not supplying enough voltage under load. I may check on those or just trash the thing. I should have ordered those while i was ordering the caps just in case. gonna be another 5 bucks in shipping now.

Edited August 18, 2014 by mickcris

[mickcris]

Gave up on the repair and got a new supply from iscout62 and it works great. I think my other supply must be dying also as my console would lock up when I hit the reset on my Atarimax flash cart. The reset button now functions like its supposed to.