OK,
This really applies to any SMPS, just titling the Alesis unit the issue was with.
I'm sure this isn't anything new to a lot of us, but just thought I'd list it here for newcomers:
This SMPS would not start. You could see the ac current draw pulsing on the Sencore PR57 as well as just monitoring the 2ndary voltages on a meter, indicating it was trying to start, but would not.
First I checked for any obvious shorts on the outputs & then just unplugged the 2ndary to prove that was not the issue.
None of the electrolytics were bulged and there was no indication of any heat having been present.
It was then that I recalled watching a Mr. Carlson's Lab on SMPS's that gave me the clue. The one he was describing was not really like this one, but had a few low value low voltage caps in it that were essential to it starting up. BTW, gotta love Paul! Don't call Saul, call Paul (;- )
So, there was this tiny-miniature radial 47uf @ 16v cap in the primary of this SMPS that I just had to check since I have this Sencore LC103, but if I didn't, I'd just replace the thing. I have no idea why they went with such a physically small variety of cap in here. There was plenty of room for a standard size radial cap.
It had changed value from 47uf to 10uf. It probably just dried up from the ambient heat of the components around it.
I was thrilled that I didn't have deal with removing all the glue on those 2ndary caps
.
Anyway, just thought I'd throw that in...probably should have thrown it out
glen
This really applies to any SMPS, just titling the Alesis unit the issue was with.
I'm sure this isn't anything new to a lot of us, but just thought I'd list it here for newcomers:
This SMPS would not start. You could see the ac current draw pulsing on the Sencore PR57 as well as just monitoring the 2ndary voltages on a meter, indicating it was trying to start, but would not.
First I checked for any obvious shorts on the outputs & then just unplugged the 2ndary to prove that was not the issue.
None of the electrolytics were bulged and there was no indication of any heat having been present.
It was then that I recalled watching a Mr. Carlson's Lab on SMPS's that gave me the clue. The one he was describing was not really like this one, but had a few low value low voltage caps in it that were essential to it starting up. BTW, gotta love Paul! Don't call Saul, call Paul (;- )
So, there was this tiny-miniature radial 47uf @ 16v cap in the primary of this SMPS that I just had to check since I have this Sencore LC103, but if I didn't, I'd just replace the thing. I have no idea why they went with such a physically small variety of cap in here. There was plenty of room for a standard size radial cap.
It had changed value from 47uf to 10uf. It probably just dried up from the ambient heat of the components around it.
I was thrilled that I didn't have deal with removing all the glue on those 2ndary caps
![Mad](https://music-electronics-forum.com/core/images/smilies/mad.png)
Anyway, just thought I'd throw that in...probably should have thrown it out
![Wink](https://music-electronics-forum.com/core/images/smilies/wink.png)