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View Full Version : Power supply caps C1 to C9? What is the function?



ftastudent2
02-26-2014, 02:51 PM
What is the function of the unidentified caps on the Sonicview 800HD power supply. They are not listed on the various post available. C5 is a large cap and I supposed this could be an important filtering cap.

Glatt
02-26-2014, 03:41 PM
I don't know about Sonicview 800HD power supply but on NfusionHD the large Cap had a buldge and when replaced it worked fine!

Terryl
02-26-2014, 06:11 PM
All the can shaped caps do is one thing, and that's filter the DC voltage on that voltage buss.

Layman's explanation:

In an AC to DC power supply there are transformers, these transformers drop the AC main voltage (110 volts) down to something (6, 12 to 24 volts AC) that can be converted to a DC voltage.(+18, +14, +12, +6, +5, +3.5 volts DC)

This smaller AC voltage goes into what is called Diodes, these Diodes only let the electricity through one way, AC voltage goes both ways, as it gets to the diodes they only let the + voltage through and leaves the - voltage behind, this causes a drop in the DC voltage as there is a hole caused by the - voltage being left out. (called AC ripple)

The electrolytic caps (the cans) store up the + voltage and fill in the holes, the bigger the cap the more it can fill in the hole, this eliminates the AC ripple and smooths out the DC voltage.

When an electrolytic cap goes bad (dries out) the AC ripple gets too high, (the cap can't store enough DC voltage to fill in the holes) this causes the DC voltage to drop or become way too noisy for the voltage regulator IC's (or other device using the DC voltage) to work correctly, or not at all.

It's a bit more complicated then this as most power supply's in the FTA recivers are switching type, I don't have the room to explain those right now.

ftastudent2
02-26-2014, 11:31 PM
All the can shaped caps do is one thing, and that's filter the DC voltage on that voltage buss.

Layman's explanation:

In an AC to DC power supply there are transformers, these transformers drop the AC main voltage (110 volts) down to something (6, 12 to 24 volts AC) that can be converted to a DC voltage.(+18, +14, +12, +6, +5, +3.5 volts DC)

This smaller AC voltage goes into what is called Diodes, these Diodes only let the electricity through one way, AC voltage goes both ways, as it gets to the diodes they only let the + voltage through and leaves the - voltage behind, this causes a drop in the DC voltage as there is a hole caused by the - voltage being left out. (called AC ripple)

The electrolytic caps (the cans) store up the + voltage and fill in the holes, the bigger the cap the more it can fill in the hole, this eliminates the AC ripple and smooths out the DC voltage.

When an electrolytic cap goes bad (dries out) the AC ripple gets too high, (the cap can't store enough DC voltage to fill in the holes) this causes the DC voltage to drop or become way too noisy for the voltage regulator IC's (or other device using the DC voltage) to work correctly, or not at all.

It's a bit more complicated then this as most power supply's in the FTA recivers are switching type, I don't have the room to explain those right now.


Nice ceremonial display of DC power supplys verbiage, even included switched. Find this one in your computer or almost any circuit utilizing cmos large scale integration technology. You missed full wave rectification, half wave rectification and the answer to the question. What is the filtering function of C1 through C9. Are they smoothing +3, +22 etc. What is their function?

PS: A schematic would be great if anyone has one. Would also like one for the mother board but won,t hold my breath on that one.

Sp0iler
02-27-2014, 12:21 AM
Hit up the guy on That famous auction site that repairs SV power supplies.
He'll know.

Good luck,
Sp0iler

Terryl
02-27-2014, 02:43 AM
Ceremonial display??...............Hummmmmmmmm

dishuser
02-27-2014, 02:57 AM
Ceremonial display??...............Hummmmmmmmmcan't make everyone happy
I guess you were supposed to answer what wasn't asked...lol