Issue with a smps for a Samson powered mixer

Thread Starter

Roque

Joined Sep 16, 2014
156
Hello to all you gurus out there
Been working on a Samson powered mixer(active) with a power supply issue replaced the M50D060S Igbt also the powered MOSFETs and the l6598 and l6562n mosfet drivers .The issue i am facing is the smps keeps ticking with no output at the secondary.
If I disconnect the pin 1 on it l6562n the smps powers up fine will attach the circuit diagram,its been giving me a lot of grief and am my wits end any thoughts or info wold be much much appreciated ,was wondering if i run the unit with the pin 1 of l6562n desoldered or disconnected would it destroy the complete unit.
 

Dodgydave

Joined Jun 22, 2012
9,940
Can't see the diagram very clearly, but Ticking is a classic symptom of a switchmode psu in over current mode, if you can post a cleaner picture then i would be looking at the outputs for shorts, ...
 

Thread Starter

Roque

Joined Sep 16, 2014
156
Can't see the diagram very clearly, but Ticking is a classic symptom of a switchmode psu in over current mode, if you can post a cleaner picture then i would be looking at the outputs for shorts, ...
Thanks mat will do so will post a better picture
 

Thread Starter

Roque

Joined Sep 16, 2014
156
Have saved it in dropbox not sure how to paste it in h
Can't see the diagram very clearly, but Ticking is a classic symptom of a switchmode psu in over current mode, if you can post a cleaner picture then i would be looking at the outputs for shorts, ...
not sure how to attach from Dropbox if i give yo the link where the schematic is posted would you be ok

The link http://music-electronics-forum.com/showthread.php?t=36132
 

Thread Starter

Roque

Joined Sep 16, 2014
156
Have desoldered pin 1 of l6562n and the unit powers up fine ,but i know its not right ,what could happen if something did go bust or would i be ok to leave it disconnected?
To be more precise with pin 1 connected and tested through a series lamp the initial glow is very bright and then it flickers and goes dim the nit powers up but the leds blink ,could it be cause its going through the series lamp
If tested in the same manner with pin 1 disconnected the lamp glows discharges pretty quick to being dim not a bright glow at initial few seconds and there is no blinking of the leds on the face plate.The reason i am afraid of is if i connect it directly to the mains without the series lamp and pin 1 connected would it blow the mosfets and will have to wait a few days till i get new mosfets :-(
 
Last edited:

Dodgydave

Joined Jun 22, 2012
9,940
Pin 4 of the L6562 is current sense, pin1 is the voltage reference feedback 2.5V, i would be looking at the mosfet ,transformer T1,and output diodesD1,2,. .
 

ebp

Joined Feb 8, 2018
2,332
The L6562 controls power factor correction. PFC circuits are complex. Its job is to make the instantaneous line current directly proportional to the instantaneous line voltage and inversely proportional to the average line voltage. It is essentially a boost converter that will produce around 400 VDC on C14. The down-stream switcher will be designed to expect a reasonably well-regulated input voltage. If it doesn't get it, it is unlikely to work properly. If the AC line voltage is 240 VAC, it might work. If it is 120 VAC it almost certainly will not.

If the equipment has been in use for a long time, my first suspect would be C14.

If the IGBT had failed short-circuit then R13 should be checked.

Everything "ahead of" the low voltage outputs must be considered to be connected directly to AC mains "hot" for safety purposes.
 
Last edited:

Thread Starter

Roque

Joined Sep 16, 2014
156
Pin 4 of the L6562 is current sense, pin1 is the voltage reference feedback 2.5V, i would be looking at the mosfet ,trans
Pin 4 of the L6562 is current sense, pin1 is the voltage reference feedback 2.5V, i would be looking at the mosfet ,transformer T1,and output diodesD1,2,. .
diodes test good the strange thing is with pin 1 disconnected have put the unit back in the case all wired up power on and its working great i have been playing music on it for over an hour now , its running on mains 240vAC now and no series lamp and its playing great ,is it a ticking time bomb to go off any moment ???? Or i may be lucky it would stay good
 

Thread Starter

Roque

Joined Sep 16, 2014
156
Hi
The L6562 controls power factor correction. PFC circuits are complex. Its job is to make the instantaneous line current directly proportional to the instantaneous line voltage and inversely proportional to the average line voltage. It is essentially a boost converter that will produce around 400 VDC on C14. The down-stream switcher will be designed to expect a reasonably well-regulated input voltage. If it doesn't get it, it is unlikely to work properly. If the AC line voltage is 240 VAC, it might work. If it is 120 VAC it almost certainly will not.

If the equipment has been in use for a long time, my first suspect would be C14.

If the IGBT had failed short-circuit then R13 should be check.

Everything "ahead of" the low voltage outputs must be considered to be connected directly to AC mains "hot" for safety purposes.
hi mate thanks for your reply
The funny thing is i have it all hooked up with the pin 1 disconnected put it back in its case all wired up and connected to ire the mains 240v A.C. and i have been playing music on it for over an hour ,like i mentioned earlier is it a weird that it may go bust any moment or would it last me for a while and stay good ,or should. Connect the pin 1 and fire it up directly without the series lamp ? Just to be safe than sorry in the future. Have replaced the C14 capacitor with a new one too done that.cheers
 
Top