Salas hotrodded blue DCB1 build - Page 222

Salas · 29th September 2012, 10:36 PM

Before, in that case.

jeff517 · 2nd October 2012, 10:09 PM

Well, plugged it in and smoked one of the large capacitors. now to figure out why.

jeff517 · 3rd October 2012, 02:19 AM

Check and double checked. Smoked one of the the 4700 mf capacitors..so my problem is on that side. Where do i start besides looking for more burnt stuff on that side?

Salas · 3rd October 2012, 02:29 AM

See if your diodes are populated in the right orientation following the printed stripes for cathode on pcb, see if any one of them is charred also. Disconnect the trafo and see with the meter in ACV mode that the wires you sent to the outer terminals of the AC in pcb connector are the expected secondary sum value. Also that each one measures half that in respect to the wire(s) you sent to connector's middle point.

Salas · 3rd October 2012, 02:37 AM

P.S. If you had used TO-220 big diodes, their backs face outwards along the pcb's edge is the orientation.

Erlend Sæterdal · 3rd October 2012, 07:13 AM

Always a finger on electrolyts when starting up . If some is getting hot turn off. You HAVE done something wrong.

atupi · 3rd October 2012, 07:39 AM

I'm using 10R and across them i have 1.87 and 1,92 V respectively. If i want to go beyond 200mA level i need just to lower this resistors or i need to to something else to increase the voltage across them ?
My voltages are almost equal between the two rails.

Salas · 3rd October 2012, 10:55 AM

Something else would mean more leds which aren't available on the pcb so the way is to lower your resistors value.

jeff517 · 6th October 2012, 08:07 PM

I remember reading on here that the graphic was reversed on the leds. Or maybe some other thread. I used the squared holes and refrence when putting in leds.
As for Transf, 12v on all output side.

Salas · 6th October 2012, 08:18 PM

Square hole is Led's anode in this pcb as crt designated that half circle symbol over the 5 Led groups, when its the cathode in the 3 Led groups. If you put just one in reverse they will not shine, but no reason to blow a reservoir cap. In fact its the first time I hear someone blows a reservoir cap. Could it be it was reversed for polarity by accidental insertion or just very unlucky to chance on a dodgy one?

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29th September 2012, 10:36 PM	#2211
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Before, in that case.

2nd October 2012, 10:09 PM	#2212
jeff517 diyAudio Member Join Date: Mar 2012 Location: Traverse City MI.	Well, plugged it in and smoked one of the large capacitors. now to figure out why.

3rd October 2012, 02:19 AM	#2213
jeff517 diyAudio Member Join Date: Mar 2012 Location: Traverse City MI.	Check and double checked. Smoked one of the the 4700 mf capacitors..so my problem is on that side. Where do i start besides looking for more burnt stuff on that side?

3rd October 2012, 02:29 AM	#2214
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	See if your diodes are populated in the right orientation following the printed stripes for cathode on pcb, see if any one of them is charred also. Disconnect the trafo and see with the meter in ACV mode that the wires you sent to the outer terminals of the AC in pcb connector are the expected secondary sum value. Also that each one measures half that in respect to the wire(s) you sent to connector's middle point.

3rd October 2012, 02:37 AM	#2215
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	P.S. If you had used TO-220 big diodes, their backs face outwards along the pcb's edge is the orientation.

3rd October 2012, 07:13 AM	#2216
Erlend Sæterdal diyAudio Member Join Date: Mar 2007	Always a finger on electrolyts when starting up . If some is getting hot turn off. You HAVE done something wrong.

3rd October 2012, 07:39 AM	#2217
atupi diyAudio Member Join Date: Oct 2010 Location: Bucharest	I'm using 10R and across them i have 1.87 and 1,92 V respectively. If i want to go beyond 200mA level i need just to lower this resistors or i need to to something else to increase the voltage across them ? My voltages are almost equal between the two rails.

3rd October 2012, 10:55 AM	#2218
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Something else would mean more leds which aren't available on the pcb so the way is to lower your resistors value.

6th October 2012, 08:07 PM	#2219
jeff517 diyAudio Member Join Date: Mar 2012 Location: Traverse City MI.	I remember reading on here that the graphic was reversed on the leds. Or maybe some other thread. I used the squared holes and refrence when putting in leds. As for Transf, 12v on all output side.

6th October 2012, 08:18 PM	#2220
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Square hole is Led's anode in this pcb as crt designated that half circle symbol over the 5 Led groups, when its the cathode in the 3 Led groups. If you put just one in reverse they will not shine, but no reason to blow a reservoir cap. In fact its the first time I hear someone blows a reservoir cap. Could it be it was reversed for polarity by accidental insertion or just very unlucky to chance on a dodgy one?