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Power supplies / Re: SST03 troubleshooting
« on: April 25, 2012, 03:33:12 PM »
I haven now also tried a 250V MKT in that position... still doesnt work. As the designer of the circuit... what could be the culprit?
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Per-Anders Sjöström
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Power supplies / Re: SST03 troubleshooting
« on: April 20, 2012, 09:35:57 AM »
what is the required rating of the caps in C4 and C5?
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Power supplies / Re: SST03 troubleshooting
« on: April 18, 2012, 02:13:01 PM »
I have replaced with another 1uF 63V WIMA... then K2 doesn't activate again!
So: it only works with C4 and C5 empty, but I do see a spark then inside K2 relay (and of course there is no softstart then...)
So: it only works with C4 and C5 empty, but I do see a spark then inside K2 relay (and of course there is no softstart then...)
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Power supplies / Re: SST03 troubleshooting
« on: April 17, 2012, 11:24:13 PM »
Hei Per Anders,
I was using a 1.25 slowblow, which blew all the time. I have now replaced for a 2A and it works now. The transformer is 400VA.
I am still running without C4 and C5 positions filled, what is the impact of that? How can I insert a suitable cap here?
Also I see sometimes a little spark around the relays... this doesnt seem to affect it though, as no fuse is blown, and the psu starts up normally. What can this be?
Thanks,
Maarten
I was using a 1.25 slowblow, which blew all the time. I have now replaced for a 2A and it works now. The transformer is 400VA.
I am still running without C4 and C5 positions filled, what is the impact of that? How can I insert a suitable cap here?
Also I see sometimes a little spark around the relays... this doesnt seem to affect it though, as no fuse is blown, and the psu starts up normally. What can this be?
Thanks,
Maarten
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Power supplies / Re: SST03 troubleshooting
« on: April 17, 2012, 08:10:51 AM »
I think it is delayed (I hear c-click I think). The caps I had in were 1uF 63V WIMA....
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Power supplies / Re: SST03 troubleshooting
« on: April 16, 2012, 10:09:38 PM »
Hi Peranders.
I have written down all voltages, and identified the fault. Voltage between D2 and D3 was 32V (good), voltage between D3 and Q1 was -0.4V. Hence I guessed there was something wrong with the caps. So I removed C4 and C5 and it worked.
Unfortunately, I am not sure if I am where I want to be.... I get a blown fuse now upon startup with transformer and PSU....
I have written down all voltages, and identified the fault. Voltage between D2 and D3 was 32V (good), voltage between D3 and Q1 was -0.4V. Hence I guessed there was something wrong with the caps. So I removed C4 and C5 and it worked.
Unfortunately, I am not sure if I am where I want to be.... I get a blown fuse now upon startup with transformer and PSU....
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Power supplies / Re: SST03 troubleshooting
« on: April 16, 2012, 07:14:55 PM »
I will post the schematic with all the voltages later... this should help I hope to identify the problem...
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Power supplies / Re: SST03 troubleshooting
« on: April 14, 2012, 10:02:25 PM »
I double checked and confirm my earlier readings. I am taking gnd at DZ1.
Using direct mains input
Using direct mains input
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Power supplies / Re: SST03 troubleshooting
« on: April 14, 2012, 09:36:41 PM »
Q1 base = -0.5V vs gnd
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Power supplies / Re: SST03 troubleshooting
« on: April 14, 2012, 09:12:37 PM »
Q1 emitter = 0V (compared to gnd)... actually 40mv (0.04V)
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Power supplies / Re: SST03 troubleshooting
« on: April 14, 2012, 07:28:41 PM »D4 is really OK and turned right?
As you see you have some problem around Q1 and Q2.
You should have 0.6-0.65 V base-emitter Q1.
Du you still have 24 volts at R12 and 0 V at R13? You should have 2 x 0.65 V.
D4 is put in according to the silkscreen. Have used a second one to verify... still same problem.
Q1 base - emitter = 0.4V and (thermally) drifting downwards
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Power supplies / Re: SST03 troubleshooting
« on: April 14, 2012, 07:22:18 PM »
I another datasheet it was more clear... it seems right on that one indeed. I have in the meantime taken a whole new pack of bc547c's and put them in. Still the same problem.
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Power supplies / Re: SST03 troubleshooting
« on: April 14, 2012, 07:06:30 PM »
Seems opposite from datasheet, no?
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Power supplies / Re: SST03 troubleshooting
« on: April 14, 2012, 06:31:56 PM »
I am looking at the traces on the board... they don't seem to correspond to the BC547 datasheet..... (e.g. Q1 emitter)..
I know that's very unlikely as the board has been tested and used..so maybe I am going crazy here...
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CDIQFjAA&url=http%3A%2F%2Fwww.datasheetcatalog.org%2Fdatasheet%2Fphilips%2FBC546_547_3.pdf&ei=b6aJT7uEItL58QOEsbjdCQ&usg=AFQjCNG0b4yJnAnVzq1AWxZKbR5tV9Al2w&sig2=JVaa6wmgXJQIBaOrwzF_7Q
I know that's very unlikely as the board has been tested and used..so maybe I am going crazy here...
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CDIQFjAA&url=http%3A%2F%2Fwww.datasheetcatalog.org%2Fdatasheet%2Fphilips%2FBC546_547_3.pdf&ei=b6aJT7uEItL58QOEsbjdCQ&usg=AFQjCNG0b4yJnAnVzq1AWxZKbR5tV9Al2w&sig2=JVaa6wmgXJQIBaOrwzF_7Q
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Power supplies / Re: SST03 troubleshooting
« on: April 14, 2012, 04:00:58 PM »
R12 = 22K
R13 = 2.2K
R13 = 2.2K
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