SST03 troubleshooting

[peranders]

R12, R13 values?

[Maarten Stevens]

R12 = 22K
R13 = 2.2K

[peranders]

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.

[Maarten Stevens]

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

[peranders]

Pins down flat side to you from left, C B E

[Maarten Stevens]

Seems opposite from datasheet, no?  :?

[peranders]

Check if it's top view or bottom view.

[Maarten Stevens]

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.

[Maarten Stevens]

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

[peranders]

Is the Q1 emitter at 24 V?

[Maarten Stevens]

Q1 emitter = 0V (compared to gnd)... actually 40mv (0.04V)

[peranders]

And Q1 base 24 volts?

[Maarten Stevens]

Q1 base = -0.5V vs gnd

[peranders]

Notice that you can't have less than zero. Check in the schematics for the electronics ground. Are you using a separate power supply or do use the mains voltage?

[Maarten Stevens]

I double checked and confirm my earlier readings. I am taking gnd at DZ1.
Using direct mains input