News:

Hi!

Welcome to my DIY audio forum.

Cheers
Per-Anders Sjöström

Main Menu

SST03 troubleshooting

Started by Maarten Stevens, April 13, 2012, 05:18:55 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

peranders

/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

Maarten Stevens


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.
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

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
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

Maarten Stevens

Seems opposite from datasheet, no?  :?

peranders

Check if it's top view or bottom view.
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

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

Quote from: peranders on April 14, 2012, 04:44:17 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


peranders

/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

Maarten Stevens

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

peranders

/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

Maarten Stevens


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?
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff

Maarten Stevens

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