So I had a go at Chromesphere's little SMD Booster (LPB-1) here:
http://www.diyguitarpedals.com.au/shop/boms/CBFX_SMD_Practice_Kit_LPB1_Boost.pdf
schematic:
http://www.diyguitarpedals.com.au/shop/boms/CBFX_SMD_Practice_Kit_LPB1_Boost_schematic.pdf
I got everything soldered on without "seemingly" any trouble but a big no-go when I fired it up.
I believe cooked something as I am getting .004vDC at the transistor base/R2 junction. I loose all signal at the collector.
All parts seam to be soldered on ok under Magnification and continuity checks ok through the parts.
Are these SMDs really heat sensitive? I can't see what else might be the issue other than a cooked part somehow.
Post a picture.
Quote from: tcpoint on May 19, 2014, 08:45:40 PM
Post a picture.
Even with macro my camera wont detail the tiny solder joints so not really going to help much.
It's strange that the 100n look yo be polarized on the schematic...other lpb schems don't have this.
I would say you either zapped the fet or the pinout of what you have isn't the same as the one the circuit is designed for.
Quote from: rullywowr on May 19, 2014, 11:38:28 PM
It's strange that the 100n look yo be polarized on the schematic...other lpb schems don't have this.
I would say you either zapped the fet or the pinout of what you have isn't the same as the one the circuit is designed for.
Thanks Ben,
I believe Paul has built and offered these little kits for a while so I am sure its user error. I am going to get a couple more and try again. I used some flux but had a little trouble getting the solder to hang right on the end of the conical iron tip so it is possible I just put too much heat on some components attempting a few solders on the same area.
New to SMD work so its all good. I am going to start with a fresh tip when attempting this again.
Hi guys,
Bugger this projects causing you headaches... :(
Yeah please ignore polarized caps on the schematic / layout this was one of the first projects I've ever offered and a bit of a learning curve, ill have to fix that at some point.
There hasn't been any revisions on the pcb and I've probably sold...maybe 30 of them, so it would seem...well...worrying lol if there is an error on the pcb. I double checked it this morning and it seemed a'ok.
The transistor pinout could be a problem, did you order the components with the pcb or source them yourself (sorry I cant remember)? The transistor that I include with the kits is a BC847C. Also note that the pinout of the transistor is not the usual CBE. The pad with the dot above it is actually the base! That got me first time I made this layout. :D
Oh hey, I also forgot to mention, make sure you have soldered the components onto the right pads! Again, being a first project, the layout is tight and somewhat messy. You could potentially solder a resistor chip across 1 pad of r2 and 1 pad of r3. The small gap is the gap between to ends of the chip. iv'e attached a photo with rough circles around the components to show how they line up with the refdes's.
Paul
Thanks Paul,
I do have the components oriented correctly so we are good there. I did order the complete kit from you so I believe the transistor is correct. I will keep playing with this one but I did order a couple more more kits from you for more SMD practice.
My eyesight is not the best for this kind of work so I will invest in some better magnification as well.