Please do it again. Also look for solder bridges in your soldering.
AC or DC it won't matter, I have put a diode there that acts as a half-wave rectifier for AC supplies and a reverse polarity protection for DC supplies.
I did just do it again, and I may have found something that I thought I had covered earlier.
I'm using KSC945CGBU transistors with this datasheet:
http://www.farnell.com/datasheets/1887774.pdf
Which shows the E-B-C configuration picture, but has the note about the "C" suffix and having center collector, or E-C-B configuration.
There is a C after the 945 above so that must be it.
I also have some BC549 transistors, which in earlier reading are acceptable and have no exceptions to the E-B-C configuration on the board.
I'll report back later after I make the transistor change.
Good luck and happy hunting.
Okay, I finally got back to this.
I took out the KSC 945 transistors, rearranged the pins and then soldered the same transistors back in place. And it works. The blinking LED blinks a bit, for maybe 3 seconds or so, and it's not much of a blink either.
I then connected up the speaker connections and gave things a go.
And it works just fine. There is no more nasty thump and wild woofer excursion at turn on.
So Success!
The transistor situation is a mess. And it's really Fairchild's mess because they have the same transistor with 2 pinouts and only one picture. Not good!
If the 30v BC549 transistors are suitable, then they should perhaps be the ones listed on the BOM.
Nonetheless, now happy
if bc type have an L after the type code then they have a different pin out.
But normally cbe. The Eline are also cbe.
The 2n types are ebc, just reverse them.
The 2sa/c have the collector in the middle, the same as all the medium and high power devices.
KSC945 will have collector in the middle, since it is a copy of a 2sc device.
For switching duty you do not need high gain. They operate saturated where you give them enough base current so that the Vce drops to near zero volts. Many will give around 40mVce to 100mVce when Ic/Ib = 10
Even a small signal transistor like the bc550 will have very low Vce at the typical relay coil currents of 10mA to 40mA.
Well, nothing like learning something the hard way. And I did not read the early posts in this thread as carefully as I presumed I did. My situation has all happened before. However, since I ordered off the BOM, the BOM I used has the KSC945C suffix transistor listed.
I will eventually get some of the non "C" transistors and fix things up right.
All in all I'm well pleased at the end result of installing this board into the amp
Don't bother.
Keep your KSC and remember that all sa/sc transistors have collector in the middle. Similarly, all power transistors have collector in the middle.
And all others, including MPSA, BC, 2N & Eline have base in the middle.
I bought this PCB and started working on it two days ago. Now I am facing the base-collector issue with transistors. When I was ordering the parts using provided BOM (which I believed was cleaned up in the meanwhile) I thought that these issues were surely corrected, because some posts were one year old.
If I understand the situation now correctly that is not the case. For some reason the statement in BOM is still false. I've got transistors where the following is written on it: C945 GCC13. The datasheet provided by mouser is also missleading and not clear. So I am not sure what to do ... And how it is possible that you are selling something with such missleading information provideed with it ?
Now I am not a big fun of switching the legs of transistors. Did anybody tried successfully another transistor and actually put this PCB in work with them ?
If I understand the situation now correctly that is not the case. For some reason the statement in BOM is still false. I've got transistors where the following is written on it: C945 GCC13. The datasheet provided by mouser is also missleading and not clear. So I am not sure what to do ... And how it is possible that you are selling something with such missleading information provideed with it ?
Now I am not a big fun of switching the legs of transistors. Did anybody tried successfully another transistor and actually put this PCB in work with them ?
I have, as well as others. I used the transistor version with pins in EBC order (Fairchild KSC945YTA), like the board is marked Look through the build file (http://www.diyaudio.com/forums/diya...r-turn-delay-dc-protector-board-set-v3-2.html) for more details.
Thanks mcandmar
Caps checked against pics and for correct square pin round pin configuration. There is one thing that is confusing me, and that is the requirement to Flip/reverse 2n222's. On the data sheet for this type it shows EBC pin orientation, which should drop in as per the pcb silhouette.
Caps checked against pics and for correct square pin round pin configuration. There is one thing that is confusing me, and that is the requirement to Flip/reverse 2n222's. On the data sheet for this type it shows EBC pin orientation, which should drop in as per the pcb silhouette.
I assembled the pcb completely and connected it to Hammond 183 transformer of 20VA with two seconderies of 12V each - connected serially they provide 24V. One LED blinkied for about two or three seconds and then remain lit. The other one was on immediately after I connected the transformer. I also measured the output and the relay really was triggered after these two or three seconds. So that seems to be ok. Now I have to find out how to check disconecting the outputs in case there is a DC on input. Battery comes first on my mind ...
BOM should be updated because of this mess with transistors, but also some links to Mouser are not valid any more (for example those for LEDs). I do not understand why is this so difficult to do it and it would save a lot of time (and money) for new buyers.
The pcb itself is of very good quality and soldering was a real fun. For that I have to say bravo to these guys that did it ...
BOM should be updated because of this mess with transistors, but also some links to Mouser are not valid any more (for example those for LEDs). I do not understand why is this so difficult to do it and it would save a lot of time (and money) for new buyers.
The pcb itself is of very good quality and soldering was a real fun. For that I have to say bravo to these guys that did it ...
I am afraid I have to agree with those sentiments. This is the most mixed up, confusing thread I have ever read at DIYAudio...this mess needs cleaned up with correct relevant info and BOM or deleted. Sorry guys!
Russellc
read the instructions and formulate your questions. Then post your question here.
This....
! Agree with Russellc.Very confusing indeed. Sorry.
So if i have to be specific: What do i need to change to the boards to make them work?