It's actually about 1.2-1.3v between + and _ rails and I find all the legs on Q3 have rail voltage on them. I should see about 2 volts less on the collector if I'm not mistaken. I think the diode may be toast. If it is, I think I know why and will discuss if correct.
Any thoughts you wish to through out are welcome.
Any thoughts you wish to through out are welcome.
@X or jhofland (I hope)
Got my new boards and parts to populate. Thanks to all who make that possible including Michaels time saving Mouser BOM.
My question relates to the snubbers discussion #216-218. I have gotten into the habit of Q test jigging all my trafos, so I would like to verify parts and position.
#1, Are R1 and R2 the snubber resistor positions and are C2 and C3 effectively the series capacitors for R1 and R2. Called Cs by Mark. and then C3 and C4 the parallel capacitors - called Cx by mark. #2, will I be oK with the values of 150nF for C2 &3 and 10nF for 3 & 4. R1 & R2 will be between 12 and 20ohms. New trafos coming.
Thanks for your oversight. Trying not to mess up the SLB project.
Regards,
Don
thanks JT
I was just getting ready to start my SLB build when I saw your post. Thank you. I was thinking there was something wrong with me. My brain was really struggling to decode those J5-J7,J6-J14 pictograms.
And thanks to X for explaining the real way to figure it out.
Don
I was just getting ready to start my SLB build when I saw your post. Thank you. I was thinking there was something wrong with me. My brain was really struggling to decode those J5-J7,J6-J14 pictograms.
And thanks to X for explaining the real way to figure it out.
Don
Solder issue
Populating my v1.2 SLB boards. Great boards by the way. Thank you. Ran into the issue discussed in post #669. Happened on the C23 install. All was going smoothly until then. Thought it was a good idea to review my soldering practices. I use a Hakko 951 and on this board with a T15-D16 tip. The tip is a 1.7mm chisel tip. Been doing it hot, 750F. kind of a standard Kester 63/37 w/3.3% rosen 0.8mm dia.
Looking for specific suggestions on all these items/questions.
1. tip number or dimensions
2. temperature
3. Solder
4. possible cleaning with acid wash
5. possible (washing) with flux only and pre heating with said to prep pad
Did I miss anything?
My gut feeling is this is not a contamination issue rather a board build issue that causes imperfect technics to show up where I may have gotten by previously.
All comments and suggestions welcome. Has anybody knowingly solved this issue?
Thank you very much.
Regards,
Don
Populating my v1.2 SLB boards. Great boards by the way. Thank you. Ran into the issue discussed in post #669. Happened on the C23 install. All was going smoothly until then. Thought it was a good idea to review my soldering practices. I use a Hakko 951 and on this board with a T15-D16 tip. The tip is a 1.7mm chisel tip. Been doing it hot, 750F. kind of a standard Kester 63/37 w/3.3% rosen 0.8mm dia.
Looking for specific suggestions on all these items/questions.
1. tip number or dimensions
2. temperature
3. Solder
4. possible cleaning with acid wash
5. possible (washing) with flux only and pre heating with said to prep pad
Did I miss anything?
My gut feeling is this is not a contamination issue rather a board build issue that causes imperfect technics to show up where I may have gotten by previously.
All comments and suggestions welcome. Has anybody knowingly solved this issue?
Thank you very much.
Regards,
Don
I use a big fat 3mm chisel tip and Weller 75w iron set at 390C. 65:35 Pb:Sn rosin core solder. If you have a problem, melt extra solder on chisel tip and hold it so chisel is flat against pin/pad interface to get the most heat transfer. If you have a big air gun preheat the joint area and PCB for 30 Sec before using the iron.
Either hot air gun works make sure the temp is not so hot that it melts your other components. What you want is to warm the PCB up to 125C to 145C with the hot air, that’s generally a safe temp for the components. Especially if blown from bottom side where there are no components. Then the iron has to work a lot less harder to melt and wet the solder. An IR thermometer is useful.
When I tested my 4ohm Alpha Nirvana to clipping (1x SLB per channel), I got voltage clipping happening (22v DC rails ... into 3 ohms) when the amp board was pumping out 5.8a.
Andy
Gremlin Dispatched
This post an another further back describe an issue I was having with the neg rail being 1-1.2v higher than the pos. I looked over all the solders with a big magnifier, saw nothing that raised flags and proceeded to test nodes. I found the first abnormal reading at C16+C18 1000uF caps, the reading were elevated here. I went on to test all the resistors and pulled the BJTs for testing. All looked good to me. I even lifted some connections so I could test caps properly... nothing amiss. WTF?
Okay, so for having looked at this over the course of 3 days, I came to the conclusion it was a board trace, or connection issue of some kind. I started running traces...
I got to one point in my work and found when I tested across one trace, which included a resister, I could see the proper resistance across the resistor and at both ends of the trace. OKay problem elsewhere... After going through everything I decided to drop some power back on and do some more tests. As I went back to the same trace again I had an open on the trace. Huh! shut down the power and wait 15 mins had a smoke and thought about that. Go back to trace and check continuity without power and guess what, I have it and can see the resistor too. WTF? I gator clip the leads on the far end of each trace and take a probe and push/pull jiggle, no change in reading.
Thinking I must have been wrong I dropped power on it again and checked again, but this time I pushed, pulled and jiggled and saw 3 volts where there was none before. Oh my, took power off and waited, then I got out the soldering iron and heated the part up and removed it... test okay, looks okay, so I put it back in. This was in an area of the board it can be hard to get solder flow on the pads.
Now take into account I looked at this area with a loupe and saw nothing amiss. I flowed solder from both top and bottom this time and fired it back up. Quick test with a bit of shake in my hands from ground to C16 and the voltage was spot on... switch to NVout and voltage is perfect. SONOFA
It appears as though the the connection was testing good when no voltage was present and opened when voltage was applied. That was a hard fix for a rookie like myself, but it was also a very rewarding to do it myself.
I had sent a PM to X on this asking for some help and he said he would give me a hand, but I really wanted to fix this myself. This circuit isn't very complicated and I couldn't believe it was kicking my *** so badly. It became I either fix it or take a hammer to it, but be damned if I was going to ask for more help.
Well, I'm glad the hammer remained in the toolbox. It's time to fire it up today. I already tested the MX board and just need to drop the daughter on and solder up the inputs. All goes well, I will be listening to my first true mono build of the M2X.
NOTE: Take extra care when testing with probes on this board. Large areas of the board (planes) are either hot or grnd and a probe slightly off the pad can pierce the insulation and cause a short.
Example, I was test the BCE for proper voltage and I slipped off the leg and the probe which pierced the insulating layer on the board. This took the 29v rail right into the ground plane. Crack! WTF? I was looking at the meter and didn't understand how I shorted something. THe probe was only off the intended position by a mm or 2, but enough. I guess my catlike reflexes and a very robust circuit saved my *** as the supply still works as intended, but mind your probes. Especially when you are trying to probe the proud soldered leads... You have to apply some pressure to get a proper reading and it's so very easy to slip off and if the barrel of the probe is still in contact with the lead and pierces the ground plane....
Be careful!!
JT
This post an another further back describe an issue I was having with the neg rail being 1-1.2v higher than the pos. I looked over all the solders with a big magnifier, saw nothing that raised flags and proceeded to test nodes. I found the first abnormal reading at C16+C18 1000uF caps, the reading were elevated here. I went on to test all the resistors and pulled the BJTs for testing. All looked good to me. I even lifted some connections so I could test caps properly... nothing amiss. WTF?
Okay, so for having looked at this over the course of 3 days, I came to the conclusion it was a board trace, or connection issue of some kind. I started running traces...
I got to one point in my work and found when I tested across one trace, which included a resister, I could see the proper resistance across the resistor and at both ends of the trace. OKay problem elsewhere... After going through everything I decided to drop some power back on and do some more tests. As I went back to the same trace again I had an open on the trace. Huh! shut down the power and wait 15 mins had a smoke and thought about that. Go back to trace and check continuity without power and guess what, I have it and can see the resistor too. WTF? I gator clip the leads on the far end of each trace and take a probe and push/pull jiggle, no change in reading.
Thinking I must have been wrong I dropped power on it again and checked again, but this time I pushed, pulled and jiggled and saw 3 volts where there was none before. Oh my, took power off and waited, then I got out the soldering iron and heated the part up and removed it... test okay, looks okay, so I put it back in. This was in an area of the board it can be hard to get solder flow on the pads.
Now take into account I looked at this area with a loupe and saw nothing amiss. I flowed solder from both top and bottom this time and fired it back up. Quick test with a bit of shake in my hands from ground to C16 and the voltage was spot on... switch to NVout and voltage is perfect. SONOFA
It appears as though the the connection was testing good when no voltage was present and opened when voltage was applied. That was a hard fix for a rookie like myself, but it was also a very rewarding to do it myself.
I had sent a PM to X on this asking for some help and he said he would give me a hand, but I really wanted to fix this myself. This circuit isn't very complicated and I couldn't believe it was kicking my *** so badly. It became I either fix it or take a hammer to it, but be damned if I was going to ask for more help.
Well, I'm glad the hammer remained in the toolbox. It's time to fire it up today. I already tested the MX board and just need to drop the daughter on and solder up the inputs. All goes well, I will be listening to my first true mono build of the M2X.
NOTE: Take extra care when testing with probes on this board. Large areas of the board (planes) are either hot or grnd and a probe slightly off the pad can pierce the insulation and cause a short.
Example, I was test the BCE for proper voltage and I slipped off the leg and the probe which pierced the insulating layer on the board. This took the 29v rail right into the ground plane. Crack! WTF? I was looking at the meter and didn't understand how I shorted something. THe probe was only off the intended position by a mm or 2, but enough. I guess my catlike reflexes and a very robust circuit saved my *** as the supply still works as intended, but mind your probes. Especially when you are trying to probe the proud soldered leads... You have to apply some pressure to get a proper reading and it's so very easy to slip off and if the barrel of the probe is still in contact with the lead and pierces the ground plane....
Be careful!!
JT
Last edited: