crappyjones123 Posted October 29, 2009 Report Share Posted October 29, 2009 Received this kit a few weeks ago and after working with it on and off i have the board populated. before i actually start the casework, if anyone has any comments/concerns/suggestions regarding just the soldering portion or anything else for that matter please feel free to post them. i have very unsteady hands so some of the pictures might be out of focus. my apologies. anyhow here are some pictures. the output transformers are allegedly custom wound for decware. thats about all i know about them. no clue as to the output impedance and what not. el cheapo el 84's from leeds radio in nyc. didnt want to use any expensive stuff while the amp is still in the testing stages. got an assortment of 5 6922's from ebay. Quote Link to comment Share on other sites More sharing options...
luvdunhill Posted October 30, 2009 Report Share Posted October 30, 2009 in general, you are applying too much solder. The joints should have a volcano shape. Have you powered it up yet? Quote Link to comment Share on other sites More sharing options...
grenert Posted October 30, 2009 Report Share Posted October 30, 2009 Other than being wasteful of solder and unattractive, is there really any functional problem with solder joints like these? Quote Link to comment Share on other sites More sharing options...
luvdunhill Posted October 30, 2009 Report Share Posted October 30, 2009 Other than being wasteful of solder and unattractive, is there really any functional problem with solder joints like these? My suspicions, and they are purely suspicions, is that lead free solder was used at too low of a temperature. I'd have to see the other side of the joint to be sure that adequate wicking was taking place, but this would be my concern. Quote Link to comment Share on other sites More sharing options...
n_maher Posted October 30, 2009 Report Share Posted October 30, 2009 I tend to use too much solder, almost as a rule. My thinking is that it doesn't hurt and allows me to make sure that I'm getting enough wicking. Quote Link to comment Share on other sites More sharing options...
Looser101 Posted October 30, 2009 Report Share Posted October 30, 2009 I see some potentially bad solder joints: Pic 2 right below the left tube socket. Pic 2 to the left of the right tube socket. Some of the other pics are too blurry to be able to see much. Some additional heat or on time might help flow some of those joints better. Quote Link to comment Share on other sites More sharing options...
justin Posted October 30, 2009 Report Share Posted October 30, 2009 I think the best way to evaluate solder joints is to look at the OTHER side of the board. Ideally the solder joint looks almost the same on both sides of the board. Sometimes this is impossible because the PCB hole size is too small or the component lead is too wide Quote Link to comment Share on other sites More sharing options...
luvdunhill Posted October 30, 2009 Report Share Posted October 30, 2009 (edited) Sometimes this is impossible because the PCB hole size is too small or the component lead is too wide I've always wondered, is there a rule of thumb for hole much larger the hole should be than the component lead? Edited October 30, 2009 by luvdunhill Quote Link to comment Share on other sites More sharing options...
spritzer Posted October 30, 2009 Report Share Posted October 30, 2009 I'm with Justin on this, just enough solder so that it makes a nice peak on both sides of the board. Quote Link to comment Share on other sites More sharing options...
grenert Posted October 30, 2009 Report Share Posted October 30, 2009 One trick I've done when the lead is a tight fit is to insert the lead, add some flux, and pull the lead back out a couple of times so that at least the flux has coated the inside. Hopefully that will make the solder more likely to wick to the other side. Quote Link to comment Share on other sites More sharing options...
crappyjones123 Posted October 30, 2009 Author Report Share Posted October 30, 2009 solder is on both sides of the board. will post pictures of it later. i was doing what george at tubelab suggested. put the board between two books and let gravity do its job with the solder so the component is held in place. lead free solder was used. and i did solder at supposedly low temperatures (600F) as i was scared i might damage the board/parts by setting it too high. now it has come to my attention that 600F is a little low. +1 for luvdunhill Quote Link to comment Share on other sites More sharing options...
Beefy Posted October 30, 2009 Report Share Posted October 30, 2009 I think the best way to evaluate solder joints is to look at the OTHER side of the board. Ideally the solder joint looks almost the same on both sides of the board. Sometimes this is impossible because the PCB hole size is too small or the component lead is too wide My soldering is usually like this on 'easy' joints...... but ground plane joints, almost never lead free solder was used. and i did solder at supposedly low temperatures (600F) as i was scared i might damage the board/parts by setting it too high. now it has come to my attention that 600F is a little low. +1 for luvdunhill Yeah, if you have a 'cold' iron on the part for a long time, you are more likely to damage the component than a hot iron for a short time. Just like kitchen knives. You are much more likely to hurt yourself by pushing hard with a blunt knife, than using much less force with a very sharp knife. Quote Link to comment Share on other sites More sharing options...
crappyjones123 Posted October 31, 2009 Author Report Share Posted October 31, 2009 email that i sent to steve deckert (owner of decware) "I have the whole amp wired up right now just to test everything and have a few problems. 1. The output transformers or one of them is making a high pitched noise. Its continuous. 2. There was a burning smell about 30 seconds after I turned on the amp. I turned it off immediately. I haven’t turned it on still. The voltages are as follows, A – 343.5V B – 300.1V C – 8.64V D – 3.061V Attached are pictures of the amp currently. Any ideas would be appreciated. " all voltages are within spec. Quote Link to comment Share on other sites More sharing options...
spritzer Posted October 31, 2009 Report Share Posted October 31, 2009 Is that bolt in the middle of the PCB touching some of the traces next to it? The soldermask isn't a great insulator and high voltage will arc over a short span. Quote Link to comment Share on other sites More sharing options...
crappyjones123 Posted October 31, 2009 Author Report Share Posted October 31, 2009 yes there is a bolt there. should i remove it? edit: nut removed. Quote Link to comment Share on other sites More sharing options...
spritzer Posted October 31, 2009 Report Share Posted October 31, 2009 Next step would be to make sure you have the right resistors in all the right spots and that all caps are pointing the right way. I would also reflowt all solder joints to just make sure there aren't any cold ones. Please make sure the caps are fully drained before touching the board though. Quote Link to comment Share on other sites More sharing options...
Looser101 Posted October 31, 2009 Report Share Posted October 31, 2009 Is that Red/Yellow wire soldered? Left side from power transformer. Quote Link to comment Share on other sites More sharing options...
Looser101 Posted October 31, 2009 Report Share Posted October 31, 2009 Caps look oriented correctly. Resistors, from the colors I can read, also look correct. Quote Link to comment Share on other sites More sharing options...
crappyjones123 Posted October 31, 2009 Author Report Share Posted October 31, 2009 Is that Red/Yellow wire soldered? Left side from power transformer. yes. i checked all the resistors with a dmm. correct values. reflowed solder to all joints. Quote Link to comment Share on other sites More sharing options...
Looser101 Posted October 31, 2009 Report Share Posted October 31, 2009 There should be two "D" voltage measurements, one for each side of the tube, but I doubt that is the source of the problem. Quote Link to comment Share on other sites More sharing options...
luvdunhill Posted October 31, 2009 Report Share Posted October 31, 2009 My soldering is usually like this on 'easy' joints...... but ground plane joints, almost never one tip is to heat the board up with a heat gun before doing ground plane joints. Also, buy my Hakko Blue, that will help as well (i.e. use a nice big tip) Quote Link to comment Share on other sites More sharing options...
crappyjones123 Posted October 31, 2009 Author Report Share Posted October 31, 2009 turned it on again, no more opt noise. however, voltages for A and B are out of spec Quote Link to comment Share on other sites More sharing options...
Looser101 Posted October 31, 2009 Report Share Posted October 31, 2009 I checked your work against the manual and I don't see anything obvious. Solder joints may be a problem as some still look iffy and I can't see jumper J2. Quote Link to comment Share on other sites More sharing options...
Looser101 Posted October 31, 2009 Report Share Posted October 31, 2009 If you have another set of output tubes change them out. Quote Link to comment Share on other sites More sharing options...
crappyjones123 Posted November 1, 2009 Author Report Share Posted November 1, 2009 J2 jumper is there. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.