Building Colin's SECA kit

16781012

Comments

  • I had +- 17.5V out of the p/s board.
    Have you fitted the diodes on the amp board?

    Any chance of posting a couple of pics?
  • I'll take a couple of pics now.
  • I get +- 15.5v on the amp board but after a few minutes one of the supplies has dropped to 6.5v.
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    I've got more thermal pads arriving tomorrow which is why some are missing in the pics above.
  • edited March 2016
    I'm comparing my PSU board to the pic of Ben's board that Colin put together.  Originally I had populated more parts than were required on the PSU and I thought I'd removed them all, but I can see at least one difference.  Q8 for example is populated on my board but blank on Ben's.  I'll remove that and check rest of board for differences.

    Edit:  Found more differences.  I'll update my PSU board and try again.
  • edited March 2016
    Good spot Kieth but I think that the DC should pass through those Diodes. I'd prefer those bypassed though all the same.

    15V is a little low and dropping down further indicates that something may need a little attention. 

    Don't forget to isolate the Regs with top hats between the IC and bolt and check between tabs and chassis for continuity which you should NOT have.

    Hold off on switching on until you have the regulator IC's located to the heatsink. You don't want those babies to get to toasty.

    And then

    Maybe disconnect your SECA board from the PSU and measure the PSU output unloaded just to be sure which board the fault ''may'' be on.

    Another suggestion but not a must would be to change out the wires from PSU to SECA so that you can clearly identify +ve ,-ve and OV rails. I tend to be a little forgetful and colour coding helps stop me going ouch as often. Likewise for the return lines for the speaker output. maybe white for the + and blue for the grounds.

    Not important but helps my OCD stay calm under fire.

    Nice work though and with another little push you'll have a superb sounding amp.

    keep us posted.
  • edited March 2016
    Thanks Shoom. With the amp disconnected I have +15.6v and -15.7v on the PSU output.  To avoid toasting the regulator IC's I only left it on a short while, but the voltages remained constant.  I'm going to check over my amp build now - can't see anything else different compared to Ben's PSU board...not checked the SMD part values admittedly.

    EDIT:  Resistors at R1 and R2 look different on my PSU board compared to Ben's.  I'll check my BoM.
  • edited March 2016
    image

    Just a quick note the relay contact must be linked on the relay.

    As shown here.

    image

    Next if one PSU PCB is shutting down to 6.5V then this could be a hot bit somewhere, please check build, There has also been a few mods and this may help to find the info I will spend the day tidying it up and reposting.

    Also I see the REG chip are not on heat sinks, they do have internal temp shut down so I suspect they are getting hot and causing the shut down. Please fix them insulated to the heat sink.

  • Thanks Colin. I'm waiting on postman to deliver me some more pads.
  • Do you have the bias trimmer turned fully ant clockwise otherwise full current will run when switched on.
  • Yes. The bias trimmer is fully anti clockwise.
  • Just to be sure

    Did you fit the Zenner under the board on the SECA across the IC?
  • shoom said:
    Just to be sure

    Did you fit the Zenner under the board on the SECA across the IC?
    I do hope so , Please God (Panic panic) >:)
  • edited March 2016
    Yes, I remember doing that because I had to check with Colin which pins it went across. Still waiting for Parcelfarce to deliver my pads 8->

    PS thanks for all the help so far. With the amount of support here I'm confident my amp will be playing sweet music soon.
  • edited March 2016
    ''Yes, I remember doing that because I had to check with Colin which pins it went across.''

    Good work. I nearly forgot to fit them on my build.

    ''With the amount of support here I'm confident my amp will be playing sweet music soon''

    All part of the fun.

    I'm just up the road should you need eyeballs on the build but it's going to be something small I'm sure.
  • Thanks Shaun that's good to know.  
  • They should be fine just carefully bend the transistor pins so that the device fits snugly against the heatsink.
  • I can't help with technical advice (tho I'm taking some unjustified satisfaction from the fact that photos I posted have acted to help somewhat ;-) ), but I would like to provide some moral support here...
    I'm cheering you on from the sidelines Brumjam!
    =D>

    (It will get sorted! >:D< )
  • Yikes now we have sparks 8-X. All I did was fit the pads behind both IC's. None of the fuses went and can't see any parts that have obviously been fried. With hindsight I should have asked Colin to build these boards for me :D
  • Docfoster said:

    I can't help with technical advice (tho I'm taking some unjustified satisfaction from the fact that photos I posted have acted to help somewhat ;-) ), but I would like to provide some moral support here...
    I'm cheering you on from the sidelines Brumjam!
    =D>

    (It will get sorted! >:D< )

    Thanks Ben. I won't be defeated.....electrocuted maybe but not defeated >:)
  • edited March 2016
    Brumjam said:
    I can't help with technical advice (tho I'm taking some unjustified satisfaction from the fact that photos I posted have acted to help somewhat ;-) ), but I would like to provide some moral support here...
    I'm cheering you on from the sidelines Brumjam!
    =D>

    (It will get sorted! >:D< )
    Thanks Ben. I won't be defeated.....electrocuted maybe but not defeated >:)
    That is exactly the sort of response that we (and probably especially Colin) are looking for.
    =D>

    8-X
  • It is possible that you have a short between the small transistors where you fitted the isolation pads and the chassis. Sometimes those top hats just do not fit correctly.
  • I think I've made a mistake with RL1 - last night I soldered a piece of wire on the top of the board to join two points as advised by Colin. Now I've had a look under the board and can see I put a piece of wire on the opposing side as well. Not sure if this would cause fireworks but it needs fixing anyway.
  • Ok first IC is screwed down and no sparks this time. Second one going in now.....fingers crossed [-O<
  • Links either side no problem.

    But as Alan said the TOP hats are a pain and need care when fitting , oh why are there sparks is the power on whilst you fit it to heat sink, I do hope not.
  • I usually use the continuity tester setting on my multimeter  to check for shorts between the reg tabs and chassis.

    it will show those up before switch on.

    I noticed from your pictures some extra soldering around the spot that Col told you to solder a link.

    The link that Col identified is the only one needed so maybe take any others out.

    Nearly there.

    good work
  • It must have been a short as I've turned it on now and no more fireworks. Voltages are +16v and -15.4v. Still going after five mins of being on.

    I'm going to check my soldering now on the current adjustment pot. Getting closer to music.
  • edited March 2016
    Brumjam said:
    It must have been a short as I've turned it on now and no more fireworks. Voltages are +16v and -15.4v. Still going after five mins of being on. I'm going to check my soldering now on the current adjustment pot. Getting closer to music.
    That sounds like good news.
    Waiting for further news...

    image
  • :))

    Family has stopped play for time being. To quote Arnie 'I'll be back'.
  • Well we're glad you're safe.

    Make the most of the company. :-)
  • Those voltages still look a little low to me.

    I have 17.8V + and - on both boards.

    Are the SMD zenners soldered in with the correct orientation on the PSU board?

    It's hard to tell from the photo's.

    Another easy mistake that I almost made.

    I'll try to list them all in case it helps.

    ''Make the most of the company''

    Yes good idea.

    I usually get the Mother in Law to switch on my new builds. I just tell her it's a new sort of toaster whilst slowly backing away. :-))

  • edited March 2016
    Do you mean at positions D1 -D4 Shaun? I can take a close up photo.
  • Brumjam said:
    Do you mean at positions D1 -D4 Shaun? I can take a close up photo.
    What voltage is the transformer? 

    What resistor value did you use in :-
    R3
    R4
    R16

    R5
    R6
    R15

    Best Col
  • 18v transformers from the BoM.

    R3 = 240R
    R4 = 2K7
    R16 = 470R

    R5 = 240R
    R6 = 2K7
    R16 = 470R

    Some of these parts had different values on original BoM, so I had to remove some of these resistors and solder in the new values - I only mention this because my soldering wasn't brilliant given proximity to other parts. Should I focus on checking the solder on these parts?

    Thanks, James
  • A quick clean with isopropyl alcohol and a check with a magnifying glass can save a problem down the line. And a bulb tester is worth making for when you first switch on although you can't set the bias with one connected in the mains line other than to turn the bias trimmer and watch if the bulb starts to glow assuming it isn't already.
  • OK you should get with these values about +/-17.5V after the regulator PSU board and on light load the RAW DC should be about +/-24-25VDC 
  • Sorted List of Output Voltages with R3/R5 and R4/R6+R15/R16


    On table R1 read R3 or R5 and R2 read R4+R16 or R5+R15

    i.e. 240R, 2700R+470R = 240R, 3179R

    1.43V R1 = 470, R2 = 68
    1.47V R1 = 470, R2 = 82
    1.48V R1 = 370, R2 = 68
    1.51V R1 = 330, R2 = 68
    1.51V R1 = 390, R2 = 82
    1.52V R1 = 470, R2 = 100
    1.53V R1 = 370, R2 = 82
    1.56V R1 = 330, R2 = 82
    1.57V R1 = 270, R2 = 68
    1.57V R1 = 470, R2 = 120
    1.57V R1 = 390, R2 = 100
    1.59V R1 = 370, R2 = 100
    1.60V R1 = 240, R2 = 68
    1.63V R1 = 330, R2 = 100
    1.63V R1 = 270, R2 = 82
    1.64V R1 = 390, R2 = 120
    1.64V R1 = 220, R2 = 68
    1.65V R1 = 470, R2 = 150
    1.66V R1 = 370, R2 = 120
    1.68V R1 = 240, R2 = 82
    1.71V R1 = 330, R2 = 120
    1.71V R1 = 270, R2 = 100
    1.72V R1 = 220, R2 = 82
    1.72V R1 = 180, R2 = 68
    1.73V R1 = 470, R2 = 180
    1.73V R1 = 390, R2 = 150
    1.76V R1 = 370, R2 = 150
    1.77V R1 = 240, R2 = 100
    1.81V R1 = 270, R2 = 120
    1.82V R1 = 150, R2 = 68
    1.82V R1 = 330, R2 = 150
    1.82V R1 = 180, R2 = 82
    1.83V R1 = 390, R2 = 180
    1.84V R1 = 470, R2 = 220
    1.86V R1 = 370, R2 = 180
    1.88V R1 = 240, R2 = 120
    1.89V R1 = 470, R2 = 240
    1.93V R1 = 330, R2 = 180
    1.93V R1 = 150, R2 = 82
    1.94V R1 = 270, R2 = 150
    1.96V R1 = 390, R2 = 220
    1.97V R1 = 470, R2 = 270
    1.99V R1 = 370, R2 = 220
    2.02V R1 = 390, R2 = 240
    2.03V R1 = 240, R2 = 150
    2.06V R1 = 370, R2 = 240
    2.08V R1 = 330, R2 = 220
    2.10V R1 = 220, R2 = 150
    2.12V R1 = 390, R2 = 270
    2.13V R1 = 470, R2 = 330
    2.16V R1 = 330, R2 = 240
    2.16V R1 = 370, R2 = 270
    2.19V R1 = 240, R2 = 180
    2.23V R1 = 470, R2 = 370
    2.25V R1 = 150, R2 = 120
    2.27V R1 = 270, R2 = 220
    2.27V R1 = 330, R2 = 270
    2.29V R1 = 470, R2 = 390
    2.29V R1 = 180, R2 = 150
    2.31V R1 = 390, R2 = 330
    2.36V R1 = 270, R2 = 240
    2.37V R1 = 370, R2 = 330
    2.40V R1 = 240, R2 = 220
    2.44V R1 = 390, R2 = 370
    2.50V R1 = 470, R2 = 470
    2.57V R1 = 370, R2 = 390
    2.61V R1 = 220, R2 = 240
    2.65V R1 = 330, R2 = 370
    2.66V R1 = 240, R2 = 270
    2.73V R1 = 330, R2 = 390
    2.74V R1 = 470, R2 = 560
    2.75V R1 = 150, R2 = 180
    2.76V R1 = 390, R2 = 470
    2.78V R1 = 270, R2 = 330
    2.78V R1 = 220, R2 = 270
    2.84V R1 = 370, R2 = 470
    2.92V R1 = 180, R2 = 240
    2.96V R1 = 270, R2 = 370
    2.97V R1 = 240, R2 = 330
    3.03V R1 = 330, R2 = 470
    3.05V R1 = 390, R2 = 560
    3.06V R1 = 270, R2 = 390
    3.06V R1 = 470, R2 = 680
    3.08V R1 = 150, R2 = 220
    3.13V R1 = 220, R2 = 330
    3.14V R1 = 370, R2 = 560
    3.18V R1 = 240, R2 = 370
    3.25V R1 = 150, R2 = 240
    3.28V R1 = 240, R2 = 390
    3.35V R1 = 220, R2 = 370
    3.37V R1 = 330, R2 = 560
    3.43V R1 = 270, R2 = 470
    3.43V R1 = 390, R2 = 680
    3.43V R1 = 470, R2 = 820
    3.47V R1 = 220, R2 = 390
    3.50V R1 = 150, R2 = 270
    3.54V R1 = 180, R2 = 330
    3.55V R1 = 370, R2 = 680
    3.70V R1 = 240, R2 = 470
    3.82V R1 = 180, R2 = 370
    3.83V R1 = 330, R2 = 680
    3.84V R1 = 270, R2 = 560
    3.88V R1 = 390, R2 = 820
    3.91V R1 = 470, R2 = 1000
    3.92V R1 = 220, R2 = 470
    3.96V R1 = 180, R2 = 390
    4.00V R1 = 150, R2 = 330
    4.02V R1 = 370, R2 = 820
    4.17V R1 = 240, R2 = 560
    4.33V R1 = 150, R2 = 370
    4.36V R1 = 330, R2 = 820
    4.40V R1 = 270, R2 = 680
    4.43V R1 = 220, R2 = 560
    4.44V R1 = 470, R2 = 1200
    4.46V R1 = 390, R2 = 1000
    4.50V R1 = 150, R2 = 390
    4.51V R1 = 180, R2 = 470
    4.63V R1 = 370, R2 = 1000
    4.79V R1 = 240, R2 = 680
    5.04V R1 = 330, R2 = 1000
    5.05V R1 = 270, R2 = 820
    5.10V R1 = 390, R2 = 1200
    5.11V R1 = 220, R2 = 680
    5.14V R1 = 180, R2 = 560
    5.17V R1 = 150, R2 = 470
    5.24V R1 = 470, R2 = 1500
    5.30V R1 = 370, R2 = 1200
    5.52V R1 = 240, R2 = 820
    5.80V R1 = 330, R2 = 1200
    5.88V R1 = 270, R2 = 1000
    5.91V R1 = 220, R2 = 820
    5.92V R1 = 150, R2 = 560
    5.97V R1 = 180, R2 = 680
    6.04V R1 = 470, R2 = 1800
    6.06V R1 = 390, R2 = 1500
    6.32V R1 = 370, R2 = 1500
    6.46V R1 = 240, R2 = 1000
    6.81V R1 = 270, R2 = 1200
    6.92V R1 = 150, R2 = 680
    6.93V R1 = 330, R2 = 1500
    6.94V R1 = 180, R2 = 820
    7.02V R1 = 390, R2 = 1800
    7.10V R1 = 470, R2 = 2200
    7.33V R1 = 370, R2 = 1800
    7.50V R1 = 240, R2 = 1200
    8.07V R1 = 330, R2 = 1800
    8.08V R1 = 150, R2 = 820
    8.19V R1 = 270, R2 = 1500
    8.30V R1 = 390, R2 = 2200
    8.43V R1 = 470, R2 = 2700
    8.68V R1 = 370, R2 = 2200
    9.06V R1 = 240, R2 = 1500
    9.58V R1 = 330, R2 = 2200
    9.77V R1 = 220, R2 = 1500
    9.90V R1 = 390, R2 = 2700
    10.03V R1 = 470, R2 = 3300
    10.37V R1 = 370, R2 = 2700
    10.63V R1 = 240, R2 = 1800
    11.25V R1 = 150, R2 = 1200
    11.44V R1 = 270, R2 = 2200
    11.48V R1 = 330, R2 = 2700
    11.67V R1 = 180, R2 = 1500
    11.83V R1 = 390, R2 = 3300
    12.40V R1 = 370, R2 = 3300
    12.71V R1 = 240, R2 = 2200
    13.75V R1 = 330, R2 = 3300
    15.31V R1 = 240, R2 = 2700
    16.25V R1 = 150, R2 = 1800
    16.53V R1 = 270, R2 = 3300
    16.59V R1 = 220, R2 = 2700
    18.44V R1 = 240, R2 = 3300
    19.58V R1 = 150, R2 = 2200
    20.00V R1 = 220, R2 = 3300
    23.75V R1 = 150, R2 = 2700
    24.17V R1 = 180, R2 = 3300
    28.75V R1 = 150, R2 = 3300

  • Marra49 said:
    A quick clean with isopropyl alcohol and a check with a magnifying glass can save a problem down the line. And a bulb tester is worth making for when you first switch on although you can't set the bias with one connected in the mains line other than to turn the bias trimmer and watch if the bulb starts to glow assuming it isn't already.

    Great Advice

    I usually use a 10x watch makers Loop for checking my SMD work.

    I was referring to DS1/2 in my previous post but I think its most likely not an issue.

    I'd still recommend testing the PSU unconnected to the SECA board just in case.

    A nice close up of your SMD work may be useful.

    just as an aside

    ''Some of these parts had different values on original BoM''

    Is there a place where the current Booms and schematics are kept?

    Could be useful.

  • They will be kept on the wiki when I get some more time with it.
  • Hi Shaun I've been testing the PSU unconnected. The voltage readings on the output are the same. If I get time today I'm going to try my other PSU.....if it measures the same then this would point to me installing wrong parts as opposed to an SMD soldering mishap. I'll post a pick of DS1 and 2 later - no harm in checking I've got these installed correctly.
  • shoom said:
    Marra49 said:
    A quick clean with isopropyl alcohol and a check with a magnifying glass can save a problem down the line. And a bulb tester is worth making for when you first switch on although you can't set the bias with one connected in the mains line other than to turn the bias trimmer and watch if the bulb starts to glow assuming it isn't already.

    Great Advice

    I usually use a 10x watch makers Loop for checking my SMD work.

    I was referring to DS1/2 in my previous post but I think its most likely not an issue.

    I'd still recommend testing the PSU unconnected to the SECA board just in case.

    A nice close up of your SMD work may be useful.

    just as an aside

    ''Some of these parts had different values on original BoM''

    Is there a place where the current Booms and schematics are kept?

    Could be useful.

    As new parts better parts and nice heatsinks I improved the amp so some parts did change also if you use large heatsinks you can up the power, so the voltage on the PSU needs to change and the transformer.

    The idea of this kits was to help others understand and have confidence in there hidden skills like Alan B and Ben, now it is Uncle Dave,s turn others like Alan E. and Quickie and the incredible James did great jobs based on learning curves they collected from past DIY.

    Me it just a shame my Dyslexia screws my ability to write it all down but thank god for this community or liked minded nut cases.

    Thank guys 
  • My PSU is close Colin, it's just a process of elimination before I find the error with the great help of everyone here.

    In a way this is a good learning experience because it forces me to learn about the circuit rather than just soldering by numbers.

    The result will be all the more satisfying when I sit down and listen to music through it

  • AntiCrap said:
    shoom said:
    Marra49 said:
    A quick clean with isopropyl alcohol and a check with a magnifying glass can save a problem down the line. And a bulb tester is worth making for when you first switch on although you can't set the bias with one connected in the mains line other than to turn the bias trimmer and watch if the bulb starts to glow assuming it isn't already.

    Great Advice

    I usually use a 10x watch makers Loop for checking my SMD work.

    I was referring to DS1/2 in my previous post but I think its most likely not an issue.

    I'd still recommend testing the PSU unconnected to the SECA board just in case.

    A nice close up of your SMD work may be useful.

    just as an aside

    ''Some of these parts had different values on original BoM''

    Is there a place where the current Booms and schematics are kept?

    Could be useful.

    As new parts better parts and nice heatsinks I improved the amp so some parts did change also if you use large heatsinks you can up the power, so the voltage on the PSU needs to change and the transformer.

    The idea of this kits was to help others understand and have confidence in there hidden skills like Alan B and Ben, now it is Uncle Dave,s turn others like Alan E. and Quickie and the incredible James did great jobs based on learning curves they collected from past DIY.

    Me it just a shame my Dyslexia screws my ability to write it all down but thank god for this community or liked minded nut cases.

    Thank guys 
    Less of the Uncle!
  • Second PSU reading +17.8v and -17.9v when connected to the amp.
  • Looking good.

    I've noticed that on a couple of builds that folks have taken the speaker connections from the amp board and not the connections on the p/s board. Does this make a difference?

    How do I choose and use an Avatar? Showing my computer illiteracy here.
  • ''The idea of this kits was to help others understand and have confidence in there hidden skills like Alan B and Ben, now it is Uncle Dave,s turn others like Alan E. and Quickie and the incredible James did great jobs based on learning curves they collected from past DIY.''

    and it's worked out very nicely in that respect. Puts me in mind of the ''good old days'' when people where actually encouraged to have a go.

    the resulting builds speak for themselves.

    ''shame my Dyslexia''

    No shame as it makes two of us. Richard Branson manages pretty well on his.

    I use MS word to sort out my gibberish.

    Brumjam

    ''The result will be all the more satisfying when I sit down and listen to music through it''

    And the really cool thing is that you'll have some idea of how to make repairs should they be needed. true longevity.

    ''Second PSU reading +17.8v and -17.9v when connected to the amp''.

    Looking good and gives you something to compare PSU 1 with.

    Really good work and total commitment.

    just a small push further needed :-)

    Keith

    ''I've noticed that on a couple of builds that folks have taken the speaker connections from the amp board and not the connections on the p/s board. Does this make a difference?''

    I did notice that but was thinking that the Speaker return taken directly back to the PSU common 0V without the added impedance of the added connector may be more elegant. but I'm sure that in real life operation it matters very little IMHO.
  • Thanks Shaun.
  • Marra49 said:

    How do I choose and use an Avatar? Showing my computer illiteracy here.
    Click on the M avatar, then at the top right of the following screen is 'Add a profile picture'.
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