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    M125 construction FINALLY started...

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    Cubdriver

    Posts : 68
    Join date : 2014-01-21
    Age : 51
    Location : Southeastern Litchfield Co, CT

    M125 construction FINALLY started...

    Post by Cubdriver on Tue Feb 24, 2015 11:53 pm

    I bought 'em back in November, and they've been waiting patiently for me to get my act together.  As of last night, the driver boards have been assembled.  I made a time lapse video of the assembly (including my screw ups, like mounting all the pots on the top of the boards at first; partway through I moved the balance ones to the underside where they're supposed to be).

    I did the same thing with the big metal PIO coupling caps that I did on the ST-70 - insulating the bodies with clear head shrink tubing (folding the extended ends down against the flat ends of the cap while they were still warm and pliable this time), and tie-wrapping the caps to self adhesive anchors stuck on the board to support them and take strain off of the leads.

    I'll attempt to embed the time lapse here; if this fails I'll put in a link.  Some pictures of the finished board will follow.

    -Pat


    Board assembly time lapse


    Last edited by Cubdriver on Wed Feb 25, 2015 2:44 pm; edited 2 times in total

    Cubdriver

    Posts : 68
    Join date : 2014-01-21
    Age : 51
    Location : Southeastern Litchfield Co, CT

    Re: M125 construction FINALLY started...

    Post by Cubdriver on Tue Feb 24, 2015 11:58 pm

    And here are some images of the finished boards:

    Bottom oblique:


    Cap end detail:


    Tiewrap anchor detail:


    Now to get ambitious and powder coat the transformer end bells...

    -Pat

    skriefal

    Posts : 116
    Join date : 2011-09-20
    Location : Utah, USA

    Re: M125 construction FINALLY started...

    Post by skriefal on Wed Feb 25, 2015 12:29 am

    Nice!

    BNR_1

    Posts : 78
    Join date : 2013-06-11

    Re: M125 construction FINALLY started...

    Post by BNR_1 on Wed Feb 25, 2015 10:06 am

    Nice job.....btw great photos. Looking forward to seeing your progress.

    Cubdriver

    Posts : 68
    Join date : 2014-01-21
    Age : 51
    Location : Southeastern Litchfield Co, CT

    Re: M125 construction FINALLY started...

    Post by Cubdriver on Wed Feb 25, 2015 1:00 pm

    Thanks.  You've gotta love a tripod for nice clear close up photos.  

    I have to say that I'm pleasantly surprised by how nicely the extended parts of the clear heatshrink folded down over the ends of the caps.  It looks almost as if it was meant to be, and was surprisingly easy to do while it was still hot and pliable - I just nudged it into place with my fingertips, and when it cooled and stiffened, it stayed nicely.  Next time I'll have a pencil or the like (something that doesn't feel pain from being burned, unlike my fingertips!) handy to do the forming.

    -Pat

    Frank111

    Posts : 83
    Join date : 2015-02-23
    Location : Minneapolis/StPaul Area

    Re: M125 construction FINALLY started...

    Post by Frank111 on Wed Feb 25, 2015 2:16 pm

    My M-125 kits are on their way, so I'll be following your postings closely! I appreciate your comments on mistakes you corrected with assembly. That's going to make me more aware of things as I proceed with the build. This is great timing!

    Frank.

    Cubdriver

    Posts : 68
    Join date : 2014-01-21
    Age : 51
    Location : Southeastern Litchfield Co, CT

    Re: M125 construction FINALLY started...

    Post by Cubdriver on Wed Feb 25, 2015 3:00 pm

    Frank, the key is to simply read the assembly instructions thoroughly.  I was happy to finally be building them, and in light of that not reading as carefully as I should have.  Bob's instructions are very good, but you need to actually read the WHOLE step, not just the beginning and end!  

    The balance pot instruction step notes that you need to check prior to installing them to be certain that they're centered in their adjustment range (the brief appearance of the DMM in the time lapse is me verifying this), then notes that they are to be installed on the underside of the board and soldered on the top, and finally that the adjustment is not to be further touched unless you have a signal generator and know what you're doing.  I followed the first part, missed the second and made a mental note of the third.  And put the pots on the top of the board.  And THEN realized what the second part of the step said.  D'oh!

    I debated just leaving them on top and sealing the adjustment screw with some nail polish, but then decided that I should do it right and move them to the correct location.

    In short, take your time, read the directions, and follow them.

    -Pat

    MontanaWay

    Posts : 767
    Join date : 2014-02-06
    Age : 58
    Location : Cameron, Montana

    Re: M125 construction FINALLY started...

    Post by MontanaWay on Wed Feb 25, 2015 4:43 pm

    there is something SERIOUSLY wrong with those photo's!!!!!!!!
    It is WAAAAAYYYYYY too clean and tidy...I could never work in those conditions!!!!!..... Shocked

    BNR_1

    Posts : 78
    Join date : 2013-06-11

    Re: M125 construction FINALLY started...

    Post by BNR_1 on Wed Feb 25, 2015 5:02 pm

    Are those adhesive anchors over pcb traces? If so do you know if they ever need to be removed are they going to pull/damage the trace?

    MontanaWay

    Posts : 767
    Join date : 2014-02-06
    Age : 58
    Location : Cameron, Montana

    Re: M125 construction FINALLY started...

    Post by MontanaWay on Wed Feb 25, 2015 5:21 pm

    BNR_1 wrote:Are those adhesive anchors over pcb traces?  If so do you know if they ever need to be removed are they going to pull/damage the trace?

    they should absolutely not do any damage what so ever to the pcb or traces. Might get a bit messy if ever one needs to remove them, but the chance of that happening is indeed very slim.
    So it is safe to do so.

    sKiZo

    Posts : 1287
    Join date : 2013-04-01
    Location : Michigan USA

    Re: M125 construction FINALLY started...

    Post by sKiZo on Wed Feb 25, 2015 5:34 pm

    Dressing your sockets? The VTA boards have copper on both sides just for that - makes for a much sturdier socket, which is a good thing if you're a roller ...



    Ditto for all the other components ...

    Cubdriver

    Posts : 68
    Join date : 2014-01-21
    Age : 51
    Location : Southeastern Litchfield Co, CT

    Re: M125 construction FINALLY started...

    Post by Cubdriver on Wed Feb 25, 2015 5:36 pm

    MontanaWay wrote:there is something SERIOUSLY wrong with those photo's!!!!!!!!
    It is WAAAAAYYYYYY too clean and tidy...I could never work in those conditions!!!!!..... Shocked

    LMAO - please note that the photos are VERY closely framed - I merely pushed the pile-o-crap out of the immediate area so it wasn't in the pics.

    This more to your liking, Montana?





    -Pat

    10-E-C

    Posts : 75
    Join date : 2014-02-12
    Age : 62
    Location : upper east tn

    Re: M125 construction FINALLY started...

    Post by 10-E-C on Wed Feb 25, 2015 5:40 pm

    I thought I saw a Puddy Cat!!!!!

    Cubdriver

    Posts : 68
    Join date : 2014-01-21
    Age : 51
    Location : Southeastern Litchfield Co, CT

    Re: M125 construction FINALLY started...

    Post by Cubdriver on Wed Feb 25, 2015 5:41 pm

    MontanaWay wrote:
    BNR_1 wrote:Are those adhesive anchors over pcb traces?  If so do you know if they ever need to be removed are they going to pull/damage the trace?

    they should absolutely not do any damage what so ever to the pcb or traces. Might get a bit messy if ever one needs to remove them, but the chance of that happening is indeed very slim.
    So it is safe to do so.

    They are over traces, but as Montana says, they can be removed without damaging anything.  I did it several times on the ST-70 board because I put them on before fitting the board, then discovered that I needed to shift the caps back due to mechanical interference under the chassis.  They're held on with foam tape - slice through the tape to separate the plastic mount from the board, then, using fingernails, orangewood spudgers and the like, the remaining foam and adhesive can be rubbed off the board with a few minutes of effort.

    -Pat


    Last edited by Cubdriver on Wed Feb 25, 2015 5:45 pm; edited 1 time in total (Reason for editing : Removed double quote)

    Cubdriver

    Posts : 68
    Join date : 2014-01-21
    Age : 51
    Location : Southeastern Litchfield Co, CT

    Re: M125 construction FINALLY started...

    Post by Cubdriver on Wed Feb 25, 2015 5:43 pm

    sKiZo wrote:Dressing your sockets? The VTA boards have copper on both sides just for that - makes for a much sturdier socket, which is a good thing if you're a roller ...



    Ditto for all the other components ...

    Dachh!  I *thought* I'd hit and re-flowed all the top connections for the sockets; apparently I missed.  Thanks for noticing, Skiz - will add some solder to them.

    -Pat

    Edit to add - I just realized that's one of the ST-70 board pics. I *did* hit the tops on this set of boards. Will perhaps revisit the ST-70 at some point, but it's working fine now (can be seen sitting on top of the bench) so that may be a future project.


    Last edited by Cubdriver on Wed Feb 25, 2015 5:49 pm; edited 1 time in total

    Cubdriver

    Posts : 68
    Join date : 2014-01-21
    Age : 51
    Location : Southeastern Litchfield Co, CT

    Re: M125 construction FINALLY started...

    Post by Cubdriver on Wed Feb 25, 2015 5:44 pm

    10-E-C wrote:I thought I saw a Puddy Cat!!!!!

    Yup, one of the two fur generators, absconding with a twist tie...

    -Pat

    MontanaWay

    Posts : 767
    Join date : 2014-02-06
    Age : 58
    Location : Cameron, Montana

    Re: M125 construction FINALLY started...

    Post by MontanaWay on Wed Feb 25, 2015 5:49 pm

    Cubdriver wrote:
    MontanaWay wrote:there is something SERIOUSLY wrong with those photo's!!!!!!!!
    It is WAAAAAYYYYYY too clean and tidy...I could never work in those conditions!!!!!..... Shocked

    LMAO - please note that the photos are VERY closely framed - I merely pushed the pile-o-crap out of the immediate area so it wasn't in the pics.

    This more to your liking, Montana?





    -Pat


    aaaaaahhhhhhh...yesssssss...now I feel more at home!!!!! What a Face

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