I have to "man up" and admit my limitations-- cannot complete Cornet2 kit

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Mullard12AX7

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Hello, all-- Some two years ago I bought a "half kit" of the totally excellent Hagerman Cornet2.
 In great anticipation I had Front Panel Express machine a special top plate (from a drill/machine guide posted by Jim Hagerman on his site) to go with the black anodized Cornet2 dedicated aluminum chassis I bought from Lansing Enclosures. The top plate has precision laser-cut holes for the tubes to stick through for both ultra-cool visuals and ventilation; they also laser etched the tube designations (12AX7, 12AU7, GZ34) next to each laser-cut opening and added a bright white lettering effect in these etchings to really make them "pop". The effect is terrific.

I also sourced the "world voltage" power transformer and all the rest of the parts. For an added cool factor I found vendors who could supply for the RIAA caps NOS 1950s Sprague Hyrel Q oil caps (REAL oil caps!!) that have been fully QC'd been on a decade capacitance bridge for selection to 2% tolerance and verification of all other parameters.
Resistors are all 2 watt metal films rather than one watt, bought on recommendation (from DigiKey). All other parts are spec quality, DigiKey or Antique Elec. Supply stock.

I sat down to begin construction. I should add that I had previously built a Bottlehead Seduction phonostage, with all its nearly invisible resistors ;0) so I felt more than confident.

Long story short, upon completion one channel worked flawlessly, and one only worked when the DC ground leg was grounded to an external "true" ground. I determined that I had bridged two of the mounting holes on capacitor C205L, and to add insult to injury, I worked past the point of fatigue and in finishing up, I made the rookie error of installing the LED that turns red then green on the wrong side of the board.

 I saw the designation "LED" printed there on the wrong side, was to tired, , and I had mounted everything else on that side, so OOPS! hat a rookie error; I felt quite the fool.

I went back and corrected the C205L issue, but in de-soldering and removing the LED, the small, round metal "eyelets" at each thru-hole of the PCB to which the LED  actually connects CAME OFF the PCB board,  from the heat of de-soldering and re-soldering. (these metal eyelets on each thru-hole in turn connect to the actual copper traces on the board)

I bought additional parts from DigiKey to correct this problem, but at this point it just seemed that every tiny issue I tried to fix (really only 4-5 problems, but still) just got WORSE with my efforts. The metal contacts would pop off the board, and I could NOT subsequently make contact/continuity with the PCB trace. I think anyone skilled at using small-gauge bare copper wire to "repair" end-to-end integrity of PCB traces which have lost the eyelets at the thru-holes will have a VERY easy time of  creating full functionality. NONE of the traces are damaged, some are just missing the eyelets and thus cannot be connected to. Sorry for my bad explanation. I can answer any questions.

I firmly believe this kit could be completed in less than one hour by someone more skilled than myself.  But I cannot get there. It is humbling, frustrating, and depressing.

My question now is... what next?

I could:

1. Try to find a tech who could charge me for the completion of my Cornet2 (and it really is like 99% complete! So close... but so far)

2. Sell it on eBay or Audiogon... with the hope of netting enough $$$ to buy a Hagerman Cornet 3, pre-built of course!!!

3. I'm totally open to other suggestions here!

Just to be safe, I purchased additional parts such as the LED,  all FIVE 47 uf 450 volt DC electrolytics from Digikey because I was now doubting the 'lytics I had bought from China via eBay, and various extra resistors etc.

I'm short the (2)  one uf output caps, but nothing else.

I can upload a HOST of pictures-- it really looks quite good! I had built the Bottlehead and can make beautiful construction, but I just made some rookie mistakes with my Hagerman Cornet2, not having built a PCB-kit. I somehow bridged a couple contacts (I GUESS) and mounted the LED on the wrong side... small errors.... but ones that have stopped me in my tracks.

It is such a downer to hear how great my friends Cornet2 sounds (just wonderful) and EVERY TIME hear him say "well, I guess you messed it up!"
 He also needed a mutual friend to bail him out of a few mistakes, so that is why it is annoying :0(

Anyway-- I can post a photo gallery tomorrow night showing much detail, and my extra parts, and overall the state of construction....

This REALLY WOULD be easy for someone with diagnostic experience the right basic equipment, especially if they are experienced in placing small, bare copper wires on a PCB to "enhance" connectivity of such which cannot be connected in the ordinary way because of the aforementioned missing metal eyelets that enable connectivity between the resistor/capacitor/LED etc and the copper trace on the PCB board itself.

Thanks in advance, more than you would ever know, to anyone who can help me out. This has very much put my ambition in check and humbled my bravado!

Thanks agin!  Chris


hagtech

If you can't find anyone else - send it in.  But my time is in short supply - so I may not get to it very quickly.

jh

S Clark

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Can you post a close up picture?  Many of us have experience in jury rigging our screw ups.  I bet an relatively easy solution may be possible.

mresseguie

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This may sound strange, but I envy you your ability to make the attempt and fail. I can't even commit to making the attempt for lack of experience and confidence.

+1 for effort!

dB Cooper

I built a lot of kits in my earlier days and not long ago bought an O2 headphone amp... assembled. My close eyesight ain't what it used to be. Recently I opened it up for a little "surgery" which involved snipping two resistors off the board to make one of the gain switch settings more suitable for my sensitive IEMs. I didn't have a problem doing that, but looking at the board, I found myself thinking, Jeez, I'm glad I didn't try to build this thing myself. Small parts, small traces, tight layout... I'd be in the same boat if I had built it up. And worst part is, it would have been no problem in my younger days.

I also have a Dyna FM3 tuner in a mostly disassembled state that I've been "meaning to" finish for... uh.. a very long time  :oops: Probably going to find a home for it here soon.

Thanks for sharing. Asking for help is a sign of strength, not of weakness, a friend of mine is always saying. And plus one on mresseguie's thoughts.

randytsuch

So I've built a fair number of projects, and along the way have had to repair things, and sometimes I alter the board for various reasons.  If you want to try to repair, I'll give some advice to help.  If I had a working TT, I might offer to repair, but my TT is in mothballs, and the tonearm wiring is broken and not likely to be repaired anytime soon.

To perform the repair, you need to right tools.  You must have a soldering iron already, hopefully it is decent.  I have a temperature controlled iron and a few size tips for it.  It's nice to have a small tip for delicate work, and a large tip when you need a lot of heat, at a minimum.

Depending on your age and eyesight, some type of magnifier may be useful.  I have a visor type one, that has assorted lenses with different powers.  I could not work without this, but I'm older and my eyesight isn't what it used to be.

The trickiest part of the repair is that you will have to scrap off the solder mask at the traces next to the damaged holes.  May sound hard, but with a little practice it's no big deal, I've done this a bunch of times.  You need an sharp rounded end exacto blade.  I have used straight exacto blades in a pinch, but it's harder and not recommended for a novice.  You may want to practice first on a scrap board, or a large area of the Cornet where it is just copper with nothing close by.  You carefully, and gently scrap away the mask until you have bare metal.  You need to create an area large enough to solder to.  Once you have this, you can solder a wire to it to repair the damage.

I built a Cornet2 a while ago, and from what I remember the traces are fairly large, with decent spacing between traces, which will make this task easier.  I've worked on DAC's with surface mount parts and very small traces, where this type of repair is much more delicate.

If you have questions, I'll try to answer as I have time, and pictures would help.

Also, I would stay away from Chinese caps.  I buy some Chinese stuff, but you need to worry about counterfeit parts, and caps are easy to fake.  So I would replace them, but that's me, you need to decide if it's worth it.  But, I would try to repair the board first, and get it working before messing with the caps.

Randy

Mike B.

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Wish I had a dollar for every component I had smoked or trace I destroyed. I totally sympathise with your predicament.

S Clark

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I'll take a shot in the dark.. If the "eyelet" is loose and the trace if lifted, I'd solder a fine wire to the LED lead(or even a bit of lead from one of your replacement capacitors), then solder that to where the trace leads (the next cap or resistor) with an extra bit of solder.  Are you using an adjustable soldering station? If so, you might turn the heat down a bit.