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Old 8th February 2010, 07:37 PM   #31
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Quote:
Originally Posted by littlerick View Post
Heres the soldering... Let the flaming begin!!!

http://img189.imageshack.us/img189/5753/picture012r.jpg

A little sloppy but not that bad for a first timer As long as you checked your solder points and they arent overlapping/shorting you should be alright.

Im in the waiting stage myself now too. Have the boards soldered up and ready to go, but I need to order up the remaining parts to finish them up.

Good luck with the final assembly and testing. Let us know how it goes.
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Old 8th February 2010, 08:09 PM   #32
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Hi littlerick.

Clean your boards with Isopropyl Alcohol and a new toothbrush. Scrub all the flux residue and solder splats off and inspect it all carefuly under a magnifying glass for shorts between pads or solder whiskers, twice. You can buy Isopropyl at a pharmacy but you will probably have to take a circuit board in to show why you want it. I had a nightmare buying it round here until I found a non jobsworth Pharmacist who doesn't think I will drink it!

Do the cleaning outside though, no smoking and don't breathe in the vapour.

I would reflow any joints that don't look all shiny and lovely. It looks like some are dull on the photo. When you switch your soldering iron on, go make yourself a tea or coffee and have a fag if you are a smoker. When you come back to the iron it will be hot enough to use rather than being nearly hot enough and giving you dry joints. Buy some tip tinner too, it keeps things nice and shiny.

Have you put AndrewT's lightbulb tester together for your powering up ceremony? It won't take long and could save you from a demoralising failure by lighting up to alert you to an assembly problem before the magic smoke does. A cheap pair of "sacrificial" test speakers is a good thing to have too.

Good luck

John
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Old 8th February 2010, 08:21 PM   #33
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Read and build the simple pass-through version light bulb doo-hicky...

... read about that here ...down near the bottom of the page. Whip that thing together.

Basically it's insurance for the first power-up...and quite brilliant, regardless of its simplicity.

I really should make one myself...
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Old 8th February 2010, 08:43 PM   #34
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He He... I just had a read of all that... its made me more nervous... however i think i will build a bulb tester to be safe.

I dont think the bang from a dodgy wired amp will be as loud as the wife telling me how much the bang just cost me. Not sure which makes me more nervous.
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Old 8th February 2010, 10:01 PM   #35
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Quote:
Originally Posted by littlerick View Post
Heres the soldering... Let the flaming begin!!!

http://img189.imageshack.us/img189/5753/picture012r.jpg
Some have too much solder and not enough heat.

G
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Old 9th February 2010, 08:34 AM   #36
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Would I be better off if I put some insulation tape around the screws holding 4780 in place or will they not affect the grounding?
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Old 9th February 2010, 03:36 PM   #37
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You may put some insulation, I did that too to be certain.

Also, check with a meter for any shorts.
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Old 9th February 2010, 08:22 PM   #38
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The enclosure is turning out to be harder than the kit to build... coordination with a drill and saw is not my best quality. However it is starting to look nice.

I am making a light bulb tester before I turn it on at all... Still trying to figure out the settings on my multimeter, but my father in law is a electrician, so I will grab him before the big day.

I'm actualy more nervous about the switch on than i have ever been about anything... Well maybe not as much as going to the dentist, but its close.
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Old 10th February 2010, 12:04 AM   #39
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Hi littlerick

Build your bulb tester now so it is available as you get nearer complete. You should test each stage in turn as you put it all together rather than once it's all together.

Check your transformer first to make certain you know which are the secondary pairs. It will be AC there so make sure you set your meter to more than the AC voltage expected. It will be a bit higher than rated as there is no load on the transformer yet.

Next check the power supply WITHOUT amp boards connected and make sure you have the right DC voltages from the power supply. Dodgy soldering can look ok but give a big resistance so if any voltage is off spec suspect that first. Your bulb should just flash as power goes on and then go out. If it stays lit above a glimmer you have a problem that is drawing too much current.

Make sure you understand how to arrange the safety ground and fusing. Stick to it like your life depended on it, it just might. If in doubt ask rather than risk it.

Only once the psu has passed testing can you connect the amp boards safely. Make sure nothing can short to the enclosure bottom plate and keep it as neat as you can. Signal wires away from power wires and that kind of thing. Test for DC on the speaker outputs before connecting any speakers too.

Then sit back and grin like an idiot at the amp you have put together sounding way better than your mates expensive shop bought kit!

John
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Old 10th February 2010, 10:33 AM   #40
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I'm sorting fuse holder for the chassis mains.. I know I need a slow blow fuse but what would be best ampage to get.

300VA 2x22v transformer and I'm on 240v mains 1,2 or 5 amp fuse?
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