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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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| Posted: Sat Dec 27, 2008 8:03 pm Post subject: |
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The thing I like most about this forum are all the people that go out of their way to help others ! 
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rabies_70
Joined: 15 Feb 2007
Posts: 1189
Location: Carlsbad, CA
TV/Projector: Sony G70Q
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| Posted: Sat Dec 27, 2008 8:36 pm Post subject: |
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Macgyver, you're the bomb. As soon as I get back from installing these custom gates I built I'm going to try to not zap myself and dig into the amps.
I can still buy a variac right?
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Ray
I am an iconoclast
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sat Dec 27, 2008 8:47 pm Post subject: |
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| rabies_70 wrote: |
I can still buy a variac right? |
I guess if you want to hook up all your outdoor christmas lights to it so you can dim them down if the neighbors are complaining. 
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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| Posted: Sat Dec 27, 2008 8:53 pm Post subject: |
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I have a neighbor who put up runway landing lights for Christmas... The guy was dimmer than I thought !
Still waiting for that 747 to come crashing through my front door though. 
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rabies_70
Joined: 15 Feb 2007
Posts: 1189
Location: Carlsbad, CA
TV/Projector: Sony G70Q
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| Posted: Sat Dec 27, 2008 8:57 pm Post subject: |
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Anybody here have any advice on what type of "dummy load" for testing amp output I should be looking at?
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Ray
I am an iconoclast
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sat Dec 27, 2008 10:19 pm Post subject: |
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| rabies_70 wrote: | | Anybody here have any advice on what type of "dummy load" for testing amp output I should be looking at? |
RAY!!!!!!!!!!!!!
The dummy load is only used for adjusting the bias section of the amp......................AFTER ITS FIXED............ and is not necessarily needed to be adjusted in the first place.
Dont mean to yell but you need to concentrate on finding the problem...........see if you can get the parts...........and see if it works with a cheapo speaker. What if it ends up not being fixable?
Unless your going into the professional amp repair business dont buy more then you need just to play.......
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rabies_70
Joined: 15 Feb 2007
Posts: 1189
Location: Carlsbad, CA
TV/Projector: Sony G70Q
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| Posted: Sat Dec 27, 2008 10:31 pm Post subject: |
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That's my problem for sure...focus grasshopper. Instead of changing the fuse I'll drop 500 on tools and testers "just in case" bwahahahaha 
I still haven't gotten out of here to go install the gates, but I did get to set up the 15 foot tall fruit tree made out of aluminum pipe that some crazy art lady paid me 14000.00 to build for her. We had it in LA a couple weeks ago and it's going back to be exhibited again. Then it should be off to NewYork, Greece and some other big cities. She want's me to build her a pair of 3d glasses next. 12 foot by 9 foot by 4 foot. I love SoCal
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Ray
I am an iconoclast
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Sat Dec 27, 2008 10:40 pm Post subject: |
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For informational purposes, you can build a dummy load but your resistors must assembled a certain way and meet or exceed the maxium wattage output of the amp your testing.
For example, for a 100 watt 8 ohm dummy load you would need (4) 8 ohm 25 watt resistors. You would wire half of them (in this case 2) in parallel and then wire the 2 halfs in series to create your correct load. Other wattages could be used but must total or exceed the wattage being tested and when more then 4 resistors are used then more math is involved for final ohm and wattage rateing.
For a 100 watt 4 ohm you would do the same except using 4 ohm resistors, or take (2) 8 ohm dummy loads and wire them in parallel. Wiring (2) 8 ohm loads in parallel will lower the load to 4 ohms and double the wattage rateing. So (2) 8 ohm 100 watt loads wired in parallel will create (1) 4 ohm 200 watt load.........................
End of todays lesson........
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jkruger
Joined: 24 Oct 2007
Posts: 2435
Location: Carlsbad, CA
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| Posted: Sun Dec 28, 2008 1:49 am Post subject: |
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Ray, I have a variac at work that I'm not using if you want to borrow it. I may have a freq generator too
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rabies_70
Joined: 15 Feb 2007
Posts: 1189
Location: Carlsbad, CA
TV/Projector: Sony G70Q
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| Posted: Sun Dec 28, 2008 2:08 am Post subject: |
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Are you sure you don't want to sell it???...wait a minute...I'm not supposed to be distracting my self with thoughts of more tools...(anyone who has seen my garage can vouch for this)
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Ray
I am an iconoclast
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jkruger
Joined: 24 Oct 2007
Posts: 2435
Location: Carlsbad, CA
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| Posted: Sun Dec 28, 2008 2:10 am Post subject: |
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Yes I have seen your garage, and you DO NOT need more tools!
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ronholm
Joined: 26 Jan 2007
Posts: 12111
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| Posted: Sun Dec 28, 2008 4:07 am Post subject: |
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| jkruger wrote: | | Yes I have seen your garage, and you DO NOT need more tools! |
LMFAO... Nice to know I ain't the only one.... The day I admitted my problem I was buying specialty tools to repair the tools I didn't need to work on a toy I didn't need..
ROTFLMFAO...
Hi my name is Ron and I am a toolaholic...
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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| Posted: Sun Dec 28, 2008 4:15 am Post subject: |
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You're forgiven my son...
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rabies_70
Joined: 15 Feb 2007
Posts: 1189
Location: Carlsbad, CA
TV/Projector: Sony G70Q
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| Posted: Mon Jan 12, 2009 8:50 am Post subject: An update |
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Not dead yet. No electrocutions yet either  
1 GFA-555 fixed. I'm way stoked even though I had emergency dental work - a crown put on two days ago. I guess the answer to the question of how to fix an amp was a wee bit more involved than I anticipated. Hat's off to you board repair guys. There is a ton of stuff to know and recall in troubleshooting an electronic fault at the board level....crazy stuff.
I took 2 electronic theory e classes, made a pdf study guide, bought a BUNCH of cool tools that are definitely very useful. Did my first soldering on a circuit board assembling a Blue ESR meter. Very nice piece of kit Anatek sells it. Figured out how to use the oscope I got last year trying to chase a different audio gremlin. Learned to use , sorta, a bunch of new tools, Audio oscillators, transistor FET testers in or out of circuit, flyback testers, LCR meters, capacitance meters, high voltage probes, variacs,DC power supplies, online resistor calculators, dummy loads.....I bought a couple isolation transformers to help keep me from getting electrocuted or from frying my new to me tools. Got them WAY cheap. 40.00 for two locally. You can see the torroid one under the oscope. The transformer is huge! What a huge outlay of cash and time to answer my question. But in the end the satisfaction of firing up the amp, and then when it didn't blow up, and using the computer sound card as a cheap preamp and some old Wharfdale Delta30.2 speakers and they didn't blow. It was all Very Cool.
What ended up being the problem on this one? I think the initial problem was a typical (so I read on the net) failure of the grounding sleeve on the rca input. They say the development of these so called super strong monster style connectors weren't envisioned when the engineers speced out the older rca inputs and they weren't designed to withstand the griping force of this connector and the sleeves end up being ripped off, occasionally causing a fuse to blow. Someone had repaired it by bypassing the stacked pcb mounted input and replaced that with individual isolated chassis mounted inputs. The solder joint for the ground connection was broken. I resoldered it and replaced the wire with something I salvaged out of an older Scott amp I was sacrificing to practice soldering and desoldering on. Replaced the fuses that were not 3AGC 6A, and I'm listening to the Alex Jones Show on a sweet Adcom GFA-555. Thanks Curt. I'm pretty sure the first place I ever read about cracked solder joints was on your web site. Now we all know you didn't find and write about the first cracked solder joint ever, but your site is where I recalled that info from and you saved me a ton of dough. Soon as I get some more paypal money I'm donating some to the site. Thanks Curt Kal; and everyone else who hangs out here spreading info.
Heres some photos of the new tools
The Blue ESR meter
The once offending amp
Time to button it up and move on to the next one.
Anyone here ever heard of TC Sounds subwoofers??? Super bad ass hand made drivers??? There a pair for sale on ebay right now. I bought a tcsub for 10.00 the other day for giggles. Going to put it on the bench soon too. It should be insane. I have never seen so many adjustments on on a plate amp in my life. Pics soon.
I also you Tubed Tesla during one of my many segues in electrical theory and repair theory. Tesla's brain was so different from the rest of us. What a trip.
http://www.youtube.com/watch?v=pTiiblwwLPk
I think I want to build a Tesla coil outside now.
_________________
Ray
I am an iconoclast
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Mon Jan 12, 2009 11:13 pm Post subject: |
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Congrats Ray.................. That thrilling feeling you got when you fired that baby up and it worked doesn't go away after time. It is there almost every time. Just ask Curt as I know he's said to me on a few occasions he still gets it most of the time and he's in the thousands. I've been in this for years also and still enjoy the feeling when you turn it on and all works as it should.
But then there's the times you hit the switch and more smoke comes out........ then its lots of 4 letter words.......
Anyways, glad it has worked out for you. Hope you have the same luck with the other one. Keep us informed.
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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| Posted: Tue Jan 13, 2009 12:11 am Post subject: |
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Great Job Ray Isn't is awesome when you fix something on your own,even with help from the guys on this site it still feels great!!
that what i love about this community, just a bunch of great Guys!!! Cool equipment! I have a dual chanel scope and I also have one of those isolation tranformers too, you think that is huge you should see the one i put in for my Theater!! 150 lbs!!! 5 Kva's !!!!
Now you need to upgrade that amp via the POOGE files ! 
Athanasios
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