jess28 Posted March 16, 2012 Share Posted March 16, 2012 hey guys,I decieded to check out the inside of a recently purchased gfa 555 when much to my surprise i found two internal fuses wrapped in f'ing foil I know this isnt good I actually remeber macguyver doing the samething back in the day. nothing looks damaged to the eye. I can only assume he did it for one of two reasons it was constantly blowing fuses or he noticed it wasnt working before i picked it up and just did it so worked when i picked it up. if i replace these with the correct fuses will it be safe to at least try to hook my speakers up? Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted March 16, 2012 Share Posted March 16, 2012 This is always a problem when someone "improves" equipment. My suggestion is to go to radio shack and get the proper fuses (and an extra one) and also buy a couple of 10 watt resistors that are about 10 Ohm. Wire them together (parallel). Use this resistor as the load rather than an actual speaker. It will save your speaker and you can use it when you check the bias in the amp (they only cost about a dollar). If the "technician" has messed around with the fuses, they may have also messed around with the bias. You can find a service manual for that amp via google for the proceedure on checking the bias. Note: the resistors will get hot. Incidentally, these are great amps but they are older. The electrolytic caps should be replaced at some point. The power supply caps can also be bypassed (goggle this also) to improve the sound. This is a cheap mod that was sometimes done in the later, series 2, units. Quote Link to comment Share on other sites More sharing options...
jhoak Posted March 16, 2012 Share Posted March 16, 2012 The service manual for the GFA-555 is available at hifiengine.com. If you're not a member there registration doesn't cost anything. Hifiengine.com is a terrific resource for owner's manuals and service manuals Quote Link to comment Share on other sites More sharing options...
jess28 Posted March 16, 2012 Author Share Posted March 16, 2012 thanks so much alreay got the fuses. the caps look fine visually at least none are buldging or leaky was planning on replacing anyway gunna run back to radioshack and hopefully get this figured out i messaged the guy very politly aked him why he did this,still hasnt gotten back to me i can telll he only did it recently the foil wasnt old, but thats a hell of a thing to do to somebody thank god i looked been running it for about a week now Quote Link to comment Share on other sites More sharing options...
oldenough Posted March 16, 2012 Share Posted March 16, 2012 You can safely use foil as long as you are sure of the electrical rating of it, I find the foil from a pack of cigarettes is generally good for 4.0 amps 120V. Baking foil, can be tricky as it tends to come in a variety of thickness', and always remember to not wrap the fuse more than once, doing this will throw all rating specs out the window. I tend to not use foil whenever possible, I prefer to dis-assemble the fuse, and replace the wire within. [] Quote Link to comment Share on other sites More sharing options...
jess28 Posted March 16, 2012 Author Share Posted March 16, 2012 now if he did change the bias could that account for the fact that this particular amp seems to run very cool compared to the other gfa 55s i've owned through out the years dont know a whole lot about the subject also he was using this amp to power the woofers on on a pair of tri-amped homade horned 3way speakers very nice looking wich would leave me to believe he has a pretty decent knowledge of electronics i would not be surprised if he messed with the amp Quote Link to comment Share on other sites More sharing options...
jess28 Posted March 16, 2012 Author Share Posted March 16, 2012 You can safely use foil as long as you are sure of the electrical rating of it, I find the foil from a pack of cigarettes is generally good for 4.0 amps 120V. Baking foil, can be tricky as it tends to come in a variety of thickness', and always remember to not wrap the fuse more than once, doing this will throw all rating specs out the window. I tend to not use foil whenever possible, I prefer to dis-assemble the fuse, and replace the wire within. 3 amp 125v Quote Link to comment Share on other sites More sharing options...
Schu Posted March 16, 2012 Share Posted March 16, 2012 I've used that technique to rescue myself from the side of the road with a blown fuse in my motorcycle. worked like a charm Quote Link to comment Share on other sites More sharing options...
Guest " " Posted March 16, 2012 Share Posted March 16, 2012 maybe the foil was to shield the fuse and improve the sound. Pen springs seem to be the most popular emergency repair...I find those in a lot of pro gear. Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted March 16, 2012 Share Posted March 16, 2012 I'll ignore the suspect advice about the benefits of using foil. It is simply a bad idea. As far as setting the bias goes, if the bias was set lower, then the heat sinks would run cooler. Usually, tweakers raise the bias and have the heat sinks run hotter. In my opinion, if the amp had been "worked on" by someone who is not a technician, then there is a huge red flag. Proceed with caution, There are plenty of Adcom GFA55's on the used market that are unmolested. Quote Link to comment Share on other sites More sharing options...
cyto Posted March 16, 2012 Share Posted March 16, 2012 hey guys,I decieded to check out the inside of a recently purchased gfa 555 when much to my surprise i found two internal fuses wrapped in f'ing foil I know this isnt good I actually remeber macguyver doing the samething back in the day. nothing looks damaged to the eye. I can only assume he did it for one of two reasons it was constantly blowing fuses or he noticed it wasnt working before i picked it up and just did it so worked when i picked it up. if i replace these with the correct fuses will it be safe to at least try to hook my speakers up? When I was an electronics tech in the 70's someone brought a Fender guitar amp into the shop and said "it smoked and burned". When I took it apart the fuse was wrapped in foil, a total loss. That is always a bad idea... Find the reason and fix it [Y] Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted March 16, 2012 Share Posted March 16, 2012 I knew a guy who could rewire a Crown DC300 to put out 250 wpc using only a Ding Dong wrapper. Quote Link to comment Share on other sites More sharing options...
fini Posted March 16, 2012 Share Posted March 16, 2012 You can safely use foil as long as you are sure of the electrical rating of it, I find the foil from a pack of cigarettes is generally good for 4.0 amps 120V. Baking foil, can be tricky as it tends to come in a variety of thickness', and always remember to not wrap the fuse more than once, doing this will throw all rating specs out the window. I tend to not use foil whenever possible, I prefer to dis-assemble the fuse, and replace the wire within. Can I send a few of my fuses for reconditioning? Rewiring fuses is a lost art form. In return, I will rebuild an equal number broken golf tees. If golf is not your game, I can re-lead your Ticonderogas. Quote Link to comment Share on other sites More sharing options...
stormin Posted March 17, 2012 Share Posted March 17, 2012 I knew a guy who could rewire a Crown DC300 to put out 250 wpc using only a Ding Dong wrapper. LMAO! Quote Link to comment Share on other sites More sharing options...
jess28 Posted March 17, 2012 Author Share Posted March 17, 2012 i'm sure there are alot of ppl who are electronics savy who find it alright to do something like that for a quick fix or what ever i am not one of those people. imo the fuses are there for a reson to protect my equipment. the seller got back to me and tried to pass it off on somebody else, saying he bought the amp used and never opened it up. i find it hard to believe that a guy who spent so much time building thoses beutiful 3 way speakers and has the knowledge of electronics he does would just hook up a used amp and hope for the best ! I almost always inspect any used gear before plugging it in .I did not do it right away this time and could have paid dearly for it thank god nothing happened taking it to my local repair shop on monday they give free estimates and can hopefully tell me if the amps ok to use Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted March 18, 2012 Share Posted March 18, 2012 I knew a guy who could rewire a Crown DC300 to put out 250 wpc using only a Ding Dong wrapper. LMAO! That's the same guy who could build a tube amp with a potato, a safety pin, and two condoms.....[] Quote Link to comment Share on other sites More sharing options...
fini Posted March 19, 2012 Share Posted March 19, 2012 I knew a guy who could rewire a Crown DC300 to put out 250 wpc using only a Ding Dong wrapper. LMAO! That's the same guy who could build a tube amp with a potato, a safety pin, and two condoms..... Aren't the two condoms Ding Dong wrappers? Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted March 19, 2012 Share Posted March 19, 2012 Best Klipsch tech quote ever 'A K43 woofer will successfully protect a 4 amp fuse) - Jim Hunter in a Technical Bulletin re the MWM woofer fuse. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.