Adcom gfa 7400 no sound

rooftop59
rooftop59 Posts: 8,121
edited February 2013 in Electronics
Hey All,

I just got an adcom gfa 7400 off fleabay. The guy said its worked perfectly right before he sent it, now the red light comes on but I get no sound out of any channel. I have tried different sources, cables, and speakers, all which work in other contexts, but nothing here. I tested the main fuse on the circuit board and the one in the back of the amp as well as the fuses for each individual channel and they are all good. I talked to the repair guy at the authorized reapir center in jersey and he basically said he thinks its highly unlikely that all five channels are out and that chances are it is small and something just came loose, which is what I am thinking as well but I don't have much experience so I am not sure what else to look for or check. Any suggestions?

Thx!
Living Room 2.2: Usher BE-718 "tiny dancers"; Dual DIY Dayton audio RSS210HF-4 Subs with Dayton SPA-250 amps; Arcam SA30; Musical Fidelity A308; Sony UBP-x1000es
Game Room 5.1.4: Denon AVR-X4200w; Sony UBP-x700; Definitive Technology Power Monitor 900 mains, CLR-3000 center, StudioMonitor 350 surrounds, ProMonitor 800 atmos x4; Sub - Monoprice Monolith 15in THX Ultra
Bedroom 2.1 Harmon Kardon HK3490; Bluesounds Node N130; Polk RT25i; ACI Titan Subwoofer
Post edited by rooftop59 on
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Comments

  • B Run
    B Run Posts: 1,888
    edited February 2013
    Were you already running an amp from your avr via pre outs? What avr or pre are you using?
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  • rooftop59
    rooftop59 Posts: 8,121
    edited February 2013
    I tested it the way I test all my amps when I first get them; I plugged my phone in using an adapter and tried every channel. nothing. I even tried my computer that worked before a nd after, but not through the amp. thoughts?
    Living Room 2.2: Usher BE-718 "tiny dancers"; Dual DIY Dayton audio RSS210HF-4 Subs with Dayton SPA-250 amps; Arcam SA30; Musical Fidelity A308; Sony UBP-x1000es
    Game Room 5.1.4:     Denon AVR-X4200w; Sony UBP-x700; Definitive Technology Power Monitor 900 mains, CLR-3000 center, StudioMonitor 350 surrounds, ProMonitor 800 atmos x4; Sub - Monoprice Monolith 15in THX Ultra
    Bedroom 2.1     Harmon Kardon HK3490; Bluesounds Node N130; Polk RT25i; ACI Titan Subwoofer
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  • B Run
    B Run Posts: 1,888
    edited February 2013
    Hmm I don't see any reason why it wouldn't be working honestly, think this is well above my knowledge level. Hopefully someone else can chime in with any ideas.
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  • deronb1
    deronb1 Posts: 5,021
    edited February 2013
    are you plugging the phone with the adapter directly into the amp or do you have a preamp?
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  • rooftop59
    rooftop59 Posts: 8,121
    edited February 2013
    straight in and use the volume on my phone. this is how I listen to music in the garage through a gfa 535 and some Polk m3s. works fine every time, but not with the 7400. as I said I also used the output from my music streamer II which was working fine before and after on my computer rig. so it's not a source problem. any other ideas?
    Living Room 2.2: Usher BE-718 "tiny dancers"; Dual DIY Dayton audio RSS210HF-4 Subs with Dayton SPA-250 amps; Arcam SA30; Musical Fidelity A308; Sony UBP-x1000es
    Game Room 5.1.4:     Denon AVR-X4200w; Sony UBP-x700; Definitive Technology Power Monitor 900 mains, CLR-3000 center, StudioMonitor 350 surrounds, ProMonitor 800 atmos x4; Sub - Monoprice Monolith 15in THX Ultra
    Bedroom 2.1     Harmon Kardon HK3490; Bluesounds Node N130; Polk RT25i; ACI Titan Subwoofer
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  • deronb1
    deronb1 Posts: 5,021
    edited February 2013
    rooftop59 wrote: »
    straight in and use the volume on my phone. this is how I listen to music in the garage through a gfa 535 and some Polk m3s. works fine every time, but not with the 7400. as I said I also used the output from my music streamer II which was working fine before and after on my computer rig. so it's not a source problem. any other ideas?

    Well, no. Unless the 7400 has a mininum mv requirement from the source for it to operate. Maybe broken solder joints where the R/L imputs connet to the board? Dunno man, wish I could be of more help.
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  • nwohlford
    nwohlford Posts: 700
    edited February 2013
    Was this the one without a top? If so, you may just want to make sure it is clean inside.

    If all the channels don't work, you have to think the amplifiers are not getting power which seems a little weird considering the light on the front comes on. (Since it seems unlikely you would have the same problem on all five channels.) Like most Adcoms, you should get a pop in your speakers when you turn it on. Do you have this happen?
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  • rooftop59
    rooftop59 Posts: 8,121
    edited February 2013
    yes it is that one and everything looks fine, but I'm no expert . And no pop. any ideas?
    Living Room 2.2: Usher BE-718 "tiny dancers"; Dual DIY Dayton audio RSS210HF-4 Subs with Dayton SPA-250 amps; Arcam SA30; Musical Fidelity A308; Sony UBP-x1000es
    Game Room 5.1.4:     Denon AVR-X4200w; Sony UBP-x700; Definitive Technology Power Monitor 900 mains, CLR-3000 center, StudioMonitor 350 surrounds, ProMonitor 800 atmos x4; Sub - Monoprice Monolith 15in THX Ultra
    Bedroom 2.1     Harmon Kardon HK3490; Bluesounds Node N130; Polk RT25i; ACI Titan Subwoofer
    · Share on FacebookShare on Twitter