I've got the 1st gen 545 and 555. The larger had two blown fuses just like that. Both work and sound great still. Thanks for showing, looks like relatively easy to test.
I had a plasma torch blow a fuse. Spent an afternoon checking everything out. Found nothing. Changed big fuse and it's still running four years later. Good work Steve.
I've had fuses that just fatigued, those were slo-blo fuses and as you know, every power up those fuses wires stretch a bit causing some fatigue.....who know, maybe the company engineer underrated the fuses... 👍 again.!
Hi, I’m a subscriber. My class A amp, (adcom gfa5802) just recently developed a slight buzzing hum on the left channel. Do you think the filter capacitors for the left channel are bad? I checked the DC voltage at the speaker terminals and they’re at 0.025V, so I think the coupling capacitors are fine. Or do you think it’s something else? Thanks in advance.
It may be one of the main filter capacitors that is failing indeed. Measure the DC voltage and compare it with the same capacitor on the other channel, if one is lover than that may be the one. Also measure the AC voltage with no signal on all of the mail large filter capacitors. If one has more AC voltage across it then that is the culprit.
Where are you located? I have the same Adcom amp with intermittent left channel cut out. I get static sometimes, and sometimes nothing. Sometimes it plays perfect. I would love to get it repaired.
I have an original 1986 GFA-535 with the custom Adcom 6800uF 63V aluminum electrolytic capacitors with three (two active) pin terminations. The amp was used for 15 years powered 24/7. Do you know of a replacement cap? If not do you know the cap's active terminals spacing? The caps are not leaking or bulging, should I even consider replacement? Thanks!
They were powered 24/7 for 15 years then sat idle for 20 years. If the caps 'look' OK it is better to increase DC voltage slowly across the cap to regrow oxide (?). That's difficult to do without the use of a variac. I have used the amp a couple of times in the last year to 'burn-in' speakers. I searched for replacement caps online from all major parts suppliers but I need to know active pin spacing?
I got a second gfa 7000 thx that the caps leaked I wonder how much to recap all of them I have two of them other one fine but should do that next and I also have a gfa 7500 thx my favorite of them all that I use now all of them are 5 channels anyway just wondering will get them all done when the price is right thanks
Possibly but if the speaker wires were shorted I would expect much more damage, like shorted output transistors and totally blown (carnage) fuses. I think it was a gentile overdriven condition.
Too bad a Chinese company owns Adcom now. Mine was made in New Jersey and was owned by Emerson Electric then. Looks like the build quality isn't bad looking on this unit though. Oh and mine is big brother...GFA-555. Not the 555 II either.
I've said this before, but Norcal has gotta be the most methodical & certainly has the best fault finding technique on the web. Unreal talent
Agreed, very good troubleshooting skills.
Thank you Frank!
@@norcal715 Frank? Frank? Frank? Frank?
What is the amp size of those two blown fuses?
Thanks for the tips on checking transistors. I have a pile of adcom equipment, and this will help me keep it alive.
I've got the 1st gen 545 and 555. The larger had two blown fuses just like that. Both work and sound great still. Thanks for showing, looks like relatively easy to test.
Thank you so much for taking the time to share this.
I had a plasma torch blow a fuse. Spent an afternoon checking everything out. Found nothing. Changed big fuse and it's still running four years later. Good work Steve.
those basic checks are a good refresher..thanks !
excellent troubleshooting skills
Excellent!
Great video, i have a mint 545 mk2 and 555 mk2 both are great amps, love them. Who is Uri Cohen ? Thanks for sharing 🙏
I've had fuses that just fatigued, those were slo-blo fuses and as you know, every power up those fuses wires stretch a bit causing some fatigue.....who know, maybe the company engineer underrated the fuses...
👍 again.!
Hi, I’m a subscriber. My class A amp, (adcom gfa5802) just recently developed a slight buzzing hum on the left channel. Do you think the filter capacitors for the left channel are bad? I checked the DC voltage at the speaker terminals and they’re at 0.025V, so I think the coupling capacitors are fine. Or do you think it’s something else? Thanks in advance.
It may be one of the main filter capacitors that is failing indeed. Measure the DC voltage and compare it with the same capacitor on the other channel, if one is lover than that may be the one. Also measure the AC voltage with no signal on all of the mail large filter capacitors. If one has more AC voltage across it then that is the culprit.
Where are you located? I have the same Adcom amp with intermittent left channel cut out. I get static sometimes, and sometimes nothing. Sometimes it plays perfect. I would love to get it repaired.
In am in Chico, California. email me Norcal715videos@gmail.com
Thank you..
I have an original 1986 GFA-535 with the custom Adcom 6800uF 63V aluminum electrolytic capacitors with three (two active) pin terminations. The amp was used for 15 years powered 24/7. Do you know of a replacement cap? If not do you know the cap's active terminals spacing? The caps are not leaking or bulging, should I even consider replacement? Thanks!
As long as the unit has been powered up continuously, I would not think you would need to replace the filter caps. Sitting idle is what kills them.
They were powered 24/7 for 15 years then sat idle for 20 years. If the caps 'look' OK it is better to increase DC voltage slowly across the cap to regrow oxide (?). That's difficult to do without the use of a variac. I have used the amp a couple of times in the last year to 'burn-in' speakers. I searched for replacement caps online from all major parts suppliers but I need to know active pin spacing?
I got a second gfa 7000 thx that the caps leaked I wonder how much to recap all of them I have two of them other one fine but should do that next and I also have a gfa 7500 thx my favorite of them all that I use now all of them are 5 channels anyway just wondering will get them all done when the price is right thanks
Could that have been caused by shorting the speaker wires?
Possibly but if the speaker wires were shorted I would expect much more damage, like shorted output transistors and totally blown (carnage) fuses. I think it was a gentile overdriven condition.
So strange how I can only see one of four comments lol ah the good old audio community
Too bad a Chinese company owns Adcom now. Mine was made in New Jersey and was owned by Emerson Electric then. Looks like the build quality isn't bad looking on this unit though. Oh and mine is big brother...GFA-555. Not the 555 II either.
how much you will charge the costumer for this repair?
I charged a total of $60 for this repair.
Could you help me . I need To replace the red pilot light on my Adcom 545. What is the voltage running to this lamp?
It should be a standard 1.9V 20ma LED
Someone shorted the speaker cable somewhere!