hello all. First post here. So al get an appology in just incase am in the wrong place.
I ahve a problem with my Arcam Alpha 5 Amp. out of the blue, it has ceased working
.
I had a look inside and noticed that the 1 amp Timed/slow blow fuse had blown. I got replacement fuses and have since blown another 5. I have removed the circut board and there is no OBVIOUS sign of damage.
I cant afford to send it to arcam to be fixed. Has anyone got any ideas what the problem maybe and how to fix it? Any help welcomed as I miss my music.
Thanx
I ahve a problem with my Arcam Alpha 5 Amp. out of the blue, it has ceased working
. I had a look inside and noticed that the 1 amp Timed/slow blow fuse had blown. I got replacement fuses and have since blown another 5. I have removed the circut board and there is no OBVIOUS sign of damage.
I cant afford to send it to arcam to be fixed. Has anyone got any ideas what the problem maybe and how to fix it? Any help welcomed as I miss my music.
Thanx
I have an Arcam Alpha 7R here for repair at the moment 
It is likely that the output MOSFETS on one or both channels (IRF540) have blown short circuit, causing a short across the power supply. IMO the heatsinks in the Alpha amps are far too small, so it's not really a surprise. There is also no TVS/MOV across the mains supply, so this amp seems to be suspect to power surges.
I would suggest that you just obtain new MOSFETS (IRF540N works, as should IRF540NPBF) and they are only about £2.50 each, BUT because you have tried so many fuses, it is likely that you have caused further damage to the circuit.
I also suggest obtaining the service manual from Arcam - they should send you this as a PDF file.
It is likely that the output MOSFETS on one or both channels (IRF540) have blown short circuit, causing a short across the power supply. IMO the heatsinks in the Alpha amps are far too small, so it's not really a surprise. There is also no TVS/MOV across the mains supply, so this amp seems to be suspect to power surges.
I would suggest that you just obtain new MOSFETS (IRF540N works, as should IRF540NPBF) and they are only about £2.50 each, BUT because you have tried so many fuses, it is likely that you have caused further damage to the circuit.
I also suggest obtaining the service manual from Arcam - they should send you this as a PDF file.
Rapid stock them, as do bigger suppliers like Farnell or RS. I would go with Rapid as they will cater for small orders - order code 47-0317. These days, I wouldn't touch Maplin with a barge pole.
If you want to confirm that the outputs are blown, unsolder them and use a continuity check or resistance check to measure between source and drain (pins 2 and 3). They are blown if they read short - you will probably find continuity between the gate and source/drain also.
If you want to confirm that the outputs are blown, unsolder them and use a continuity check or resistance check to measure between source and drain (pins 2 and 3). They are blown if they read short - you will probably find continuity between the gate and source/drain also.
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