Hi there from New Zealand,
I have a number of PSK professional power amplifiers model PPA-1000, a couple of which need servicing.
Having spent quite some hours web searching, as yet I have found only one reference to these amps, a forum elsewhere.
Does anyone out there know anything about these amps? Perhaps they are a re-badged model by someone else? Ultimately I would like to track down a schematic or even a service manual.
Hoping.......
bmt
I have a number of PSK professional power amplifiers model PPA-1000, a couple of which need servicing.
Having spent quite some hours web searching, as yet I have found only one reference to these amps, a forum elsewhere.
Does anyone out there know anything about these amps? Perhaps they are a re-badged model by someone else? Ultimately I would like to track down a schematic or even a service manual.
Hoping.......
bmt
http://www.carverpro.com/2004/download.html
Hi again, I found the pm-900 power amp is quite similar to my psk - download from site above.
HTH.
Hi again, I found the pm-900 power amp is quite similar to my psk - download from site above.
HTH.
.Hi again bmt, I've found the reason for the burn-up on my amp, and it's down to the original construction/design. I was going to email you a close up photo of the area in question but I'm under moderation as a new member. If your boards are the same as mine then it's the fixing screw for one of the 2sa1302 trannies( the one not fixed to the board) shorting out the loudspeaker feed to the relay. It's a very poor piece of construction as the screw head doesn't sit in the hole made for it in the board, but is offcentre and thus warps the board slightly and makes contact with l/s track. If you want to email me ( if you can) I can send you the photos.
Geoff.
Geoff.
The fault turned out to be an intermittant open-circuit on the bias adjuster pot, so of course, it measured OK with no current flowing...
The circuit designer should be shot for putting the pot in the wrong way, so that a failure blows up the output stage. I remember back in the '60's when vbe multipliers first appeared in amps, the advice was to put the adjuster in the 'fail safe' leg of the voltage divider - pehaps that never got translated into chinese.
Above is Graham's advice on the bias cct. for the ah1400, any circuit designers amonst us have any ideas about how to translate that into hard wired silicon?
Thanks for the links, by the way, ASEng - very useful indeed. As regards the fuseholders, On the ah2400 I have here, the fuses are soldered into the fuseholders!!!
. This is one a friend of mine bought off ebay - caveat emptor electronica ...... that's probably not correct but what the hell.....
The circuit designer should be shot for putting the pot in the wrong way, so that a failure blows up the output stage. I remember back in the '60's when vbe multipliers first appeared in amps, the advice was to put the adjuster in the 'fail safe' leg of the voltage divider - pehaps that never got translated into chinese.
Above is Graham's advice on the bias cct. for the ah1400, any circuit designers amonst us have any ideas about how to translate that into hard wired silicon?
Thanks for the links, by the way, ASEng - very useful indeed. As regards the fuseholders, On the ah2400 I have here, the fuses are soldered into the fuseholders!!!
. This is one a friend of mine bought off ebay - caveat emptor electronica ...... that's probably not correct but what the hell.....- Status
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