Pioneer A-676

[littlerick]

I have had this amp for a few years now and loved it all the way. However it has decided to give up on me, so I got my screwdriver out.

Now what I would like is to get the original amps out with PSU and volume control, and do away with the rest. The amp stopped producing sound before i stripped it but the power still lit up, I'm presuming its the output chips that are shot. Is there a way to test if the system is working at the amps output source to check the boards are ok.

I have removed both Amp boards, but have left it all wired to the PSU. I removed two boards. One that had a rack of input sockets (I want just one pair of inputs) and another that seemed to be the balance, bass, treble and various selector switches, again I dont want any of these.

So I have my PSU connected to amplifier boards.. A volume control knob on a small board and a panel of 8 speaker connectors. How can I test what I have to make sure its working or to isolate the bit thats not, without giving myself a 240v jolt.

If needed i can post a few pics of what i have.

[pacificblue]

The A-676 is probably not a chipamp. You should get hold of a schematic.

1) Check all fuses for continuity.
2) Connect the amplifier to a light bulb tester with nothing else connected.
3) Measure the rail voltages. If the fuses are okay, but the rail voltages are not, check the transformer output and the rectifiers.
4) Measure, whether you have DC voltage at more or less rail level at the speaker terminals. If yes, one or more output transistors are blown. If the amplifier is a chipamp, you need to replace the IC. If it is a solid state amplifer, you need to replace the blown transistors and their driver transistors. You also need to check the surrounding components (resistors, diodes, etc.) and replace all faulty ones. Without a schematic you will not be able to do that.

[lanchile]

Originally Posted by littlerick

I have had this amp for a few years now and loved it all the way. However it has decided to give up on me, so I got my screwdriver out.

Now what I would like is to get the original amps out with PSU and volume control, and do away with the rest. The amp stopped producing sound before i stripped it but the power still lit up, I'm presuming its the output chips that are shot. Is there a way to test if the system is working at the amps output source to check the boards are ok.

I have removed both Amp boards, but have left it all wired to the PSU. I removed two boards. One that had a rack of input sockets (I want just one pair of inputs) and another that seemed to be the balance, bass, treble and various selector switches, again I dont want any of these.

So I have my PSU connected to amplifier boards.. A volume control knob on a small board and a panel of 8 speaker connectors. How can I test what I have to make sure its working or to isolate the bit thats not, without giving myself a 240v jolt.

If needed i can post a few pics of what i have.

As Pacificblue said!. without the schematic is not easy.There are so many parts involved (except the Gainclones or chipamps or whatever you want to call them). about eliminating the boards for balance,bass,treble,selector switches etc.Be careful it is not just disconnecting boards and expect the amp to work like nothing happen.all this is like a chain,cut one of the joins and the amp is out.can it be done? sure it can!!! but again, you have to know what you are doing to do this.without the schematic it is not as easy as it looks. Good luck.

[littlerick]

Thanks guys, i took the screwdriver to it and have now removed the heatsinks and a few switches and knobs that may be useful. I have got a new kit coming and will put the old gal to good use.

[lanchile]

Originally Posted by littlerick

Thanks guys, i took the screwdriver to it and have now removed the heatsinks and a few switches and knobs that may be useful. I have got a new kit coming and will put the old gal to good use.

Good to hear that buddy!.you can always use the chassis,switches, knobs,heatsinks even the power supply ONLY if this has the right voltage and specifications for your new project.