replaced cd player op amps, various problems now

[dvdwmth]

I have a Nikko cd player i picked up for $20 and I thought Id experiment with some upgrades. I replaced the 4558 op amps with bb 2134 but I am now having some problems.

There are three op amps. Two are near the audio output so I assume that is the anolog stage and one is near the wires that connect to the transport.

When I was pulling out the original op amp near the transport I damaged the metal rings that surround the pin holes. When I put the new op amp in the transport wouldn't do anything. I used small copper wires to connect the pins to the first component down the circuit and Im fairly sure I have a good contact. When I turn the player on though, it will recognize the disk but as soon as it tries to play the disk starts to spin very fast. After that it wont recognize the disk.

I suspect the op amp near the transport connection because of its location and the compromised connection but I cannont find a short or a loose connection.

If any of you have any thoughts Id like to hear them.

Unfortunately I dont have a schematic and I just lent out my digital camera so no pics.

Thanks

 

[Fin]

Try re-installing the original opamp for the transport.

 

[dvdwmth]

is there some way to make repairs to the pcb so I dont have to use wires.

 

[Bricolo]

I'm not 100% sure but sometimes the opamp near the mechanism is used for the tray or spin motors, and aren't classical opampb but have more curent output

Try to put the original opamp back in its place

 

[markp]

It might be a multi-layer board which uses the via to connect layers. A 'via' is the metal collar through the board. If you let a little more solder flow into the hole around the opamps pins it might make contact but you might fry the opamp or burn the board in the process.

 

[dvdwmth]

i put a flashlight behind the board and it looks like its just a single layer. Good thing because if it was multi layered id be S.O.L..

I've already burned the board abit i think. I've never tried replacing parts on a pcb before so its been abit of a mess.

I think Ill try putting one of the old chips back in. But I was under the impression that the 4558 and the 2134 were interchangable.

 

[markp]

i put a flashlight behind the board and it looks like its just a single layer. Good thing because if it was multi layered id be S.O.L..

I've already burned the board abit i think. I've never tried replacing parts on a pcb before so its been abit of a mess.

I think Ill try putting one of the old chips back in. But I was under the impression that the 4558 and the 2134 were interchangable.

pin for pin, yes. The drive capabilities might be different so look at the max current they each can deliver into a load.

 

[dvdwmth]

I put the 4558 back in and I've managed to get it to play but whenever the drive would normally do nothing, like when its waiting for the play button to pressed or after hitting stop, it spins very fast. I dont think that putting 4558 back in made a difference other than that in the process of putting back in I resoldered the connections. I've had with soldering that op amp though so its staying in.

Can anybody here come up with any ideas of what to check to deal with the wild spinning. I know I'm asking alot without a schematic or even pictures but I dont have a clue here.

As for the sound quality, it seems that this was worth while. Seems to be a lot more detail. Of course its hard to tell since I cant AB it. I guess I'll have a better idea after a few days and more disks. I only played two so far.