Yamaha AX-430

[JEWilson]

Rec'd this item as damaged.
The item has been dropped.
This is a project for the kids bedroom (when fixed).

The front panel source selection pcb has been broken.
It is only a single side pcb so, I should be able to repair this.

I am having issues however with sourcing replacement parts.
These include;
1. A number of source selector switches
2. A balance pot

There is a loudness knob missing on the front as well
as the Volume control knob. Both the pots and the
mech. fixings are in place though.

I have attached 2 pdfs
First, is a set of pics of the amp
Second, is a set of pics with the damaged parts

FYI, the balance pot is a 250kMN
The switches appears to Alps SPEC type but since
this amp is circa 1989, I cannot (immediately)
appear to find the relevant or correct model.
The service manual states these as SLR-34URC3H

Any views?

[Longbow]

Re: Yamaha AX-430

The photos do not definitively show that either the pot or the selector switches are damaged. The first step is to repair the broken pcb. If possible, remove parts directly on the fault line. Super glue works wonders on this pc material. Make certain the pieces make a good fit first. Apply superglue, press together, and then spray lightly with super glue accelerator.

Next repair the broken traces with #30 insulated wire. It is best to connect end points, rather than bridging the broken traces. Photos of the damage to the switch and pot would help.

[JEWilson]

Re: Yamaha AX-430

Hi

Thx for responding
Ok.

The picture of the pot - second pdf only illustrates
the type of pot and mech. footprint I require.
Trust me, the damaged pot is destroyed beyond repair.
But where can I get the correct pot?

The leftmost three switches in the second pdf are damaged
The plastic blue material is the internals of each switch
A normal switch, black colour can be seen to the right
I know these switches are broken, they do no mechanically
work correctly. I have tried them

Thanks for the suggestion with superglue and accelerator
Where can I get the latter?

Cheers

[999999999]

Re: Yamaha AX-430

Are you sure you sent the correct 2nd PDF? I'm not seeing any switches in that pic.

If you can't find the POT, pick one electrically equivalent in function. Fortunately it looks to be panel mount so the replacement merely needs to be same dimensions or shorter body so it will fit in the space between the circuit board and the front panel, then you can use wire to connect the pins to the traces.

If you simply cannot find one short enough, then there is the fun part. You drill a hole through the entire circuit board big enough to slip the new pot through and rejoin any component traces removed by the drilled hole with jumper wire.

Superglue accelerator isn't really necessary, it just speeds up the process. You can instead wait for the glue to dry. Considering the potential stresses on the PCB from pressing buttons, I would also fortify the area where the crack was with some epoxy overlapping the joint by about a centimeter in each direction. Just make sure that doesn't get in the way of remounting the circuit board back in the amp.

Even better would be to rough up the area slightly with sandpaper so the epoxy adheres better, or at least wipe it thoroughly with alcohol first.

[JEWilson]

Re: Yamaha AX-430

Hi

2nd and 3rd pics on images0030.pdf show the switches

[999999999]

Re: Yamaha AX-430

It looks like a tedious repair. I don't have any drop in replacement suggestions, but I could be a devil's advocate and suggest that if you have a will, you can spend more time than it's worth and have it working.

I don't know the clearances though, building up a replacement circuit can depend on how crammed and jammed the board is relative to things around it. When push comes to shove (if you were on the space shuttle or a remote island) there's no end to how many standoffs and aux boards you could screw in to make it work, but obviously not being in front of it or being able to determine your will, I can only wait and help with your ideas.