Sansui AU-919 Back coupler switch missing?

[Brad Muller]

Why would someone remove the rear coupler switch on Sansui AU-919?

 

[Hyperion]

Because it is implicated in channel dropout issues, easily resolved with a proper cleaning of the switch. And presumably removed because they have no idea what they are doing.

In short, you do not know how to clean a switch properly if your solution is to remove the switch - and leave it removed.

 

[Brad Muller]

So now I have to replace the switch.

 

[Hyperion]

You should try to get another one - not sure where from though, 'Sansui Parts Shop' - does not seem to have them.

 

[Brad Muller]

I'll find one. Thanks!

 

[LBPete]

It should be a fairly standard pc mount slide switch. You can probably find a new switch that will drop right in.
- Pete

 

[LBPete]

I think these switches are double pole three position, on-on-on but I'm not sure so please check. Digikey has this one.

- Pete

 

[Hyperion]

I actually thought there was something special about this one, I can't think why now anyway Pete's cinemascope picture suggestion above looks good to me.

 

[LBPete]

Sorry about the size of the picture. I inserted a link to Digikey's image and I don't see how to adjust the size. In any case, you can see the detail, right?

It is an unusual switch because it needs three positions each of which turns something on. Unfortunately this one is not metric. You can probably find a metric one with a little more digging. Here's the data sheet for this one.

- Pete

 

[LBPete]

I've been reading more about these switches. They come in shorting and non shorting - - - make before break or break before make. That would be important to know so you don't cross connect stuff that shouldn't be cross connected. The switch mounts on board F-2838. The diagram for that board in the service manual shows the pin layout for the switch. There are two pins set off from the others. That means this one with gold contacts may fit. It's metric but doesn't have the mounting holes to attach it to the back panel. It's also a make before break switch.

- Pete

 

[Brad Muller]

Thanks for all your help Pete!

 

[ghamilton]

I need to order one of these for my 919. Did anybody ever figure out what switch to order?

 

[LBPete]

I haven't had reason to order one. The second one has the closest pin layout.

- Pete

 

[ghamilton]

If I knew how to bypass it I would. I removed the switch because it's had it. I'm just waiting for advice which way to go.

 

[ghamilton]

Pete,. I looked up the contact positions of the switch you thought would work and I figured out which pins to connect with the switch in the "Connected" position and made some little jumpers. After removing the switch off of the board I used the jumpers in it's place. It sounds even better now and no more stupid rear-switch problems either.

 

[RobinTW]

Checking the part number on line and found this link
https://www.awelectronics.com/sansui-au5900-pickup-load-switch

There are two screw holes on the top and it is different from the one that Pete posted.