Low level 60Hz speaker hum

[laatsch55]

Don't see as I've done much to help....You really should put in a set of backplanes...

 

[laatsch55]

Mike, do you still have the XPL-909's as outputs?

 

[oldphaser]

Don't see as I've done much to help....You really should put in a set of backplanes...

Lee,

Is Joe making back-plane boards for 400's now?

Ed

 

[Gepetto]

Lee,

Is Joe making back-plane boards for 400's now?

Ed

Hi Ed
Yes, 3rd generation of backplanes by now. Those have been available for about 3 years now.

 

[oldphaser]

Hi Ed
Yes, 3rd generation of backplanes by now. Those have been available for about 3 years now.

Joe,

I guess I hadn't seen any 400's yet with the backplanes.
I guess I haven't been paying close enough attention.
I will try and do better in the future.

Ed

 

[Gepetto]

Joe,

I guess I hadn't seen any 400's yet with the backplanes.
I guess I haven't been paying close enough attention.
I will try and do better in the future.

Ed

 

[laatsch55]

Joe,

I guess I hadn't seen any 400's yet with the backplanes.
I guess I haven't been paying close enough attention.
I will try and do better in the future.

Ed

REALLY?????? After God knows how many phone calls......that never came up??

 

[jbeckva]

Lee, I think Mike needs a single connection from star-ground/buss bar to the chassis. If I recall the standard practice was to run em across the middle through both left and right tie points, but after a certain point in me own wopl'ing history (probably when the backplanes came around) I always just run a single wire from the buss bar to the left's upper screw/sleeve combination. Wonder if Mike can do the same even with the old sockets and point to point wiring?

From the buss bar/star ground - One wire to chassis, the other to the driver board and of course 1 or 2 big ones for the speaker returns.

 

[laatsch55]

Yeah Jer, it's definately worth trying, that ground goes by a lot of stuff...good thinkin there Jer..,

 

[Magic Smoke]

Don't see as I've done much to help....You really should put in a set of backplanes...

Ah, you and Joe have helped plenty during build! Backplanes on the bucket list, maybe February. I tempted to order the new trany set for old backplane just see what changes!

Let see, yes I have the blue 909's Delco's with the two Motorolas per side. May be all original.

The bridge came in today so installed that with snubber caps, cleaned off mess on cooper star bar and ran teflon wire. Yesterday I ran white teflon to the two ground points now that Thermal switch wires moved to upper case.

Tomorrow I'll remove the far right ground point wire as per jbeckva, thanks jbeckva.

Mike