Author Topic: Earthing problem? Spoiler noize... (Read 337 times)

FC Bass · « **on:** July 14, 2007, 03:08:27 AM »

-No political thread- :-)
There's a hum in my '87 Spoiler, when I touch the output it's gone...
Here's a sound sample, first the noise, a turn of the filter and a note with a turn of the filter + a turn of the pickup selector. After that the same, but touching the output (dead quiet) Click here
Any thoughts?

Cheerz,
Flip

olieoliver · « **Reply #1 on:** July 14, 2007, 04:31:11 AM »

Is everything grounded good in the control cavity and pickups? That could acoount for the hum stopping when you touch the output.

FC Bass · « **Reply #2 on:** July 14, 2007, 04:56:24 AM »

I'm not sure, everything looks fine... Here are some pictures of the electronics/electronics cavity:

Note: There's also a bead in there now.

David Houck · « **Reply #3 on:** July 14, 2007, 08:00:16 AM »

Make sure all the controls are securely fastened to the body; with the knobs off, make sure the nuts are tight against the body bringing the controls against the shielding. The controls are grounded against the shielding; if not securely tightened to the body, the controls will not be properly grounded. In the pictures above, some of the controls look like they might not be properly fastened to the body.

Also, in the top picture, where the battery connector is, it looks like some of the shielding may be missing. It wouldn't hurt to touch that up with more shielding. The shielding should completely enclose the cavity.

Also, loop the leads through the ferite bead; run the leads though, loop them back, and run them through again in the same direction.

[edit: added 3rd paragraph]

(Message edited by davehouck on July 14, 2007)

FC Bass · « **Reply #4 on:** July 14, 2007, 09:37:25 AM »

Thanks for the advise

I've tested it with a wire (afraid to overtighten things)
A wire from the control housings to the shielding paint makes no difference...
A wire from the red battery, or from the white (looks grey on the picture) wire mounted on the right side of the output to the shielding paint solves the problem....
The same when I connect the wire from the Filter housing to either the red or white wire on the output...

I'm pretty sure the bolds are tight enough and the wires run through the bead correctly.
The missing shielding paint is the hole for the pickup leads, I guess there's never been paint there or the hole was made after the paint was applied...

FC Bass · « **Reply #5 on:** July 14, 2007, 10:01:03 AM »

It's like the shielding paint in the output section doesn't work...
I've tried a wire between the output housing (removed from the cavity) and the shielding paint.
The hole for the output is lowered, just like the hole for the pickup selector.
I'm using that part to show what the problem is:

Red arrow - hum
Green arrow - no hum...
(when I connect a wire from the housing of the output to that part of the shielding paint)

David Houck · « **Reply #6 on:** July 14, 2007, 09:03:35 PM »

I could be wrong, but it seems to me that the shielding may be worn and just needs to be touched up some. Anybody else have an opinion on this?

olieoliver · « **Reply #7 on:** July 15, 2007, 05:59:32 AM »

I was thinking the same thing Dave. Looks pretty wore around the joles in the photos, that or maybe a little rust. As much as we don't like it moisture has its was of getting in there.

FC Bass · « **Reply #8 on:** July 15, 2007, 07:57:38 AM »

Repaint it will be, thanx guys!
For now I've placed a wire from the output to the Filter and Pickup selector (between the housings and the shielding paint)
She's dead quiet again (when not played )

Cheerz!
Flip