On Thu, 27 Sep 2001, Bill Dawson wrote:
> -> Since I left the big cap in place, it can only be the transformer
> -> which is causing the wobble - can't it?
> ->
> -> I genuinely don't know. That's the only part I've swapped in the
> -> new 8032.
> -> Could a flakey transformer be making the screen wobble? How do
> -> transformers go flakey anyway, if indeed they *can* co flakey?
>
> Well, actually I think the transformer is the cause of the problem, but not
> in the way you are thinking. You may have an problem with the magnetic
> field of the transformer being coupled to the monitor, either via the yoke
> or directly to the CRT. Does the problem lessen as the distance between the
> transformer and the monitor is increased?
>
> See the photos of the Commodore Educator 64, Model 4064 at
> http://www.swtpc.com/commodor.htm . I remember the general position of the
> power transformer is similar to the Pets. Note the shielding of the
> transformer in the photos. This was used to prevent the problem which you
> are describing, and if this shielding is removed the wobble will occur. Try
> placing a shaded pole motor or large transformer anywhere near the sides or
> back of a modern monitor and you'll see the same wobbling effect.
>
> Hope this helps.
>
> Bill
Would it not also be true that rectifying 50Hz AC would require better
filtering than rectifying 60Hz? Hair splitting perhaps, but....
- don
Received on Fri Sep 28 2001 - 00:17:37 BST