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Argus25 · 15th Nov 2017, 1:06 am

David,

Try adding the 0.1uF caps that I did in my unit and see if that helps, I must have put them in for a reason and since they are on the supply rail pins to the logic IC's it must have been related to 5V rail voltage transients.

(Sorry about the ambiguous wording in my previous reply, using the word "carrier" when I was referring to the chroma signal).

In does appear that in the PM5519 they were not as diligent as they could have been keeping the digital and analog earths separate as possible to avoid this sort of thing and there is not a pcb ground plane, so like you say the results on testing depends a lot where your scope earth gets connected.

15th Nov 2017, 1:06 am	#32
Argus25 No Longer a Member Join Date: Oct 2016 Location: Maroochydore, Queensland, Australia. Posts: 2,679	Re: Philips PM5519 Service info David, Try adding the 0.1uF caps that I did in my unit and see if that helps, I must have put them in for a reason and since they are on the supply rail pins to the logic IC's it must have been related to 5V rail voltage transients. (Sorry about the ambiguous wording in my previous reply, using the word "carrier" when I was referring to the chroma signal). In does appear that in the PM5519 they were not as diligent as they could have been keeping the digital and analog earths separate as possible to avoid this sort of thing and there is not a pcb ground plane, so like you say the results on testing depends a lot where your scope earth gets connected.