My monitor has Philips label inside on the tube M34EAQ10X
The circuit board has number 3138 103 30854
The flyback has number PVP AT1201/T11 30161 TY E39144
This is the one I bought....
http://www.hrdiemen.com/reparation/flyback/model/6489
http://www.hrdiemen.com/reparation/flyback/scheme/6489
Their cross-reference says it fits 1081 and 1084 (and other various models listed)
They have others to suit Commodore monitors but out of all of them, the HR6489 is the only one that has the same pin layout. The flyback looks identical to the original in every way.
The actual place I bought it from (local distributor) had the same part number in their catalog for one of my other monitors (not the original Philips I bought myself back in '85) but listed it as suiting 1084AU (mine is 1081AU). At au$45 each I figured I'd just buy them and try and at least one should work since at least one has an exact matching part number. Prior to ordering I had no idea they were made by HRdiemen. I ordered the one that matched and the HR6489 is what arrived in the post.
The differences on the PCB were mostly related to one of the video chips used and it's placement but basically the same.
The Philips OEM link filenames were named as 1081 but yes they are 1084 schems. according to Ray Carlsens pages, this is the schem for the 1081....
http://personalpages.tds.net/~rcarlsen/cbm/monitors/1081/MAIN.jpg
Looks like not exactly my model though because that schem has number 3138 105 21581 (mine is 3138 103 30854)
I didn't compare every part but all of the major TDA ICs are the same. Also all of the pins on the HRdiemen schematic for the HR6489 match the 1081 schematic flyback connections. I think if it was very different it wouldn't work at all. But it does work.
This is where the problem gets impossible because there are so many different versions of Commodore monitors and most of them don't have available schematics.
The 1084 flybacks have a totally different pin layout in a half-circle and mine is a rectangle so it looks to me like this flyback is correct for this model. But it may not be 100% compatible and impossible to know for sure because of the vast variety of Commodore models out there in the wild.
Anyway it works but with jailbars. It's more pronounced on the workbench screen but they are less noticeable or virtually invisible when playing games.
Talking to a friend who repairs monitors he said the lines could probably be reduced or fixed by adding a capacitor or resistor somewhere.
If there isn't an easy fix I'll live with it (assuming you or someone else can't help?)