We need to start a new topic for rewire IPS33 voltage (120v <> 230v), maybe Kim can work out how to split the specific posts out
as this is useful in it's own right and we are getting a bit off topic. I had a look and couldn't work out an easy way...
Hey RG, no, hum in the signal isn't normal, the hum I have is purely vibration from tranny into the case/lid, not in the signal at all. As I posted earlier, when I take the top off it's quiet as a mouse...
Now I did ask before what the purpose of the capacitor between 1 & 4 is for, this may have something to do with your current issue
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Ok I pulled the "bottom" lid off my unit (as this is how you access it), and you need to use a T15 (6 pole star) screw driver bit to get the one front screw out
, I'd forgotten about that, but fortuitously I have one
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So in mine, there is a jumper wire between 2 & 3 (soldered from on top as you look at it in your pic as the board is mounted upside down). The cap (ic .01Z 500v) is soldered across the 2 power leads where they attach to the board (so the white and black leads at the top right hand corner of your pic, where they attach to AC INPUT). So remove the cap (currently between 1 & 4 as now it does nothing), and,
if it's the correct value (ic .01Z 500v), wire it between the white and black power input leads where they attach to the PCB (i.e. AC INPUT). I suspect this will fix it, but then
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@MJMP, can you ratify (or otherwise) my thinking here please.
Herby may be interested in that, I couldn't find anything memory battery related on the PCB at all
, maybe they wrote the presets to EPROM or similar
(the only went from 1 to 99, not the usual 127/8).
To get at the underside of the PCB seems you have to take it out of the unit, so I didn't, but I couldn't see anything coming through to the top of the PCB from underneath that could be for a battery.
I also removed all the little rubber feet that were transferring vibration to the bottom lid, shall let you know if that helped with the hum I get.
Edit, it didn't make it worse, maybe sightly better ? Seems the fix is remove bottom lid. Or maybe a new tranny ??