DanielAllsopp
Member
Looking for someone to take a look at my broken Phillips CM-8833-ii that I attempted to fix myself but go nowhere. Thanks 
Filled Phillips CM-8833-ii Repair
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right im going to point out some obvservations,then go ahead and repair this fully,at the moment ill go and have a hot drink
the hot that was installed isnt the correct version,this has a metal back on it that needs sil pad,without it,its a dead short from collector to emitor
for future reference,it supposed to be the fully plastic package part with no metal back plate
surprisingly,the lopt isnt dead(flyback transformer) from that ordeal,it passed a ring test,it seems fine
this also needs a new mains switch if i can find one in my parts draws
also there is a screw missing from the back panel that holds the composite and audio sockets in place, op probably lost it,ill try to find another one
ill send him a message ,this could of been much worse and quite expensive
picture below,of the transistor
the hot that was installed isnt the correct version,this has a metal back on it that needs sil pad,without it,its a dead short from collector to emitor
for future reference,it supposed to be the fully plastic package part with no metal back plate
surprisingly,the lopt isnt dead(flyback transformer) from that ordeal,it passed a ring test,it seems fine
this also needs a new mains switch if i can find one in my parts draws
also there is a screw missing from the back panel that holds the composite and audio sockets in place, op probably lost it,ill try to find another one
ill send him a message ,this could of been much worse and quite expensive
picture below,of the transistor
Attachments
its alive 
ive replaced the offending parts,and done a setup its passed
pictures for you all to look at,manditory cross hatch and colour bars picture is quite good,dont let my camera lie to you
i will pack up later,wifey wants me for something
ill go let him know
ive replaced the offending parts,and done a setup its passed
pictures for you all to look at,manditory cross hatch and colour bars picture is quite good,dont let my camera lie to you
i will pack up later,wifey wants me for something
ill go let him know
Attachments
i think i should ilaborate a bit more,lets call it an edutalkypoint,haha
the hot that was installed has a metal back plate,internally the transistor's collector is connected directly to the back plate,with me?
the heatsink,is connected to ground just like the emittor of the transistor,so dead short from collector to emitor
these are fitted in a mk1 with a sil pad,a insulation sheet,but works in pretty much the exact same way,and the heatsink its fitted to is grounded
in the mark 2 they fitted a transistor that was in fully incased insulated package,no metal back plate,such as a BU508AF or 2SD1577
service manual,suggests a BU508AF,BUT the schematics says BU508A
what i think happened ,is he read the schematics and bought the wrong one with out thinking,right? because the schematics say so,understandable...
if he had fitted a sil pad between the heatsnk and the transistor,this would of worked
this could of ended up with a dead flyback and or faulty supply if left long enough,but since i very rarely see a faulty supply on these from shorted hot's ,but i can say i have seen the hot take out the lopt primary winding,with me?
what im surprised about is i was told the led came on when its turned on,i never tried it when it came here,and i dont normally turn crt's on without checking for shorts,when im told its dead,or someone tried a self repair and it dont work after,I.E : has no rastor
what would normally happen is the 128 volt rail gets dumped to ground witha faulty hot,so the supply laods down so much the led dont come on same with a shorted winding on the lopt,it loads the supply down too much because there is no ringing(dont ask me what that means itll take ages to explain,yes i have been asked a few times)and the flyback transformer,relies on a ringing effect to work properly on the primary side,like a switchmode supply
lets not turn this into a erm,massive wall of interesting text,haha,lets leave it there
and here is a screenshot of the schematic in that area,so you can see it for yourself,but it doesnt show the heatsink the hot is fitted to,so you have an idea
the hot that was installed has a metal back plate,internally the transistor's collector is connected directly to the back plate,with me?
the heatsink,is connected to ground just like the emittor of the transistor,so dead short from collector to emitor
these are fitted in a mk1 with a sil pad,a insulation sheet,but works in pretty much the exact same way,and the heatsink its fitted to is grounded
in the mark 2 they fitted a transistor that was in fully incased insulated package,no metal back plate,such as a BU508AF or 2SD1577
service manual,suggests a BU508AF,BUT the schematics says BU508A
what i think happened ,is he read the schematics and bought the wrong one with out thinking,right? because the schematics say so,understandable...
if he had fitted a sil pad between the heatsnk and the transistor,this would of worked
this could of ended up with a dead flyback and or faulty supply if left long enough,but since i very rarely see a faulty supply on these from shorted hot's ,but i can say i have seen the hot take out the lopt primary winding,with me?
what im surprised about is i was told the led came on when its turned on,i never tried it when it came here,and i dont normally turn crt's on without checking for shorts,when im told its dead,or someone tried a self repair and it dont work after,I.E : has no rastor
what would normally happen is the 128 volt rail gets dumped to ground witha faulty hot,so the supply laods down so much the led dont come on same with a shorted winding on the lopt,it loads the supply down too much because there is no ringing(dont ask me what that means itll take ages to explain,yes i have been asked a few times)and the flyback transformer,relies on a ringing effect to work properly on the primary side,like a switchmode supply
lets not turn this into a erm,massive wall of interesting text,haha,lets leave it there
and here is a screenshot of the schematic in that area,so you can see it for yourself,but it doesnt show the heatsink the hot is fitted to,so you have an idea
Attachments
DanielAllsopp
Member
Thanks for all the updates Roy. I've just this minute got back from a long weekend in Keswick so I've had absolutely no signal unfortunately. Thanks for all your hard work, I'll have a good long read through the thread now and I'll send my details over etc to you in a PM.
Nice to see it working again though
Nice to see it working again though
DanielAllsopp
Member
Monitor arrived yesterday and I've just hooked it up this morning. Looks awesome to see my Amiga on a CRT again! Unfortunately, my A4000 is a bit of a mess but that'll be the next thing to try and tackle.
Thanks again to Roy for sorting my monitor out; great service, and very quick too!
Thanks again to Roy for sorting my monitor out; great service, and very quick too!
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