Re: Power Mac G4 MDD "Mirror-Door" won't power up
Update-main cap 375V SB and ON.PFC part of ML4824 work fine.After replace of R122-2/increased resistivity from 10 ohm to 3.5Mohm/ PFC "blink" halogen bulb of 150W.
Still no change in secondary side-voltages drops....
Announcement
Collapse
No announcement yet.
User Profile
Collapse
-
Re: Power Mac G4 MDD "Mirror-Door" won't power up
Yesterday I can't work on it,but today I replaced all small caps with Rubycon and the results:
1. no load 300V main cap
2. load 3.3V/1 Ohm drop to2.95V;5V/4 Ohm drop to 3.6V;295V main cap
3. load 12V bigger than 0.3A-PSU shuts down
Pins 4 and 19 of SUB1 are some feedback from opto's,
8 is PWM to 11N50/switchers of T1/,
9 is feedback PWM,
10 feedback from PFC,
5,11,15,16 not connected
12 +15V from 7815
6,7,13,14 GND
17,18 temp. sensor...
Leave a comment:
-
Re: Power Mac G4 MDD "Mirror-Door" won't power up
And the results-nothing changed except 300V on main cap.
Main suply 220V,STW20NM50 are new,from same tube,every replacemant is exact value/may be crap caps,but same value/.
Any ideas ...???
I traced the KA3504-PGin and PGout not connected,+12V current sense too.
Leave a comment:
-
Re: Power Mac G4 MDD "Mirror-Door" won't power up
Thank You!
And what about Rubycon?I have one 470/400V(used) and I'll try it tomorow.Small caps no matter crap or not must work at least 48 hours.I'm gona replace only main,cose see R107-current sensor for PFC.
Bad main cap will draw more charge current,right?
And one more thing:
with those loads except 12V/not load on line 12V/, 5V become 3.8V and 3.3V become 2.98VLast edited by gogo75; 04-15-2012, 11:35 AM.
Leave a comment:
-
Re: Power Mac G4 MDD "Mirror-Door" won't power up
All small caps are Fujicon RK,main filter cap YAGEO LG.
PSU is open,on table.Test with resistors(resisitive wire) and with water rheostat.
Voltage acros main cap is 280v-no load,255-260v min. load.
Normal load-acording to label on PSU
3.3V-2.0 to 17A /in my case-2.3A
5V- 1.0 to 20A /in my case 1.3-1.4
12V-1. to 16A /in my case 1.4-1.5
-12V-0 to .4A / abbout 30mA
25Vsb-0 to 4.2A /bulb 24V/5W
5Vsb-0 to 1.5A /bulb 6V/3WLast edited by gogo75; 04-14-2012, 10:56 AM.
Leave a comment:
-
Re: Power Mac G4 MDD "Mirror-Door" won't power up
Hello from Bulgaria!
I had to repair one Samsung PSCF401601B(C).Started with "text book"-TH2,Q1,Q2,C122,D101,D102,C129,C130,C135,C137 & CC141.At that point all OK-I got the +5v sb & +25v sb and +3.3v,+5v,+12v,-12v with no load.
With load less than a minimum labeled on the cover no problems,but with normal load it shuts down.
Where I must look?SUB1 with PCF or SUB2 with KA3504?
Some measurement points?
Leave a comment:
No activity results to display
Show More
Leave a comment: