karlfoxman
- Feb 12, 2011
- 11
- Joined
- Feb 12, 2011
- Messages
- 11
I have been working on this projector for a while now and its really stumping me!
This is what it started doing;
Turn on mains, blown fuse, bridge rectifier, MOSFET Q102, PNP Q103, Q104
R103, R104, R105, R106. Output pin 7 IC101 (FA5501)
Replaced all of these and tested using 12v-240v Inverter on current limit at 12v. Pulled 1A @12V off load.
Now we had no problems but we cant see IC102 working, I believe its a FA5508. No datasheet! So I looked and found it had same pin outs as FA5542. But we tested voltage on Vcc of IC102, found 20v. Looking at datasheet for FA5542 the 20v comes from the internals of the IC and is picked up from pin 8 (VH) This is a voltage enabling the Mosfet Q201 to get the transformer T201 to produce the voltages for the rest of the PSU. I am really stuck with this problem now as all the parts we replaced do not make the PSU work. We get no outputs from any of the 'cold side' OF T201
Attached is some datasheet for FA5542 (Closest I can find for FA5508)
Also screenshot of Schematics for PSU
Obviously the FA5501 (IC101) is not recieving Vcc as there is no 4.1v to pull up on/off pin of CN102 so the rectified mains is around 330v where it would be 370 if IC101 was working, the way I see it IC102 should power up first.
Thanks in advance for any help.
http://img10.imageshack.us/f/rs55psu.jpg/
http://www.fujielectric.com/device/semi/products/ic/ac_dc_green.html
Click on the FA5542 link pdf, near top page.
This is what it started doing;
Turn on mains, blown fuse, bridge rectifier, MOSFET Q102, PNP Q103, Q104
R103, R104, R105, R106. Output pin 7 IC101 (FA5501)
Replaced all of these and tested using 12v-240v Inverter on current limit at 12v. Pulled 1A @12V off load.
Now we had no problems but we cant see IC102 working, I believe its a FA5508. No datasheet! So I looked and found it had same pin outs as FA5542. But we tested voltage on Vcc of IC102, found 20v. Looking at datasheet for FA5542 the 20v comes from the internals of the IC and is picked up from pin 8 (VH) This is a voltage enabling the Mosfet Q201 to get the transformer T201 to produce the voltages for the rest of the PSU. I am really stuck with this problem now as all the parts we replaced do not make the PSU work. We get no outputs from any of the 'cold side' OF T201
Attached is some datasheet for FA5542 (Closest I can find for FA5508)
Also screenshot of Schematics for PSU
Obviously the FA5501 (IC101) is not recieving Vcc as there is no 4.1v to pull up on/off pin of CN102 so the rectified mains is around 330v where it would be 370 if IC101 was working, the way I see it IC102 should power up first.
Thanks in advance for any help.
http://img10.imageshack.us/f/rs55psu.jpg/
http://www.fujielectric.com/device/semi/products/ic/ac_dc_green.html
Click on the FA5542 link pdf, near top page.
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