CurtPalme.com Home Theater Forum

mrrepel · Joined: 24 Aug 2011 Posts: 12

Hi all,

I've bought 2 BD808 projectors for cheap from a conference room for spare parts. Both have the same problem. The 3,15A fuse in the SMPS keeps popping. The SMPS used is the R7621705 with sub board R7621705S.

After some searching i found these artikels:
http://www.curtpalme.com/docs/Barco_FSB08_Failure_of_SMPU_R7621706.pdf

http://www.curtpalme.com/docs/Barco_FSB04_SMPU_Capacitor_Upgrade.pdf

After this i started measuring and found that the power transistor BU2525AW was shorted out. Is it enough to replace the transistor and capacitors mentioned in the upgrade ? And if so, would the BU2525AF be an replacement ?

Gr.

Barry

Ile · Posted: Thu Sep 01, 2011 9:35 am Post subject: Re: BD808 no power / blows fuses

mrrepel · Joined: 24 Aug 2011 Posts: 12

Thanks for the reply Ile.

I also thought they where the same. There is a mika ( dutch word ? ) isolator between the transistor and the metal cooling fin so they are not electrically connected.

I've ordered some transistors and the TDA's so i can swap these out to. I'll post the results here. If someone has some suggestions about swapping out parts for stability please reply.

Greetz,

Barry

mrrepel · Joined: 24 Aug 2011 Posts: 12

Today i got the parts. I've soldered in:
- New line driver (TDA)
- New power transistor (BU)
- New capicators in low voltage circuit

What a bit*h to remove components from a old PCB without destroying the copper traces. I've destroyed two islands on the BU transistor. They came a bit lose. To be shure i've soldered in a piece of solid copper wire over the trace.

After this i tried to switch on the units... Closer, but no cigar. I got 2 units now, one with EHT and quad removed for other unit, one complete. Lets call them A and B.

SMPS A in A = noting happens, fuse fine
SMPS B in A = noting happens, fuse fine
SMPS A in B = noting happens, fuse fine
SMPS B in B = noting happens, fuse fine

As in noting happens, no lights on controller board or anything. Seems complete dead.

After swapping SMPS B from B to A, without power attached, i heard a little electrical "pop". I tried to start the unit, nothing. After removing it to see what the pop was, the fuse was blown. BU transistor still seems fine. My fingers noticed that there was still a charge in the main capicator Embarassed

I've got a BG808S in my bedroom witch works. Would it be OK to test the repaired SMPS from the BD808(nonS) in the BG808S or is this with lots of fingercrossing that i don't demolish my BG808S ? If i brake the BG808S, my marriage will be broken also Wink

Thanks and greetz.

mrrepel · Joined: 24 Aug 2011 Posts: 12

Just remembered i had an BD801S lying around. This one had the same SMPS as the BD808 unit. I've switched the SMPS from the 801 to the 808 and everything works. Conclusion: SMPS from 808 still faulty. If anyone has ideas about fixing the defective SMPS unit's.... i am all ears.
Gr.

Barry

mrrepel · Joined: 24 Aug 2011 Posts: 12

Hmm the TDA ic hasn't got its supply voltage. Now checking the powersupply to the TDA ic.

mrrepel · Joined: 24 Aug 2011 Posts: 12

Looks like the standby board. Swapped this out with the working one and the projector started.....for a second and went in to error mode RCU / Error. Standbyvoltage is OK and processor cycles showing.

Going to inspect the stanby board.

Edit:
Really have to mark the boards. Put in de correct SMPS motherboard with "defective" sub powerboard. PJ shows standby but wont fire up.