Just a quick post to share how I repaired a Philips CDR-870 cd player/recorder.
It wasn't turning on at all when arrived. Turned out a connector got loose, from Power supply to main board! First time I saw something that simple for DOA.
Then, it would not read discs. Had a look at the drive: wouldn't clamp the disc. Discovered two broken pins which are "joints" of the disc clamp. No way that glue would work - would break again. Also, one of the broken pins had got lost. My luck here was that I had another very similar (almost identical) player: CDR-880. So I could compare how a working unit would be.
I managed to drill two tiny holes in each side and insert and glue in place a bit of hard wire, to make new pins. It worked. Had to make a spacer at the back, because clearances were different, I simply used a blob of hot glue as spacer. So, now it would clamp fine the disc, but still it was failing to read TOC on most CDs! They wouldn't spin! Laser tested out working (digital camera test), was also focussing. Then I tried the old trick: gave a small "impulse" with my finger to the disc at the critical moment when it tried to spin it - and yes, then it would spin and TOC was read most of times!
I was clueless. Decided to swap drives between the two players. Now that was weird! The drive turned out to be fine, my repair was perfect. So the problem was in the Mainboard!
I had a close look, comparing the two mainboards and then it struck me: a discovered a tiny SMD component that had simply broken off and vanished!!!! it was in the circuit are related to motor drive (hall motor), so really important and would explain the disc not spinning well. Now, the problem was to identify the component. Fortunately I had the other good mainboard from the other player, because as the component had vanished, and service manual is NOT complete, I would never have discovered the lost component.
A good search on the net revealed it was a shottky diode.
I had no SMD shottky diodes, so I found a normal shottky diode and managed to solder it in place. Tested and YES, working absolutely fine now!
Another player back to service. It's a pitty these recorders reject most of modern media, though... so I'm selling both.
It wasn't turning on at all when arrived. Turned out a connector got loose, from Power supply to main board! First time I saw something that simple for DOA.
Then, it would not read discs. Had a look at the drive: wouldn't clamp the disc. Discovered two broken pins which are "joints" of the disc clamp. No way that glue would work - would break again. Also, one of the broken pins had got lost. My luck here was that I had another very similar (almost identical) player: CDR-880. So I could compare how a working unit would be.
I managed to drill two tiny holes in each side and insert and glue in place a bit of hard wire, to make new pins. It worked. Had to make a spacer at the back, because clearances were different, I simply used a blob of hot glue as spacer. So, now it would clamp fine the disc, but still it was failing to read TOC on most CDs! They wouldn't spin! Laser tested out working (digital camera test), was also focussing. Then I tried the old trick: gave a small "impulse" with my finger to the disc at the critical moment when it tried to spin it - and yes, then it would spin and TOC was read most of times!
I was clueless. Decided to swap drives between the two players. Now that was weird! The drive turned out to be fine, my repair was perfect. So the problem was in the Mainboard!
I had a close look, comparing the two mainboards and then it struck me: a discovered a tiny SMD component that had simply broken off and vanished!!!! it was in the circuit are related to motor drive (hall motor), so really important and would explain the disc not spinning well. Now, the problem was to identify the component. Fortunately I had the other good mainboard from the other player, because as the component had vanished, and service manual is NOT complete, I would never have discovered the lost component.
A good search on the net revealed it was a shottky diode.
I had no SMD shottky diodes, so I found a normal shottky diode and managed to solder it in place. Tested and YES, working absolutely fine now!
Another player back to service. It's a pitty these recorders reject most of modern media, though... so I'm selling both.
