Hi everybody.
some weeks ago i got a magnavox cd100 and a philips cd303 (all philips ic saa7010 model) , both dead, both really messed up from a previous technician.
CD100 is already working fine but CD303 is driving me nuts.
when first received player was reading discs fine but doing nothing else, no display, upon inspection mab8410 was backwards, completely shot, after testing with cd100's mab display lit up and started to react better, though display was completely random and blinking very fast, still no sound.
tested all socketed IC on cd100 and all worked fine, also the CD100 ic on the 303 did no change.
the PSU has lm317t and all caps replaced, all voltages are there.
if i ground UNEC i can get sound, so i know the OPamps and mute relays are working, still the sound is completely distorted, theres audible music on the background but most of the output is noise.
HF signal looks fine on the pcb in, though in the input of saa7010 look a little bit worse, and Data out of saa7010 is a complete mess.
I'm confused on what to do next, what to check?, can be the display and the sound failure related?
Thanks to all!
some weeks ago i got a magnavox cd100 and a philips cd303 (all philips ic saa7010 model) , both dead, both really messed up from a previous technician.
CD100 is already working fine but CD303 is driving me nuts.
when first received player was reading discs fine but doing nothing else, no display, upon inspection mab8410 was backwards, completely shot, after testing with cd100's mab display lit up and started to react better, though display was completely random and blinking very fast, still no sound.
tested all socketed IC on cd100 and all worked fine, also the CD100 ic on the 303 did no change.
the PSU has lm317t and all caps replaced, all voltages are there.
if i ground UNEC i can get sound, so i know the OPamps and mute relays are working, still the sound is completely distorted, theres audible music on the background but most of the output is noise.
HF signal looks fine on the pcb in, though in the input of saa7010 look a little bit worse, and Data out of saa7010 is a complete mess.
I'm confused on what to do next, what to check?, can be the display and the sound failure related?
Thanks to all!
If there is a separate DRAM chip (such as a uPD41416) then that could be highly suspect for distorted sound/noise. Its a moderately common failure item generally.
No idea on the display tbh although the Philips LED modules themselves were a massive failure item with dead/missing/flashing segments. Hard to say if its just the module or some other issue.
No idea on the display tbh although the Philips LED modules themselves were a massive failure item with dead/missing/flashing segments. Hard to say if its just the module or some other issue.
Yes there is but already replaced it and same problem, all the "big" ic were replaced, is something from the data extraction from RF, sin RF gets fine to the PCB, distortes a little getting to the decoder and data out is a mess, though, the decoder was also replaced and the effect is same.
The Display is a mistery, if i lift the clock signal and touch it with my finger it suddenly works better, you can see numbers counting but still a mess, can also be that the MAB8410 is from a CD100, a unit with no display at all
I've no bright ideas I'm afraid 
The fact you have acquired these 'already worked on' throws up lots of possibilities unfortunately. I'm also not sure whether the MAB8410 is model specific. As far as I recall its a mask programmed CPU meaning it is already pre-programmed for the intended application. It might be worth following up on that and seeing if they are listed as different part numbers between the models. There might also be a clue in any digits following the MAB8410P code as they often relate to the pre-programmed ROM in the chip.
The fact you have acquired these 'already worked on' throws up lots of possibilities unfortunately. I'm also not sure whether the MAB8410 is model specific. As far as I recall its a mask programmed CPU meaning it is already pre-programmed for the intended application. It might be worth following up on that and seeing if they are listed as different part numbers between the models. There might also be a clue in any digits following the MAB8410P code as they often relate to the pre-programmed ROM in the chip.
I've no bright ideas I'm afraid
The fact you have acquired these 'already worked on' throws up lots of possibilities unfortunately. I'm also not sure whether the MAB8410 is model specific. As far as I recall its a mask programmed CPU meaning it is already pre-programmed for the intended application. It might be worth following up on that and seeing if they are listed as different part numbers between the models. There might also be a clue in any digits following the MAB8410P code as they often relate to the pre-programmed ROM in the chip.
I'm clueless also, about the software inside yes, they are different, one says 002c and the other 006c, still a replacement with the original mask is on the way, that can shed some light on the display issue.
about the audio i'm blank, the mab has no effect at all in sound, for the servo part has a mab8440 that's 100% compatible with the one on the CD100, and is also tested working fine.
one useful information maybe.. i found an open diode in the powersupply, replaced but still same failure, could be another diode failing maybe...
There are just so many possibilities when a unit has been 'got at' previously. Finding a genuinely faulty part like a diode maybe suggests there could be more problems around that area. Philips used to use dozens of safety resistors (generally... don't know if these use them) and they often can fail by going high resistance, particularly if they have been overloaded. Its always worth checking and scoping rails at their destinations and not just on the power supply.
The 002c and 006c do sound suspiciously like version numbers.
The 002c and 006c do sound suspiciously like version numbers.
002c and 006c are actually version numbers, is a good idea to check tensions on destination, as for the ics on the decoder board all have correct voltages acording to service manual, what is strange is that if i remove or replace certain components it doesnt care, it just do the same behavior
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