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yaffle2345
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Post subject: Re: [DVL-909] Won't power on Posted: 19 Mar 2019, 00:07 |
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Joined: 03 Mar 2019, 15:15 Posts: 96 Location: United Kingdom Has thanked: 9 times Been thanked: 19 times
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I'm having a similar problem with my 909 - it's completely dead. I should say I don't know much about electronics, but I do have a multimeter - how difficult can it be? The board's a VWR1287 and all the fuses (7 little ones and the big one) seem fine. On the outputs: CN202 has +14V on pin 2, +5V on 10 and -27V on 14. But the +5V on 4 and the +3.3V on 7 and 8 all seem to be 0V CN203 has -14V & +14V on 2 & 3, but the +5V & -5V on 6, 7, 8, & 9 are all 0V. There seems to be a little darkening on the board around resistors R105, R106 & R109, as if they've been very hot, although they don't show as being open-circuit (although I don't know if that can be said for certain while they're on the board). If anyone has any advice on the best way to proceed, it would be much appreciated The post above mentions checking Q101, what's the best way to check a voltage regulator, do I have to test the voltages with the power supply connected? What voltages should I expect to see there?
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framal
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Post subject: Re: [DVL-909] Won't power on Posted: 29 Mar 2019, 00:41 |
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Joined: 26 Mar 2019, 01:28 Posts: 8 Location: New Zealand Has thanked: 1 time Been thanked: 3 times
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yaffle2345
Ic311 which supplies 5v and Ic411 which supplies 3.3v each have a CT pin which require a 2v switching signal to switch from STANDBY to ON.
That signal is controlled from the remote and is only operational when the power supply board is installed in the laser disc player.
The darkening, on the pc board, around R105,R106 & R109 is not uncommon.These resistors,all 68k,form a voltage divider across the rectified
mains DC.They,along with C116, provide the KICK START for the SMPS.Please check C116,1mfd/400v, for both ESR and capacitance.
The ESR reading should be a low value, approximately 7-8, and the capacitance should be approximately 1mfd.If in doubt change it.
I recommend that you also check the filtering capacitors,C211,C611,C311,C312,C511&C512 on the power supply secondary.If any are faulty
they can affect the supply's operation.Q101,Q150&Q151 are all N channel mosfets,ShinDengen 2SK2333.
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yaffle2345
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Post subject: Re: [DVL-909] Won't power on Posted: 29 Mar 2019, 18:15 |
Honest fan |
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Joined: 03 Mar 2019, 15:15 Posts: 96 Location: United Kingdom Has thanked: 9 times Been thanked: 19 times
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framal wrote: yaffle2345.... Thanks very much for the reply, there's a lot of information in there which I'll be working through as soon as I have some spare time
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yaffle2345
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Post subject: Re: [DVL-909] Won't power on Posted: 07 Apr 2019, 12:32 |
Honest fan |
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Joined: 03 Mar 2019, 15:15 Posts: 96 Location: United Kingdom Has thanked: 9 times Been thanked: 19 times
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framal wrote: These resistors,all 68k,form a voltage divider across the rectified mains DC. They,along with C116, provide the KICK START for the SMPS.Please check C116,1mfd/400v, for both ESR and capacitance. The ESR reading should be a low value, approximately 7-8, and the capacitance should be approximately 1mfd.If in doubt change it.
Just to follow up, I removed C116 and replaced it (not having the equipment to check it as indicated), and that fixed the problem - thanks, very happy
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admin
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Post subject: Re: [DVL-909] Won't power on Posted: 07 Apr 2019, 12:48 |
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Joined: 07 Aug 2002, 23:37 Posts: 4569 Location: Tokyo Has thanked: 299 times Been thanked: 1166 times
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yaffle2345 wrote: Just to follow up, I removed C116 and replaced it (not having the equipment to check it as indicated), and that fixed the problem - thanks, very happy Thank you for the update! DVL-* power issues seem to be very common. Having (confirmed) ways to potentially save them always sounds great! Julien
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