Hello,
As a newbie learning experience and fun, over the last couple of months I've been slowly upgrading a cdb 560 which is essentially the same main board as a cdb 650. I've been using a webpage pdf from an Israeli site that shows upgrades to the 650 board. I first recapped electrolytics, following the webpage, to the same capacitance but higher voltage and quality. At this same time I replaced the four 1N4002 diodes with the recommended 11DQ10 Schottky type. Sound was very nice and a major improvement.
I also changed the SMD decoupling capacitors to Wima .22uf, replaced opamps with OPA2134.
The PDF guide suggested changing eight diodes to 11DQ10's. Originally I had only done the four 1N4002's and not the BAX18 types. After about a month I then decided to change out the BAX18's to 11DQ10's. I didn't notice any improvement in sound. Then I replaced the other remaining BAX18 diodes on the board to 11DQ10's. But, as I was trying my CD's I realized I could no longer play CDR's. This player played CDR's without any problems at all before this modification. I honestly don't know if it stopped playing cdr's after the first four BAX18's or after the last four since I only played a couple redbook cds between this modification. I immediately returned all the BAX18's to their original spots and was able to play some cdr's but not others where as before I could play any cdr. I have a particular cdr that all my players play with no issue that this player also used to play without issue but now refuses to read TOC. I have other CDR's that will play but I have to press play a bunch of times before it will read and this seems to be random when it will play. It also seems that when the unit is dead cold it will play cdr's more easily than when warmed up.
So any ideas what could have happened and what could have been affected? Could this now be a problem with the IC's?
Since this mistake I have replaced all wires with new multistrand, all regulators with new equivalents, all transistors with new equivalents/replacements, new 1n4148 diodes and I have checked laser current and offset(this cdm board has both). Laser lens is clean, and swingarm clean and lubed. This made some improvement in reading cdr's. If I increase the laser from 50mv to 55mv max it won't read a cdr at all, likewise if I go lower than 50mv it won't read them. I replaced the voltage regulator 78M15 with a 7815 and the cdr which wouldn't read at all is reading TOC intermittently and playing if I press play a bunch of times, still random but an improvement none the less. I don't know where to go from here.
At this time I decided to recap the CDM since up to this point I had left it alone since it seemed to be working fine. I replaced the caps and transistors. No difference in play.
I am having trouble finding replacements for some of the diodes like the BAX18's. There are some 1% 3600pf Philips made capacitors on the CDM board could these be problematic? The only replacements I can find for the 3600pf are Mica and they are fairly expensive and I don't know if mica is a suitable replacement anyway.
I would like to get it to play cdr's reliably like it once did and all my other players play them fine.
Thanks,
Mark K.
As a newbie learning experience and fun, over the last couple of months I've been slowly upgrading a cdb 560 which is essentially the same main board as a cdb 650. I've been using a webpage pdf from an Israeli site that shows upgrades to the 650 board. I first recapped electrolytics, following the webpage, to the same capacitance but higher voltage and quality. At this same time I replaced the four 1N4002 diodes with the recommended 11DQ10 Schottky type. Sound was very nice and a major improvement.
I also changed the SMD decoupling capacitors to Wima .22uf, replaced opamps with OPA2134.
The PDF guide suggested changing eight diodes to 11DQ10's. Originally I had only done the four 1N4002's and not the BAX18 types. After about a month I then decided to change out the BAX18's to 11DQ10's. I didn't notice any improvement in sound. Then I replaced the other remaining BAX18 diodes on the board to 11DQ10's. But, as I was trying my CD's I realized I could no longer play CDR's. This player played CDR's without any problems at all before this modification. I honestly don't know if it stopped playing cdr's after the first four BAX18's or after the last four since I only played a couple redbook cds between this modification. I immediately returned all the BAX18's to their original spots and was able to play some cdr's but not others where as before I could play any cdr. I have a particular cdr that all my players play with no issue that this player also used to play without issue but now refuses to read TOC. I have other CDR's that will play but I have to press play a bunch of times before it will read and this seems to be random when it will play. It also seems that when the unit is dead cold it will play cdr's more easily than when warmed up.
So any ideas what could have happened and what could have been affected? Could this now be a problem with the IC's?
Since this mistake I have replaced all wires with new multistrand, all regulators with new equivalents, all transistors with new equivalents/replacements, new 1n4148 diodes and I have checked laser current and offset(this cdm board has both). Laser lens is clean, and swingarm clean and lubed. This made some improvement in reading cdr's. If I increase the laser from 50mv to 55mv max it won't read a cdr at all, likewise if I go lower than 50mv it won't read them. I replaced the voltage regulator 78M15 with a 7815 and the cdr which wouldn't read at all is reading TOC intermittently and playing if I press play a bunch of times, still random but an improvement none the less. I don't know where to go from here.
At this time I decided to recap the CDM since up to this point I had left it alone since it seemed to be working fine. I replaced the caps and transistors. No difference in play.
I am having trouble finding replacements for some of the diodes like the BAX18's. There are some 1% 3600pf Philips made capacitors on the CDM board could these be problematic? The only replacements I can find for the 3600pf are Mica and they are fairly expensive and I don't know if mica is a suitable replacement anyway.
I would like to get it to play cdr's reliably like it once did and all my other players play them fine.
Thanks,
Mark K.
The Philips cdm-2 mechanism is renowned for NOT playing CDRs !!
If you have replaced the caps on the CDM board, it is very important to replace the blue Philips axial caps with the same value not more!!
Andy
If you have replaced the caps on the CDM board, it is very important to replace the blue Philips axial caps with the same value not more!!
Andy
The blue axial caps on the cdm board are 3600pf 1% "Polysterene film/foil" according to the SM and either 160 or 250 Volt (some ambiguity).
I can get mica 3600pf at 1% values from mouser, and the next closest is 2% Polypropylene both of which are in stock.
Mark K.
I can get mica 3600pf at 1% values from mouser, and the next closest is 2% Polypropylene both of which are in stock.
Mark K.
I replaced the one 33uf axial electrolytic with same value and higher voltage this replacement was a Vishay manufacturer part# MAL202138339E3. The radial electrolytics were also replaced with same values, those are 2x47uf and 2x220uf, and were replaced with Panasonic FR and Nichicon HE respectively.
Thanks,
Mark K.
Thanks,
Mark K.
Hi,
Can anyone tell me if the high precision blue Philips axial 3600pf 1% capacitors on the CDM servo board are worth trying to replace or not? Can they affect anything related to TOC read and play or not and can they even go bad? Can they be replaced with Mica 1% or not?
Thanks,
Mark K.
Can anyone tell me if the high precision blue Philips axial 3600pf 1% capacitors on the CDM servo board are worth trying to replace or not? Can they affect anything related to TOC read and play or not and can they even go bad? Can they be replaced with Mica 1% or not?
Thanks,
Mark K.
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