If you get the diode the wrong way round it can cause damage because it would rectify the "wrong" half of the cycle and give a negative instead of positive voltage for example. If it were in a bridge then it would overheat. The PCB diagrams are too faint to really see whats going on but you should be able to work it out from the circuit diagram.
That glass ??? looking diode in the picture looks frazzled.
Too many issues seem to have arisen with all this. With the greatest respectI think you have to realise that the work you have done is probably the cause of all the problems.
thanks for having a look
There is a reset signal coming to pin 1 on of the servo chip from decoder A.The vertical glass looking thing on the picture is the ground. It was evil looking and mixed with some glue holding the big cap next to it from the beginning. I've desoldered and cleaned that part now and replaced the cap with a new one.
This was intended as a learning project and I haven't given up hopes yet. All the comments have helped me quite a lot in understanding how a cd player works, so I am really thankful for that. It's definitely me who's broken the cd player to refuse to play pink floyd
and soldering at ~300 C works best for my solder - no more dry joints in the future for me
Attachments
I don't know what to suggest to you now... it really needs a scope and various things looking at in detail. One common problem (I've just remembered) with the Philips based kit is the solid core wire used... it doesn't stand much moving around where it enters the various multi-plugs. Don't think that's the problem here but one to remember.
Yes, come back to it in a while, recheck all your work and have another go
Yes, come back to it in a while, recheck all your work and have another go
I took that to be a soldered connection to the ground plane rather than a diode.
The rectifier diodes are all the right way as they are, AFAICS. The underside (first shown above) view of the board is bonkers (6581 and 6587 would short out the transformer each half cycle). Go by the top view (your second view, on the right).
Was that solder-blob track patch re-done? The board is flexible, the solder isn't. Vibration will break the joint.
I would assume all your bits are now the right way round and functioning OK (assuming the headphone output is working).
Fitting the flexible connector from the mech to the main board is a pain on these machines, but you must do it carefully and correctly or it will certainly give problems. Make sure the clamp is fully relaxed by pulling up the socket surround fully, before gently pushing the ribbon fully home. Then push the socket surround down fully to clamp the connection.
When the player "resets", I wonder at what level? When the player returns to the start of the CD, does the display continue to show the number of tracks, or does it have to read the TOC again? I understand that it begins playing again without needing to be told; does it normally play itself upon loading, without the need to press play? Older philips machines don't do this, but I think they changed for the later CDM4 models.
If you jump the offending tracks, or direct-select the next track, does it play OK? If you fast-forward through an offending track, does it still reset?
Can the reset be provoked by tapping the board?
Does it have a test mode, entered by pressing some keys at switch-on? It might be interesting to see what happens at the same failure points. If the main system chip is resetting, then presumably it would jump out of test mode?
Are you absolutely sure that it played those problem tracks before?
Hold the board by the heavy transformer when you move it, to avoid flexing the flimsy board.
If the manual shows any diagnostic tests or settings that can be done using a voltmeter underneath the mech, it may be worth doing them now. If the bottom chassis panel is not removable, setting up for this involves running the mech on its side with no top clamp. Ha ha, not funny, and access is still tricky. You can try little blobs of blu-tak around the inside rim of the disk, instead of the recommended butchered puck.
Assuming none of this identifies the problem then make double sure that connections are correct and all the solder joints are OK, including those on all the bits you've moved like the connectors, and there are no bridges of solder-splash between traces, and that you have done whatever tests you are able to do underneath the mech. Then reassemble carefully and don't take it apart again without some kind of diagnosis or clear theory. That will come from patient measurement, trying to capture the moment of failure, at many points.
Also from more fully detailing the circumstances of failure. What happens if you burn a copy of that Pink Floyd with the tracks in a different order? We're not convinced by the loud bits theory.
Without a scope we'll all stay flummoxed, probably.
The rectifier diodes are all the right way as they are, AFAICS. The underside (first shown above) view of the board is bonkers (6581 and 6587 would short out the transformer each half cycle). Go by the top view (your second view, on the right).
Was that solder-blob track patch re-done? The board is flexible, the solder isn't. Vibration will break the joint.
I would assume all your bits are now the right way round and functioning OK (assuming the headphone output is working).
Fitting the flexible connector from the mech to the main board is a pain on these machines, but you must do it carefully and correctly or it will certainly give problems. Make sure the clamp is fully relaxed by pulling up the socket surround fully, before gently pushing the ribbon fully home. Then push the socket surround down fully to clamp the connection.
When the player "resets", I wonder at what level? When the player returns to the start of the CD, does the display continue to show the number of tracks, or does it have to read the TOC again? I understand that it begins playing again without needing to be told; does it normally play itself upon loading, without the need to press play? Older philips machines don't do this, but I think they changed for the later CDM4 models.
If you jump the offending tracks, or direct-select the next track, does it play OK? If you fast-forward through an offending track, does it still reset?
Can the reset be provoked by tapping the board?
Does it have a test mode, entered by pressing some keys at switch-on? It might be interesting to see what happens at the same failure points. If the main system chip is resetting, then presumably it would jump out of test mode?
Are you absolutely sure that it played those problem tracks before?
Hold the board by the heavy transformer when you move it, to avoid flexing the flimsy board.
If the manual shows any diagnostic tests or settings that can be done using a voltmeter underneath the mech, it may be worth doing them now. If the bottom chassis panel is not removable, setting up for this involves running the mech on its side with no top clamp. Ha ha, not funny, and access is still tricky. You can try little blobs of blu-tak around the inside rim of the disk, instead of the recommended butchered puck.
Assuming none of this identifies the problem then make double sure that connections are correct and all the solder joints are OK, including those on all the bits you've moved like the connectors, and there are no bridges of solder-splash between traces, and that you have done whatever tests you are able to do underneath the mech. Then reassemble carefully and don't take it apart again without some kind of diagnosis or clear theory. That will come from patient measurement, trying to capture the moment of failure, at many points.
Also from more fully detailing the circumstances of failure. What happens if you burn a copy of that Pink Floyd with the tracks in a different order? We're not convinced by the loud bits theory.
Without a scope we'll all stay flummoxed, probably.
Yes, I've redone all the solder-blobs ground on top
Thought something like this might happen. I've started cleaning up my desk and put the headphone opamp back in and now it works normally again! I feel kind of bad for misleading, but on my v-dac the opamps could be out and the dac played so I thought here it would not make a difference either. After placing the opamp wrong way in and burning a 15V regulator, the opamp stayed on my desk after regulator replacement.
it's very flimsy and by now I must have done it more than 30 times.. that's why I was a bit worried if at some point I bent and damaged the cable
when the player resets, the display shows the number of tracks and total time (but I think it reads the TOC again. At reset the cd rotation slows down for a split second and then I think the TOC re-read happens and the track and total cd time appear). It does not start playing after reset or cd insertion, I always have to push play first.
plays other tracks normally.. I still have to say at loud parts of some tracks the reset happened. Direc-selecting next track doesn't cause a reset. Fast-forward I haven't tried. I could take the opamp out again and test.
did not tap it
test mode exists ( search cece + pause + repeat + power on)- but I wasn't able to get in. the pause button requires sometimes a hard push to pause.
sound really tricky. For such a maneuver might be worthwhile adding an foil cdm adaptor and extension cable (the datasheet on second post shows hot to do it).
I'll try to figure out what the absence of the headphone opamp causes. Might be useful if someone else at some point makes a similar mistake.
I've already started looking at how the prices for a two channel 60 Mhz scopes are ranging.
I really have to say a big thank you for taking the time and looking at my cd player reset problem. I've learned a lot and will definitely continue playing around. At the same time I am really happy it is working again.
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