I have a Philips CD150 (CDM2/10) I am giving attention.
The previous owner claims it would read some cds etc. and that the laser lens just need a bit of a clean ... but right from the start I have Err message.
I have recapped it fully hoping that a general rundown was the problem but still Err.
The discs spin up and the laser pops in and out trying to focus.
I have followed the instructions in the manual to get to run some checks in service mode. The arm swings freely BUT there is no light from the laser (this should be visible, right?!)
So can I presume the laser diode is kaputt?
Anything else I can check?
There is certainly power getting to various parts of the mechanism but no laser light show.
I should probably have had a better look and run these checks before I did the recap - but learning and improving technique with each project.
All help/suggestions much appreciated.
The previous owner claims it would read some cds etc. and that the laser lens just need a bit of a clean ... but right from the start I have Err message.
I have recapped it fully hoping that a general rundown was the problem but still Err.
The discs spin up and the laser pops in and out trying to focus.
I have followed the instructions in the manual to get to run some checks in service mode. The arm swings freely BUT there is no light from the laser (this should be visible, right?!)
So can I presume the laser diode is kaputt?
Anything else I can check?
There is certainly power getting to various parts of the mechanism but no laser light show.
I should probably have had a better look and run these checks before I did the recap - but learning and improving technique with each project.
All help/suggestions much appreciated.
The disc will spin only after the pickup detects a reflective surface, therefore the laser is probably OK. The same goes for the focusing. There could be a number of causes to check and investigate: spindle height, focus and radial offset, laser current, dry solder joints, even Xtal overtoning in some cases.
No, with Philips players the disc always spins contrary to Japanese players where the disc only spins after Focus OK signal.
At power on and with no disc in the tray, the CD150 platter gives a little kick spinning for around 0.25 of a second.
The fact its showing 'ERR' suggests (as Willi says) that it is at least finding focus. The laser 'light' on these is not easy to see by eye. Its worth checking the laser current to get an idea of what's going on. If you look at the circuit there will be a low value series resistor feeding the laser drive transistor. Measuring the voltage across this will allow the current to be calculated. I would guess it would be in the 45 to 60ma region.
Did you change all the caps on the servo board under the laser ?
The fact its showing 'ERR' suggests (as Willi says) that it is at least finding focus. The laser 'light' on these is not easy to see by eye. Its worth checking the laser current to get an idea of what's going on. If you look at the circuit there will be a low value series resistor feeding the laser drive transistor. Measuring the voltage across this will allow the current to be calculated. I would guess it would be in the 45 to 60ma region.
Did you change all the caps on the servo board under the laser ?
Thanks to all the learned replies above.
I will work through them over the next couple of days and let you know how I get on.
But first I have to replace the L272M opamp I fried with my poking things in where they don't belong, this afternoon - hopefully that is all I fried. I was trying to find the right pins to see if there was a current to the laser as per my first respondant's suggestion. Was a subtle bit of fireworks actually, but just another reminder than I only know enough to be dangerous, but not yet enough to be safe.
I will work through them over the next couple of days and let you know how I get on.
But first I have to replace the L272M opamp I fried with my poking things in where they don't belong, this afternoon - hopefully that is all I fried. I was trying to find the right pins to see if there was a current to the laser as per my first respondant's suggestion. Was a subtle bit of fireworks actually, but just another reminder than I only know enough to be dangerous, but not yet enough to be safe.
That's right - but the pins feeding the flexible tape that leads off to the motors and laser are all there in a nice line! Told you I was poking around places I had no reason to be.
My advice is to place it on a socket because during the alignment procedure you will be poking it more. When the player is out of alignment by far due to ageing, the continuous current output from L272M (1A is a lot for that IC package) can actually fry one channel and there is a chance it was already partially fried and this is why the player didn't work.
Thanks. That is very helpful. Could only buy these guys in a minimum quantity of 10 so we'll see how many I can burn through.
(How does RS Components make any money when they do free postage on an order of mere pennies? I can order stuff until 8pm and have them arrive on my doorstep tomorrow at 8am! (I must be near the beginning of the van run) That is not far from the definition of instant gratification)
CPC does free delivery on orders over £5.00 (Edit... just looking at RS. No minimum order charge now ? Guess they realised they were losing out big time
)
RS tried to go it alone in hanging on to delivery charges. When other companies offer it for free, who you going to order off ?
L272, £0.49 +vat.
FAIRCHILD SEMICONDUCTOR - L272M - Operational Amplifier, Dual, 350 kHz, 2 Amplifier, 1 V/µs, 4V to 28V, DIP, 8 Pins | CPC UK
) RS tried to go it alone in hanging on to delivery charges. When other companies offer it for free, who you going to order off ?
L272, £0.49 +vat.
FAIRCHILD SEMICONDUCTOR - L272M - Operational Amplifier, Dual, 350 kHz, 2 Amplifier, 1 V/µs, 4V to 28V, DIP, 8 Pins | CPC UK
I haven't used them - but free over £5 is very reasonable. Farnell free over £30(+vat), Mouser is similar I think. So RS it is most of the time, but they don't carry everything that you might want (like Elna Silmic II for example) so I have had to hold back on buying until I have enough need/want to go over to Farnell.
Just checked on Element 14, which I meant with Farnell above, looks like they have changed their postage structure too since I last used them a couple of months ago - now £20(ex.vat) minimum order and only £3.95 post for smaller - I think it was £12 p&p a few months ago. Mouser still free ship over £33(ex.vat) and £12 postage!
There should be a knock on the door with those L272s in about 20mins!
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Quick thought on the CD150...
The single core wire used for all the connections on the multiway plugs can be fragile and easily broken.
There is also a single black wire from the front panel to the main PCB that is secured with a single 'push' connector. I seem to remember that if this wasn't OK then things could burn up... a long time ago since I worked on these.
The single core wire used for all the connections on the multiway plugs can be fragile and easily broken.
There is also a single black wire from the front panel to the main PCB that is secured with a single 'push' connector. I seem to remember that if this wasn't OK then things could burn up... a long time ago since I worked on these.
Yes. I had read that elsewhere. Have given them all a good tug a couple of times checking and rechecking. They seem sound but I will keep it in mind this problem area.
Arghh! Amateur!
After my fail yesterday, installed new L272 on a socket, radial motor ok BUT now lens not popping up and down - must have fried the focus driver with yesterday's action. Kicking myself.
Will check current to laser as per Mooly's instructions above anyway.
These boards are very delicate now and around where I have soldered the new L272 socket it is looking a bit ropey - but the pin 1 going out to the focus motor is looking one of the better ones. I might try adding some jumpers to next component in case I have damage the traces from that chip
After my fail yesterday, installed new L272 on a socket, radial motor ok BUT now lens not popping up and down - must have fried the focus driver with yesterday's action. Kicking myself.
Will check current to laser as per Mooly's instructions above anyway.
These boards are very delicate now and around where I have soldered the new L272 socket it is looking a bit ropey - but the pin 1 going out to the focus motor is looking one of the better ones. I might try adding some jumpers to next component in case I have damage the traces from that chip
Fixed traces from pins 6,7,8.
THink I am checking continuity ok.
There is a SMD 8E2 resistor (3142) immediately adjacent to pin 1 which feeds to focus. That's a small value right? When I measure this guy using MM (AMPROBE 5XP-A) I do not get reading at lowest setting (200R) as expected - it is not until turn range up to 2M that I get a reading off it. I have not isolated at all just on the board. If it was burnt out it would be open circuit, right? No continuity there
So paused writing this while I took the trouble to take this resistor off the board so I could measure it isolated ... The poor little thing fell apart. Oh dear. Wonder if there are others like this.
Back to the RS shopping cart.
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