Hi,
Need help with this CD player. It turns on but is unresponsive in that pressing the open/close button doesn't open the tray. It's not the belt. I've had the lid off and the only thing to note is that when you press the open/close button, the laser does try to focus. I've manually opened and loaded a disc but there is little to no rotation of the disc. I also used my meter at the spindle connector and found that the +7.5V is missing but the -7.5V is present.
Does anyone know of a reason why this would happen?
I had the same model CD player a while back with the same problem but sold it on as spares/repair as I didn't have time to try to find out about repairing it. This tells me that it must be a common problem so thought I'd ask here first.
Thanks for your time.
Need help with this CD player. It turns on but is unresponsive in that pressing the open/close button doesn't open the tray. It's not the belt. I've had the lid off and the only thing to note is that when you press the open/close button, the laser does try to focus. I've manually opened and loaded a disc but there is little to no rotation of the disc. I also used my meter at the spindle connector and found that the +7.5V is missing but the -7.5V is present.
Does anyone know of a reason why this would happen?
I had the same model CD player a while back with the same problem but sold it on as spares/repair as I didn't have time to try to find out about repairing it. This tells me that it must be a common problem so thought I'd ask here first.
Thanks for your time.
Service Manual here.............
Technics SL-P990 - Manual - Infra-Red Remote Control Compact Disc Player - HiFi Engine
I think these had fuses in the supplies. Little Orange/Yellow things if I remember correctly.
Check these. There must have been a reason why it failed, if one has, so best not to just replace it. Have a read of the Schematic and do some tests in the PSU.
You maybe have a failed/failing Spindle Motor.
P.
Technics SL-P990 - Manual - Infra-Red Remote Control Compact Disc Player - HiFi Engine
I think these had fuses in the supplies. Little Orange/Yellow things if I remember correctly.
Check these. There must have been a reason why it failed, if one has, so best not to just replace it. Have a read of the Schematic and do some tests in the PSU.
You maybe have a failed/failing Spindle Motor.
P.
There are two fuses but these are fine. There aren't any other fuses or components acting like a fuse I don't think.
I have noticed something... There are 4 components which look like mini transistors but have only two legs. They are marked N15 and are in positions SJ11, SJ12, SJ13 and SJ14. With my meter set for continuity, measured from leg to leg of each N15 i get a beep on three of them but one is as though it's open circuit.I will try to find out what they are and see if that could be the culprit.
Any other input would be great, please.
I have noticed something... There are 4 components which look like mini transistors but have only two legs. They are marked N15 and are in positions SJ11, SJ12, SJ13 and SJ14. With my meter set for continuity, measured from leg to leg of each N15 i get a beep on three of them but one is as though it's open circuit.I will try to find out what they are and see if that could be the culprit.
Any other input would be great, please.
Seems they are actually fuses. The one which is open circuit is SJ11 on the main PCB. Why could this have failed?
I cannot find the SJ... you refer to.
All the PCB mounted fuses are labelled ICP...
Can you clarify?
P.
All the PCB mounted fuses are labelled ICP...
Can you clarify?
P.
Hi,
I've found out that it was one of the aforementioned N19 components which are very fast acting fuses. They look like transistors but have only 2 pins, there are 4 of them and one was blown. I replaced the blown one with a same part (found from a low-end Technics CD player I had - seems Technics used these components in lots of players.
Anyway, replaced the bad component, and powered it up. It allowed me to open the tray - Great! It works!!... or so i thought. I placed a disc on the tray, pressed close button, tray went in and laser mech made a funny sort of noise and with little movement of the disc. I pressed open button but the same thing has happened. The same fuse has now blown again, rendering the player unresponsive when pressing open/close.
There is something that is making that fuse blow. Could it be that the transport is bad? As it's only when the transport is trying to read that the fuse blows. I'm also wondering if the past owner had messed around with the pots which adjust laser/tracking etc(I bought the unit from a house clearance so have no history of it) - would that blow the fuse if they were set too high?
I have one more N19 fuse but am reluctant to use it until I know more.
I've found out that it was one of the aforementioned N19 components which are very fast acting fuses. They look like transistors but have only 2 pins, there are 4 of them and one was blown. I replaced the blown one with a same part (found from a low-end Technics CD player I had - seems Technics used these components in lots of players.
Anyway, replaced the bad component, and powered it up. It allowed me to open the tray - Great! It works!!... or so i thought. I placed a disc on the tray, pressed close button, tray went in and laser mech made a funny sort of noise and with little movement of the disc. I pressed open button but the same thing has happened. The same fuse has now blown again, rendering the player unresponsive when pressing open/close.
There is something that is making that fuse blow. Could it be that the transport is bad? As it's only when the transport is trying to read that the fuse blows. I'm also wondering if the past owner had messed around with the pots which adjust laser/tracking etc(I bought the unit from a house clearance so have no history of it) - would that blow the fuse if they were set too high?
I have one more N19 fuse but am reluctant to use it until I know more.
From that description the fuse seems to fail as soon as the spindle motor should spin up the disc. I would +1 percival007's suggestion of a spindle motor problem.
Rundmaus
Rundmaus
The location of the fuse is SJ11. This is printed on both sides of the PCB.
I've taken the transport mech out and the spindle isn't a normal motor but has a magnet on the bottom which hovers over coils which are mounted on a separate PCB. This PCB is marked SUPD1440 and has three coils, three normal looking caps, a bunch of surface mounted caps and an IC chip. Looking online, there's mention of the caps and/or IC being known to fail.
How would I test the IC?
I've taken the transport mech out and the spindle isn't a normal motor but has a magnet on the bottom which hovers over coils which are mounted on a separate PCB. This PCB is marked SUPD1440 and has three coils, three normal looking caps, a bunch of surface mounted caps and an IC chip. Looking online, there's mention of the caps and/or IC being known to fail.
How would I test the IC?
Sorry, don't mean to be picky, but in the Service manual I linked to, I can see no mention of SJ11 or any SJ's.
All the two pin Semi-Conductor Fuses are labelled as ICP...
On the Board Layout can you tell me where to find SJ11?
Any chance of a photo?
P
All the two pin Semi-Conductor Fuses are labelled as ICP...
On the Board Layout can you tell me where to find SJ11?
Any chance of a photo?
P
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No problem, there must be different versions.
The SJ11 is in the power supply section and has R22 in front of it, C15 behind it and D25 to the left.
The SJ11 is in the power supply section and has R22 in front of it, C15 behind it and D25 to the left.
Thanks.
As far as I can make out then, SJ11 is the same as ICP3 in series with the +7V Supply for the SP Motor.
If the Fuse remains OK with the unit just at 'idle' then all the Caps across the Supply must be OK (may be worth changing once fixed though) and it blows only as it is asked to spin the Motor, then either the Motor is physically stuck and unable to turn (?) (both Fuses (+/-) perhaps would go here though (?) ).
Or the Drive IC is failed. Difficult to test though.
Try lifting the connections to the Coils and measuring the DC Resistance from the Pins on the IC (7,8 &9) to 0V, +7V & -7V respectively. I would assume they all should be the same, if one is wildly different from the others then possibly a failed IC (?). Not a definitive test though I suppose.
Also measure the DC Resistance of the Coils whilst you have them disconnected.
They will be low resistance I would guess so you'll need a good Meter.
Although I have discounted the Caps across the Supply as it sits there in 'idle' (?) can you 'scope the Supplies? It may be worth doing to make sure they are all OK and clean.
Away for a couple of days now but do let us know how it goes.
P
As far as I can make out then, SJ11 is the same as ICP3 in series with the +7V Supply for the SP Motor.
If the Fuse remains OK with the unit just at 'idle' then all the Caps across the Supply must be OK (may be worth changing once fixed though) and it blows only as it is asked to spin the Motor, then either the Motor is physically stuck and unable to turn (?) (both Fuses (+/-) perhaps would go here though (?) ).
Or the Drive IC is failed. Difficult to test though.
Try lifting the connections to the Coils and measuring the DC Resistance from the Pins on the IC (7,8 &9) to 0V, +7V & -7V respectively. I would assume they all should be the same, if one is wildly different from the others then possibly a failed IC (?). Not a definitive test though I suppose.
Also measure the DC Resistance of the Coils whilst you have them disconnected.
They will be low resistance I would guess so you'll need a good Meter.
Although I have discounted the Caps across the Supply as it sits there in 'idle' (?) can you 'scope the Supplies? It may be worth doing to make sure they are all OK and clean.
Away for a couple of days now but do let us know how it goes.
P
Those metal can capacitors are known for failing on the motor board. Replace those and give it a spin.
That was it! Replaced them two capacitors and it's now working perfectly.
Thanks so much for all the help. Really happy!
Thanks so much for all the help. Really happy!
Hi. Topic is long silent, but maybe someone is still active. Which capacitors were "shot" in your case? All the best.
Hi guys. Tried out a few things, managed to buy a new driver board after I confirmed that the chip was dead. Turns out the chip on these driver boards tend to over heat and in later slp990 versions that chip had a factor included radiator to dissipate the heat. Either ways, new working board is in place. CD motor works! Turns, but with a small push meaning that it requires calibration according to the official technics documentation - however i have found different things. Some transistors after 5 minutes of on time get very hot. Another part that gets hot is the capacitors around the IC area ( see the image rhiollyrubgt sent, it is that left area of the power section). Somehow my fuses are ok, but! the 7.5v line (also viisble in that photo) is giving me 2.2v could anyone help? Cheers.
Thanks for this very useful thread. Replaced 1uF 50V and 33uF 25V SMD capacitors on spindle board, put a new 0.6A fuse in SJ11 position on the main board, and the player started working again!