It does... I'm afraid that's all pretty normal in commercial gear though.
A lot of manufacturers will tell you discolouration due to heat is "normal" and a characteristic of the material used. Honest
OK... What I would do is replace all four of those 1000uf caps. As this is a bit of an "unknown" model to me I would also look to replacing the four diodes in the bridge D4/5/6 and 7 I think (it's bit tiny
R44 of course... that could be a problem getting a suitable safety resistor easily and cheaply. They are called safety resistors because they burn out without to much drama... smoke etc... which tends to frighten the customers lol.
The LM317 too probably...
The LM337 is probably OK, and if the output voltage is correct then that confirms it.
That should get the PSU fully working and assuming there isn't a further problem that has either been caused or has caused R44 to fail then that should be it.
Those bulging caps in some ways are a good sign that it is just a PSU issue
I would just also suggest that Danza test the diodes and caps that he pulls out. This would help give him an idea whether replacing them is going to solve his problem. Diode testing per the previous link. To test those high-value caps -- first discharge them; I think in this case he can safely just short the leads together. Then set an analog VOM to test ohms and connect the leads as appropriate. He should get some sort of a reading that then falls at a slow-ish speed. No reading at all, or pegging the meter -- either one means they are dead.
Whoa, many replies!
Thanks so much all, hopefully it's just the PSU side, and it'll be up and running again. I got the impression the CDP was abused when I received it - numerous marks and much of the lettering partially rubbed off due to button pressing. It wouldn't surprise me if it's been heavily used/abused!
I'll check all components as they come out of the player, and sort out ordering the replacements as soon as I can.
There's very little room around the regulators for a heatsink as the DAC PCB above leaves very little clearance. I'll have to choose the caps carefully too, just in case they're too tall.
Incidentally, the regs had a heatsink code printed on the PCB, but as I said, there's barely any room for them there.
Cheers!
Thanks so much all, hopefully it's just the PSU side, and it'll be up and running again. I got the impression the CDP was abused when I received it - numerous marks and much of the lettering partially rubbed off due to button pressing. It wouldn't surprise me if it's been heavily used/abused!
I'll check all components as they come out of the player, and sort out ordering the replacements as soon as I can.
There's very little room around the regulators for a heatsink as the DAC PCB above leaves very little clearance. I'll have to choose the caps carefully too, just in case they're too tall.
Incidentally, the regs had a heatsink code printed on the PCB, but as I said, there's barely any room for them there.
Cheers!
The problem with failed electroylitics is that the E.S.R. rises. A meter test isn't really good enough... E.S.R. is the equivalent series resistance.
A good analogy is a battery. New and it reads 1.5 volts, when it's flat it still reads similar. What has happened is the series resitance of the cell has increased limiting current and causing the terminal voltage to drop.
The cap is similar, measure it on a meter and it will read it's marked value, and similarly appear to charge and discharge OK. Now use that cap where there is a strong AC component (the ripple from the rectifiers) and that cap firstly doesn't "smooth" out the voltage and secondly the high E.S.R. causes power loss in the cap which means heat... so a failing cap quickly becomes a failed one.
The caps I need are 25V 1000uF. The lead spacing is 5mm, so the 35V caps would do, but they're a bit on the hefty side (too large in in diameter). I'll order all the bits in a little while, and fit them when they arrive. Hopefully that'll cure it!
Incidentally, I wiggled C48 gently to see if I could measure the spacing, and it dropped off the board and left a leg behind!
Incidentally, I wiggled C48 gently to see if I could measure the spacing, and it dropped off the board and left a leg behind!
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There are these,
RUBYCON|25YXF1000MY12521.|CAPACITOR, LOW-Z 25V 1000UF | CPC
If they are 25 volt parts and you have 31 volts across them unloaded... hmmm not good design at all that.
When you fit the new parts check the voltage across them.
RUBYCON|25YXF1000MY12521.|CAPACITOR, LOW-Z 25V 1000UF | CPC
If they are 25 volt parts and you have 31 volts across them unloaded... hmmm not good design at all that.
When you fit the new parts check the voltage across them.
The A suffix seems to be a part selected for better regulation tolerance over the supply range. Not a dynamic that should be a big issue in your circuit compared to ripple rejection and noise, which are the same. Still, I don't doubt there are people that claim the A part sounds better.
Anyway, with all the time it will take to fabricate heatsinks to double the surface area of those TO-220's I'd measure the mains in an attempt to understand why the supply voltage is so high. There is just about no way you should be getting 31V onto the input filter caps by design, and if you are then 25V rated ones will blow again.
Anyway, with all the time it will take to fabricate heatsinks to double the surface area of those TO-220's I'd measure the mains in an attempt to understand why the supply voltage is so high. There is just about no way you should be getting 31V onto the input filter caps by design, and if you are then 25V rated ones will blow again.
Yes, your 240 volts supply.
The rails (31 volt off load) will fall when loaded correctly (we hope) but it's just not good practice to have a 3.3 ohm safety resistor (think fuse), such that if it fails (as fuses do) the other parts could explode... it's madness. You can buy little clip on heatsinks for TO220 packages... see how hot they run I guess.
The rails (31 volt off load) will fall when loaded correctly (we hope) but it's just not good practice to have a 3.3 ohm safety resistor (think fuse), such that if it fails (as fuses do) the other parts could explode... it's madness. You can buy little clip on heatsinks for TO220 packages... see how hot they run I guess.
A couple of heatsinks here,
http://cpc.farnell.com/eg-g-vactec/576802b00000/heatsink-warthto220clip/dp/SCWHS2
Your Search Results | CPC
Also the tab of the regulator is connected to "vout" I think for the positive reg and "Vin" for the negative so they are not isolated so musn't touch anything unless you used an insulating kit.
http://cpc.farnell.com/eg-g-vactec/576802b00000/heatsink-warthto220clip/dp/SCWHS2
Your Search Results | CPC
Also the tab of the regulator is connected to "vout" I think for the positive reg and "Vin" for the negative so they are not isolated so musn't touch anything unless you used an insulating kit.
BTW -- I've owned an Alpha 8SE player since it was new (late 1998, I think). The 7, 8, and 9 all came out at the same time and were the same except for the DAC board. Arcam would "upgrade" your player for you for a fee.
I dimly remember that, at least with early ones, there was some sort of problem that happened only with the 9. It may even have been only with 7s and 8s that were upgraded to become 9s. I think it was related to heat, and further problems caused by that heat. Either on account of the 9's DAC board simply taking up more space and cutting down on air flow, or because it made greater demands on the rest of the system.
I just thought this might be what happened to your player. If you're patient enough, you might find something on Google.
I dimly remember that, at least with early ones, there was some sort of problem that happened only with the 9. It may even have been only with 7s and 8s that were upgraded to become 9s. I think it was related to heat, and further problems caused by that heat. Either on account of the 9's DAC board simply taking up more space and cutting down on air flow, or because it made greater demands on the rest of the system.
I just thought this might be what happened to your player. If you're patient enough, you might find something on Google.
Right, everything's soldered. Checked, double checked and checked again.
It's still misbehaving, with the following symptoms:
-On powering on, regardless of whether there's a disc inserted, all the track number leds illuminate then go out, and the display stays at '0'. Track selection does not work.
-At the same time, the laser 'illuminates' and bobs up and down twice, then settles and ceases illumination (it did nothing before the repair).
-If I move the laser along the sled manually, it goes back to the 'start' position of the CD upon power on. It does not move otherwise, i.e. does not scan across the disc or anything else.
-At no point does the spindle motor engage - the disc remains stationary. Note that before I performed the repair, the motor would spin up for a couple of seconds on power on, then stop.
I'm beginning to think it's a lemon. Any thoughts?
It's still misbehaving, with the following symptoms:
-On powering on, regardless of whether there's a disc inserted, all the track number leds illuminate then go out, and the display stays at '0'. Track selection does not work.
-At the same time, the laser 'illuminates' and bobs up and down twice, then settles and ceases illumination (it did nothing before the repair).
-If I move the laser along the sled manually, it goes back to the 'start' position of the CD upon power on. It does not move otherwise, i.e. does not scan across the disc or anything else.
-At no point does the spindle motor engage - the disc remains stationary. Note that before I performed the repair, the motor would spin up for a couple of seconds on power on, then stop.
I'm beginning to think it's a lemon. Any thoughts?
First things first, golden rule, check and confirm ALL voltage rails are correct from the PSU and within a normal 5% or so tolerance. And welcome to some true faultfinding
The disc won't spin untill focus is found... it's much easier focusing on a stationery object than a moving one
Check all the rails first...
The disc won't spin untill focus is found... it's much easier focusing on a stationery object than a moving one
Check all the rails first...
I can't understand what's happening with the spindle servo from the circuit drawings you posted. If the display is acting differently then you might have a new problem with a logic supply or ground. New unrelated symptoms after a repair could mean, you would hope, a harmless faulty connection. You said you checked that, but how are the supply voltages now?
From what you say it all sounds to be pretty much behaving now and mechanically doing what it should.
Is it a full manual you have ?
You might be able to identify a FOK line which is focus OK somewhere around the servos. This should change logic level when a disc is inserted and focus is found, assuming it gets that far. That will happen during those few moments the lens bobs up and down.
Have you cleaned the lens ? Does it all look bright and clean too ?
Is it a full manual you have ?
You might be able to identify a FOK line which is focus OK somewhere around the servos. This should change logic level when a disc is inserted and focus is found, assuming it gets that far. That will happen during those few moments the lens bobs up and down.
Have you cleaned the lens ? Does it all look bright and clean too ?
Cheers guys.
I know that checking the power supplies is the next step, but I'm unsure as to where to put the probes of my multimeter. What part of the player do I use for the ground? The laser lens looked a little cloudy, so I wiped it with a cotton bud thinking 'that'll do'. I'll give it another go. The player is in bits at work at the moment. I'll pop over and bring it home for some action on the kitchen table.
Anyway, the manual has this on the power supplies:
I have the full service manual, but it's all rather Greek to me really!
I know that checking the power supplies is the next step, but I'm unsure as to where to put the probes of my multimeter. What part of the player do I use for the ground? The laser lens looked a little cloudy, so I wiped it with a cotton bud thinking 'that'll do'. I'll give it another go. The player is in bits at work at the moment. I'll pop over and bring it home for some action on the kitchen table.
Anyway, the manual has this on the power supplies:
Alpha Series CD Service Manual said:
I have the full service manual, but it's all rather Greek to me really!
Right, I've cleaned the lens properly with some alcohol-free lens cleaner from work, and it's still the same so definitely time for a bit more testing.
One thing I didn't mention earlier is the fact that the IR remote receiver illuminates briefly upon powering on, not that this likely makes any difference.
One thing I didn't mention earlier is the fact that the IR remote receiver illuminates briefly upon powering on, not that this likely makes any difference.
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It seems that the 7.3V supply might also be used for the spindle motor, so if the loading motor is running that supply is probably OK. Beyond verifying the rest of the supply voltages are good, since the audio section supplies that you repaired probably have nothing to do with the malfunction, troubleshooting can get a little more involved. If you post the other two drawing sheets it may be easier to help. By any chance did you have to unplug the pickup assembly connector during disassembly?
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