Had a high voltage cable lift the pavement here yesterday, and now my cd player is shot. My PC also took a hit. When I went to load it, the tray made a right noise before coming out, then when it did I sent it back empty and it just span for 30 seconds so I pulled the plug. Upon powering up again, all looked well, but the sound was distorted. Kinda crunchy and thin. I used an external dac worth £3.50 and that worked, but sounded like £3.50 and I had never used it before so can't say if that was right. But it played to a low standard.
So, off to find drawings Arcam Alpha 8 CD - Manual - Compact Disc Player - HiFi Engine
Lift the lid, and a smoothing cap on the analogue psu has popped. Swapped it out from the 1000 to an 820, but it's 22 years old now and I thought that close.
All the screws back in.. back in the stack. Bugger.. It still don't work, but it's different. I think for the first second it may of been ok. But poor quality was soon heard, and within 15 seconds it had gone from music to white noise. Then it tried to play the track from the start again. I pulled the plug and came here for advice.
Thank you for getting this far with my story 🙂
I think with that decay over time it's going to be a cap, but I don't know where to start looking.
So, off to find drawings Arcam Alpha 8 CD - Manual - Compact Disc Player - HiFi Engine
Lift the lid, and a smoothing cap on the analogue psu has popped. Swapped it out from the 1000 to an 820, but it's 22 years old now and I thought that close.
All the screws back in.. back in the stack. Bugger.. It still don't work, but it's different. I think for the first second it may of been ok. But poor quality was soon heard, and within 15 seconds it had gone from music to white noise. Then it tried to play the track from the start again. I pulled the plug and came here for advice.
Thank you for getting this far with my story 🙂
I think with that decay over time it's going to be a cap, but I don't know where to start looking.
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Half a cd later, the offboard dac just sounds like a £3.50 dac should. But it's rather odd that using the analogue outs turned to mush and started the track again. Yet using the digital out it didn't try and start again. Perhaps there is some noise I'm reducing. I must do a second run using the analogue outs and dac together. It's in bits again now.. looking aimlessly at the dac board. Which just might have a smoothing cap issue C64
The fact that other caps may look okay, does not mean they ARE okay... They have probably dried out and lost their nominal capacitance rating.
You should replace all 25V capacitors: C44, 45 and C47, 48.
It shouldn't be that difficult to measure all power supply voltages from the circuit diagram.
SK204 would be a nice place to check the regulated (stabilised) voltage rails...
You should replace all 25V capacitors: C44, 45 and C47, 48.
It shouldn't be that difficult to measure all power supply voltages from the circuit diagram.
SK204 would be a nice place to check the regulated (stabilised) voltage rails...
... aslo, check the PCB tracks around Zenner diodes D17 and D18.... they tend to run hot, which can cause cold solder joints or even damaged tracks.
C36 is an important capacitor and it is located close to D17... I'd replace that cap as well.
C36 is an important capacitor and it is located close to D17... I'd replace that cap as well.
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Thank you. I have popped it aside for a couple of days, looking at scopes. It seems the rail with the bust cap goes to the dac where another suspect looking cap resides before the next regulator, c64. I was looking at the 8 not 8se drawings before so couldn't spot it.
I have found myself looking at the Arcam cds50 and the 192. The 50 doesn't have a single review though, but does have the dac my pc can use. I think it's a lemon.
Must fix this though 🙂
I have found myself looking at the Arcam cds50 and the 192. The 50 doesn't have a single review though, but does have the dac my pc can use. I think it's a lemon.
Must fix this though 🙂
I ordered the caps. The 4, the big one, and the one on the dac along with it's companion on the other rail. The YK was hard to find, so I reluctantly used it's replacement the PK. Tempted as I was to use low impedance one's instead.
No joy but some movement. The issue is steady distortion now. It's not going downhill. I wish I had repeated that run when it went downhill and lost the time data. I sort of did by trying again with the external dac which played. So I can't understand the time display going off that time. Almost like I must ignore it, but it happened. In my mind that would point to the the transport, but then it wouldn't of played through the dac any better.
I need to refresh my viewpoint.
It sounds a bit like a radio that's not tuned in. When it's quiet, it's quiet. The sound is like it's not tuned in though. It's hashed. In the 10 mins I played it, it stopped for a moment and its possible that tapping the player makes it skip more than it used to. Though I never stood tapping it before, it doesn't take a lot.
I have no idea what sort of corruption is possible in the digital realm, that it would pass out to the analogue stages without realising it was wrong.
I have another part looking black. I had to wipe it to see what it said. A little square blue PP cap. C42 on the dac board. It's in the drawings, but in the top right corner, connected to a couple of other parts, that connect to nothing else. An isolated drawing, making references to powering a chip I can't see. It's position on the board makes it look like it's just on one channel though, and both channels are bad. Maybe one worse than the other though.
I got another dac out, dropped the power lead, picked up the wrong one, and killed it. What a week..
I really wanted to put up a sound clip, but that might be beyond me since I scrapped youtube
I need to refresh my viewpoint.
It sounds a bit like a radio that's not tuned in. When it's quiet, it's quiet. The sound is like it's not tuned in though. It's hashed. In the 10 mins I played it, it stopped for a moment and its possible that tapping the player makes it skip more than it used to. Though I never stood tapping it before, it doesn't take a lot.
I have no idea what sort of corruption is possible in the digital realm, that it would pass out to the analogue stages without realising it was wrong.
I have another part looking black. I had to wipe it to see what it said. A little square blue PP cap. C42 on the dac board. It's in the drawings, but in the top right corner, connected to a couple of other parts, that connect to nothing else. An isolated drawing, making references to powering a chip I can't see. It's position on the board makes it look like it's just on one channel though, and both channels are bad. Maybe one worse than the other though.
I got another dac out, dropped the power lead, picked up the wrong one, and killed it. What a week..
I really wanted to put up a sound clip, but that might be beyond me since I scrapped youtube
I can only spend 5 mins a day on this before it annoys me that I'm having to. I don't have a TV and now I'm locked in with a CD player the electric board have blown up for me. I just can't face it for long.
The main board has a couple of 18v regulators. It's where I found the first bad cap. This main board is shared by the 7 8 and 9 models. On the 7, the regs have no heatsink. On the 9 the minus rail has one but not the plus. I can't see a pic of an 8 but like the 9 I have just the minus rail using a heatsink. The positive one is hot. It's darkened the board. It's only hot with the dac board plugged in. Other models must use this +/- 18v for the dac but mines 15v so the 18v goes straight through the same type of regulators on the dac board to drop the 18 to 15 and they don't get hot. I have found one other use for the +18vdc so I guess that's the problem part on the dac. It's the low jitter clock as they call it. A part that was physically damped with goo that while I have had it open, has dripped off. It's an odd area of the circuit board. It you were to draw a box around it, then 3 sides have had the board sawn through. It's very isolated.
Does the clock usually run hot ? That 18v regulators temperature says no. The general design and use of that +/-18v set says it should have a heatsink though.
I haven't found a single test pad and I'm lacking the figures that should be present. For instance I have a pair of voltage references but while they measure 2.68v I have no idea if they should. The DAC's for dummies sites are not getting down to that level of design detail, and frankly... I'm pissed off about having to learn so much when it's not my fault.
Beer time..
The main board has a couple of 18v regulators. It's where I found the first bad cap. This main board is shared by the 7 8 and 9 models. On the 7, the regs have no heatsink. On the 9 the minus rail has one but not the plus. I can't see a pic of an 8 but like the 9 I have just the minus rail using a heatsink. The positive one is hot. It's darkened the board. It's only hot with the dac board plugged in. Other models must use this +/- 18v for the dac but mines 15v so the 18v goes straight through the same type of regulators on the dac board to drop the 18 to 15 and they don't get hot. I have found one other use for the +18vdc so I guess that's the problem part on the dac. It's the low jitter clock as they call it. A part that was physically damped with goo that while I have had it open, has dripped off. It's an odd area of the circuit board. It you were to draw a box around it, then 3 sides have had the board sawn through. It's very isolated.
Does the clock usually run hot ? That 18v regulators temperature says no. The general design and use of that +/-18v set says it should have a heatsink though.
I haven't found a single test pad and I'm lacking the figures that should be present. For instance I have a pair of voltage references but while they measure 2.68v I have no idea if they should. The DAC's for dummies sites are not getting down to that level of design detail, and frankly... I'm pissed off about having to learn so much when it's not my fault.
Beer time..
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Well I have something. The power to the clocks supply regulator comes though a 47ohm which stays cold. I think the stuff might of melted off some other way, as it's pooled on the transformer which isn't really possible without transfer. There too far apart. So I'm going to ignore that. This same 47r also powers a 5v regulator for the pwm noise shaper. The power first passes a 100r fuse resistor. Almost a volt is lost over that resistor, so the reg only gets 5.2 and coming out of this 5v reg I have 3.5v. Now my meters isn't great, but at 240 it's as good as a good fluke and while the clocks identical regulator chip is providing 4.5v from it's 6v input, this 3.5v is surely quite a shift. Though I also have almost a volt less at the regulator to begin with.
I think both 3.5 and 4.5 are too low, because both regs are running below their drop-out voltage with is likely about 8v. The 47r gets the 18v and makes 15v available to the transistor Q6 which gives my two regs this low voltage. Q6 must be a broken regulator circuit. As you have guessed.. I don't remember even the most basic stuff from school.
The electricity supply company have a lot to answer for
I think both 3.5 and 4.5 are too low, because both regs are running below their drop-out voltage with is likely about 8v. The 47r gets the 18v and makes 15v available to the transistor Q6 which gives my two regs this low voltage. Q6 must be a broken regulator circuit. As you have guessed.. I don't remember even the most basic stuff from school.
The electricity supply company have a lot to answer for
For the mere humans among us, here's my brain drain
arcam5v — ImgBB
I feel quite sure Q6 is a regulator and the fault is very close. I don't see a zener or divider though. Just C51 which lives right by the area I have lost resin from. The nearest component. It's kinda screaming at me but I don't understand this simple looking circuit.
An externally hosted image should be here but it was not working when we last tested it.
arcam5v — ImgBB
I feel quite sure Q6 is a regulator and the fault is very close. I don't see a zener or divider though. Just C51 which lives right by the area I have lost resin from. The nearest component. It's kinda screaming at me but I don't understand this simple looking circuit.
The power starts at 18v and looses 3 of them over the 47ohm resistor and inductor. Ignoring the inductors resistance, that looks like 63mA and Q6 usually lives in circuits around 30ma to 50mA. It's a 250mW device, doing about double that right now. It's base voltage is just under 10v, so I think the emitter should be 9v. Even then you can't really have 50mA. The existence of a base voltage makes me think Q6 is intact though. However, wouldn't it be a wide open flood gate with the base voltage almost 4v above the emitter? It's dropping voltage.
I see 0.8v (ish) over the 100ohm fuse resistor feeding the PWM chip, so maybe 8mA. Little cause for immediate concern, if looking for a drain. So it's the clock area taking the power. Which did seem to melt it's very soft grease like damping goo. The 5v regs both drop about 1.6v sat wide open unable to reach 5v.
With 4.5v and 55mA at the oscillator area, we have 250mW. It only takes a few to solder. It could get hot?
I think Q6 with such a voltage across it, with that base/emitter voltage, must be dead. I still have something taking 250mW though. A thermal imaging camera would be great about now. Z13A doesn't seen to be doing anything. I'm sure I'm missing it, as they can't of started with B.
I see 0.8v (ish) over the 100ohm fuse resistor feeding the PWM chip, so maybe 8mA. Little cause for immediate concern, if looking for a drain. So it's the clock area taking the power. Which did seem to melt it's very soft grease like damping goo. The 5v regs both drop about 1.6v sat wide open unable to reach 5v.
With 4.5v and 55mA at the oscillator area, we have 250mW. It only takes a few to solder. It could get hot?
I think Q6 with such a voltage across it, with that base/emitter voltage, must be dead. I still have something taking 250mW though. A thermal imaging camera would be great about now. Z13A doesn't seen to be doing anything. I'm sure I'm missing it, as they can't of started with B.
The random clicks n pops while not in use, are typically clock related. Which is where I'm looking.
The PWM chip should take my calculated 8mA, for it's internal clock. Then 22mA more for it's digital circuits. Perhaps they were idle. Or perhaps measuring power with a wet finger is my idea of accurate measurements.
The clock area supplies power to the chip Z13 which shapes the wave. That chip has a 50mA max rating.
Q6 that supplies them, with their combined 80mA at full tilt, is a 100mA device. Not usually used over 30-50mA. Q6 has a bigger brother in the family they could of used, so I know Z13 isn't really needing that 50mA just for supplying data to a few chips.
I have my roughly 63mA to find between these two, and the Colpitts itself.
I have ordered Q6 by post. 10 of them cost very little. I measured the Vbe at 3.8v so I don't think it should have that 9v across it. I have never seen a transistor fail in such a way though. I find them nearly always offering a short circuit. Sometimes open. This doesn't feel comfortable, but I will change it, to see what I can learn from it. I know one thing. It's smaller then the tip of my iron.
The PWM chip should take my calculated 8mA, for it's internal clock. Then 22mA more for it's digital circuits. Perhaps they were idle. Or perhaps measuring power with a wet finger is my idea of accurate measurements.
The clock area supplies power to the chip Z13 which shapes the wave. That chip has a 50mA max rating.
Q6 that supplies them, with their combined 80mA at full tilt, is a 100mA device. Not usually used over 30-50mA. Q6 has a bigger brother in the family they could of used, so I know Z13 isn't really needing that 50mA just for supplying data to a few chips.
I have my roughly 63mA to find between these two, and the Colpitts itself.
I have ordered Q6 by post. 10 of them cost very little. I measured the Vbe at 3.8v so I don't think it should have that 9v across it. I have never seen a transistor fail in such a way though. I find them nearly always offering a short circuit. Sometimes open. This doesn't feel comfortable, but I will change it, to see what I can learn from it. I know one thing. It's smaller then the tip of my iron.
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I found the 17megs from the clock, or close enough considering the meter I used. So my rough sounding output is looking like the low voltage at the PWM chip. The voltage references of 2.5v seem unlikely as 5v is more typical. It's an hdcd player though and it looks like the references are moved to achieve a 6db gain shift. There is still an unusually low power demand by the pwm chip, but with it's minimum voltage not being met, I will look past that. There is still too much power heading to Q6 though, the dropper. I'm thinking it's fried, and I'm looking at the two electrolytics after it soon. The chip that does the shaping is at least partially working. I got my 17megs after it. Though it's 4 devices in one, the other 3 are in series so won't be hard to look over. There is a test point between each though, so it's important.
How many weeks has this taken... I wish I had some time off work.
How many weeks has this taken... I wish I had some time off work.
A month to the day, fixed!
It was Q6, a transistor used to drop the voltage supplied to two voltage regulators. It is itself supplied from a voltage regulator, supplied from a voltage regulator. Yes 4 in a row and number 3 broke. Because it's too small so I expect this even smaller packaged one won't last long before I fit the next size.
Sounds different somehow. A touch more grainy but with a little more image and more weight. Likely from the capacitors being refreshed.
Its just 15 mins into the first CD. Wait for it.... lol
It was Q6, a transistor used to drop the voltage supplied to two voltage regulators. It is itself supplied from a voltage regulator, supplied from a voltage regulator. Yes 4 in a row and number 3 broke. Because it's too small so I expect this even smaller packaged one won't last long before I fit the next size.
Sounds different somehow. A touch more grainy but with a little more image and more weight. Likely from the capacitors being refreshed.
Its just 15 mins into the first CD. Wait for it.... lol