No the 250V was not a joke but it was discussed right when 230V was introduced. The higher the voltage the less loss and the thinner the cabling can be. That is why 110/115V is such a bad idea. I had US colleagues who had to transform 115 to 230V and elsewhere back again just to avoid more expensive bus bars etc. in high power situations which proves the point. 60 Hz was a nice choice.
Anyway, the change from 220 to 230V already had enough impact and the subject was not current anymore. I still am surprised seeing old equipment still at the 220V settings when they do have a 230 or 240V setting. Apparently not many people care.
As to why solely large value film caps are not a good choice: many classic regulators do not like extremely low ESR at their outputs. Only very modern LDO regs accept extremely low ESR.
And to the subject of cap replacement: forget you are dutch and just replace them all and also for known good stuff like Panasonic FC as it is the definite solution 😀 Cause is not only the heat but also the choice for cheap brands in a struggle to stay alive. When you see Lelon or Capxon caps you know something is wrong.
Generic info: I will not go deeper in the specific device but many brands also use 5V regs on 15V supply lines. It can help to add a small transformer/rectifier/filter cap on a PCB in such cases. Or the secondary voltages are chosen way too high in which case the 240V mains setting can have a slight positive effect. I designed complete replacement boards with LDO regs for such cases but that is not economical. Adding ventilation holes or slots can be done as well in cases where heat buildup occurs. Replacing the heatsinks for larger or higher ones can be a solution too. Just use your "gezond verstand" and you will have optimal results.
Anyway, the change from 220 to 230V already had enough impact and the subject was not current anymore. I still am surprised seeing old equipment still at the 220V settings when they do have a 230 or 240V setting. Apparently not many people care.
As to why solely large value film caps are not a good choice: many classic regulators do not like extremely low ESR at their outputs. Only very modern LDO regs accept extremely low ESR.
And to the subject of cap replacement: forget you are dutch and just replace them all and also for known good stuff like Panasonic FC as it is the definite solution 😀 Cause is not only the heat but also the choice for cheap brands in a struggle to stay alive. When you see Lelon or Capxon caps you know something is wrong.
Generic info: I will not go deeper in the specific device but many brands also use 5V regs on 15V supply lines. It can help to add a small transformer/rectifier/filter cap on a PCB in such cases. Or the secondary voltages are chosen way too high in which case the 240V mains setting can have a slight positive effect. I designed complete replacement boards with LDO regs for such cases but that is not economical. Adding ventilation holes or slots can be done as well in cases where heat buildup occurs. Replacing the heatsinks for larger or higher ones can be a solution too. Just use your "gezond verstand" and you will have optimal results.
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Jean-Paul,
Thnx!
However, it was not very wise of Cambridge (to say the least) to use these rubbish capacitors, because the Player was not cheap at all .
(Clearly a case of Penny wise- Pound foolish, because they have alienated a lot of customers, by now.
Cheers, Martin
Thnx!
However, it was not very wise of Cambridge (to say the least) to use these rubbish capacitors, because the Player was not cheap at all .
(Clearly a case of Penny wise- Pound foolish, because they have alienated a lot of customers, by now.
Cheers, Martin
I guess they think: who cares? Most people buy stuff that someone else advises. Even if it is crap, when the marketing is good the sales is good. They would even buy a second device from the same manufacturer and tell you they are satisfied. It keeps surprising me that many consumers don't have the slightest idea what quality means. Maybe they are used to throwing away stuff anyway after 2 years?
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Your careful explorations helped get my player out of the 'fix later' pile. Many thanks.
There are related design flaws in the charging mute/relay circuit in the 640C Mk1 ; R30
and the 640C Mk2 ; R11 They should both be increased in Wattage handling from 1/8W to a minimum of 1/2W.
Changing their related polar capacitors of 47μF and 4.7μF to polymers make the relays more responsive.
The design flaw in the 840C mute circuit:
I installed doubled and halved values, where you have tripled and ‘thirded’ the components:
C270: 35V 1000μF polymer, (superb ripple handling 3.3A).
C212: 63v 10μF polymer.
R140, R160 to 27 Ohm 5W metal Film (less inductance).
Love those hermetically sealed Finder relays.
Works a charm, though the heat that R140, R160 generate still seems too much.
Maybe 12W Mills resistors would be the reliable solution.
Since the images here, all rectifier diodes were replaced with exceptionally low noise, ultra fast recovery with ‘soft knee’ characteristics,
the NXP BYV29X 600.
The noise suppression caps surrounding the AD1955 power consumers:
Have you tried installing values that Analogue Devices specify in their data sheet? The sonic improvements are astonishing. Under mount TDK MLCC X7R. The more stable C0G values do not go beyond 0.33μF/ 0.47μF - if one can find them! The ESR on the X7R 10μF and the 47μF is also consistent across their range at 0.07 Ohms, impressive, a desirable characteristic when it comes to digital IC’s inputs, being mindful not to allow digital ‘ringing’ with too low an ESR:-
C159, C55; 47μF.
C152, C156, C159, C154, C54, C99; 10μF
Lastly, if you get around to checking this thread some time:
Have you tried replacing the 78xx/79xx regs with the LM2940CT? (LM2990 it’s functional compliment) Superb results in CD players for the most sensitive devices, Clocks, DAC’s, overrating noise suppressors on the outputs with Polymer caps. They’re much cheaper than those Class D regs (eg Tent labs, etc) Though I have found that increasing capacitance can raise heat emission, which is definitely a concern in the 840 with its 21 regs!
There are related design flaws in the charging mute/relay circuit in the 640C Mk1 ; R30
and the 640C Mk2 ; R11 They should both be increased in Wattage handling from 1/8W to a minimum of 1/2W.
Changing their related polar capacitors of 47μF and 4.7μF to polymers make the relays more responsive.
The design flaw in the 840C mute circuit:
I installed doubled and halved values, where you have tripled and ‘thirded’ the components:
C270: 35V 1000μF polymer, (superb ripple handling 3.3A).
C212: 63v 10μF polymer.
R140, R160 to 27 Ohm 5W metal Film (less inductance).
Love those hermetically sealed Finder relays.
Works a charm, though the heat that R140, R160 generate still seems too much.
Maybe 12W Mills resistors would be the reliable solution.
Since the images here, all rectifier diodes were replaced with exceptionally low noise, ultra fast recovery with ‘soft knee’ characteristics,
the NXP BYV29X 600.
The noise suppression caps surrounding the AD1955 power consumers:
Have you tried installing values that Analogue Devices specify in their data sheet? The sonic improvements are astonishing. Under mount TDK MLCC X7R. The more stable C0G values do not go beyond 0.33μF/ 0.47μF - if one can find them! The ESR on the X7R 10μF and the 47μF is also consistent across their range at 0.07 Ohms, impressive, a desirable characteristic when it comes to digital IC’s inputs, being mindful not to allow digital ‘ringing’ with too low an ESR:-
C159, C55; 47μF.
C152, C156, C159, C154, C54, C99; 10μF
Lastly, if you get around to checking this thread some time:
Have you tried replacing the 78xx/79xx regs with the LM2940CT? (LM2990 it’s functional compliment) Superb results in CD players for the most sensitive devices, Clocks, DAC’s, overrating noise suppressors on the outputs with Polymer caps. They’re much cheaper than those Class D regs (eg Tent labs, etc) Though I have found that increasing capacitance can raise heat emission, which is definitely a concern in the 840 with its 21 regs!