Right. First disconnect the original +5V supply from Q811 to R508 and R511. Install two Spowers and feed the regulated +5V after R508 and R511. Job done
Nice work on the 3 TX board you made. Think I'll go the same route. What are the gold boxes? Ah, the 47R for U312! Its starting to make sense.
On the decoder , surely when I remove the resistors the supply is disconnected anyway.
My understanding is remove the resistors, drop the output leg on Reg into hole of removed resistor (hole nearest IC), +5v supply to input leg and ground leg to top of board.
Have I got that right. Just want avoid costly mistakes.
Thinking about it, Is there anything wrong with using the other hole ( resistor +5v supply) left by resistor to supply the Reg.
thanks guys
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Yes that is the way to goNice work on the 3 TX board you made. Think I'll go the same route. What are the gold boxes? Ah, the 47R for U312! Its starting to make sense.
On the decoder , surely when I remove the resistors the supply is disconnected anyway.
My understanding is remove the resistors, drop the output leg on Reg into hole of removed resistor (hole nearest IC), +5v supply to input leg and ground leg to top of board.
Have I got that right. Just want avoid costly mistakes.
Thinking about it, Is there anything wrong with using the other hole ( resistor +5v supply) left by resistor to supply the Reg.
thanks guys
Hey everyone. I got my hands on a CD63 which has a strange behavior.
I got it knowing it was faulty. First time I tried it, it seemed to work, but after a few minutes, disc would not start playing once detected, and a few minutes more later, disc would be detected only when it wants.
I've swapped the laser with a known used woking one : same behavior.
Today I've put a new laser (from china). For 10 minutes it worked like a charm. I've put the cover back on, and put another CD. And then again, same behavior. Disc detected when it wants, and when it sees it, it won't play it.
I believe laser has nothing to do with this fault, but I have no idea where to start looking, and what for.
Any suggestions ?
I got it knowing it was faulty. First time I tried it, it seemed to work, but after a few minutes, disc would not start playing once detected, and a few minutes more later, disc would be detected only when it wants.
I've swapped the laser with a known used woking one : same behavior.
Today I've put a new laser (from china). For 10 minutes it worked like a charm. I've put the cover back on, and put another CD. And then again, same behavior. Disc detected when it wants, and when it sees it, it won't play it.
I believe laser has nothing to do with this fault, but I have no idea where to start looking, and what for.
Any suggestions ?
I'm pretty sure Brent used +-12V on his old beast. I used 7808/7908 when I did mine back then and it was very close to dropping out. In fact, I did this on a non-SE CD63 and when you hit play the current demand dropped the voltage to the regs so much it caused reading errors 50% of the time. So clearly the main thing is to beef up the supplies, with a separate PSU if you can. What voltage you use is probably not critical. This is possibly the best single mod for the CD63
re big tx
As simon says a big tx here most rewarding ive used a 50va tx for the servo followed by 3 pos and 3 neg regs @ 12v massive improvements.
alan
I'm pretty sure Brent used +-12V on his old beast. I used 7808/7908 when I did mine back then and it was very close to dropping out. In fact, I did this on a non-SE CD63 and when you hit play the current demand dropped the voltage to the regs so much it caused reading errors 50% of the time. So clearly the main thing is to beef up the supplies, with a separate PSU if you can. What voltage you use is probably not critical. This is possibly the best single mod for the CD63
As simon says a big tx here most rewarding ive used a 50va tx for the servo followed by 3 pos and 3 neg regs @ 12v massive improvements
.alan
I'm pretty sure Brent used +-12V on his old beast. I used 7808/7908 when I did mine back then and it was very close to dropping out. In fact, I did this on a non-SE CD63 and when you hit play the current demand dropped the voltage to the regs so much it caused reading errors 50% of the time. So clearly the main thing is to beef up the supplies, with a separate PSU if you can. What voltage you use is probably not critical. This is possibly the best single mod for the CD63
I'm going to do the 3 TX upgrade so trying to figure the best voltages.
15Va 18v feeding 15v spowers for analogue
50Va 15v or 12v TX for servo drivers feeding 12v or 9v regs
7Va 12v for the rest
If Brent used 12v reg for the drivers then it must be good.
Thought I'd ask the question before hitting the checkout button at Farnell
Maybe I should use a 15v TX for the 12v regs then
Cheers Simon
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As simon says a big tx here most rewarding ive used a 50va tx for the servo followed by 3 pos and 3 neg regs @ 12v massive improvements
alan
Yeah so I hear. Lots of other mods done so this is pretty much the last thing to do. Can't wait to hear it
Just noticed that in eBay there is a low cost +5V voltage regulator using TI TPS7A4700 chip which can be used to directly replace 7805 regulators.
TekDevice 5V 1A 4.17uVrms Ultra Low Noise LDO Voltage Regulator For DAC Preamp | eBay
The specification of this chip looks very encouraging. I may order one or two to try it out.
TekDevice 5V 1A 4.17uVrms Ultra Low Noise LDO Voltage Regulator For DAC Preamp | eBay
The specification of this chip looks very encouraging. I may order one or two to try it out.
I have just e-mailed the seller asking him if he sells both + and - regulators. I told him I need +/- 12V or +/-15V to drive the opamps.
The seller said he is presently working on the -ve regulators and will launch it when it has passed the QC test. That might open another cheap option for modders to choose as we need quite a number of regulators in the CD63.
The seller said he is presently working on the -ve regulators and will launch it when it has passed the QC test. That might open another cheap option for modders to choose as we need quite a number of regulators in the CD63.
regs
May be a cheaper alternative to spowers but whats the noise floor like? Doubt they are much better than lm317 based regs.
May be a cheaper alternative to spowers but whats the noise floor like? Doubt they are much better than lm317 based regs.
So I guess it's a voltage reference chip, some decoupling caps and resistors to set the output voltage. I'd be amazed if it was as good as Brent's S-Powers and the like but in some applications this is likely to massively outperform standard regs like LM317 and the fixed ones. Low noise it probably is, but beyond that my electronics knowledge is too limited to say how good it will be. I would, however, be very wary of the 1A current claim as there's no large output device visible and the main chip is very small!
Look in the datasheet from TI. Here it says 1A. Of cause it will give you 1A. It a regulator, not a voltage reference chip.
"The TPS7A47 is a family of positive voltage (+36 V), ultralow-noise (4.17 μVRMS) low dropout linear regulators (LDO) capable of sourcing a 1-A load."
It might be good
"The TPS7A47 is a family of positive voltage (+36 V), ultralow-noise (4.17 μVRMS) low dropout linear regulators (LDO) capable of sourcing a 1-A load."
It might be good