Troubleshooting CD67
Hello all,
I'm fighting with my CD67 which became silent after unsuccessful try to feed separate +5V to DAC.
I've connected the player to receiver using digital out and it is playing, so it's not completly dead
I've connected 'scope and measured digital inputs to DAC and it seems to be ok, but the DAC output looks the same in stop and play modes (picture attached). 
I've noticed in service manual that DAC pin 13 (MLEN) has to be 0V and pin 14 (RSTN) has to be 5V. In my player it is vice versa i.e. MLEN is 4.94V and RSTN is 0.12V. 
Is this another error in service manual or this could be my source of problem?
If somebody could measure these values, that would help me a lot. MLEN can be measured at U151 in CD67 or U174 in CD63/53/43. RSTN can be measured at U152 in CD67 or U173 in CD63/53/43.
Hello all,
I'm fighting with my CD67 which became silent after unsuccessful try to feed separate +5V to DAC.
I've connected the player to receiver using digital out and it is playing, so it's not completly dead
I've connected 'scope and measured digital inputs to DAC and it seems to be ok, but the DAC output looks the same in stop and play modes (picture attached). I've noticed in service manual that DAC pin 13 (MLEN) has to be 0V and pin 14 (RSTN) has to be 5V. In my player it is vice versa i.e. MLEN is 4.94V and RSTN is 0.12V. Is this another error in service manual or this could be my source of problem?If somebody could measure these values, that would help me a lot. MLEN can be measured at U151 in CD67 or U174 in CD63/53/43. RSTN can be measured at U152 in CD67 or U173 in CD63/53/43.
Attachments
Re: Troubleshooting CD67
Hi Renatas,
It appears that 0V for MLEN is an error in the manual. I measured both RSTN and MLEN and they are both +5V in play and stop mode.
Your MLEN pin seems to be in order, but RSTN is held low somehow. Could it be a short to ground? The groundplane is running alongside the trace to U152. You can try lifting the pin, it should go high when it's unconnected, because it has an internal pull-up.
Regards,
Ray.
renatas said:
Hi Renatas,
It appears that 0V for MLEN is an error in the manual. I measured both RSTN and MLEN and they are both +5V in play and stop mode.
Your MLEN pin seems to be in order, but RSTN is held low somehow. Could it be a short to ground? The groundplane is running alongside the trace to U152. You can try lifting the pin, it should go high when it's unconnected, because it has an internal pull-up.
Regards,
Ray.
poynton said:
Yeah, I noticed that some time ago, there was a lot of smoke hanging around this thread
.I agree, bigger is not always better. But an increase from 3300u to 4700u won't cause any problems. Indeed if the ESR goes too low, the regulator can become unstable. Most regulators can handle a big output cap very well these days. The reverse diode is a good point, it won't hurt to insert one from input to output, gy21.
Regards,
Ray.
6h5c said:
Yeah, I noticed that some time ago, there was a lot of smoke hanging around this thread
I agree, bigger is not always better. But an increase from 3300u to 4700u won't cause any problems. Indeed if the ESR goes too low, the regulator can become unstable. Most regulators can handle a big output cap very well these days. The reverse diode is a good point, it won't hurt to insert one from input to output, gy21.
Regards,
Ray.
Thanks Ray,
The raise of C805, C806 from 470u to 2200u also won't cause a problem? I saw that you did it in your cd67se mod list and also tnt does it so it should be fine I think.
I'm using Panasonic FC for all replacements, so I think the esr is not to low.
For now I will stick with the default regulators.
Re: Re: Troubleshooting CD67
Hi Ray,
the same idea came to my head yesterday, so I checked that and, yes, it is short to ground. I didn't notice any possible connections between RSTN pin and GND, so I thought cap CD08 is defective, but it wasn't. I lifted DAC pin 14 and it still has connection to ground I gues I need new DAC
6h5c said:
Hi Ray,
the same idea came to my head yesterday, so I checked that and, yes, it is short to ground. I didn't notice any possible connections between RSTN pin and GND, so I thought cap CD08 is defective, but it wasn't. I lifted DAC pin 14 and it still has connection to ground
I gues I need new DAC
Re: Re: Re: Troubleshooting CD67
Hi Renatas,
Is pin 14 shorted internally? If it's low-ohmic to ground then that would be a real bummer. But maybe the internal pull-up is screwed-up somehow? Try connecting it to +5V with a 10k or 4k7, as a last resort.....
Regards,
Ray.
renatas said:Hi Ray,
the same idea came to my head yesterday, so I checked that and, yes, it is short to ground. I didn't notice any possible connections between RSTN pin and GND, so I thought cap CD08 is defective, but it wasn't. I lifted DAC pin 14 and it still has connection to ground
Hi Renatas,
Is pin 14 shorted internally? If it's low-ohmic to ground then that would be a real bummer. But maybe the internal pull-up is screwed-up somehow? Try connecting it to +5V with a 10k or 4k7, as a last resort.....
Regards,
Ray.
diverse outputs
After some messing around with output trannies -what diminished output levels too much- I tried Ray's discrete output stage with transistors (BC550). The results are very good, almost as good as the 1G4 tube output.
Next step will be separate PSU's and finally the starground, still waiting for the Tent clock to arrive...
The setup for the new PSU will be one (4VA) 9Vac trannie with two secundairs feeding four outputs. Each consisting of a bridge rectifier (Schottky BAT85 or 1N5817) - 1.000uF Rubycon ZLH - Murata 36mH/4.5 ohm common mode coil -1.000 Rubycon ZLH - Micrell MIC29302 regulator. Decoupling on the DAC with 1uF Black Gate NX-series.
Pictures coming up soon.
After some messing around with output trannies -what diminished output levels too much- I tried Ray's discrete output stage with transistors (BC550). The results are very good, almost as good as the 1G4 tube output.
Next step will be separate PSU's and finally the starground, still waiting for the Tent clock to arrive...
The setup for the new PSU will be one (4VA) 9Vac trannie with two secundairs feeding four outputs. Each consisting of a bridge rectifier (Schottky BAT85 or 1N5817) - 1.000uF Rubycon ZLH - Murata 36mH/4.5 ohm common mode coil -1.000 Rubycon ZLH - Micrell MIC29302 regulator. Decoupling on the DAC with 1uF Black Gate NX-series.
Pictures coming up soon.
Attachments
Re: diverse outputs
passive filter -> bc550c's buffer
allan
ps need to stop listening to continue with next upgrades
hmmmm
disco said:After some messing around with output trannies -what diminished output levels too much- I tried Ray's discrete output stage with transistors (BC550). The results are very good, almost as good as the 1G4 tube output.
Next step will be separate PSU's and finally the starground, still waiting for the Tent clock to arrive...
The setup for the new PSU will be one (4VA) 9Vac trannie with two secundairs feeding four outputs. Each consisting of a bridge rectifier (Schottky BAT85 or 1N5817) - 1.000uF Rubycon ZLH - Murata 36mH/4.5 ohm common mode coil -1.000 Rubycon ZLH - Micrell MIC29302 regulator. Decoupling on the DAC with 1uF Black Gate NX-series.
Pictures coming up soon.
passive filter -> bc550c's buffer
allan
ps need to stop listening
to continue with next upgradeshmmmm
Re: diverse outputs
Good work there disco, and I see Krall in the player
Was listening to that for a while last night and I was stunned in places by the realism of the piano and guitar, and how amazingly solid the bass was. Big caps defo work around the DAC and servo, even if they're not needed. And you can flame me, but I'll still like big caps
Last night I started looking at where to put regs and caps on veroboard, probably starting with Rowe's recommended 3 x 7805, initially they'll just be fed from the +20v. In the future these will be split up more (one reg per circuit most likely) and fed from external AC. I can't wait to see how much more can be squeezed out!!!
Cheers
Simon
disco said:After some messing around with output trannies -what diminished output levels too much- I tried Ray's discrete output stage with transistors (BC550). The results are very good, almost as good as the 1G4 tube output.
Next step will be separate PSU's and finally the starground, still waiting for the Tent clock to arrive...
The setup for the new PSU will be one (4VA) 9Vac trannie with two secundairs feeding four outputs. Each consisting of a bridge rectifier (Schottky BAT85 or 1N5817) - 1.000uF Rubycon ZLH - Murata 36mH/4.5 ohm common mode coil -1.000 Rubycon ZLH - Micrell MIC29302 regulator. Decoupling on the DAC with 1uF Black Gate NX-series.
Pictures coming up soon.
Good work there disco, and I see Krall in the player
Was listening to that for a while last night and I was stunned in places by the realism of the piano and guitar, and how amazingly solid the bass was. Big caps defo work around the DAC and servo, even if they're not needed. And you can flame me, but I'll still like big caps
Last night I started looking at where to put regs and caps on veroboard, probably starting with Rowe's recommended 3 x 7805, initially they'll just be fed from the +20v. In the future these will be split up more (one reg per circuit most likely) and fed from external AC. I can't wait to see how much more can be squeezed out!!!
Cheers
Simon
Re: Re: Re: diverse outputs
lol! Yep, definately. It sounds great and using big uns gives me peace of mind, and it looks cool
I don't deny that a similarly pleasing result may have come from using, say, 470uF Panasonic FC caps, but I'm not prepared to risk further pcb damage by trying
Simon
6h5c said:
You like 'em round and big....
lol! Yep, definately. It sounds great and using big uns gives me peace of mind, and it looks cool
I don't deny that a similarly pleasing result may have come from using, say, 470uF Panasonic FC caps, but I'm not prepared to risk further pcb damage by trying
Simon
Re: Re: Re: Re: diverse outputs
I'd prefer the red head!
SimontY said:
lol! Yep, definately. It sounds great and using big uns gives me peace of mind, and it looks cool
I don't deny that a similarly pleasing result may have come from using, say, 470uF Panasonic FC caps, but I'm not prepared to risk further pcb damage by trying
Simon
I'd prefer the red head!
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