Lots to read here!
I just purchased a studio DAC from about 1983. I think it was built by Decca / Polygram themselves for studio work. Contains two TDA1540s on a bespoke board. Should be good to mod and breath life back into again.
Will be a challenge to work out how the digital input works... is on a multi-pin, Edac style connector, not sure what receiver chip it uses yet (I have other projects to work on first..).
I just purchased a studio DAC from about 1983. I think it was built by Decca / Polygram themselves for studio work. Contains two TDA1540s on a bespoke board. Should be good to mod and breath life back into again.
Will be a challenge to work out how the digital input works... is on a multi-pin, Edac style connector, not sure what receiver chip it uses yet (I have other projects to work on first..).
I performed a valve amplification with 6n2p-ev. Tests indicated an 8v output, a little high. I tried other valves with lower gain, for about 2v output. The final amplification is done with 6sn7-gt.
Images of the amplifier stage.
A sound recording with 6sn7-gt valves (the photograph in the video is older with 6n2p).
YouTube
Images of the amplifier stage.
A sound recording with 6sn7-gt valves (the photograph in the video is older with 6n2p).
YouTube
hello~
now i'm trying to repair my Marantz CD 34 and mod it.
and i found something strange when i ordering the caps to replace.
acording to manual from this website
Service Revision Philips CD304, Revox B225 Manual
every caps on my marantz CD-34 seems smaller than Philips CD-104
anyone has a Marantz CD-34,too?
thx for help!
now i'm trying to repair my Marantz CD 34 and mod it.
and i found something strange when i ordering the caps to replace.
acording to manual from this website
Service Revision Philips CD304, Revox B225 Manual
every caps on my marantz CD-34 seems smaller than Philips CD-104
anyone has a Marantz CD-34,too?
thx for help!
Hi tenjosajiki,
in the mentioned manuals at dindiki are not the original capacitor values of a CD 104 and other are listed. The values are enlarged where useful. Only on the servo board and the laser board some values remain unchanged, the values are important in these places. Otherwise it applies sensibly the values increase, even if larger values mean more costs. And of course choose a good capacitor quality ...
thank you so much Nanocamp!
now I have another problem.
after i recap all capacitors, mod my 104 to NOS mod.
the spin motor didn't turn.
when i put CD in, the motor didn't spin.
and sometimes the error LED lights up, sometime not.
before i try to mod this player.
the CDM1 works w/o any fault.
maybe i made some mistake on PCB?
thx for your help!
best
now I have another problem.
after i recap all capacitors, mod my 104 to NOS mod.
the spin motor didn't turn.
when i put CD in, the motor didn't spin.
and sometimes the error LED lights up, sometime not.
before i try to mod this player.
the CDM1 works w/o any fault.
maybe i made some mistake on PCB?
thx for your help!
best
Just for the pure fun I was replacing the original HF cable of my CD304. I discovered that the HF signal was originally routed to the screen of the cable. Any background for Philips doing that or just a fault in manufacturing?
Edit: Never mind, I mixed up the send/recive sides of the cable...
Edit: Never mind, I mixed up the send/recive sides of the cable...
Last edited:
Evening all,
Long story short. I found a cd104 at the rubbish dump in the rain. brought it home and completely rebuilt the power supply as it smelt "burnt".
powered up and had some TOC reading issues which were somewhat solved by resoldering all the Griplets. But once music started playing one channel was dead whilst the other had a really loud hissing with faint music. i measured the outputs of both op amps and instead of reading 3.4v i was getting 2.4v and 1.2v so i assumed this was the issue. while tracing the circuit and trying to figure out what else might of gone bad i found an issue between what is on the schematic and whats on the pcb.
when i measure from pin 22 of the DAC to pin 2 of the opamp i get continuity on both left and right. (this is correct according to the schematic.) but when i measure from pin 22 to 2566 i get continuity but to 2601 i get nothing. i looked on the back and the traces are going from 2601 to pin 1 of the opamp so what im seeing isnt matching up to the schematic.
am i missing something here or have others experienced this problem?
Long story short. I found a cd104 at the rubbish dump in the rain. brought it home and completely rebuilt the power supply as it smelt "burnt".
powered up and had some TOC reading issues which were somewhat solved by resoldering all the Griplets. But once music started playing one channel was dead whilst the other had a really loud hissing with faint music. i measured the outputs of both op amps and instead of reading 3.4v i was getting 2.4v and 1.2v so i assumed this was the issue. while tracing the circuit and trying to figure out what else might of gone bad i found an issue between what is on the schematic and whats on the pcb.
when i measure from pin 22 of the DAC to pin 2 of the opamp i get continuity on both left and right. (this is correct according to the schematic.) but when i measure from pin 22 to 2566 i get continuity but to 2601 i get nothing. i looked on the back and the traces are going from 2601 to pin 1 of the opamp so what im seeing isnt matching up to the schematic.
am i missing something here or have others experienced this problem?
Hello Everyone,
I finally have a 100% working CD104! Thanks to you guys! other great sources of information that i used which i found to be invaluable were:
- Mike Leach's servicing guide that can be found by a google search or visiting hifiengine. the service guide was also available here.
- ~ Classic CD Player Modification & Modernisation ~ i found this helpful as it mentioned some symptoms that my player was having.
- ReVox B225 CD Player: Distorted sound – Mark's Repair Blog this helped diagnose my odd dead channel/hissing fault which i will describe below. different player but similar circuit.
I originally found the poor machine at my local recovery yard (rubbish dump that resell things that can be reused) out on the ground in the mud and the rain.
before turning it on i could smell that some burning had happened at some stage but for $5 i couldn't leave it there. Plus it would be good for parts for my working CD104.
before even attempting to power it up i pulled the whole thing apart and completely rebuilt the power supply board replacing everything on it except for a couple of resistors. I also installed some RCA jacks on the heatsink. i double checked the transformer windings and voltages out of the power supply and everything worked as it should. I put the player back together and this is where the real fun began.
- Issue 1 disc fails to read TOC
this issue is well documented and was a fairly straight forward fix. As i knew the griplets/rivets were most likely the cause. I removed the decoder board and removed the solder from the griplets, used a piece of wire which in this case was simply the lead of some resistors i had and put it through the hole which took a little bit of force and soldered both sides. i reassembled the board and now the TOC starts reading!
- Issue 2 loud hissing with faint music one channel, one channel dead
Now that i had the TOC reading issue fixed i attempted to play music. This intermittently worked but i will describe that issue below. when the CD was playing one channel was getting a really loud hissing noise with very faint music on one channel and the other channel was completely dead. checked the read relays and they were fine and working as they should. I then measured the NE5532N opamp outputs (6525 & 6523) and found the dead channel to only be outputting around 1.2v instead of 3.4v. The hissing channel opamp was outputting around 2.3v. thinking this was the issue i replaced the opamps and while i was at it i replaced all the electrolytic capacitors. I found all the capacitors to be completely out of spec. out of all the 22uf capacitors i measured the closest i found was 10uf. The signal capacitors (2608 & 2573) were terrible too. one was around 1uf the other 0uF! after replacing all these i was confident the issue would be resolved. i was wrong. although the faint music was now louder there was still a lot of hissing and one channel was dead. the voltages on the opamp were still the same too. After searching throughout the internet i finally found someone with a similar issue (See above, markgrob). with my oscilloscope i saw the inputs to the SAA7030 (pin 17 & 20 of 6517) looked ok. but the dead channel output (pin 3 & 10) was showing just a consistent square wave. instead of investing more money into the player i opted to remove the chip and do the well documented NOS mod to the player. it worked! the hiss was gone and the dead channel was alive!
- Issue 3 track skipping
even though i finally had sound which i was ecstatic about the tracking was still terrible. playing track 1 worked 50% of the time and skipping beyond 1 track at a time caused the player to fail. This issue i was a bit lazy and didn't do too much troubleshooting but more assumed it was the radial arm. I read on the above mentioned Keith Snooks page a similar problem was mentioned and it was suggested to resolder the griplets and replace capacitors 2265 and 2266. I did this and by the way one of the old capacitors read 0uf while the other 10uf. put the player back together and it works flawlessly!
Originally i was never truly a believer that griplets and capacitors could cause so many issues but after all this i 100% recommend resoldering all the griplets which isn't a massive task and is completely free to do. i also recommend replacing all the electrolytics. there arent too many to replace on the servo and decoder board and they are all small values which are cheap anyway. Can potentially save you a lot of grief in the long run.
I hope this longwinded post can potentially help some of you out
I finally have a 100% working CD104! Thanks to you guys! other great sources of information that i used which i found to be invaluable were:
- Mike Leach's servicing guide that can be found by a google search or visiting hifiengine. the service guide was also available here.
- ~ Classic CD Player Modification & Modernisation ~ i found this helpful as it mentioned some symptoms that my player was having.
- ReVox B225 CD Player: Distorted sound – Mark's Repair Blog this helped diagnose my odd dead channel/hissing fault which i will describe below. different player but similar circuit.
I originally found the poor machine at my local recovery yard (rubbish dump that resell things that can be reused) out on the ground in the mud and the rain.
before turning it on i could smell that some burning had happened at some stage but for $5 i couldn't leave it there. Plus it would be good for parts for my working CD104.
before even attempting to power it up i pulled the whole thing apart and completely rebuilt the power supply board replacing everything on it except for a couple of resistors. I also installed some RCA jacks on the heatsink. i double checked the transformer windings and voltages out of the power supply and everything worked as it should. I put the player back together and this is where the real fun began.
- Issue 1 disc fails to read TOC
this issue is well documented and was a fairly straight forward fix. As i knew the griplets/rivets were most likely the cause. I removed the decoder board and removed the solder from the griplets, used a piece of wire which in this case was simply the lead of some resistors i had and put it through the hole which took a little bit of force and soldered both sides. i reassembled the board and now the TOC starts reading!
- Issue 2 loud hissing with faint music one channel, one channel dead
Now that i had the TOC reading issue fixed i attempted to play music. This intermittently worked but i will describe that issue below. when the CD was playing one channel was getting a really loud hissing noise with very faint music on one channel and the other channel was completely dead. checked the read relays and they were fine and working as they should. I then measured the NE5532N opamp outputs (6525 & 6523) and found the dead channel to only be outputting around 1.2v instead of 3.4v. The hissing channel opamp was outputting around 2.3v. thinking this was the issue i replaced the opamps and while i was at it i replaced all the electrolytic capacitors. I found all the capacitors to be completely out of spec. out of all the 22uf capacitors i measured the closest i found was 10uf. The signal capacitors (2608 & 2573) were terrible too. one was around 1uf the other 0uF! after replacing all these i was confident the issue would be resolved. i was wrong. although the faint music was now louder there was still a lot of hissing and one channel was dead. the voltages on the opamp were still the same too. After searching throughout the internet i finally found someone with a similar issue (See above, markgrob). with my oscilloscope i saw the inputs to the SAA7030 (pin 17 & 20 of 6517) looked ok. but the dead channel output (pin 3 & 10) was showing just a consistent square wave. instead of investing more money into the player i opted to remove the chip and do the well documented NOS mod to the player. it worked! the hiss was gone and the dead channel was alive!
- Issue 3 track skipping
even though i finally had sound which i was ecstatic about the tracking was still terrible. playing track 1 worked 50% of the time and skipping beyond 1 track at a time caused the player to fail. This issue i was a bit lazy and didn't do too much troubleshooting but more assumed it was the radial arm. I read on the above mentioned Keith Snooks page a similar problem was mentioned and it was suggested to resolder the griplets and replace capacitors 2265 and 2266. I did this and by the way one of the old capacitors read 0uf while the other 10uf. put the player back together and it works flawlessly!
Originally i was never truly a believer that griplets and capacitors could cause so many issues but after all this i 100% recommend resoldering all the griplets which isn't a massive task and is completely free to do. i also recommend replacing all the electrolytics. there arent too many to replace on the servo and decoder board and they are all small values which are cheap anyway. Can potentially save you a lot of grief in the long run.
I hope this longwinded post can potentially help some of you out
Hello everyone,
I wonder if anyone out there can help me?
The situation is that I have a CD104 running in NOS mode which plays very well except that the display is not working.
The initial symptom was when switching on, the display was sometimes blank, on pressing stop/reset the two lines appeared, recently this too stopped. This leads me to suspect a capacitor, but where?
The player has had the griplets done and rechecked, all electrolytic caps replaced on the Server and Decoder boards, NOS installed and all the other electrolytic caps replaced on the other boards. This would appear to be a data issue not getting to the display board, I am rather stumped on where to look next.
Does anyone have any ideas please?
I wonder if anyone out there can help me?
The situation is that I have a CD104 running in NOS mode which plays very well except that the display is not working.
The initial symptom was when switching on, the display was sometimes blank, on pressing stop/reset the two lines appeared, recently this too stopped. This leads me to suspect a capacitor, but where?
The player has had the griplets done and rechecked, all electrolytic caps replaced on the Server and Decoder boards, NOS installed and all the other electrolytic caps replaced on the other boards. This would appear to be a data issue not getting to the display board, I am rather stumped on where to look next.
Does anyone have any ideas please?
Almost sure to be the actual thick film display module at fault... super common issue across all Philips and Philips based players that use it.
There are a few threads around on this and I've a feeling they might be available from somewhere... or they were at one point. Some ingenious fixes are using a PIC to construct a new module.
NSM4202A LED Display Module Replacement for Philips / Sony CDM Transports
LCD readout - broken ? or bad joints
There are a few threads around on this and I've a feeling they might be available from somewhere... or they were at one point. Some ingenious fixes are using a PIC to construct a new module.
NSM4202A LED Display Module Replacement for Philips / Sony CDM Transports
LCD readout - broken ? or bad joints
Two duff modules is a distinct possibility. The problem is usually missing or intermittent segments although I can't recall any that were totally out but I guess it must happen.
Display faults have never been anything else on these other than the module but if you want to check then you need to pull a diagram and check all the pins for supply, ground and serial clock and data (on a scope). If there is data present then 99.9% certain the data is OK and the module is duff.
A unofficial 'test' is that they can be made better or worse by applying pressure to them. If anything at all changes then its duff.
Display faults have never been anything else on these other than the module but if you want to check then you need to pull a diagram and check all the pins for supply, ground and serial clock and data (on a scope). If there is data present then 99.9% certain the data is OK and the module is duff.
A unofficial 'test' is that they can be made better or worse by applying pressure to them. If anything at all changes then its duff.
Hi,
One step forward and a couple back I am afraid, I finally tracked down the issue with the display, the power supply was not functioning properly, it was hanging on by a thread, when I measured the voltage it was OK, the issue was that it could not supply the power required. When I measured the supply resistance it was over 50 ohms, on rebuilding the connection the supply worked and the display now functions, I now have a motor that runs continuously at high speed, any idea where to look now please?