Repair and modding of Sony DoDeCaHorn CFD-900
- Thread starter yammi99
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Thanks so much yammi99.Hi salmansh8,
welcome to Boomboxery. Finally you found the link
The LED mod is not that difficult, but you need some electric knowledge and soldering skills. Originally in display there are small incandescent bulbs. They take to much power to be operated in battery mode. Therefore I removed all from the PCB and replaced them by 3mm orange LED's. On backside of PCB I modified the conductive paths so, that all LED's are connected in parallel. You need to cut some paths and connect some. Finally you need a pre-resistor in series to all the LED's.
Would be at the end such a circuit (example with 3 LED's in parallel):
View attachment 52832
The value of the pre-resistor depends on supply voltage, LED parameters and number of LED's.
I searched on the SONY mainboard a point were I have a permanent voltage in POWER ON state and no voltage in POWER OFF state, all in battery mode. You see this point on my last foto above ("Display LED"). In this case it is 5V. Furthermore you need a GROUND point (- Pole). You find it also on the foto.
To these points I connected the 2-wire cable that is attached to the display light PCB.
I used in total 17 LED's, because with LED's the light was not so equal as with original bulbs.
For calculation of pre-rsistor you find an example here:
LED in parallel - calculator
View attachment 52833
I hope, this explanation helps a little bit.
If you don't want to connect all LED's in parallel, you could built it for example also like this:
View attachment 52835
Radio raheem
Requiem Æternam
Superb mod....great skill.....jvc made many like this known as the hyper bass system in fact most manufacturers were using this system under different names in the 90's....just a simple bass chamber with a small speaker installed...great work...the biggest one i have seen to date is the jvc pc x 1000....i think the original manufacturer may have been Bose, but you paid a premium using there system though
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Yeah, it sounds funny "DoDeCaHorn", "G-Horn" etc.....but there's one thing. Sony is really amazing when it comes to sound (not talking about high and lows) but.... Their sound feels very natural without having to much rely on DSP and other processing. I have felt this thing identical in Sony products in the Mini HiFi lines as well. Also, their equalizer is very adaptive and feels to really change very well when you switch for example from "Rock" to "Pop" or "Soul" etc....
I searched on the SONY mainboard a point were I have a permanent voltage in POWER ON state and no voltage in POWER OFF state, all in battery mode. You see this point on my last foto above ("Display LED"). In this case it is 5V. Furthermore you need a GROUND point (- Pole). You find it also on the foto.Hi salmansh8,
welcome to Boomboxery. Finally you found the link
The LED mod is not that difficult, but you need some electric knowledge and soldering skills. Originally in display there are small incandescent bulbs. They take to much power to be operated in battery mode. Therefore I removed all from the PCB and replaced them by 3mm orange LED's. On backside of PCB I modified the conductive paths so, that all LED's are connected in parallel. You need to cut some paths and connect some. Finally you need a pre-resistor in series to all the LED's.
Would be at the end such a circuit (example with 3 LED's in parallel):
View attachment 52832
The value of the pre-resistor depends on supply voltage, LED parameters and number of LED's.
I searched on the SONY mainboard a point were I have a permanent voltage in POWER ON state and no voltage in POWER OFF state, all in battery mode. You see this point on my last foto above ("Display LED"). In this case it is 5V. Furthermore you need a GROUND point (- Pole). You find it also on the foto.
To these points I connected the 2-wire cable that is attached to the display light PCB.
I used in total 17 LED's, because with LED's the light was not so equal as with original bulbs.
For calculation of pre-rsistor you find an example here:
LED in parallel - calculator
View attachment 52833
I hope, this explanation helps a little bit.
If you don't want to connect all LED's in parallel, you could built it for example also like this:
View attachment 52835
To these points I connected the 2-wire cable that is attached to the display light PCB.
Can you please explain the above a little bit. I'm a little lost here. Do I need an external wire that I need to connect to the PCB? (the 2 wire cable) I'm also not sure on the points so if you can help a little bit more...that will be great.
Hi Yammi99,
I tried the same modification for the battery mode backlights but it has started giving weird results. I used the exact same pole and the point on the board where we have permanent voltage in Power On state. The end result that I'm getting is, i) there's no sound output (only the subwoofer is emitting a very tiny amount of sound and sound from main speakers is totally gone, ii) The power volume will not work when operated with remote, iii) Only Tape-B is able to be operated with remote.
However, when I restored everything to original, everything starts working.....can you give me thoughts? what could be going wrong?
I tried the same modification for the battery mode backlights but it has started giving weird results. I used the exact same pole and the point on the board where we have permanent voltage in Power On state. The end result that I'm getting is, i) there's no sound output (only the subwoofer is emitting a very tiny amount of sound and sound from main speakers is totally gone, ii) The power volume will not work when operated with remote, iii) Only Tape-B is able to be operated with remote.
However, when I restored everything to original, everything starts working.....can you give me thoughts? what could be going wrong?
It could be, that you created a kind of a short circuit or a bypass or an overload. Did you modify the backlight PCB to have the LED's connected in parallel (cut and connect conductive paths on PCB)? Maybe for testing you connect just one LED and a proper pre-resistor to the points on mainboard to check if the strange behavior still exists. If yes, it could be that the circuit wiring on your SONY has changed. Then you need to find another connection point on the mainboard. Without a wiring diagram this is of course a "try and error" procedure.
Hello to everyone! Just received my CFD-900 from Japan and... it's not working. It turns on, displays are backlit, but any of the fuctions aren't available (except clock and setting the equalizer). And the "Muting" LED is always on, without any reactions on that button pressing. Looks like it can be some dead ICs what in that case means I have no chances to make this thing work. Any ideas? Maybe is there any "hard reset" switch?
At first you should open the box and clean everything inside. Old Japanese boomboxes are often full of dust and other pollution. Then you should check the connectors. Just remove them, use some contact spray and attach again. Furthermore often the tip switches are oxidized or damaged, so that they don't work anymore. The CFD-900 has dozens of switches. Maybe the Mute switch is permanently activated. You need to desolder old switches and use new ones.
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