I have an old Krell MD-2 CD turntable, and (among other issues) several segments have gone out on the LED display. After looking around online, I found one person in France that had built a replacement, but details were kind of scarce, so tried to reverse engineer my display module based upon the tidbits of information that I was able to uncover.
After hooking it up to a scope, it appeared to use SPI (keep in mind that I'm not very smart), but I just got rubbish when I created a small Arduino program to read the data, so I traipsed through the available LED drivers on DigiKey, and came across the MM5450 as one of the very few chips that didn't require I2C. Upon reviewing the data stream again, it appeared to fit with what was required to drive this chip. Anyway, I did the best that I could to guess the pinout of my existing display board (it uses an unmarked glob to hold down the IC die), and was able to reconcile it with the MM5450 pinout, so I made up a board, bought some parts, and tried it out. It appears to be fully functional, so I thought that I would share it here so that others can create a replacement for themselves as necessary. I'm kind of hoping that since this hardware is over 25 years old (and apparently out of production for quite some time) that Philips won't mind too much the publishing of plans for a replacement...
Anyway, here goes with the information:
Feel free to use this information however you wish, so long as you don't make anyone pay for it. I don't care if you charge someone to assemble a board for them or something (it's none of my business), but the information should be kept in the open. I abhor GPL-like licensing, but I do expect you to not be a turd.
I am just a hobbyist (and a really unintelligent one at that), so I do not make any representation that information is accurate, safe, or suitable for any purpose, even a purpose that may be implied by the information. In other words, I did the best that I could, it worked for me, but it's not on me if you hurt yourself or start a fire or something.
I have the board shared at OSH Park (https://oshpark.com/shared_projects/P3nC9ISV) for convenience. I make nothing from this link or design (AFIAK), and I don't care from where you order your board.
BOM:
Electrical Schematic:
View attachment NSM4202A Schematic.pdf
Front of PCB:
Back of PCB:
Gerbers for PCB:
View attachment NSM4202A.zip
DipTrace Schematic and Board Files:
View attachment NSM4202A DipTrace Files.zip
After hooking it up to a scope, it appeared to use SPI (keep in mind that I'm not very smart), but I just got rubbish when I created a small Arduino program to read the data, so I traipsed through the available LED drivers on DigiKey, and came across the MM5450 as one of the very few chips that didn't require I2C. Upon reviewing the data stream again, it appeared to fit with what was required to drive this chip. Anyway, I did the best that I could to guess the pinout of my existing display board (it uses an unmarked glob to hold down the IC die), and was able to reconcile it with the MM5450 pinout, so I made up a board, bought some parts, and tried it out. It appears to be fully functional, so I thought that I would share it here so that others can create a replacement for themselves as necessary. I'm kind of hoping that since this hardware is over 25 years old (and apparently out of production for quite some time) that Philips won't mind too much the publishing of plans for a replacement...
Anyway, here goes with the information:
Feel free to use this information however you wish, so long as you don't make anyone pay for it. I don't care if you charge someone to assemble a board for them or something (it's none of my business), but the information should be kept in the open. I abhor GPL-like licensing, but I do expect you to not be a turd.
I am just a hobbyist (and a really unintelligent one at that), so I do not make any representation that information is accurate, safe, or suitable for any purpose, even a purpose that may be implied by the information. In other words, I did the best that I could, it worked for me, but it's not on me if you hurt yourself or start a fire or something.
I have the board shared at OSH Park (https://oshpark.com/shared_projects/P3nC9ISV) for convenience. I make nothing from this link or design (AFIAK), and I don't care from where you order your board.
BOM:
- U1 - Micrel MM5450 (PLCC-44) LED Display Driver
- DS1-DS4 - Kingbright ACSA03-41SGWA-F01 7-Segment Common-Anode LED Display (Green, other colors probably available)
- D1-D2 - 0603 SMD LED (Green for use with the specified green LED digits)
- R1 - 7.5kOhm (or higher) 1206 SMD Resistor (controls brightness)
- C1 - 1000pF 1206 SMD Capacitor
- J1-J3 - 0.1" header system of your choice
Electrical Schematic:
View attachment NSM4202A Schematic.pdf
Front of PCB:
Back of PCB:
Gerbers for PCB:
View attachment NSM4202A.zip
DipTrace Schematic and Board Files:
View attachment NSM4202A DipTrace Files.zip
I have created an NSM4002 / NSM4202 replacement
Regards Bram Jacobse
BOM:
U1 - Micrel MM5450 (PLCC-44) LED Display Driver
DS1-DS4 - Kingbright ACSA03-41SGWA-F01 7-Segment Common-Anode LED Display (Green, other colors probably available)
R1 - 10kOhm (or higher) 1206 SMD Resistor (controls brightness)
C1 - 1000pF 1206 SMD Capacitor
C2 - 100nF 1206 SMD Capacitor
J1 - 0.1" header system of your choice
Gerber files
View attachment gerber-NSM4202_v1_3.zip
Regards Bram Jacobse
BOM:
U1 - Micrel MM5450 (PLCC-44) LED Display Driver
DS1-DS4 - Kingbright ACSA03-41SGWA-F01 7-Segment Common-Anode LED Display (Green, other colors probably available)
R1 - 10kOhm (or higher) 1206 SMD Resistor (controls brightness)
C1 - 1000pF 1206 SMD Capacitor
C2 - 100nF 1206 SMD Capacitor
J1 - 0.1" header system of your choice
Gerber files
View attachment gerber-NSM4202_v1_3.zip
Alive again!
Hi guys,
I've several old Philips gear in use. My "Daily Player", a CD-460, also had the common problem with missing digits on the 4202(A). Not a big issue, as long as something could be seen. But during the last year most of the segments were lost.
I've found this thread, but as my eyes for some circumstances cannot deal with SMD, I asked Bram if he'll be willing to put a complete display together for me
. And he did!
Installation was easy, and now my old buddy not only plays music like a young fellow, it even looks like one. Exact this player was the first CDP my father owned back in the 80's, and little Ingo liked watching the rotating CD through the window.
Thanks a lot, Bram, for sharing your work on Diyaudio and again a big thank you for the kind service!
Best regards
Ingo
(BTW: Complete reworked with NOS-conversion, but even better in combination with the Parasound D/A converter 1100HD.)
Hi guys,
I've several old Philips gear in use. My "Daily Player", a CD-460, also had the common problem with missing digits on the 4202(A). Not a big issue, as long as something could be seen. But during the last year most of the segments were lost.
I've found this thread, but as my eyes for some circumstances cannot deal with SMD, I asked Bram if he'll be willing to put a complete display together for me
. And he did!Installation was easy, and now my old buddy not only plays music like a young fellow, it even looks like one
. Exact this player was the first CDP my father owned back in the 80's, and little Ingo liked watching the rotating CD through the window. Thanks a lot, Bram, for sharing your work on Diyaudio and again a big thank you for the kind service!
Best regards
Ingo
(BTW: Complete reworked with NOS-conversion, but even better in combination with the Parasound D/A converter 1100HD.)
Attachments
Last edited:
those original display modules were a problem from the very beginning.
More off my NSM4202 en NSM4202a project can be found here
NSM4202a naar NSM4202 & NSM4002 - MFBfreaks.com
NSM4202a naar NSM4202 & NSM4002 - MFBfreaks.com
Hi, reviving an old thread .... I recently got a CD 350 from the recycle centre and beside some new caps it requires also a new display, some segments of the third and fourth digits are dead (digit one and two are ok indeed ...). I saw on ebay the new display replica but I'm not sure the CD 350 is worth what the new display costs, it is just a basic entry level player from mid 80's. Has anyone ever investigated what actually goes bad in the original display ? Is it the led controller, the led itself or the via's connecting the two sides of the board ?
Thanks
Thanks
The bond wires fail inside the epoxied chip. The LEDs seems to be fine and still work but the controller can no longer control segments with broken bond wires. If the wire from the data or clock input fails nothing will be displayed. There is no other way to fix these but replace the display module. A customer of mine wanted one replaced in a Tanndberg 3015A CD player. After buying a used module from ebay that was completely dead I decide to make a replacement boards.
https://www.ebay.com/itm/145147749466
https://www.ebay.com/itm/145147749466