NSM4202A LED Display Module Replacement for Philips / Sony CDM Transports - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 29th July 2014, 01:54 AM   #1
diyAudio Member
Join Date: Jan 2012
Default NSM4202A LED Display Module Replacement for Philips / Sony CDM Transports

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.

  • 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:
NSM4202A Schematic.pdf

Front of PCB:
NSM4202A Front.png

Back of PCB:
NSM4202A Back.png

Gerbers for PCB:

DipTrace Schematic and Board Files:
NSM4202A DipTrace Files.zip
  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
anyone know a source for a NSM4202A LED board gto127 Parts 6 4th October 2014 11:35 AM
Where can I get a replacement laser (CDM-0) for a Philips CD100 drjarmin Digital Source 5 12th August 2013 12:56 AM
Philips CD950 display replacement Superhill Digital Source 2 1st July 2013 05:40 PM
WANTED: Replacement CD-PRO2 VFD Display Module Rarkov Parts 0 23rd August 2003 08:26 PM

New To Site? Need Help?

All times are GMT. The time now is 08:37 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2