I have an old CD player that has trouble playing CDs. Luckily I found a service manual:
https://www.dropbox.com/s/uy6285ikhnu03y7/philips_mcm204_ver-1.1_sm.pdfOn page 8 it describes how to perform an eye-pattern test. However, either I'm blind, or the shcematic on page 8 does not correspond to any of the schematics found towards the end of the PDF.
Can anybody point out the correct probe point?
Check at the RF Test Point. If you see a weak blurry eye pattern, most likely the laser has degraded. You might crank up the power on the laser if it has apot, but that is only going to last a short while. Replace the laser. Cheaper to buy a new Blu-Ray player!
You need to use the same page # sceme that the manual does - 2 number pages .
On page 5-5 I'm guessing what your looking for is CON505 in the far left - center ?
Check at the RF Test Point. If you see a weak blurry eye pattern, most likely the laser has degraded. You might crank up the power on the laser if it has apot, but that is only going to last a short while. Replace the laser. Cheaper to buy a new Blu-Ray player!
Thanks!
I'll try it and post the waveform. Only problem is my crappy oscilloscope (DS1052e). It has persistence mode but the resolution is very low.
For to see a CD player eye-pattern you must use an analog oscilloscope....
For to see a CD player eye-pattern you must use an analog oscilloscope....
Actually that isn't true these days. What is needed is the proper triggering. Dual slope triggering (X) will give you a decent eye pattern. My Fluke 199C was the first digital scope I used for eye patterns, and my Rigol DS4000 series scope does a good job as well.
Actually that isn't true these days. What is needed is the proper triggering. Dual slope triggering (X) will give you a decent eye pattern. My Fluke 199C was the first digital scope I used for eye patterns, and my Rigol DS4000 series scope does a good job as well.
But at what pice?! ... Comparing with a good old used analog scope, that you can buy for a song...
Even a very cheapy make of scopes (the Sgilents) can show an eye diagram (SDS1102CML) ..
From the original poster we are talking about CD player eye-pattern. That's how a CD Player eye-pattern must look like...
Even a very cheapy make of scopes (the Sgilents) can show an eye diagram (SDS1102CML) ..
From the original poster we are talking about CD player eye-pattern. That's how a CD Player eye-pattern must look like...
Yes I know. I was just saying (and showing) that even today's cheapo digital oscilloscopes can show an eye diagram, so you don't really need an analogue scope to show an eye diagram, unless you have quite an old digital scope that is.
So, please show a CD player eye-pattern in a digital scope.
Okay. Just repaired a circa 1993 Kenwood CD player today (based on Sony laser and chipset). I grabbed some eye pattern screenshots while I was in there. This is with a Rigol DS4000 series 'scope. First one is cross slope trigger, second is positive slope, and third is negative slope. No persistence, 20Mhz bandwidth limit on. Very useable, and scope measurements are meaningful.
