Grundig cd7500 - 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
Reply
 
Thread Tools Search this Thread
Old 14th May 2011, 09:16 PM   #1
diyAudio Member
 
Join Date: Jan 2010
Default Grundig cd7500

Hi!

I almost new to the forum, maybe I posted a couple of times but I even did not remmember! I will fisrts introduce me.

I am not a electronic eengineer, but actualy I am a sound eengineer, so I have some electronics knowledge, but to be honest, I just undestand quite simple Tube amps electronics. I dont have experience with digital things.

Well, to the point. I got a Grundig CD 7500 from a garage sale, but unfortunately it does not work. It powers and lights but the LED does not. Nothing to worry yet.

Here comes the worst. The cd does not move and on the output there is a lot of noise, kind of brown noise. Ive been reading for a couple of days on forums and the noise could be caused by a faulty power supply. But I did not found any suggestion about the cd transport. The weird thing is that when I turn the unit off, the cd moves for half second.

I measured the transport engine and no voltage appear on normal and a 2.6volts spikes appear when the unit is disconnected.

Please, I need spiritual advice on this one. And a schematic!

Thanks

Carlos
  Reply With Quote
Old 14th May 2011, 09:48 PM   #2
danico is offline danico  Hungary
diyAudio Member
 
Join Date: Feb 2010
Location: Hungary
Hi there!

You can have the manual from here:Service manual, eprom result list | ElektroTanya | Service manuals and repair tips for electronics experts

Look for the philips cd-303, its allmost identical. Acording to this site
Steerpike's Toys
" Based on a Philips CD-303, but with improved DAC & Decoder board (NO Sony chips in here!), and a special uniquely Grundig grounding layout.
It was broken when I got it, not reading discs at all. But a replaced 6n8 capacitor on the servo board restored it to full functionality. The cabinet was very badly scratched, but is getting re-painted, and new wood side panels (instead of original plastic).
It has the highly regarded Philips CDM-0 mechanism & optical unit, and TDA1540 D/A converters, which are also reputed to sound special. It really does sound GOOD!

I hope you can fix it, this is one my favorite player.
Just messure the voltage from the regulators,probably a bad cap.

I fined the treat ,too:Grundig 7500 (Phil CD303, Mar CD73) radial servo malfunction: advice please

Last edited by danico; 14th May 2011 at 10:09 PM.
  Reply With Quote
Old 14th May 2011, 10:08 PM   #3
diyAudio Member
 
Join Date: Jan 2010
Hi Danico

Thanks a lot. I will now check the schematic to see what component may be interrupting engine voltage.
  Reply With Quote
Old 15th May 2011, 12:31 AM   #4
amc184 is offline amc184  New Zealand
diyAudio Member
 
amc184's Avatar
 
Join Date: May 2007
Location: Christchurch
Hi Carlos,

That's a nice CD player you've bought, hopefully you can get it going. The Grundig CD7500 is actually exactly the same as a Phillips CD303. The CD303 had two versions; one with a mixed Philips and Sony chipset and one with a complete Philips chipset. I've owned a CD303 with a Philips only, and I too bought it broken (and later fixed it). Unfortunately, though I looked hard, I never did find a service manual that covered this version of the CD303.

There are two things that I would look at on your player:
- The electrolytic capacitors. These components will have long since died. If you're serious about fixing this player and keeping it afterward, I would replace all of them. If you aren't keen on that idea, start with the ones in the servo, particularly the ones on the PCB attached to the laser mechanism itself.
- The silver axial film capacitors. Though film capacitors are generally reliable, there are a certain type of silver axial film that Philips used in these player that can go open circuit. This is the 6.8nF capacitor that Steerpike mentions in the site Danico linked to.

Good luck with your player.
__________________
Inside Classic Audio, my blog on repairs, modifications and anything else to do with audio.
  Reply With Quote
Old 15th May 2011, 12:46 PM   #5
diyAudio Member
 
Join Date: Jan 2010
Hi

Thanks. I had planned to do a complete recap, but first I wanted to know if the motor was broken. I will do a recap of the PSU and the Laser PCB, and then see what happens.

Cheers
  Reply With Quote
Old 15th May 2011, 01:55 PM   #6
diyAudio Member
 
Join Date: Jan 2010
Thanks

I will try to recap it in parts to see what happens.

Cheers
  Reply With Quote

Reply


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
Grundig 3028 HELP Omegaman Tubes / Valves 7 28th December 2010 05:57 PM
Grundig A-9000 broken :( mat_one Solid State 9 26th November 2008 02:01 PM
Grundig CD303, anyone know it? tubenut Digital Source 0 30th May 2008 06:33 PM
Grundig CD7550 schematics jives11 Digital Source 11 5th February 2008 05:04 PM
Grundig V-5000 schematics zb2310 Solid State 5 13th May 2007 07:18 AM


New To Site? Need Help?

All times are GMT. The time now is 02:58 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2