Magnavox CDB 492 Recap/Mods

[jheu02]

This was another quick project that's (almost) complete...explanation to follow. I've recapped amps/tuners/etc. to keep things running optimally, but have neglected my sources. so, I decided to pull this off the shelf (curb find) and recap it. If you know these older Magnavox/Philips units, you know it's got a great transport CD4 and a pretty decent D/A converter TDA1543 (not the 1541A, but good reviews none-the-less). It's almost complete as I hadn't thought to do this prior to placing my Mouser order for some stock items and specialties for later projects, so I didn't have the main filter cap in stock, nor 2 caps that were short enough for some locations. Photos show critical height (Length) caps.

I used a mix of Nichicon, Panasonic, and Chemicon caps that I had on hand and also replaced the 2 output LM833N Op Amps with sockets which currently have OPA2134 Burr Browns in them. I also decided to open some holes in the case bottom so that I can replace the couple odd caps in the future when I eventually place another order. this will save me from the full tear apart this requires to get at the board.

Sound is NOT disappointing!

And now the pics because :worthless

Before (crappy iPad photo)

After (with some notes)

Case Cutouts for PS and odd short cap

Op Amps

Power Supply (max height of 20mm for the 1000/16V and 470/35V caps due to transport)

Components Back In

 

[guiller]

Nice project. Thanks for sharing the pictures.

 

[jheu02]

Finally got the last two PS caps in with film bypass and one "short" cap that I needed to order for under the transport mechanism. I guess most of the improvement has come from replacing the stock opamps with the OPA2134s, but this thing does sound sweet!

 

[Lavane]

Nice work! I've been looking for a Magnavox/Phillips/Marantz top loader. Don't care what brand is on it. I just like the window on top. Plus its a top loader!

 

[jheu02]

Found another one of these at GW (actually CDB490). Will try to do some listening tests of stock vs recapped/modified as I have some duplicate discs I can set up and run concurrently.

 

[jheu02]

If interested, here's the results of an initial comparison of stock vs recapped/modded.

 

[shamrock.]

Does this player a have muting transistors?
If so it could be worth trying removing them

 

[onanysunday]

It's been a year I know and maybe a longshot, but if anyone's still following this thread I have a question. I am currently doing something very similar right now with an almost identical Magnavox model as this. Recapping / replacing opamps on a (1989) Magnavox CD 2000 that is almost identical to a CDB 490/492. I was also interested in upgrading the 12 diodes in the power supply section to a faster response type. Cannot find any spec info on the seven black # MW 8841 171-1 and five blue MW 8847 171-1 as seen in my photo which is very similar to the last two you posted. Did you change these out or know what their specs are so that I can purchase upgrades for them? It appears diode specs are an extremely well-guarded trade secret and any information is hard to find based off the numbers printed on the sides of them. I know I can test their resistance after removing them from the circuit, but I was also curious about other ratings such as speed, recovery, voltage ratings etc..

 

[Horgman]

Hey! I'm new to AK and the hobby of device repair. I ran into this old post looking for a schematic for a Magnavox CD 2000. I just picked up one of these players out of the garbage and first things first it needs the on off switch on the board. Did you find a schematic for it number 1 and where would I find a replacement switch? Mouser?
Thanks