Md4 recorder mini disc. will only power up error 04

Table of Contents errors can be the result of bad compact disk, bad laser or the head cannot get into position to read the TOC, Make sure that the new laser is aligned correctly and that the head has no obstructions at either end of the rails. Last but not least you may want to make sure the laser is working and you can check that by using a camera like the one on your cell phone, With the cover off, insert a cd in the drive and have your camera pointed at the area of the laser. You should see the laser light on your camera.

Well, what it means is

TOC errors often mean the recording head/optical block is cooked. A cleaner might work, but often it's the end of the MDR.

Are you sure the battery is correctly (fully) charged? Try removing the battery and running on (only) the charger.

try cleaning the lens with a minidisc lens cleaner.

open the unit and check the laser position - it should be all the way to the left. that's where it should start to read the disk.

TOC errors often mean the recording head/optical block is cooked. A cleaner might work, but often it's the end of the MDR.

Read these:

https://groups.google.com/forum/#!topic/alt.audio.minidisc/63uCBegyG8A

http://www.minidisc.org/repair_q2.html
http://forums.sonyinsider.com/topic/21439-fun-with-the-sharp-702-utoc-error-fixed/

http://www.mazdas247.com/forum/showthread.php?98358-TOC-Error-on-brand-new-disc!

http://www.borus.de/minidisc/303.htm

hi there is nothing to do by yourself. you need to take your md player to the next authorized service. seems the optical device that reads the discs has worn out, compareable to turntables you need to change the `needle` ;)

Problem solved: Downloaded service manual and after studying it for awhile found the fault.
1. On power up in "timer record" mode the 520 proceeds to record selected input until the timer shuts the power to the 520 off.
2. TOC info is stored in memory along with error code history.
3. On power up TOC is read from memory and written to disk and second recording started.
4. Found BT451 had failed (causing loss of 2 above) as soon as the power is removed from the 520.
5. Replaced BT451
BT451 1-528-739-11 BATTERY, LITHIUM (SECONDARY)
(Sanyo ML2016-HJ1 40mA/h 3v rechargeable is suitable replacement) shop around as prices vary

I actually fitted a Lithium battery removed from an old satnav I had lying around! bit of overkill really as it 1400mA/h

Note a faulty BT451 can cause quite a few other problems as well so it's worth checking out and replacing if low or not holding it's charge...........

Many unit that have a less than professional MD mechanism need lubrication and freeing up the mechanism by use and applying grease where it is needed. There is no incentive for the company to use good lubrication as they won't sell you a new unit down the line not to mention these mechanisms were not designed to last 20 years- some of them barely make it 1 year.

I'm thinking you are recording longer than the battery can support the deck for power. Sony always said if you are going to record a long time you need to plug it in. Possibly your battery is old? Try it using the power brick plugged in does it still do this?
The TOC is the recorder trying to write to the disc. The recorder saves to memory and then writes to disc before ejecting the disc. It also could be a bad disc or dirt on the heads or a number of other things.

Hi,

According to you You don't have use your disk play for a huge time, so that it may damaged or lens became dirty.

You can clear the lens with lens cleaner (clear the optical head).

check the battery was properly charged or working.

Check the disk moved properly.

To prevent the disk erase or damage slide the accidental erase prevention tab.

You can show it to the Technician.

Possible that the disc is not reading and so the the TOC- table of content error must be referred.
It can be due to a poor head tracking or the failure of the data being read or processed.
Clean the head and use a good disc to be checked once again. If so the optical head can be faulty as it might be getting weaker.

Sounds like you lost power when you were finishing recording a disc. On a home unit it got unplugged before you had the TOC written, or on a battery unit the battery died when it was writing the TOC (table of contents) for the disk.

When you get done recording, do you wait until the "TOC" light stops flashing? If you cut off power before the Table Of Contents is written, then it can't find all your music. Even if you eject, it should still flash a little red TOC or UPDATE before it spits the disc out. Check for that. okay?