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Pioneer dvf727 won't load discs, not arm alignment
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Sat Jul 05, 2014 3:47 am    Post subject: Reply with quote

After looking at the schematic, I can not point to a specific item. Based on your last reply, it sounds like the initial detection of the door open/close carousel spin are working OK.
Since the disc load out from the carousel is not working, it is either thinking that the carousel is not reaching at the right spot electrically or not getting the correct pulse from the optoisolator? You mentioned the leaf switch is in fact making it but did you follow it all the way back to the IC? What if there is an issue with a ribbon cable of some sort? Some of this is rather difficult to follow on the forum.
Also, when you mentioned about it "repeating the load/unload", it may very well be a failure of pickup/spindle motor that is putting too much of a load on the circuit and causing it to stop as it keeps repeating itself.
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srb151



Joined: 28 Jun 2014
Posts: 11

PostPosted: Sat Jul 05, 2014 9:54 pm    Post subject: Reply with quote

Ok, thanks. I hate to throw parts at it, but I'm thinking I'll try replacing
the pickup/spindle assy. The load/unload in the service mode seems more
like an attempt to reload the disc after failing to read it after a minute or so.
That's why I was interested in the system logic, if it would not issue a load
command if a fault was found in the pickup/spindle, or would it load anyway,
and then reject after a failure. What throws me are the lack of error codes
for anything other than load timeout. Thanks again for the help. Let you
know how the shotgun of the pickup works.
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Sun Jul 06, 2014 2:44 am    Post subject: Reply with quote

The shotgun approach is definitely not something I am fond of but sometimes that may be the only way.
It is rather unusual not to get an error code but you never know about the software and exactly how it was coded to flag an error?
As far as logic sequence, it is pretty much straight forward. What is not clear is how it reacts based on every single fault.
Basic sequence, using a CD as follows; Once a disc is rotated to the exact spot by means of pulses generated of the optoisolator, it locks the carousel and signals the processor to issue a load command by way of a motor driver. This starts the loading arm which pulls the disc in to the mechanism. Once the load limit switch signals the complete load, the laser is turned on attempting to focus on the disc. When focused, a FOK signal is sent back which generates a spindle drive command while the laser attempts to read the TOC. (table of content)
Once started, the servo looks for a specific speed as the laser attempts to read (clear diamond pattern on the scope). Once that is achieved, it reverts back to stop and waits for the next command.
This is similar for a DVD except a separate laser (within the P/U) is used and instead of stopping the disc it ends up looping at the start menu.

Now as to how many times this is repeated, some units will attempt for several times but to the best of my knowledge, there is always a "timeout" feature which usually ends up with some sort of an error. Very often service modes allow you to override such features which may be the case here--don't know for sure?
On the pioneer pickups VXX2653 I have seen problems with spindle and the laser but it is next to impossible to say for sure without a spare.
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srb151



Joined: 28 Jun 2014
Posts: 11

PostPosted: Wed Aug 27, 2014 1:46 am    Post subject: I've narrowed it down..... Reply with quote

I had bought a second unit to use in my home theater. It was supposed to
have been a working unit, but I didn't get around to testing it until now.
(I need to get smarter about that). This one loaded the disc but did not
play. A quick look around, and I found the spindle motor not operating.
I took the whole drive assy from the one that wouldn't load, plugged it in
to the newer unit, and the discs now wouldn't load. I swapped the motor
off of the non loading drive to the newer on and bingo, It works perfectly.
Therefore, the first unit must be detecting a problem with either the
pickup or stepper motor (I would bet the pickup). When I get a chance, I'll
order a new pickup and stepper and see what happens. Thanks for your
help.
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