Originally Posted by michidragon
Okay, excellent news - this looks good - for anyone who may want to replace the traverse unit on their 3910 themselves.
I'll document this as much as I can, hopefully to a successful end:
I got a hold of the service manual; and it:
1) States the procedure to test for a failed traverse unit, using a simple multimeter, by measuring DVD voltage (div. 14 for mA) across two test points; and by measuring CD voltage (div. 12 for mA) across two test points. No special test CDs are needed.
Opening up my DVD-3910 today, I noticed, on the back of the DVD mechanism, two numbers: CD - 2.19 mA / DVD - 2.19 mA
There is a section in the service manual: "Judging for Traverse Unit Replacement":"NO DISC indicated, etc. Check Iop according to the measuring method described in step 2 below. If the checked value is 1.5 times or more than the initial Iop indicaated on the rear of the mechanism unit, the traverse unit should be replaced."
There are two points on the DVD board: "DVD Laser Drive Measuring Point", "CD Laser Drive Measuring Point". -- "DVD Laser Drive current is calculated by Measured Voltage Value / 14; CD Laser Drive current is calculated by Measured Voltage Value / 12".
"Playback the title-1 of (test disc) or commercially available DVD disc."
"Playback the track-1 of (test disc) or commercially available CD disc.""If the present value of the laser drive current is 150% up to initial value, it is the point of the pickup replacement."
So..there's where those original values came in. Handy that they wrote them on there in the factory. (Every 3910 should have this.)
This is where I'm having trouble - I can only assume this means "above 150% of initial value". Nothing else would make sense...
2) here's the good part:"No mechanism adjustment is required as the whole unit is replaced with a new one."
and"In the case of the pickup replacement, replace the Traverse Unit with no adjustment."
Just in case you didn't hear it the first time.
This is good indeed, and means this might be a success and an easy repalcement for 3910 owners; bringing the repair cost down from $300-$500 to around $120.
Also, it seems that this newer traverse unit might be improved. There was a 'technical bulletin' saying that the "9KA-2A-506B" has been replaced with the currently orderable part, "9KA-2A-708". Maybe Denon was made aware of these reliability issues and the -708 part may be a later revision.
We shall see! I couldn't find anyone else doing this on the 'net, and, FYI I have a 2910 and 5910CI as well, from what I can tell the part numbers are different, but the procedure should be identical.
So, there's an update on this and we'll see how it goes.
I'll measure my Iop values tomorrow and let everyone know how it goes.