Servicing Onkyo C-707CHX

[operagost]

I didn't want to revive a zombie thread, so my original reference is here: https://audiokarma.org/forums/index...d-changer-drawer-will-not-open-solved.779499/

I picked up an Onkyo 3 disc changer for $5, and found the usual belt issue. I got a belt kit from ebay, and managed to get them in by only removing the chassis from the casing and popping off the front panel. Now, I rediscover why I avoided changing belts in anything for decades, because in trying to install them I jammed the lower CD tray in the drive area. I imagine I'm in for having to disassemble that CD changing mechanism now, but so I don't cause myself any more grief or break anything (if I haven't already) I was wondering if anyone had suggestions. Thanks!

 

[JumboMumbo]

So, I actually spend several hours this past weekend trying to fix one of these things. The belts had broken on mine. Not knowing how to open the drawer manually (turning the bottom left belt wheel counter clockwise), I ended up tearing into the thing removing the trays. This was a mistake since it releases a lot of small parts, certain gears need to be aligned in specific ways on reassembly, and the trays are an absolute nightmare to get back into the mechanism correctly. Also, the service manual for this thing is useless for the most part. Bad english, and useless pictures. I was able to reassemble the thing multiple times, but every time when I tried to operate it with the buttons tray 3 would not lift up and come forward. Even though I was able to get it to cycle by manually turning the wheel (top right belt wheel) that cycles the trays. I gave up on mine, I paid $5, so not bad for a CDP dissection learning experience.

My advice is avoid removing the trays or disassembling the rail mechanism at all costs, it's extremely hard to get back together. Remove the top metal cover, manually release the tray by turning the bottom left wheel counterclockwise (this can be difficult since you need to reach in under the tray and need to overcome a spring at the end of the travel). Once the tray is slid out you can get the belts on fairly easy. I think there's some specific position the gears/gear switches need to be in when you reassemble the whole thing for the electronics to recognize the tray positions.

In your case since you already replaced the belts, I think that since a belt may have slipped or something it got the gearing out of sync with the switches. Look at the right rail, the white gear in the center has two switches that ride on it connected to a board. I think this needs to have a certain alignment to work correctly. I could be wrong, though.

Don't let this unit discourage you from replacing belts. Due to the compact design of this player, it is an absolute nightmare to work on.

 

[operagost]

I paid $6 for mine but also a few bucks for belts

So I might dump it on eBay as-is and see if I can get my money back if I can't figure it out. Thanks for the hints, though, I'm going to try.

 

[spartanmanor]

I know this is an older thread but I wanted to add more info for anyone needing to replace belts on the Onkyo C-707CHX. I purchased this cd player along with the R-805X tuner amplifier for next to nothing just recently. The belts in the CD player were toast.

Unfortunately there is no easy way to get to the belts without taking things apart. I did try and rotate the the door release wheel but could not get enough torque on it to do anything. I eventually removed the 8 small screws holding the upper and lower half of the tray together. Once you do this the gearing will come apart and the alignment can be a nightmare to get back in order. I was able to find this video online of the tray operation which did help in deciphering things a little:

I have yet to get the belts but after spending almost a day with this I think I have it close to where I can place the order. I am including some photos of the areas that are important to note.

Gear (1): This is the transfer gear which supplies power to gears on both sides of the tray via the metal shaft and matching gear on the opposite side. This will come off most likely once the tray top and bottom are separated. The gears on this shaft have a shim behind them that are easily lost and a PIA to put back on without them falling off again. The shaft clicks into a small hole in the plastic sliding tray. The gear train this powers is the same on either side of the tray and must stay in alignment for things to work. You can see the tops of the furthest large white gear (5) it is connected to in the video I have linked earlier. There is a indent in the top of this gear (5) which needs to be in the 12 o'clock position when resting. I will provide a photo of this later.

Gear (2): This gear is on an open shaft that will not retain it and will fall off once things are opened up. It also has a shim on the backside that will go missing instantly and is a pain to keep in place when reinstalling things. Gear (2) needs to align with gear (3) which floats on its own shaft. Gear (3) moves up and down the shaft when the tray is opened. You will notice a black retaining clip next to gear (2) which needs to fit into the notch of gear (3).

I ended up leaving out the three CD trays when I re-ensembled everything. It appears they can be slid back in. They have notched sides which are driven by the smaller orbital gears (4)

I believe it took me at least 2 hours of failed attempts before I was able to get all these pieces to align to put it together again. Gravity is not your friend on this project.

 

[gtsdave]

I agree, it is a pain to work on especially when you dont realize one of the gears is split. After removing the 8 screws on the disc sled, remove the top portion off. It might be tricky as there is a micro switch that might be caught up inside the white gear, pry it away very carefully. The micro switch is grey with 2 black plastic posts that ride inside the gear.
Hopefully the bar that syncs the two rails is still in place. If not, there is a hole between the white center gear and the black gear that the bar fits into. Align the gears so that the grove change is facing the front at the 3 or 9 o'clock position (depending how you look at it.
I ended up placeing one disc tray in the rear (the one with the two posts on the bottom (that one is disc 30) under the hold down bracket. Then with the disc rail fully open towards the left, place disc 20 on the bottom of the rail in the front Place the 4 spindles with the spikes inserted into the gear grove. Place disc 10 on top of disc 20, riding the front spindles. The open end of the trays face the front.
Now the tricky part is the put the top half on top of the bottom rail and have the 2 disc trays be on top of the front portion bottom inside lip. Try starting with the top rail at an angle and gently rock it in. Remember the micro switch that you got hung up on when seperating the top and bottom? Place a piece of paper between the micro switch and the gear and it will drop in.
The gear I found to split is located in the middle of the CD assembly bottom portion. There is a motor connected to a wheel that spins a 2 inch bar. At the end of the bar is a small gear the is part of a 3 gear assembly. That gear was split which sometimes would move with the bar and most times just not rotate at all. Used thread locker to hold in place (for now) I used the blue thread locker. When I first applied it, I noticed a thin blue line which showed me it was split.

 

[Passat]

A much much better manual for reassembling the changer is the service manual for the Denon UD-M50.

Elektrotanya for electronics experts

Electronics forum for electronics experts to repair defective appliance.

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The changer inside is exactly the same as in the Onkyo.
The Onkyo CHR-185II and CHR-185X has even the same changer.