SC-901 CD Changer Maintenance

Post by **sleddriver** » 07 Apr 2018, 17:43

Been having trouble recently with the 901 playing CD's. Two of the discs had several fine scratches. For a minute I thought the aluminum layer was actually oxidizing as they're about 20yrs old now. However they polished out fine (fortunately). Even after this, neither disk would play.

The top metal cover is easily removed after removing two small screws on the rear and gently prying up.

Here's a list of things I cleaned using denatured alcohol, q-tips and forceps.

Both upper & lower disc clamps.
Both upper & lower disc roller bars.
Twin blue 'eyes' on bottom, aft of the hub.
Laser lens.

I was able to extend the cartridge carriage by locating its gear train and moving the gears by hand. Once begun, the front tray can be gently pulled out to full extension. I cleaned the tray internals using a Q-tip + isopropyl alcohol.

I also took time to remove dried up grease from racks & sliders and relubed with LPS #1 I collected by spraying into a small glass jar. Definitely don't want to spray anything inside. I also used this to lubricate sliding points and pivots.

If the disc clamp isn't clean, the disc won't be held tightly and will slip, causing the tracking mechanism to lose its place. Many pick up discs by the center hole, thus transferring what's on their fingers to the clamp, which over time gets dirty with it. It's best to only hold the disc by the edges. To hold the clamp in place, I inserted a fine regular screwdriver into a side slot to gently wedge it into place. I was able to clean about 180° at a time, then rotate it, and clean the other half. Also important is the top clamp. Reach way in there with a q-tip held by the forceps.

The disc roller bars move the discs out of and into the cartridge. Over time, they'll become embedded with dust & dirt and loose their grip, causing a "clank" sound when in operation. Clean both from the front. You can rotate the upper roller from the top hole, next to the extend/retract gear. When that one's done, extend the mechanism further and you'll notice the lower roller bar rise up to join its mate. Put the player on its back, facing up and shine a light down inside. Clean both until deep black. I treated both with ReGrip since I had some, but any rubber/vinyl protectant will be suitable.

The laser lens is at the very back, on the right hand side of the hub when viewed from the front. Wet the q-tip with ethanol, then sling it to remove excess before wiping the lens off.

I cleaned and relubed as many sliding surfaces as I could reach with a drop of LPS1.

Result? Instant loading of discs with no slipping, slamming or clunking. Previously "unplayable" discs played with no issues.

raivis_rsn · Post by **raivis_rsn** » 08 Apr 2018, 00:35

Did this recently to my SC-901. But now mine has stopped to play fm radio. No sound. It scans for stations but couldn't find anything. Antenna is working fine. CDs and tape work just fine. Any ideas?

Post by **scot850** » 08 Apr 2018, 11:30

Probably obvious, but have you checked the antenna/aerial is pushed fully home in the back of the radio? They sometimes need a bit of force to get them to fully seat.

Neil.

Post by **sleddriver** » 08 Apr 2018, 11:44

raivis_rsn wrote: ↑08 Apr 2018, 00:35 Did this recently to my SC-901. But now mine has stopped to play fm radio. No sound. It scans for stations but couldn't find anything. Antenna is working fine. CDs and tape work just fine. Any ideas?

No I don't.
I suggest you start a new thread though as FM reception doesn't have anything to do with the topic.

Post by **scot850** » 08 Apr 2018, 13:22

I wrote up a how to on this also a while ago with pictures, but the main thing is these units often got a bad rap due to bad maintenance rather than the product itself. Glad you got it fixed though as it is a satisfying repair and they are good head units.

Neil

Post by **sleddriver** » 09 Apr 2018, 12:30

scot850 wrote: ↑08 Apr 2018, 13:22 I wrote up a how to on this also a while ago with pictures, but the main thing is these units often got a bad rap due to bad maintenance rather than the product itself. Glad you got it fixed though as it is a satisfying repair and they are good head units.Neil

Hi Neil. Thanks for mentioning your how-to. Didn't realize there was a 900 radio. I was searching for 901. Having a large circular hole like that in the top of the 901 chassis sure would greatly improve inner access! No joy though. I did read the other article you linked to while searching. Good of you to mention the 'disc rollers'. Mine had never been cleaned! Missed them last time I was in there. Clean ones are critical to proper disc transport out-of and into the cartridge.

Last night I heard only a single sound cutout even while driving over several rough roads due to a clean disc clamp and no internal disk slamming due to clean rollers.

I also noticed the tiny spring is no longer in place to hold the cartridge door shut. Odd that...not sure when it fell out.

raivis_rsn · Post by **raivis_rsn** » 09 Apr 2018, 23:30

sleddriver wrote: ↑09 Apr 2018, 12:30 I also noticed the tiny spring is no longer in place to hold the cartridge door shut. Odd that...not sure when it fell out.

Mine has that issue too. Spring falls off because that holding pin is very tiny and it breaks. I hot-glued needle in its place and got a spring from old Pioneer radio. Works pretty well.