Repairing an older remote

prod · Post by **prod** » Sun Oct 22, 2006 7:37 am

I have a Pioneer CU-AV009 learning remote from around 1990 that no longer works. It does not emit any IR codes and the status LED does not light on each keypress as it is supposed to. A year ago it was working, except a few buttons had to be pressed harder. Now nothing works and it appears to be dead.
I have opened it and inspected visually, the pcb and components appear to be ok.
I have found proper battery voltage at the + and - terminals on the pcb, but I dont know where to go after that.
Can anyone help me further?

http://www.remotes.com/store/pioneer/cuav009.html

MaskedMan · Post by **MaskedMan** » Sun Oct 22, 2006 9:11 am

Is that one of the remotes where the battery door is part of the circuit from the batteries? Without it no power?

zaphod7501 · Post by **zaphod7501** » Sun Oct 22, 2006 9:43 am

Just a few things to suggest.
Did you leave it with batteries installed (which are now dead)?
Visual inspection: Look closely at the leads and soldering on the output LED (under magnification if possible). Look for the oscillator (small square plastic block with 2 or 3 leads). If it uses that type, the leads can crack close to the body of the device.
Try: Clean the battery terminals even if they look OK and make sure they have enough tension to press tightly on the battery.
Use: Any battery except Mallory - Duracell - Coppertop. In 30+ years of service literally 50% of all battery operated small devices have had brand new dead Duracells.

Possible scenario: With batteries in device: as they drop in voltage, the CPU starts running hotter and hotter until if fails. We're talking miniscule temperatures obviously, but it's a processor that only is supposed to draw micro current. If a button had gotten stuck "ON" the same thing could happen, just much faster. Some remotes have been known to start sending constant output signals when the battery drops low also creating the same "button stuck" situation. The result is a working remote that dies for no reason in the drawer.

Post by **The Robman** » Sun Oct 22, 2006 9:57 am

Hey Steve, if the problem was caused by the scenario in your last paragraph, would that result in a deal, un-reparable remote? If we're talking about a fried CPU, it sure sounds that way.

Hey Prod, are you able to control your Pioneer using one of your JP1 remotes? (ie, do you have an upgrade for it)

prod · Post by **prod** » Sun Oct 22, 2006 1:59 pm

Thanks for the quick responses guys.
Yes, the battery cover hits a switch to close the battery circuit, but I have checked that to make sure it is working. I have also tried shorting it by soldering a wire across the switch. Still no go. Have used known good batteries too. I am getting good voltage on the pcb by the batteries, so connections seem ok.
I will try to have a closer look at the components and their connections. I have an idea what a bad solder joint looks like, but they all seem ok.

Rob: I had a separate thread on using my RCU810 here: https://www.hifi-remote.com/forums/viewt ... highlight= The problem is right now I need to use amp device code 0030 with about 10 learned buttons. This is taking up too much memory and doesnt leave enough for my other devices.
I need to make an upgrade (im new to this) that includes the 0030 buttons I need plus the learned buttons, but apparently for that I need this remote working to get the codes. My other devices are similar, I need device code plus a few memory hogging learned functions.
This was the reason for me starting with JP1, but so far I have only been able to make a backup copy of the learned buttons for the remote that no longer works.

Post by **The Robman** » Sun Oct 22, 2006 2:42 pm

OK, I've responded in the other thread.

zaphod7501 · Post by **zaphod7501** » Sun Oct 22, 2006 4:59 pm

The Robman wrote:Hey Steve, if the problem was caused by the scenario in your last paragraph, would that result in a deal, un-reparable remote? If we're talking about a fried CPU, it sure sounds that way.

I've seen a couple of Sony remotes die this way and I've personally killed a remote that got a button stuck down (in a couch cushion).

In the "Old Days" we could actually get some of the CPUs as repair parts until they outsourced production and all the parts vanished. A dead CPU now means an unrepairable remote.

zaphod7501 · Post by **zaphod7501** » Sun Oct 22, 2006 5:05 pm

prod wrote:Thanks for the quick responses guys.

Something else (unlikely but...) to try. Remove the contact pad and clean the board with isopropyl alchohol. (clean the pad too) Take a toothbrush to the solder side of the board and the leads of the chip. Any corossion or resistance between pins will lock up the CPU also.