CurtPalme.com Home Theater Forum

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

The warning is still a good one to know. If you had pulled the white wires and the clicking stopped (which is impossible, as the only thing that runs on the neck boards with the power connected but turned off is the filaments) then you would probably have attempted to power up the unit, and gotten three spot burned tubes for your trouble.

cerickson · Joined: 13 Oct 2016 Posts: 32

I appreciate the info on that.. Thanks for the heads up for future

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

could be a bad CLM too. It uses the +15 volt rail and drives the wired remote according to Tim's site
http://etechvideo.com/techarticle2.htm

The CLM draws +5 volts and +12 volts ( should read +15 I think) from the low voltage power supply, to power the I/O processor and memory ICs and to power the IR receiver and the wired keypad, if installed. On Marquees built after 1994, the wired keypad is easily removed and configured for IR battery operation by moving a small jumper in the battery compartment and adding four AA batteries.

the very first thing that gets power after the LVPS itself is CLM itself and remotes/ IR sensor.

barclay66 · Posted: Thu Mar 02, 2017 8:48 pm Post subject:

Hi,

not quite.
The CLM receives +5V and +12V from the standby section of the LVPS. This section works as a separate power supply which produces the voltages as soon as the LVPS is connected to the mains line. It powers the I/O processor which reacts to commands from the wired and/or wireless remote control.
The CLM controls the activity of the rest of the LVPS including the -15/+15V and -5/+5V lines. It uses those supplies for the main logic and generation of all kinds of signals. A short on the +15V line at the CLM may be caused by one of the op amps or D/A converters or a short on one of the daughter boards. It should be possible to eliminate the CLM as a culprit by measuring the resistance across C2 (upper right corner of the CLM). Healthy values are in the mega ohms range (just checked with a known working CLM)...

Regards,
barclay66

gjaky · Joined: 05 Jun 2010 Posts: 2802 Location: Budapest, Hungary

I just want to add that with boards like this the yellow tantallum capacitors can easily get shorted by excessive inrush current, which may be an old LVPS unit.