Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: ChadTower on February 09, 2008, 05:35:17 pm
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I'm still working on this XM501... tried the rejuvinator, didn't do anything. I was poking at the controls and noticed that the brightness pot seems to do nothing. The rest all show a response. I haven't found any spots where it is visibly removed from the circuit.
The schematic lists it as a 200k resistor, R21 as shown below. When I turn it all the way down resistance reads as 5ohms. All the way up - 132k. I don't see how to tell from the schematic what the low reading should be but can I assume that 132k isn't enough at max and that this thing should be replaced?
FWIW, I can tone it to R22.
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You're getting false readings because of other components in the circuit.
You need to temporarily unsolder all wires going to that pot in order to test it accurately.
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You need to temporarily unsolder all wires going to that pot in order to test it accurately.
I was afraid of that.
It was brought up in my project thread, and I have thought of this but didn't understand enough to consider it fully, but would the signal from a VCR be displayed as dim, and thus maybe I have a good monitor that I'm still trying to fix? I have been considering that maybe the signal from the VCR isn't strong enough to be bright on the monitor.
EDIT: out of circuit it tests to 175k fully open. Good enough or should I replace it?
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since turning the ctl is producing no effect , also suggest verifing 150 v source , check r95, r22, then check c10 and q21 for possible shorts ....
qrz