I need enlightenment.
I was trying to adjust the 4.7K pot for the laser
output and tried to measure across R101, or
3501, as indicated on a shematic for CDM4/19
published on one of the threads. (test points
1 and 2 on that schematic.)
So I put a probe on one side of R101 and
the other on the other side, and voila, R103
begins to smoke and now the turntable won't
turn anymore. WHat happened?
Ok, I am ignorant ...
I was trying to adjust the 4.7K pot for the laser
output and tried to measure across R101, or
3501, as indicated on a shematic for CDM4/19
published on one of the threads. (test points
1 and 2 on that schematic.)
So I put a probe on one side of R101 and
the other on the other side, and voila, R103
begins to smoke and now the turntable won't
turn anymore. WHat happened?
Ok, I am ignorant ...
R103 is a safety resistor
Not sure why it fused when you measured, but R103 is nothing more than a 4.7 ohm "safety" resistor that would easily blow when drawing more than specced current.
Replace with 4.7 ohm resistor (or even a wire link) and HOPEFULLY things will work again!
Let us know.
Ryan
Not sure why it fused when you measured, but R103 is nothing more than a 4.7 ohm "safety" resistor that would easily blow when drawing more than specced current.
Replace with 4.7 ohm resistor (or even a wire link) and HOPEFULLY things will work again!
Let us know.
Ryan
Does this seem like a plausible explanation:
The multimeter I used (Sperry DM-4100A) has
a relatively low impedance (1M) and perhaps
this loaded the circuit too much and drew too
much current for this circuit.
??
The multimeter I used (Sperry DM-4100A) has
a relatively low impedance (1M) and perhaps
this loaded the circuit too much and drew too
much current for this circuit.
??
"............... has a relatively low impedance (1M) and perhaps
this loaded the circuit too much and drew too
much current.................."
Hi Mikelo,
You seriously need to read up on basic electronics first !
I'm not joking. With what you said above , it shows that you might not understand enough to work easily with the things you are dealing with.
1M is not a "low" impedance here . It will be a very 'low' additional load on the circuit and certainly cannot blow a resistor by putting the leads across it. While lots of people will help you , from your side you need to at least understand the basics reasonably well. That way the help from members will be easier for you to understand and implement.
Cheers.
this loaded the circuit too much and drew too
much current.................."
Hi Mikelo,
You seriously need to read up on basic electronics first !
I'm not joking. With what you said above , it shows that you might not understand enough to work easily with the things you are dealing with.
1M is not a "low" impedance here . It will be a very 'low' additional load on the circuit and certainly cannot blow a resistor by putting the leads across it. While lots of people will help you , from your side you need to at least understand the basics reasonably well. That way the help from members will be easier for you to understand and implement.
Cheers.
I know I am very ignorant, and I
appreciate your gentle enlightenment.
But giving the benefit of the doubt is
also nice thing to do even when addressing
stupid people like me.
I understand that 1M is fairly high,
certainly much higher than 4.7ohm, but
it is much lower than 10M, which is the
input impedance for better multimeters.
When I said "relatively low" I meant
relatively low to other digital
multimeters I am familiar with. (By the
way, this is a 50mV circuit.)
appreciate your gentle enlightenment.
But giving the benefit of the doubt is
also nice thing to do even when addressing
stupid people like me.
I understand that 1M is fairly high,
certainly much higher than 4.7ohm, but
it is much lower than 10M, which is the
input impedance for better multimeters.
When I said "relatively low" I meant
relatively low to other digital
multimeters I am familiar with. (By the
way, this is a 50mV circuit.)
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