Author Topic: Output Issues On CP4500

May 02, 2022, 08:45:36 PM
Reply #25

forcemusicgroup

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TP7 value seems to be extremely high compared to what im supposed to be getting ---------12.15VAC where as its supposed to be 1.5vac

May 02, 2022, 08:48:58 PM
Reply #26

forcemusicgroup

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TP7 at 0 makeup is 1.3vac and @+20 makeup is at 13.12vac
« Last Edit: May 04, 2022, 05:31:49 PM by forcemusicgroup »

May 04, 2022, 04:32:35 PM
Reply #27

JPK

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In which step do you get this result?

TP7 at -20 makeup
I assume you mean @0 MAKEUP.

You need to be more specific in your descriptions or I can't make any deduction.
JPK

May 04, 2022, 05:30:36 PM
Reply #28

forcemusicgroup

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Yes at 0 make up those are the values 

May 06, 2022, 05:03:17 PM
Reply #29

JPK

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You didn't reply to the question:
In which step do you get this result?
Without knowing the context I cannot make any deduction.
JPK

May 07, 2022, 12:25:42 AM
Reply #30

forcemusicgroup

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step 1 voltages

v+ 15.2
v- 16.2
-12v 11.5
+12v 11.7

step 2

tp 1,2,3,4,11,12 =0VDC

step 3

tp12 = -2.9vdc

step 4

tp13 @-1.8vdc
      @2.9vdc

step 5 

tp4 @-15TH =0.21
    @+15TH =.058
TP5 @+15TH =.334VDC
      @-15TH =-2.221VDC
TP11@+15TH =.012
      @-15TH=-3.39
TP12@-15TH=3.4VDC
        @+15TH=0

STEP 6
TP1=1.5VAC
TP2=1.439VAC
TP3=1.51VAC
TP4=0.06VAC
DCV = -0.001

STEP 7
TP1=1.5VAC
TP2=0.470VAC
TP3=1.51VAC
TP4=0.217VAC
TP11=-3.39VDC
TP12=1.03VDC
TP13=1.59VDC

CHANNEL 2

-V = 16.21
+V = 14.77
-12V= 11.87VDC
+12 = 12.03

STEP 2 C2

TP6=0
TP7=0
TP8=0
TP9=0

STEP3 C2

TP6=1.5VAC
TP7=1.36VAC
TP8=1.5
TP9=0.06

STEP4 C2
TP6=1.5VAC
TP7=0.4VAC
TP8=1.5VAC
TP9= 0.2VAC

VDC U16 =.058
« Last Edit: May 07, 2022, 12:35:47 AM by forcemusicgroup »

May 09, 2022, 10:05:40 AM
Reply #31

JPK

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step 3
tp12 = -2.9vdc


In step 3 conditions, does the voltage on TP12 go to 0V when Makeup is at 0 ?
Without and with channel 2 installed?
JPK

May 09, 2022, 12:32:22 PM
Reply #32

forcemusicgroup

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Yes. 0v with channel 2 installed and without... fluctuating no more than .5 -/+vac moving make up 0 to +15
« Last Edit: May 09, 2022, 12:34:20 PM by forcemusicgroup »

May 09, 2022, 03:42:07 PM
Reply #33

JPK

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Sorry, not understanding:
The voltage measured on TP12 are DC volts and without input signal (step 3).
JPK

May 09, 2022, 05:29:50 PM
Reply #34

forcemusicgroup

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With make up @+20 I get -2.384vdc with second channel attached

-2.37vdc without board 2 attached 

May 11, 2022, 11:31:17 AM
Reply #35

JPK

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What I need to know is: 

In step 3 conditions, does the voltage on TP12 go down to 0V when Makeup is at 0 ?
Without and with channel 2 installed?

JPK

May 11, 2022, 01:57:05 PM
Reply #36

forcemusicgroup

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May 12, 2022, 04:08:32 PM
Reply #37

JPK

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Channel 2 - step 3
Is TP7 still too low (1.36VAC instead of 1.5VAC) if you remove U17?
Check the resistor value (with power off, U16 removed, Trimmer T2 fully CW) between TP7 and U16 pin 6 : 5k7 ?
Check the resistor value (with power off, U16 removed, Trimmer T2 fully CCW) between TP7 and U16 pin 6 : 4k7 ?
JPK

May 12, 2022, 04:44:45 PM
Reply #38

forcemusicgroup

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Will do stand by

May 12, 2022, 05:07:03 PM
Reply #39

forcemusicgroup

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tp7 with u17 removed comes to 1.694 vac

May 12, 2022, 05:14:20 PM
Reply #40

forcemusicgroup

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Check the resistor value (with power off, U16 removed, Trimmer T2 fully CW) between TP7 and U16 pin 6 : 5k7 ? = 5.682k ohm

Check the resistor value (with power off, U16 removed, Trimmer T2 fully CCW) between TP7 and U16 pin 6 : 4k7 ? 4.699 k ohm

May 13, 2022, 05:44:31 PM
Reply #41

JPK

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tp7 with u17 removed comes to 1.694 vac
It seems that U17 is bad.
Try replacing it with U7.
JPK

May 13, 2022, 05:56:09 PM
Reply #42

forcemusicgroup

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Ok changed. What should I be looking for

May 14, 2022, 10:07:50 AM
Reply #43

JPK

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In channel2 step 3, is the level on TP7 back to 1.5VAC instead of 1.36VAC.
JPK

May 14, 2022, 10:24:43 AM
Reply #44

forcemusicgroup

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Same. I noticed that when I changed out the chips that the volume changes channels. The 1646 chips are new from 
Mouser.

May 16, 2022, 08:51:05 AM
Reply #45

JPK

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I noticed that when I changed out the chips that the volume changes channels.
Can you please explain? What change on what channel ?
JPK

May 16, 2022, 12:13:15 PM
Reply #46

forcemusicgroup

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Moving and changing the 1646 from ch a to b 

May 17, 2022, 04:23:12 PM
Reply #47

JPK

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The THAT 1646 must be defective.
JPK

May 17, 2022, 04:32:49 PM
Reply #48

forcemusicgroup

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Well I've tried several. And still can't get a match. It's off by 1.7db

May 18, 2022, 03:24:56 PM
Reply #49

JPK

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Sorry, I am out of ideas.
Do you want to send it to us for a check? Contact me here.
JPK