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Build A PhonoClone 3 on a PCB Powered by Batteries

Grainger49 said:
If you mis-oriented a chip it is toast, guess how I know. Try swapping the chips from right to left and see if the problem follows the chips.

Then you get to start tracing the circuit. Passive components are very, very seldom defective. But you could get the wrong part in the wrong place. Most resistors can be measured in the circuit.

Post your progress.
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And the good news is he has a working side so taking measurements from the same points on each board will be telling.
 
HypnoToad said:
Reverse the interconnects to rule out your cables and other external devices, that is to make sure its not something outside the Phonoclone.

Reversed both the input and output interconnects and the sound moved from one speaker to the other. Verified that the TT worked on the phono jack and that the AUX1 worked with a CD player


HypnoToad said:
Start with the obvious and make sure the op amps are orientated the right way and seated properly.
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They are seated well and correct

HypnoToad said:
Check the input and output wiring on the board making sure they are going to the right RCA's.
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I verified continuity from the outside part of the RCA jack to the connection on the board.

HypnoToad said:
Measure to see you have +9v and -9v at the supply pins for the op amps, pin 4 to ground for -9v and pin 7 to ground for +9v. You count the pins counterclockwise from pin 1 which has the crater next to it.
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Measured properly at pins 4 and 7 on both op amps

HypnoToad said:
Look for solder bridges on the solder side of the board.
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No obvious solder bridges and I reflowed the solder on all the op amp pins

Between the Packer game and this I'm a bit frustrated. :(
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Now take your DMM and measure resistances from the + RCA inputs to each component on each board and see if they are the same/similar. The working board should have the right values. Let us know if and where there is a discrepancy.
 
I'll check that next but one thing I noticed that has me confused is that when all 4 interconnects are hooked up as they should I only get sound out of the right speaker, but regardless of what input I remove I still get sound out of the right channel.

That doesn't seem right to me.
 
I got the guilt trip from the wife to spend some time with the family. I'll swap the chip when she goes to bed.

Thanks for all the help so far.
 
I swapped the input and output op amps and the sound remained in the right channel, so it would appear that they are OK.

These are the measurements from the output side RCAs.
Right channel - Left channel
R1 - 68.4k - 68.3k
R2 - 586.9k - 585.1k
R3 - 586.8k - 584.4k
R4 - 70.4k - 70.3k
R5 - .882m - .879m
R6 - 585.5k - 584.1k
R7 - .2 - .2
R8 - .765m - .762m

Output op amp
Pin 1 - 400+ - 400+
Pin 2 - 70.4k - 70.4k
Pin 3 - 582.2k - 580.7k
Pin 4 - 400+ - 400+
Pin 5 - 400+ - 400+
Pin 6 - .844m - .840m
Pin 7 - 70+ - 70+
Pin 8 -.868m - .865m

Input op amp
Pin 1 - 100+ - 100+
Pin 2 - 580k - 578.9k
Pin 3 - 68.3k - 68.3k
Pin 4 - 380+ - 380+
Pin 5 - 0 - 0
Pin 6 - 570+ - 570+
Pin 7 - 140+ - 140+
Pin 8 - 150+ - 150+

On the op amps: When there is a + or - sign in the value it's because the DMM started around that value and would continue to escalate or decline.
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These are the measurements from the input side RCAs.
Right Channel - Left Channel
R1 - 514.2k - 512.8k
R2 - .1 - .1
R3 - 2.766k - 2.758k
R4 - 515.2k - 513.5k
R5 - .879m - .875m
R6 - 2.766k - 2.758k
R7 - 581.6k - 579.7k
R8 - .768m - .765m

Output op amp
Pin 1 - .750+ - .750+
Pin 2 - 2.765k - 2.758k
Pin 3 - 360+ - 360+
Pin 4 - .740+ - .740+
Pin 5 - .770+ - .770+
Pin 6 - .767m - .767m
Pin 7 - 440k - 438.1k
Pin 8 - 1.130- - 1.130-

Input op amp
Pin 1 - 444k - 442.1k
Pin 2 - .1 - .2
Pin 3 - 310+ - 310+
Pin 4 - 570+ - 570+
Pin 5 - 0 - 0
Pin 6 - 563.5k - 563.3k
Pin 7 - 439.7k - 437.5k
Pin 8 - 442.4k - 440.8k
 
The strange thing is that it's almost like both the left and right channels are being output to the right channel. When I disconnect the left input I still get sound in the right speaker as I would expect, but when I remove the right input I still get sound from the right speaker with the left input still connected.

UPDATED

What I stated above changed when I hooked it up to a different receiver. The right speaker only made sound, but it went silent if I disconnected either RCA input. Now I'm really confused.

END OF UPDATE

I don't understand how this is possible. The +\- input wires from the left channel board go to the left input RCA and the +\- output wires from the left channel board go to the left output RCA. This is the same for the right channel with the corresponding right RCAs.

To rule out the Marantz 1060 as a culprit I'm going to hook it up to another receiver's aux inputs. Although a CD player hooked up to the AUX1 plays fine. The TT also plays fine when connected to the built in phonostage.

Could it be a grounding issue??
 
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Are you sure you haven't got one of the RCA connections back to front? That is the negative going to the positive and vice verse? Or the input going to the output even, just trying to rule everything out.
 
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Where is the ground wire from the lug that the TT ground connects to supposed to be connected to in the circuit?

I have mine connected to the ground loop off of the batteries. Is that correct?
 
x2turbo said:
Where is the ground wire from the lug that the TT ground connects to supposed to be connected to in the circuit?

I have mine connected to the ground loop off of the batteries. Is that correct?
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Makes no difference on both of mine. Disconnect the ground wire from the TT and see if it makes a difference you will probably find you don't even need one when using batteries.

Disconnect the LED etc. It's time to start trying things.

It's something really simple like I keep saying that's not right.

Both boards are the same and both have the same components, they both have the same measurements so IMO it has to be in the way it's wired up.

Either something is wired incorrectly, shorting or not connected/connecting properly it has to be one of those but without being there it's hard to diagnose.

Maybe it's a faulty RCA jack?
 
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I, too, have to vote for this, it is simple, but first . . . take a step back. Sit down and listen to a, ugh, CD. Have a cold one. Sleep on it.

At this point you are too close to the problem and you just need to walk away for a little while.

HypnoToad said:
Hmmmmmmmmmmmmmm :scratch2: Everything seems right so it must be something simple.
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You were reading my mind. I took a break last night and will dive back in today. I have a sneaky suspicion it is a bad solder joint on one of the op amp pins. A couple of the are being a real PITA on taking solder. It keeps wicking up the pin on to the solder pen.
 
Is it a problem to isolate one board at a time from the power supply to troubleshoot or do I have to split the batteries too to avoid 18v?
 
Unfortunately I haven't had time to work on it. Hopefully tomorrow I can start strategically taking it apart and find out what's wrong.
 
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