Paragon, 1 Channel no sound..... PLEASE HELP!

[aienco]

Hello, I went through all the other Paragon threads. I wasn't sure whether to post under those threads or start a new one. I chose the later. Anyway, I have been building electronic kits for 40 odd years and I can mostly resolve the issues with basic troubleshooting even though I am far from an expert..

My Paragon build has a strange issue. At first it was all working fine. Then all of the sudden, Channel one decided it would not work anymore )NO SOUND. The probe just yeilds a buzz no matter what component I touch. I have some weird voltages on the ic's. This is where I am stuck. I am not certain where to look to find the cause of these strange voltages.

D7 voltage is 9.14V

IC1 with ic in.. Without Chip in..
1. 8.27 4.3
2. 8.2 0
3. 8.3 0
4. 16.5 8.7
5. 0 0
6. 0 0
7. 0 4.0
8. 0 0

IC2 with Chip... Without Chip
1. 8.25 4.3
2. 8.27 4.2
3. 8.31 4.3
4. 16.5 8.7
5. 0 8.7
6. 7.31 4.0
7. 8.06 0

IC3 with Chip in..... Without Chip
1. 9.13 8.9
2. 5.5 8.5
3. 0 0
4. 3.0 3.9 keeps going down with probe left on pin 4
5. 2.97 0
6. 4.3 0
7. 5.6 0
8. 9.14 8.9

I hope someone can shed some light on this. I have another board and I am about to give up on this one and start with the new one...

Thanks.. Tony.

 

[Mcknib]

They look ok to me

R12 and 13 should divide whatever's coming out at D15 cathode in half, then it goes to all your VREF points

You can ignore IC3 pins 5, 6 and 7 with them being unconnected

I don't know 100% but with C22 inverted pin 4 voltage would be inverted because negative side goes to pin 4? So kinda like putting your meter positive probe on a negative connection

 

[Robert]

Let's ignore the voltages for juuust a moment and focus on this.

The probe just yeilds a buzz no matter what component I touch.

First, I'll assume the probe does give good audio on the side that is working properly?


If so, probe these points (Red, Green, Blue, Orange) for audio and post the results.

 

[aienco]

On the probe DOES give audio on the side that is working. Only on the side that isn't, i get a buzz.. The only place I get audio out of those four is RED. The others are just silent.

 

[Robert]

Your problem is most likely on the footswitch board. (Solder connection or footswitch itself)

 

[aienco]

i have suspect that, but i have resoldered on it 4 times. I might connect a seperate footswitch and see if that fixes it.

 

[music6000]

You shoud only have Continuity as pictured,
You should have No Continuity from Left or Right pins to the middle row!

 

[aienco]

Ok, well I have just jumpered that connection on the switch and I know get audio on all four colours, however still no audio on output?

 

[music6000]

Ok, well I have just jumpered that connection on the switch and I know get audio on all four colours, however still no audio on output?

Check the Footswitch on the side that doesn't work as pictured above for continuity!.

 

[aienco]

Have done that checks ok. BUT I am going to temporarily wire in another switch just in case... I will post back results. Thank you for your patience

 

[aienco]

Ok, may be getting somewhere. THe switch wired in now gives me audio on the output. But I have a new issue?? I think its new. The sound on the other channel, is 10 times louder. NO exageration. Or the channel that is/was faulty is 10 times quieter. Depends how you look at it..

 

[aienco]

I've checked the pot. Thats working fine. I checked the path from the pot to the output and that stays at the volume set. The other channel is the same but much louder.

 

[music6000]

I've checked the pot. Thats working fine. I checked the path from the pot to the output and that stays at the volume set. The other channel is the same but much louder.

I asked about Continuity with the Footswitch's before you changed it out, How is the new one wired different from the Original.
The reason I asked is you have a lot of Solder & Heat on both of the Footswitch pads, hence Solder can bridge underneath to another Pad.
How have you adapted the new Footswitch that appears to be working now.
Pictures of where you are now would help us.

 

[Dan M]

i have resoldered on it 4 times.

I'd be concerned about a solder bridge underneath the board on the footswitch pads. Or a melted switch due to a lot of heat being applied.
I've learned to not completely fill the footswitch connections with solder for both of these reasons.

 

[aienco]

Here is how I have temporary wired it. I hope you can make sense of it. The Right side of this shot, is the one working & Bypass.

 

[music6000]

Pull IC 2 out and check for Continuity between pads 1 & 2, 2 & 3, 3 & 4, 5 & 6, 6 & 7 , 7 & 8.
Compare to IC 1.

 

[aienco]

They're all good. No shorts

 

[music6000]

What happened here :

 

[aienco]

Thats just a black bit of wire. I cut the leg off the pot because it was shorting against the LED Metal socket. So I just replaced it with wire.

 

[aienco]

I have just noticed that with the switches hard wired in now, I no longer get audio out of that side. So pin 2 from the left, RED, no longer gets audio. But i have just mirred the switch so it should work ??

 

[aienco]

Again, though, If i jumper it so that red gets audio. It still has the issue where the other channel is so much louder..