funandfunny20
New member
Thanks Paul. I think I'd rather just get new stuffin' and the board…
Should I just order the S.E.X. C4S upgrade kit?
Should I just order the S.E.X. C4S upgrade kit?
Completed Stereomour—left channel crackles/pops/hisses/distorts [solved]
- Thread starter funandfunny20
- Start date
funandfunny20
New member
Got a new PC board (and parts), soldered, and installed.
The only resistance readings I have that are out of spec are: Terminal 20 is 1.4 instead of 1.2; C3 settles at 395; and terminal 12 settles at 387.
Is this a major problem?
Suggestions?
Thanks in advance!
The only resistance readings I have that are out of spec are: Terminal 20 is 1.4 instead of 1.2; C3 settles at 395; and terminal 12 settles at 387.
Is this a major problem?
Suggestions?
Thanks in advance!
funandfunny20
New member
Did the voltage tests:
Here are the issues. 1) Kreg on the A side is only at .9v. 2) the LED closest to IB/OB is not lighting up. I re-soldered it, but to no avail…still not glowing.
What should I check now?
Here are the issues. 1) Kreg on the A side is only at .9v. 2) the LED closest to IB/OB is not lighting up. I re-soldered it, but to no avail…still not glowing.
What should I check now?
funandfunny20
New member
I again, tried soldering the LED closest to OB/IB, and it worked! Did my voltage tests and everything sounded good..for five minutes before the RIGHT channel made this terrible loud popping/crackling noise.
I turned over the amp and started taking measurements again. After the amped is turned on, all four LEDs glow as they should. After about 10 seconds, I noticed that the LED closest to OB/IB is starts glowing way brighter than the other two on the side closest to the volume knob. And, also, the LED closest to the transformer and on the A side goes completely.
I performed all voltage measurements again this morning and everything is within spec, except for OB is at 374 instead of 165-220.
Both kregs are at 2.5.
Terminal 4 22.;
I turned over the amp and started taking measurements again. After the amped is turned on, all four LEDs glow as they should. After about 10 seconds, I noticed that the LED closest to OB/IB is starts glowing way brighter than the other two on the side closest to the volume knob. And, also, the LED closest to the transformer and on the A side goes completely.
I performed all voltage measurements again this morning and everything is within spec, except for OB is at 374 instead of 165-220.
Both kregs are at 2.5.
Terminal 4 22.;
funandfunny20
New member
Does anybody have any suggestions?
I would triple check the 220 Ohm stoppers, you may have a broken one.
To be safe, you can replace them with easily sources carbon film resistors between 10 and 1000 ohms of whatever wattage you happen to find.
PB
To be safe, you can replace them with easily sources carbon film resistors between 10 and 1000 ohms of whatever wattage you happen to find.
PB
funandfunny20
New member
Hello!
I tested the resistors and both measured 220 and 230 respectively. This leads me to believe that they are no burnt out.
Any other suggestions?
Thanks….sorry for all the bother.
I tested the resistors and both measured 220 and 230 respectively. This leads me to believe that they are no burnt out.
Any other suggestions?
Thanks….sorry for all the bother.
funandfunny20
New member
Just tried another resistance check—terminal 14 reads 0.
Any ideas as to what I should check next?
Any ideas as to what I should check next?
If terminal 14 reads 0 Ohms, then you'll get no left channel.
If terminal 14 reads 0 Ohms, then OA will be 0V.
I would suspect a wiring error at the 9 pin socket, or contact between pin 6 on the 9 pin socket and pin 5, or potentially contact between pins 6 and 7 (less likely).
-PB
If terminal 14 reads 0 Ohms, then OA will be 0V.
I would suspect a wiring error at the 9 pin socket, or contact between pin 6 on the 9 pin socket and pin 5, or potentially contact between pins 6 and 7 (less likely).
-PB
funandfunny20
New member
Okay,
Just got home a measured the amps…there are a couple of odd measurements. The amp's right channel currently crackles/distorts like a bad tube. So, I switched the tubes and the problem still persists on the same side.
Resistance:
T1 *; T2 *; T3 0; T4 248.4; T5 1.406; T6 0; T7 107k; T8 0; T9 97k; T10 0; T11 1.64; T12 248; T13 0; T14 *; T15 *; T16 1.18; T17 *; T18 0; T19 *; T20 1.18; A1 1.19; A2 *; A3 248; A4 1.19; C1 1.4; C2 *; C3 248; C4 1.4
The one's out of spec are C1 AND C4.
Voltage:
HV+ 398;
T1 370; T2 195; T3 0; T4 fluctuates around 0; T5 61; T6 0; T7 0; T8 0; T9 0; T10 0; T11 60; T12 fluctuates around 24.0; T13 0; T14 220; T15 369; T16 60; T17 398; T18 0; T19 398; T20 60; A1 61; A2 368; A3 fluctuates around 30.0; A4 62; C1 61; C2 370; C3 fluctuates around 40.0; C4 61; IA 399; IB 399; OA 199; OB 220; KREGS 2.48; -regs 0.
T1 *; T2 *; T3 0; T4 248.4; T5 1.406; T6 0; T7 107k; T8 0; T9 97k; T10 0; T11 1.64; T12 248; T13 0; T14 *; T15 *; T16 1.18; T17 *; T18 0; T19 *; T20 1.18; A1 1.19; A2 *; A3 248; A4 1.19; C1 1.4; C2 *; C3 248; C4 1.4
What do you guys think?
Just got home a measured the amps…there are a couple of odd measurements. The amp's right channel currently crackles/distorts like a bad tube. So, I switched the tubes and the problem still persists on the same side.
Resistance:
T1 *; T2 *; T3 0; T4 248.4; T5 1.406; T6 0; T7 107k; T8 0; T9 97k; T10 0; T11 1.64; T12 248; T13 0; T14 *; T15 *; T16 1.18; T17 *; T18 0; T19 *; T20 1.18; A1 1.19; A2 *; A3 248; A4 1.19; C1 1.4; C2 *; C3 248; C4 1.4
The one's out of spec are C1 AND C4.
Voltage:
HV+ 398;
T1 370; T2 195; T3 0; T4 fluctuates around 0; T5 61; T6 0; T7 0; T8 0; T9 0; T10 0; T11 60; T12 fluctuates around 24.0; T13 0; T14 220; T15 369; T16 60; T17 398; T18 0; T19 398; T20 60; A1 61; A2 368; A3 fluctuates around 30.0; A4 62; C1 61; C2 370; C3 fluctuates around 40.0; C4 61; IA 399; IB 399; OA 199; OB 220; KREGS 2.48; -regs 0.
T1 *; T2 *; T3 0; T4 248.4; T5 1.406; T6 0; T7 107k; T8 0; T9 97k; T10 0; T11 1.64; T12 248; T13 0; T14 *; T15 *; T16 1.18; T17 *; T18 0; T19 *; T20 1.18; A1 1.19; A2 *; A3 248; A4 1.19; C1 1.4; C2 *; C3 248; C4 1.4
What do you guys think?
funandfunny20
New member
Thanks Doc…it appears the issue is solved—the amp is working!
However, I'm slightly skeptical of my work, so I'll post back later if the amp stays working tonight and tomorrow. Crossing my fingers.
However, I'm slightly skeptical of my work, so I'll post back later if the amp stays working tonight and tomorrow. Crossing my fingers.
funandfunny20
New member
So, I'm still having issues.
About every couple of minutes the amp pops and cracks loudly on the right channel. When you tap the amp, it pops/cracks.
This is definitely a sign of a loose solder joint somewhere, correct?
I've resoldered everything associated with the right's socket. Meaning, A1-4, Terminals 1-5 have all been resoldered. I know it's a definite shot in the dark, but should I resolder any other areas of the amp? I feel like I've thoroughly gone through the C4S board.
Any help would be greatly appreciated.
About every couple of minutes the amp pops and cracks loudly on the right channel. When you tap the amp, it pops/cracks.
This is definitely a sign of a loose solder joint somewhere, correct?
I've resoldered everything associated with the right's socket. Meaning, A1-4, Terminals 1-5 have all been resoldered. I know it's a definite shot in the dark, but should I resolder any other areas of the amp? I feel like I've thoroughly gone through the C4S board.
Any help would be greatly appreciated.
funandfunny20 said:
Yeah, you're spot on!
Run it with a cheap speaker hooked up to it, then start gently poking and prodding with a wooden chopstick to determine where the funky joint is. (It will force a pop when you it it)
Do not hesitate to poke the transistors on the C4S board, one of them may be the culprit as well.
I see Peebs was typing at the same time -
Yeah if you have eliminated a tube as the cause it's most likely that there is a connection that is getting flaky as the amp warms up. That would have me looking for two wires that might be a little too close together and making contact when they expand as they get warm, or a wire soldered thru a terminal that might not have a really smooth fillet of solder between the wire and the terminal. Sometimes a joint that looks like that actually has a layer of flux inside the joint that is breaking the continuity.
Just as a general example a very nice customer came by this week with a very nicely built Crack. All voltages were good and LEDs lit, but he was only getting sound from one channel. It turned out that tucked under one of the Speedball boards there was a wire with the insulation pulled back a little more than average, and it was just barely brushing the terminal next to the one it was soldered to. It took me a couple of tries to find it by poking around with an unsharpened pencil. When I touch the wire or the things connected to it it made some gnarly crackles (which is why we troubleshoot with $20 headphones!). I reshaped it a bit to make sure it wouldn't touch anymore and we had two channels playing.
Yeah if you have eliminated a tube as the cause it's most likely that there is a connection that is getting flaky as the amp warms up. That would have me looking for two wires that might be a little too close together and making contact when they expand as they get warm, or a wire soldered thru a terminal that might not have a really smooth fillet of solder between the wire and the terminal. Sometimes a joint that looks like that actually has a layer of flux inside the joint that is breaking the continuity.
Just as a general example a very nice customer came by this week with a very nicely built Crack. All voltages were good and LEDs lit, but he was only getting sound from one channel. It turned out that tucked under one of the Speedball boards there was a wire with the insulation pulled back a little more than average, and it was just barely brushing the terminal next to the one it was soldered to. It took me a couple of tries to find it by poking around with an unsharpened pencil. When I touch the wire or the things connected to it it made some gnarly crackles (which is why we troubleshoot with $20 headphones!). I reshaped it a bit to make sure it wouldn't touch anymore and we had two channels playing.
