Completed sex kit: No sound from right channel

Apologies for my confusion - too many kits and versions, so I mis-remember the values.

There is a 220 ohm grid stopper at pin 4 on the circuit, which has (I think) been replaced with the 237 since we have a large number of them on hand for many kits.

There is a 150K 2-watt resistor on pin 5; it's larger than the others.

There is a 1270 on pin 6.

The C4S kit has 499 ohm resistors and 150K 2-watt resistors - yes, a second set of the latter - it's easier than trying to re-use the old ones!
 
Ok, so I got replacement resistors coming in the mail. That being said, is it possible that once the out of spec voltages are corrected that my issue of no second channel and scratchy left channel will be resolved?
 
So far we have addressed one channel's driver, pins B4-5-6. There are probably similar problems with A4-5-6 - at least the wrong 1270 ohm resistor. I can't figure out why the plate voltage A6 is correct but the cathode A5 is not, so check and fix all those resistors and we'll see what problems remain.
 
Ok. Corrected placement of 1.27 resistors and installed 249ohm resistors. Went back through resistances and voltages out of spec and everything now within range. Left channel seems to be working properly. Output is clear and strong.

However, still no sound from right channel. Checked wiring at output transformers. Resoldered some connections at transformers and headphone jack but still nothing. Removed left channel from operation and turned volume all the way up and right channel has very dim, scratchy sound. Any guidance would be greatly appreciated.

Michael
 
If the voltages on the tube pins are within the normal range, then the tubes are working correctly and the problem is at either the input or the output.

With gain all the way down, listen very closely (headphones are easier to hear with if you have some; otherwise put your ear right at the speaker, in a quiet room if necessary). If both channels produce the same tiny level of hiss and hum, then the problem is probably at the input or gain control. If you can hear some left channel but the right is completely silent, then it is at the output or the output transformers.
 
Check your input jacks for a solder bridge from the center post to the outer shell.
 
Yahooooooooooooo!!!!!! That did the trick!!!!!! I sured up the jacks with additional solder.  Thank you so much for all your assistance and patience!!!
 
Ok, so after installing the C4S upgrade I have noticed that I am having the same problem again with the right channel...the sound output issue.  Since I thought I rectified it last, I have not messed with the RCA connections but in completing the upgrade I disconnected the RCA cables and obviously reinstalled thereafter.  I do get sound, but if I touch the cord connected to the jack, sound will drop and I have to manipulate the cord inserted into the right channel to obtain sound again.  My wife's response to this is the obvious....leave it alone and stop messing with it.  I had thought I rectified the issue by touching up the solder joint but apparently that did not completely cure the problem.  Should I be troubleshooting elsewhere?
 
mpent said:
Should I be troubleshooting elsewhere?
Click to expand...

Nope, just confirm that the cable isn't the issue (switch channels at the SEX amp), then perhaps consider replacing the jack or checking for metal burrs that are making your short.

-PB
 
Argh! It appears that I have a faulty jack. After resoldering the connection 2x and rewiring the jack after that didn't work, I inspected the jack comparing it to the other and I'm guessing that it is defective in that the base of the jack where the center pin protrudes...there is no seal around the pin. The working jack has a small white ring which what I think to be the defective jack is missing. Also, peering inside the connection port to where the RCA cable connects, doesn't look the same...looks perhaps corroded if that's possible. It also grabs the cable pretty tight whereas the working jack has a smooth insertion and release.

Michael
 
So I got the replacement RCA jack today. Was sure this would be the fix but unfortunately it was not. Replaced jack and still no sound from right channel. I then replaced the whole wiring scheme from right input jack to volume pot and still...nothing.

Went through voltages and some values have changed. Those that are off are:

B1- 135.5
A5- upper terminal reads 2.117 while lower terminal reads 77.1

I am at a loss at this point. Having the same overall issue as before. Right channel, with volume all the way up, sound output is barely existent and scratchy. Can anyone help?
 
If B1 is 135.5, then 19 should also be 135.5.

If 19 is not 135.5, but 0 instead, pull the 220 Ohm carbon comp from 19 to B1 and replace it with a piece of wire.

-PB
 
There is only one B5 terminal. I guess you mean the upper and lower holes in the terminal? If they read different voltages, then something is not connected - i.e. not soldered well. Since the plate load resistor is soldered first, it's probably in the lower hole, and it reads 77 volts, within spec - it's probably OK. However, the coupling cap between stages (0.1uF) apparently reads near zero, indicating that it is not soldered well to the terminal. That would mean that it cannot carry signal to the second, power stage - hence low volume, no bass, and likely an intermittent (scratchy) contact.

If the terminal seems to have too much solder on it, remove the solder (either the wire braid stuff or a solder-sucker) and start over with clean parts. But if it looks short on solder, you can just make sure the wire AND the terminal are both hot enough to melt solder before removing the iron, by touching the solder to the terminal and again to the wire, melting a bit each time. The solder bits should then flow together and you'll have a nice joint.

Of course I may have mis-interpreted the post - words are a poor substitute for actually seeing the thing!
 
Ok, I just switched unit back on to double check voltage. B1 was 135 and 19 was 150, then the 220ohm carbon comp connecting the terminals sizzled and fell apart.

Paul, I was referring to terminal A5 with the reading 2.117. B5 reading was 64.

As such, I am assuming I need to replace the 220ohm resistor and troubleshoot terminal A5 as per Paul's instructions.

Can anyone speculate how/why this is happening? I know this is a long thread but I am not understanding how I went from all voltages within spec with a proper functioning unit to this? The lingering issue has been the sound output from right channel so I guess the unit has not really been properly functioning per say. Paul, PB...can you please read through this thread and perhaps clue me in????
 
The 220 Ohm carbon composition resistors are a little delicate.  Replace the sizzled one with a piece of wire and let us know if that solves your problems.

-PB
 
I replaced the 220 ohm resistor throughout.  At B1 and 19 I got readings in the 60s before it blew again. Replaced with piece of wire and getting about the same readings.
 
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