X-101-C in need of help

[MadPik]

Got everything underneath replaced and now just waiting for the can caps to arrive. I gave it a brief test and had some slight buzzing that changed with volume and mostly went away if I touched the chassis. When I accidentally touched the chassis turning the power switch off I got a slight shock. I'm guessing in moving components/wires to get to the capacitors, volume pot, etc. that I crossed something somewhere so I'm going to look everything over when I have the time. The can caps are scheduled to arrive on Thursday so I'm going to wait until they are installed before powering it up again.

On a side-note, Hayseed Hamfest has absolutely phenomenal customer service. My original order showed as shipped but the tracking was stuck in the "USPS awaiting the package" phase for about a week. I emailed Hayseed assuming they had printed the label and were still assembling my order. They were fairly confident my original order had shipped, but since they couldn't confirm they ran another order down there emergency line and shipped them out the same afternoon.

 

[N8Nagel]

I'll second their customer service. Unfortunately it meant that I didn't get my receiver done when I wanted to, but a little while after I ordered I got an email that they'd made my caps and they were all in spec but they didn't like the way one of them tested so they were remaking it.

 

[larryderouin]

BTDT. Tom's good people. When TOM ain't happy, nobody at the plant is happy!

Madpik. As far as the shock is concerned, it's probably the normal slight tingle if the power cord is in one way (neutral is now HOT). Flip the plug over and test again. If less or no tingle, mark the UPSIDE (or conversely if you have an upside down plug, the bottom. Mark it so you can orient it with the marked ide AWAY from the Ground lug. There is no "death cap" in the X-101-C so the hot lead needs to go to the switch.

 

[MadPik]

First the good. Got the new cap cans and got the installed. Woohoo!

Now the bad - I have no right channel output. I visually inspected everywhere I have done work and didn't see anything open and obvious (no crossed terminals, no wires I forgot to reconnect, etc. So far my troubleshooting has covered:

1. Making sure speakers and input were all connected properly. - Yes
2. Making sure the source was putting out both channels. - Yes
3. Swapping RCA inputs so see if there was any change. - Still no right channel
4. Trying the Tuner input instead of the AUX. - Still no right channel
5. Swapping speaker wires right to left. - Still no right channel
6. Swapping all the tubes around (power tubes and preamp, phase, etc.) - Still no right channel
7. The faint buzz I get when the volume is up but there is no input from the source still seems to come from both speakers.

Any ideas on a cause? What are my next steps? Thanks!

 

[larryderouin]

Check the heater voltages on the preamp tubes (v1 thru V6 inclusive). Make sure they are correct.
Wiggle each tube in turn. Probably one of the preamp tubes...V1 thru V6 (all 12ax7's). If you get crackes or pops in the right side, then.......
Clean and retighten all of the tube sockets. Use DeOxit on the tube pins and insert and pull each repeatedly. Go down to lowes and get a set of Welding tip cleaner files. (about $4.00 a set) Run them in and out to clean the environmental crud off the leafs in each pin socket. Then with a jewelers screwdriver carefully push each leaf toward the middle of the pin socket. Test.

The faint buzz may be the lack of bottom cover shielding. Put the cover on and hold it down with one or two screws. See if you get the buzz now.
Report back.

 

[bhamham]

Check the 'U' shaped jacks that go to the in and out for the reverb. Ch B is right; you don't want it pushed in too much. I hope it's as simple as something like that. Good luck!

 

[MadPik]

I think the buzz is the shielding. I do get some sound out of the right channel when the fader is adjusted all the way to the right, but it is very faint and I'm thinking it is probably just the audio from the left channel carrying over.

Check the heater voltages on the preamp tubes (v1 thru V6 inclusive). Make sure they are correct.

What is the correct method/voltages. I see the heater voltage is 12.6 in series or 8.3 parallel. Are those the voltages I am looking for? I measured from the heater sockets (4 and 5) with the other probe grounded to the chassis and got values in the 10 through 40 range. Only one tube was reading in the 10s. The rest were 30-45ish.

 

[MadPik]

Check the 'U' shaped jacks that go to the in and out for the reverb. Ch B is right; you don't want it pushed in too much. I hope it's as simple as something like that. Good luck!

Solved It! While I was waiting for the cap cans to arrive I went through and cleaned all the input/outputs again and had removed the reverb jumpers. I must have pushed one in too far. Backing them out a little solved no right channel problem.

 

[MadPik]

Next question: So both channels are working and both have the same volume output when changing between channels with the balance knob. However, the right channel (if I remember correctly) has much less treble and sounds slightly muffled in comparison. Since you can adjust the bass and treble for each channel independently, increasing the treble for the right channel makes both channels sound alike.

So in theory it’s not a problem but my brain can’t get over the “that’s not how it should be” aspect. Could this be a tube issue? Treble pot? Something else?

Thanks!

 

[N8Nagel]

I had that issue on a Pilot 654, it was the treble pot. Wiggling the shaft for that channel's treble control confirmed it

 

[larryderouin]

Did you De-Oxit the pots and Exercise them 40-50 times lock to lock after spraying? Then back it up with FADERLUBE?

As for the Reverb Jumpers. Take a length of Heatshrink and cut it so it fits around the closed end and just a slight bit on the straights. Heat it up to set it. Now you can push them in without shorting the plug.

 

[MadPik]

Did you De-Oxit the pots and Exercise them 40-50 times lock to lock after spraying? Then back it up with FADERLUBE?

I gave them an initial clean but likely not as thorough as it should have been. I'm going to add an inrush thermistor before I close everything up so I'll give the pots another round of deoxit followed by some faderlube.

As for the Reverb Jumpers. Take a length of Heatshrink and cut it so it fits around the closed end and just a slight bit on the straights. Heat it up to set it. Now you can push them in without shorting the plug.

Brilliant!

 

[MadPik]

Well, everyone... I think I'm done tinkering with the Fisher for the time being. It back in its case and making beautiful music again. Thank you so much for all the help and guidance. Here are some final pics, its currently hooked up to a pair of McIntosh XR-14s. Perhaps my next project will be replacing the electrolytic capacitors in those as I've heard they tend to slowly wear out with age...plus I need another rainy day project.



Thanks again everyone! Ya'll rock! Keep being awesome!