Egnater tourmaster 4212 low output on channel 1

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acsheetmetalco

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Low output on channel one clean/overdrive. Channel 2 clean/overdrive is normal. Any ideas?
 
Do you own a Tourmaster and a Renegade?

Or are you asking for someone else?

Have you swapped the power tubes yet? Or V2?
 
Correction. Overdrive 1 channel is the only channel with low output and when I turn gain all the way up, it completely cuts volume off.
 
Yes, changed out all tubes, no change. I'm thinking maybe it's the gain pot. When I turned it all the way up, there is no output at all. Also, I'm reading that vintage/modern switch is on backwards. Wonder if this has any effect at all on low output on overdrive 1 channel?
 
Bad pot solder joints are likely, and not uncommon on the Tourmaster. It would seem that when the pots were soldered in, they depended on the pot brackets for proper alignment, and did not use an actual jig. Once the pots are tightened in place, any misalignment becomes stress on the solder joint. I've seen this before on the Tourmaster, and the only cure is to reflow all the pot joints, but in place. Not an easy task. Pot failure is not unheard of either, which means the pot must be replaced.

I have found "Classic/Modern" toggles installed upside down as well. Nothing new there. According to the schematic, "Modern" is when contacts are the toggle are closed. Easier way to tell is that "Classic" sounds a tad louder than "Modern". I think the toggles are indexed to keep them from turning in the hole, so I just unsoldered the wire on the end lug, and soldered it to the opposite lug (leave wire on the middle lug alone).

Another problem is loss of the reverb, which often times is due to defective H11F1 optoisolator used for the switching. This opto is used for channel muting as well.

Also, sporadic fuse blowing, with no apparent tube issues. Generally due to the thermistor (SL22 14007) not doing an adequate job of controlling current inrush when turning on the unit. I've added a second one, directly at the power switch. Also due to the totally cheap ass junk Chinese caps used in the power section (see also - all pots). Generally, the best fix for this is a complete recap of the power card.

I've covered all these issues here;
viewtopic.php?f=26&t=199046#p2214594
 
this guy above can help

i stil need to go over my TMcombo like above

first things first, channel four quit working.. tried ALL new SET of tubes..something wonk inside

shame, as i have said, i LOVED the sound of this amp and would REALLY l ike for it to be working right.
 
Yeah, they're a great amp... when they're working. When not, they're a giant PITA to troubleshoot and fix. Mine is a first generation unit as well. It needed a new power transformer to start with, and I had to put countless hours of work (and money) into it to get to a state where I was happy with it. By "happy" I mean it'll light up and work reliably every time I throw the switch on it. It's been my primary go-to amp for about 5 years now.

It's one of those amps that makes for a great studio amp. Put it in a corner, play the crap out of it, make sure that it doesn't get moved around, and it won't disappoint. Personally, I would never gig with it. They're just too flaky and fragile to be carting around.

Ultimately, the design philosophy behind the amp was sound, but the engineering execution was nothing short of suspect at best.
 
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