My wife asks me why I haven't bought a guitar in over a year. I think she has some shoes she's longing for...Anyone ever wonder if our spouses have accounts on this forum? Just for "lurking" purposes.
Two Channel H issues.....and a proper solution
- Thread starter BMiller
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I’m trying to convince mine that the guitar case is the new purse.
Oh yes. The fuse blows with no tubes installed. It's pointing me toward the power filtering section or the power transformer. I still haven't had a chance to dig in deeper.
Bluesverb
Currently in a long term relationship with myself!
Than I would say the power section is a good point to start with.
I would look for loose wires or pieces of solder that have shorted out across connections, to include the fuse holders and the amp's light.
I would then look for obvious "burnt" or shorted parts on the circuit boards, namely where the power transformer connects.
I would "lift" the wires coming out of the power transformer.
Does the amp's light come on at all?
Those are great troubleshooting tips for any amp issue.
It's funny that you mention the light. It's an incandescent bulb. When I purchased the amp (used) the bulb was DOA. That didn't bother me as it gets it power off of the heater circuit (well, at least in the M and F amps I've worked on). I ended up replacing the bulb and it worked.....for awhile. But even after it failed, the amp continued to work as normal. Hmmmmm......thought provoking.
So the fuse blows whenever the amp is switched from Standby to On (even with no tubes in). The issue occurred when I was practicing. I was playing and took a break for whatever reason. I didn't put the amp on standby, just turned the guitar volume down, hung it up, and walked away for a bit. Came back and the amp was dead (blown fuse). I think that it is a bad rectifier diode that is taking it down.....but not sure yet.
I wish that I had more time to spend at my bench!
I had that happen with a bad rectifier tube in my Lone Star. Kept blowing fuses, and I didn’t know why, since the tube looked to be good. I replaced the tube, and never a problem since (Oh yeah, I nearly forgot; since I know next to nothing about fixing amps, I do a Lucky Voodoo Dance when I switch the amp on or off, just in case).
“Tell us about the Lucky Voodoo Dance, Les.”
“OK, well, to do this you need a djembe drum, a rubber raincoat, and a Native American shaker.”
“What do you need the raincoat for?”
“Sometimes I screw up the dance and it rains.”
“Tell us about the Lucky Voodoo Dance, Les.”
“OK, well, to do this you need a djembe drum, a rubber raincoat, and a Native American shaker.”
“What do you need the raincoat for?”
“Sometimes I screw up the dance and it rains.”
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Just one case for why one shouldn’t put off colonoscopies
Sorry, I can’t seem to resist mixing juvenile “humor” with public service messages
Bluesverb
Currently in a long term relationship with myself!
Diodes was going to be one of my recommendations, however, anything can cause a short. It just so happens that I would recommend lifting the legs of the power transformer and see if you can narrow it down to a specific circuit, like the DC conversion/bias circuit. Kind of difficult to do with no schematic.
BTW-- their amps have had issues of all sorts. I kind of lost interest in turning mine on. I have a special 100 watt high gain run of the H amp, one of the original C amps, and an HX/DA with a tube effects loop.
Believe it or not, I am way deep into the 5150III 50 watters. That said, they have the thinnest circuit boards I have ever seen in an amp. But, I have had no issues with them at all.
BTW-- their amps have had issues of all sorts. I kind of lost interest in turning mine on. I have a special 100 watt high gain run of the H amp, one of the original C amps, and an HX/DA with a tube effects loop.
Believe it or not, I am way deep into the 5150III 50 watters. That said, they have the thinnest circuit boards I have ever seen in an amp. But, I have had no issues with them at all.
D
Deleted member 5962
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That would be my first guess.
Very good points and yes, lifting the legs of the PT is my next step and seeing if I can trace the circuits. This was the reason behind buying a working amp.....well, besides the fact that I like the sound of the amp.
You know, those 50W 5150IIIs look interesting. I've heard great sounds out of the first generation (P built) and wouldn't mind owning one. But I'm currently in the dog house over this latest purchase soooo......
D
Deleted member 5962
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I was on a 5150 mission until I got the Archon. That said, the 5150 is my favorite model in the AmpliFire. It sounds great and it definitely RIPS!
My 2-Channel H issue is that I downsized my digs a couple of years ago, so I am short on space. I am reticent to part with the amp because I developed the Em7 Battery-less LED Footswitch Mod using it. To the best of my knowledge, it is the only 2-Channel H that has a Footswitch with LEDs that does not require a battery, that is, unless someone else implemented the mod that I originally posted here in 2012.
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dmatthews
Dave's not here
Awesome. I made my pedal but with a battery because I didn't want to do the surgery, but kudos on the innovation!
The circuit requires moving the relay supply V- on the ground connection of the jack to the MOSFET source connections on the board. The V- relay connections on the tip and ring terminals on the jack are wired to their respective MOSFET drain connections. The gate connections on the MOSFETs replace the V- relay connections on the tip and ring. The relay supply is tapped and wired to the ground connection on the jack. You can either build a footswitch from scratch like I did for my amp, or you can rewire an off-the-shelf pedal. The mod takes advantage of the fact the relay V+ voltage is high enough to withstand an LED forward voltage drop and still have enough voltage left over to turn a logic-level N-Channel MOSFET completely on. Any logic-level N-Channel MOSFET with a low Rds(on) will work in the circuit (a 2N7000 should work, but the leads are in a different order than the power MOSFET that I used).
http://forums.prsguitars.com/thread...itch-mod-for-pre-custom-2-channel-amps.23835/
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