Trouble In Paradise

[ronstephens]

I sold my Randall RM4 rig and bought a Renegade 112 combo (a return/refurb from GC, so no warranty) less than a year ago. It arrived in pristine condition and sounded spectacular. But then... between sets 1 & 2 on the very first gig it went dead. Local repair guy replaced a fried resistor in the power supply. Ok - stuff happens. (cost: $50.00)

Then, a few weeks ago, I fired it up in the studio and the output was barely audible. After a few minutes is came on, but switching channels caused it to go quiet again - and switching back didn't help. Local repair guy suspected plate voltage wasn't coming on - as if the Standby switch was still on. Of course it worked great in the shop, so he touched up a few suspect solder joints and let it run overnight. It still worked perfectly in the morning so I picked it up and used it w/o problem that night. (cost: 65.00)

This morning I'm back in the studio and guess what. It's out again as described in the preceding paragraph. I'll take it back to the shop tomorrow. (estimated cost: $50+)

Egnater repair was sympathetic, but nothing they could do w/o warranty. So, just under $1000 to purchase, another $165 in repairs. My confidence is shaken. Blame Chinese manufacturing? OK. But I'm really feeling like I got stuck with a lemon.

Besides whining, I'm hoping someone here might have an idea where, exactly, this problem might be? How do standby, channel switching, and plate voltage interact?

Thanks,

 

[shimmilou]

Hi ronstephens,

It is possible that you could have a tube problem. Do you have spares that you could try?

 

[ronstephens]

Hi ronstephens,

It is possible that you could have a tube problem. Do you have spares that you could try?

I have a few 12AX7s. Where would I begin?

 

[shimmilou]

Since the problem seems to be common to both channels, V1, V5 and V6 are all common to both channels, take your pick, I would start with V6 which is the PI, then V5 which is for the loop and feeds the PI, then V1 which is the input and first gain stage for each channel. Just a possibility, but at least it's a start and something that is easy enough to try as these three tubes are used for both channels, while V2 is exclusive to channel 1, V3 and V4 are exclusive to channel 2.

The standby switch just turns on the high voltage (DC Plate voltage) to the tubes before playing, and while in standby turns off the high voltage to the tubes and only the heater voltage (orange glow) remains to the tubes to keep them warm and ready. When channel switching, the different tubes and different circuit arrangement (pots, caps, etc) for each particular channel are selected for use in that channel. Note the different knobs used with each channel.

 

[ronstephens]

Thanks for the suggestions. I'll start swapping tubes.

 

[bruce egnater]

I would be a little suspect of the shop that keeps attempting to repair it but it keeps coming back.....and they charge you each time? I am suspicious of the accuracy of the first repair where "a resistor fried"? Resistors typically don't just "fry" for no reason. Simply replacing the resistor without attempting to find the cause would not really be completing the repair. Then another issue occurs but they couldn't verify it so they touched up a few solder joints (code for we don't know what's wrong but need to spend some time to charge you for) .....and other $65?? Now the same problem occurs that they couldn't verify last time and you will pay them again $50-65?? I would be pissed, too. Try the tube swaps that shimmilou suggests and report back. I'm not saying your repair shop is being dishonest but I don't think they are properly handling both the amp problems and you as a customer. Feel free to contact me directly at begnater@aol.com if you wish.

 

[ronstephens]

I would be a little suspect of the shop that keeps attempting to repair it but it keeps coming back.....and they charge you each time? I am suspicious of the accuracy of the first repair where "a resistor fried"? Resistors typically don't just "fry" for no reason. Simply replacing the resistor without attempting to find the cause would not really be completing the repair. Then another issue occurs but they couldn't verify it so they touched up a few solder joints (code for we don't know what's wrong but need to spend some time to charge you for) .....and other $65?? Now the same problem occurs that they couldn't verify last time and you will pay them again $50-65?? I would be pissed, too. Try the tube swaps that shimmilou suggests and report back. I'm not saying your repair shop is being dishonest but I don't think they are properly handling both the amp problems and you as a customer. Feel free to contact me directly at begnater@aol.com if you wish.

Thanks Bruce! Post tube swap - I replaced all the 12AX7s - so far so good.