JCM2000 DSL100 popping R9 resistor

[mcblink]

Thank you! It looks like these are exactly the same as the originals. Do these just have a certain life expectancy and you just want to proactively replace them or have these new one's been re-engineered so that once you replace them, you're good for the long term?

I think they're just the same as original, I don't think they've been re-engineered. Just a pro-active measure. I've a sneaky suspicion that this could be possibly why your R9 let the magic smoke out...but I'm not a tech, just a hunch based on my own, unfortunately, numerous experiences with my TSL100....but then I never tried to fire it up without all the connections being connected in the correct locations either

In this picture, this is the new main board...AND the Dr. Tube stable bias mod... and I still had some issues, as we can see here from this R6 that exploded....




The culprit??

Ended up being those stupid bias trim pots. Bought 4 new pots, just so I had a couple extra around. Replaced the old ones with the new ones. No more problems, to my pleasant surprise. Finally.


Make sure all your connections are good to go first though. Lol

 

[Gunner64]

Thank you! It looks like these are exactly the same as the originals. Do these just have a certain life expectancy and you just want to proactively replace them or have these new one's been re-engineered so that once you replace them, you're good for the long term?

The ones I got from them are the identical pots as the originals.

 

[mcblink]

R6 and R9 act as fuses...They're SUPPOSED to blow if something goes wrong to avoid any damage further down the line. I would recommend not replacing those with a higher value, and instead, identify the cause of the problem.

Notice how they're stood up quite a ways off the board....this is to avoid damaging the board/traces if/when they blow...make sure to keep any replacement up and away from the board as well

 

[Leonard Neemoil]

I think they're just the same as original, I don't think they've been re-engineered. Just a pro-active measure. I've a sneaky suspicion that this could be possibly why your R9 let the magic smoke out...but I'm not a tech, just a hunch based on my own, unfortunately, numerous experiences with my TSL100....but then I never tried to fire it up without all the connections being connected in the correct locations either

In this picture, this is the new main board...AND the Dr. Tube stable bias mod... and I still had some issues, as we can see here from this R6 that exploded....

View attachment 120173


The culprit??

Ended up being those stupid bias trim pots. Bought 4 new pots, just so I had a couple extra around. Replaced the old ones with the new ones. No more problems, to my pleasant surprise. Finally.


Make sure all your connections are good to go first though. Lol

I thought there were some that are better than the originals that people recommend. Been a couple of years since I researched it though so I could be wrong.

 

[Gunner64]

R6 and R9 act as fuses...They're SUPPOSED to blow if something goes wrong to avoid any damage further down the line. I would recommend not replacing those with a higher value, and instead, identify the cause of the problem.

Notice how they're stood up quite a ways off the board....this is to avoid damaging the board/traces if/when they blow...make sure to keep any replacement up and away from the board as well

Glad you got that sorted, the very reason When I hear of the dsl bias issue I always say replace the pots first and assess your situation after that. The pots may be the root cause and not the pcb issues..if the pots are toast a new pcb or Dr. Tube kit is worthless.

 

[Gunner64]

I thought there were some that are better than the originals that people recommend. Been a couple of years since I researched it though so I could be wrong.

They were the only ones I found that fit the footprint of the little pcb they mount to.

 

[mcblink]

Glad you got that sorted, the very reason When I hear of the dsl bias issue I always say replace the pots first and assess your situation after that. The pots may be the root cause and not the pcb issues..if the pots are toast a new pcb or Dr. Tube kit is worthless.

I suspect this was probably the issue the entire time, though there's no way for me to prove it lol

That's the story of my life: learn the hard way.

 

[Leonard Neemoil]

I suspect this was probably the issue the entire time, though there's no way for me to prove it lol

That's the story of my life: learn the hard way.

 

[jshort74]

After turning the amp on with no power tubes first with no issue and again with the tubes in and adjusting the bias to 87mV on each side, everything seems to be working well. I ordered a couple new bias pots to put in when they arrive. Thanks for all the help!

 

[Chris-in-LA]

Is this what I should expect the limiter to do with this amp and bulb combination? Is it good to go?

Yes, that sounds about right.