So the simulation.may have been correct after all 🤣.
I was so confused why i was getting 50v at the 12v point. (*&^# stupid software doesnt work blah blah) 🤣
I was so confused why i was getting 50v at the 12v point. (*&^# stupid software doesnt work blah blah) 🤣
It was correct for sure. That circuit needs load.
If you would simulate negative side. The one with 2955 transistor there is no parallel resistor and that one would work as expected.
If you would simulate negative side. The one with 2955 transistor there is no parallel resistor and that one would work as expected.
Hey Changedsoul,
new video from XrayTony is out. I have not watched it yet but still there might be something interesting there for you.
new video from XrayTony is out. I have not watched it yet but still there might be something interesting there for you.
Thanks for that!
His was pulling 13.5watts at idle. Mine is 35. Still need to track down the drain on it.
Glad you posted that though because now i have a known good value of what to expect.
His was pulling 13.5watts at idle. Mine is 35. Still need to track down the drain on it.
Glad you posted that though because now i have a known good value of what to expect.
It is pulling very little power at the beginning because idle was super low from the start. Later he adjusts it a little bit higher. Check idle. Might be yours is too high.
Cheers
Cheers
Mine is defdintly to high.
Ive been playing with ltspice trying to draw up section and see what simulation says compared to actual measurements.
I feel so out of my depth lol. Nothing is lineing up with realality.
Ive been playing with ltspice trying to draw up section and see what simulation says compared to actual measurements.
I feel so out of my depth lol. Nothing is lineing up with realality.
Have you tried to adjust it lower? Is it adjusting? Are both channels behaving the same?
If you can't adjust it you have still maybe some component blown.
Right now I can't suggest anything because I'm at the work in the middle of the gig and I have no schematic on hand.
We can discuss it later or tomorrow.
If you can't adjust it you have still maybe some component blown.
Right now I can't suggest anything because I'm at the work in the middle of the gig and I have no schematic on hand.
We can discuss it later or tomorrow.
The high voltage.pot has been been adjusted for around 118v and both channels are biased acording to service manual.
I had a few fried components thatvhave been replaced.
Both channels seems to behave the same so I suspect the power supply board.
I really have no clue what it could be.
Ill justbkeep poking at it until somwthing stands out i guess.
I had a few fried components thatvhave been replaced.
Both channels seems to behave the same so I suspect the power supply board.
I really have no clue what it could be.
Ill justbkeep poking at it until somwthing stands out i guess.
Mains is normal,
Its pilling 1.3 amps. Service manual says less than a half an amp. So nothing serious, but not correct.
Its pilling 1.3 amps. Service manual says less than a half an amp. So nothing serious, but not correct.
Huh...that's a lot really.
Is it like that plugged directly to the mains or going through variac?
Is the amp original or it was bought from some other country. 50/60hz difference could do such things.
Is it like that plugged directly to the mains or going through variac?
Is the amp original or it was bought from some other country. 50/60hz difference could do such things.
Far as i know its original. Its been dead for a good 15 years until i got it from my brother and tried to repair it.
It is going through a variac, but direct plugged in gives sames results.
It is going through a variac, but direct plugged in gives sames results.
Let me do some loud thinking.
1.3A if you are in 120V world is like over 150W. Let's say 1A is roughly what is that "good measure" above what would be normal. Speaking roughly. That would be still over 100W of powerndraw which would show as heat. 100W is a lot of the heat. Even if trafo would be absorbing that it would get quite hot relatively fast.
I Think you would notice heat building up somewhere. It leads me to think maybe you have a problem with your meter. Maybe it can't digest triac chopping the phase. Maybe is only detecting really short peaks. Have you tried different meter? Old lazy moving coil one would be my first choice.
The amp at idle will run almost totally cold. If there is 100W of heat really being dissipated somewhere again I really think you would notice it.
1.3A if you are in 120V world is like over 150W. Let's say 1A is roughly what is that "good measure" above what would be normal. Speaking roughly. That would be still over 100W of powerndraw which would show as heat. 100W is a lot of the heat. Even if trafo would be absorbing that it would get quite hot relatively fast.
I Think you would notice heat building up somewhere. It leads me to think maybe you have a problem with your meter. Maybe it can't digest triac chopping the phase. Maybe is only detecting really short peaks. Have you tried different meter? Old lazy moving coil one would be my first choice.
The amp at idle will run almost totally cold. If there is 100W of heat really being dissipated somewhere again I really think you would notice it.
So i have another amp and assumed it was working fine.
I did what should not have been done and pulled the triac board and mag coil out and used them as a donor.
Using the donor parts i was still pulling 1.3 amps.
I used a killawatt meter that was plugged into, and i desoldered one of the mains and put it inline with my dmm (eevblog 121GW), they both show the same.
So i dont feel its the mag coil or the variac board unless the other amp was bad too(i never actually checked it 🤦♂️).
Basic testing and thermal cam shows both channels seem to be acting the same.
Nothing is getting very hot except the 2w resistors on the 12v supply.
Letting it sit idle for a while, everything is still cold.
Im waiting onna signal gernerator for testing the amp further, and also yesting the capacitors.
Im hoping i find some large caps thst are showing a large esr, but still nothing is getting warm so i really have no clue what could still be wrong.
I might plug it in and see how it sounds and just ignore the extra current draw lol.
I did what should not have been done and pulled the triac board and mag coil out and used them as a donor.
Using the donor parts i was still pulling 1.3 amps.
I used a killawatt meter that was plugged into, and i desoldered one of the mains and put it inline with my dmm (eevblog 121GW), they both show the same.
So i dont feel its the mag coil or the variac board unless the other amp was bad too(i never actually checked it 🤦♂️).
Basic testing and thermal cam shows both channels seem to be acting the same.
Nothing is getting very hot except the 2w resistors on the 12v supply.
Letting it sit idle for a while, everything is still cold.
Im waiting onna signal gernerator for testing the amp further, and also yesting the capacitors.
Im hoping i find some large caps thst are showing a large esr, but still nothing is getting warm so i really have no clue what could still be wrong.
I might plug it in and see how it sounds and just ignore the extra current draw lol.
I'll think about it. I'm finishing the gig now. I need to close down the club and drive to my "summer house". I'll be back in some 3 hours and if I think of something constructive I'll respond.
I would appreciate it.
If all the caps check out, im not not sure what to think.
The service manual maybe is wrong? Or perhapsnwas written after the design was changed a bit?
Looking over the schematic, the two amps i have seem to differ slightly from all variants of the schematics.
Its possible they have been tampered with before i got them.
If all the caps check out, im not not sure what to think.
The service manual maybe is wrong? Or perhapsnwas written after the design was changed a bit?
Looking over the schematic, the two amps i have seem to differ slightly from all variants of the schematics.
Its possible they have been tampered with before i got them.