Here is the documentation that I have from Kk the boards. Does that helps with our troubleshooting?
well, yes and no. the schematic isn't labeled.
so if someone asks for Vdrop on r5...sure its a 221 but is it the 1 we are looking for on the schematic?
dose anyone know if they are labled the same as papas? dosent look like it.
you guys might have to do some tracing out on the pcbs. i can circul the ones i want..🙁
Yeah, I see what you mean. I started doing that, labeling on the actual schematic with the resistors listed on the PCB.
Sure, but I don't have it with me. i'm on the road at the moment.. I will do it probably on Saturday, that will be my first opportunity.
I'm glad you asked me to unhook my big mosfets (244's). I used double sided heat conducting tape to fix them to the heatsink, so if I need to replace any of those it will be a tough thing to do.. that double sided tape sticks very well.. I'm a rookie, I should have anticipated I would fry up a couple components in the process.... I was soooo careful though, so I'm bummed it's not working perfectly...
I'm glad you asked me to unhook my big mosfets (244's). I used double sided heat conducting tape to fix them to the heatsink, so if I need to replace any of those it will be a tough thing to do.. that double sided tape sticks very well.. I'm a rookie, I should have anticipated I would fry up a couple components in the process.... I was soooo careful though, so I'm bummed it's not working perfectly...
That's fine.
Why be bummed? We are learning what the diffrent parts do sepratly and then putting it all together to get the whole picture.
Any ol'joe can put something together. But it takes more to know what its doing and why.
Nelsons best gift to diyers IMO.... Knowlage.
Why be bummed? We are learning what the diffrent parts do sepratly and then putting it all together to get the whole picture.
Any ol'joe can put something together. But it takes more to know what its doing and why.
Nelsons best gift to diyers IMO.... Knowlage.
I got the variac! This saturday I'll jump right on it. I started with the mapping of the R-numbers to the schematic. I haven't gotten very far, but wanted to make sure this is what you were looking for..
Wow, nuts. I realized i have my mpsa18s installed backwards.. thanks to karajaks photo. Good news, im glad i found one mistake. More good news is that they are at the edge of the board.. now i need to figure out how to de-solder.
The variac is very nice, seems pretty solid.
The variac is very nice, seems pretty solid.
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Do you have solder wick or a solder sucker?
If not be careful unsoldering, dosent take real long to kill a transistor that small.
That might be your trouble. Do you have a spare?
If not be careful unsoldering, dosent take real long to kill a transistor that small.
That might be your trouble. Do you have a spare?
Ok, i couldn't wait.. i corrected the issue with the mpas, where the flat side is facing outward...
I get a different result now... i used the variac to slowly bring it up to full voltage. The great news is that power consumption is ~300 watt. 🙂) i measured a DC voltage of 15mv between speaker terminals... some concerning observations: the IRFs got very hot, the 244s did not seem to get all that hot from feeling the heatsink just below the 244s. The big resistors got warm, so did the mur diodes.
I'm pretty excited, because i got a different, and better result! However, what should i do next? Im still concerned i may not be out of the woods yet, but awesome progress so far already... 🙂 🙄
I get a different result now... i used the variac to slowly bring it up to full voltage. The great news is that power consumption is ~300 watt. 🙂) i measured a DC voltage of 15mv between speaker terminals... some concerning observations: the IRFs got very hot, the 244s did not seem to get all that hot from feeling the heatsink just below the 244s. The big resistors got warm, so did the mur diodes.
I'm pretty excited, because i got a different, and better result! However, what should i do next? Im still concerned i may not be out of the woods yet, but awesome progress so far already... 🙂 🙄
Con gradS!
15 mv is good.
Messure the 18's E to C should have 4-5 v
Then the 221 ohm resistor that feeds the CCS 9610. 4ish volts there.if all is well
keep the amp meter on it. Let it cook for awhle monitoring the meter. All gose well there... Test it! I would say use test speakers.
Then rock out knowing your hooked on diy plan your next project.
15 mv is good.
Messure the 18's E to C should have 4-5 v
Then the 221 ohm resistor that feeds the CCS 9610. 4ish volts there.if all is well
keep the amp meter on it. Let it cook for awhle monitoring the meter. All gose well there... Test it! I would say use test speakers.
Then rock out knowing your hooked on diy plan your next project.
9610 are going to get hot, one so much so it hurts.
Big fets are hot... But has to warm up the sink. In a hour or 2 if all is well the whole block wil be a space heater.
Forgot.... Check for .5Vdc-ish across the source res.
Before you get to testing. And just so we make sure might not be a bad idea to check for voltage on the input. So you don't fry a preamp.
Big fets are hot... But has to warm up the sink. In a hour or 2 if all is well the whole block wil be a space heater.
Forgot.... Check for .5Vdc-ish across the source res.
Before you get to testing. And just so we make sure might not be a bad idea to check for voltage on the input. So you don't fry a preamp.
This is a thrill! I have had it on for about 15 minutes, overall draw is around 300 watt.
I put a small sink on the irf who is on the lop left of the schematic.
I measured voltage across the rails is at 79.1V
Source resistors are at .55v
Input voltage is zero
E to C on the mpsa18s is 4.6V
The 221 ohm resistor feeding the irf, is that the resistor connected to gate or source? I think the CCS irf is the one on the top left of the schematic (its gate goes to the source of the other two irfs), the other irfs are linked with their sources.
Ha ha, listen to me, i almost sound like an expert. 🙂 :-D. 😛
I was very surprised that the rectifier MURs are getting very hot. The schematic didnt call for a sink, but i mounted them on angle aluminum anyway and it is heating up well, maybe they need a bigger piece.
I'm going to make a sink to couple the two irfs and another for the CCS irf.
Wow, its a good day if you ask me.... you guys pulled me through it...
Im going to compare my board to what karajak posted to see if i can spot anything different....
Thanks again!
I put a small sink on the irf who is on the lop left of the schematic.
I measured voltage across the rails is at 79.1V
Source resistors are at .55v
Input voltage is zero
E to C on the mpsa18s is 4.6V
The 221 ohm resistor feeding the irf, is that the resistor connected to gate or source? I think the CCS irf is the one on the top left of the schematic (its gate goes to the source of the other two irfs), the other irfs are linked with their sources.
Ha ha, listen to me, i almost sound like an expert. 🙂 :-D. 😛
I was very surprised that the rectifier MURs are getting very hot. The schematic didnt call for a sink, but i mounted them on angle aluminum anyway and it is heating up well, maybe they need a bigger piece.
I'm going to make a sink to couple the two irfs and another for the CCS irf.
Wow, its a good day if you ask me.... you guys pulled me through it...
Im going to compare my board to what karajak posted to see if i can spot anything different....
Thanks again!
hello 🙂 good to hear 🙂 its a wonderfull amp 🙂
i guess your rail voltage is rail to rail? so +/- 40V about.
so a 2x35V transformer? 🙂
i guess your rail voltage is rail to rail? so +/- 40V about.
so a 2x35V transformer? 🙂
Yes CCS is top left of scematic. 221 on the source. The gate goes to another 221 and a zeener diode, and resistor I think. I'm moble right now can't look.
However check the rails Ground to + and Ground to- and make sure they are same-ish.
However check the rails Ground to + and Ground to- and make sure they are same-ish.
That is correct, and i had the variac to 100v
I have the antek 35v toroid / 1000va, they are huge... 😀
If i bring the variac to 110v. The rails are exactly 44V each... how fun is that!!
Wow, this is fun.. i need to tidy up the pieces before i can actually listen to it... I'm tempted to listen to it on the bench.... 😛
I have the antek 35v toroid / 1000va, they are huge... 😀
If i bring the variac to 110v. The rails are exactly 44V each... how fun is that!!
Wow, this is fun.. i need to tidy up the pieces before i can actually listen to it... I'm tempted to listen to it on the bench.... 😛
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