I have not got mine to work 100procent, mainly is the lower part of board that gets fed to much voltage,q8 got 9v on C while almost 0 at base etc. Damn wish there was a schematic. Cant figure out what is wrong, all is like schematic:/
Hmm, maybe it is that iam using a polarized 0.1uf cap with positive facing upwards at blend 1 section that makes it weird. If it is supposed to travel back there from 2.2m resistor at base etc. Will try that.
iam not done errow searching, but according to schematic there is a value wrong at the si Filter, just above q8 there is a 100K resistor that according to schematic should be 10k Before heading to the 22k resistor and also the 1n8.
In schematic its R10 dont take my word for it yet tho.
Also 10K resistor that goes from trimmer doesnt make sense for me, it goes from trimmer up to AC176 C, according to schematic it is supposed to be between 9v and 3 - 2 of trimmer Before trimmer heading up with a jumper or something to C of AC176, but maybe something i dont understand there.
When you wake up can you check my last reply and see if i missunderstood or if it is something wrong, because now top pin is straight in 9v line - when according to schematic it should be a resistor between that and top line.
Now I'm awake.:-) Ok. yes it should be 10k in the Si Filter. Will fix it. As for the trimmer: Yes it is true that the trimpot is connected to 9v and the other side is connected to collector through 10k. But in this case, the order doesn't matter, it will work the same anyway, 10k is a liminting resistor to protect the transistor from to much voltage. Sometimes I flip caps and resistors in the layouts for space and "flow" reasons. But as I said, the order doesn't matter as long as you don't have an additional component connected to the trimpot/10k junction.
Yeah it works like it is supposed to, iam getting sound out of it now, but for some reason Collector of Q8 is getting almost 9v, tried doing a voltage divider but that just made it weird with 2m2 resistor. Have you done the Circuit and got it working as it is? I may have some bad component somewhere, tried changing the 20K but it still feeds full voltage right through it. All other transistors got desired voltage, may try change 10K blend pot - its a old one so maybe it is causing issues.
really odd on the Q8 collector voltage...20k should definitely drop it down. And I can't any other way for the voltage to "sneak" in into transistor. I doubt the Blend pot could be the issue since there is a DC blocking cap between the pot and the base of Q8. Are you sure all the components is in the right spot, especially around Q8 and no solder bridges or misplaced cuts?
You could try a higher value in place of 20k....say 470k. If you still have 9v there is definitley a connection from 9v to collector that shouldn't be.
And no, I have not fired this one up yet but is is definitely in the que.
What's the reason for the change in transformers between III and IV? The 42TL019 has a lower secondary impedance at 0.6k compared to 2k, but in real world terms what does that mean? Cheers Ben
Nice! Just gotta get that transformer then I'll start. Thanks!
ReplyDeleteDid it work?
DeleteI have not got mine to work 100procent, mainly is the lower part of board that gets fed to much voltage,q8 got 9v on C while almost 0 at base etc. Damn wish there was a schematic.
DeleteCant figure out what is wrong, all is like schematic:/
Hmm, maybe it is that iam using a polarized 0.1uf cap with positive facing upwards at blend 1 section that makes it weird. If it is supposed to travel back there from 2.2m resistor at base etc. Will try that.
DeleteIt could be, let me know if it works.
DeleteI'll post a link to the schematic as soon as I get home.
Here is the schematic.
Deletehttps://drive.google.com/file/d/1a0p1v22tQZkWvbCB9aFCe2UhnHgcuTx8/view
iam not done errow searching, but according to schematic there is a value wrong at the si Filter, just above q8 there is a 100K resistor that according to schematic should be 10k Before heading to the 22k resistor and also the 1n8.
DeleteIn schematic its R10
dont take my word for it yet tho.
Also 10K resistor that goes from trimmer doesnt make sense for me, it goes from trimmer up to AC176 C, according to schematic it is supposed to be between 9v and 3 - 2 of trimmer Before trimmer heading up with a jumper or something to C of AC176, but maybe something i dont understand there.
DeleteWhen you wake up can you check my last reply and see if i missunderstood or if it is something wrong, because now top pin is straight in 9v line - when according to schematic it should be a resistor between that and top line.
DeleteNow I'm awake.:-)
DeleteOk. yes it should be 10k in the Si Filter. Will fix it.
As for the trimmer: Yes it is true that the trimpot is connected to 9v and the other side is connected to collector through 10k.
But in this case, the order doesn't matter, it will work the same anyway, 10k is a liminting resistor to protect the transistor from to much voltage.
Sometimes I flip caps and resistors in the layouts for space and "flow" reasons.
But as I said, the order doesn't matter as long as you don't have an additional component connected to the trimpot/10k junction.
Yeah it works like it is supposed to, iam getting sound out of it now, but for some reason Collector of Q8 is getting almost 9v, tried doing a voltage divider but that just made it weird with 2m2 resistor. Have you done the Circuit and got it working as it is? I may have some bad component somewhere, tried changing the 20K but it still feeds full voltage right through it. All other transistors got desired voltage, may try change 10K blend pot - its a old one so maybe it is causing issues.
Deletereally odd on the Q8 collector voltage...20k should definitely drop it down. And I can't any other way for the voltage to "sneak" in into transistor. I doubt the Blend pot could be the issue since there is a DC blocking cap between the pot and the base of Q8.
DeleteAre you sure all the components is in the right spot, especially around Q8 and no solder bridges or misplaced cuts?
You could try a higher value in place of 20k....say 470k. If you still have 9v there is definitley a connection from 9v to collector that shouldn't be.
And no, I have not fired this one up yet but is is definitely in the que.
Nicely done Anders
ReplyDeleteWow, thanks! Thank you and to Dino for tracing those interesting Spaceman circuits.
DeleteWhat's the reason for the change in transformers between III and IV? The 42TL019 has a lower secondary impedance at 0.6k compared to 2k, but in real world terms what does that mean?
ReplyDeleteCheers
Ben