Avalon VT 737 sp

[pucho812]

Ok the 7372 card is the I/O card. It is used in conjunction with the tubes.
It's been a long time since I have seen schematics for the main board, there are a lot of parallel processes going on which is why the unit is practically noise free. with a ridiculously low noise floor.

 

[punkt]

Ok the 7372 card is the I/O card. It is used in conjunction with the tubes.
It's been a long time since I have seen schematics for the main board, there are a lot of parallel processes going on which is why the unit is practically noise free. with a ridiculously low noise floor.

I also recapped the 7374 just in case, would u recommend to recap the last card too?

 

[pucho812]

Eureka, my avalon works again, line and mic, rumble noise when pressing in phase also disappeard

issue lied within in the 7372, must been one of the caps on the left

I also recapped the 7374 just in case, would u recommend to recap the last card too?

7374 is the compressor card.
7373 is the EQ card. It shouldn't cause any issues to recap the eq card at this time with the usual replacement 10UF and 100UF. About the only issue I see here is if you accidentally plug the card back in but miss a pin like you had previously done on another card. The 7373 card has two headers. While they are offset so that you can't so the card will only fit one way it's still possible to be a pin off. So do exercise caution when you do.

 

[punkt]

7374 is the compressor card.
7373 is the EQ card. It shouldn't cause any issues to recap the eq card at this time with the usual replacement 10UF and 100UF. About the only issue I see here is if you accidentally plug the card back in but miss a pin like you had previously done on another card. The 7373 card has two headers. While they are offset so that you can't so the card will only fit one way it's still possible to be a pin off. So do exercise caution when you do.

Hahaha thanks, yea i learned from my mistake and now always look to lineup the screwholes, okiladokili, i will recapd the 73 in the near future, i already screwed everything in place and hope i dont have to open it up again

 

[pucho812]

Hahaha thanks, yea i learned from my mistake and now always look to lineup the screwholes, okiladokili, i will recapd the 73 in the near future, i already screwed everything in place and hope i dont have to open it up again

Avalons commitment to excellence and striving for perfection, the tolerance on the mechanicals is super tight. In my shop time there, we had single post it note style paper that we would slip under the pots before putting on the knobs. It ensured the knobs wouldn't rub the faceplate but also shows the tight tolerances I mentioned previously. again great job on accomplishing getting it back to working. it feels good.

 

[TheseGoToEleven]

Eureka, my avalon works again, line and mic, rumble noise when pressing in phase also disappeard

issue lied within in the 7372, must been one of the caps on the left

Congratulations! Aging caps on the 7372 is a common source of problems.

I'm surprised these changes would affect the phase button, as all that does is connect a 12V DC signal to relay K2, causing it to swap the hot & cold pins of the Line Out XLR jack. But glad the problem is gone and crossing fingers that it stays that way.

 

[punkt]

Congratulations! Aging caps on the 7372 is a common source of problems.

I'm surprised these changes would affect the phase button, as all that does is connect a 12V DC signal to relay K2, causing it to swap the hot & cold pins of the Line Out XLR jack. But glad the problem is gone and crossing fingers that it stays that way.

Thanks everyone for their patience and support
maybe it was because of the shorted r19?

 

[punkt]

Just recapped the 7372, think i did a great job being my frist time doing this

 

[pucho812]

Just recapped the 7372, think i did a great job being my frist time doing this

except that is the 7373 card, aka eq card. But yeah not bad at all.

 

[punkt]

except that is the 7373 card, aka eq card. But yeah not bad at all.

haha yea, replaced all the caps on all 3 cards tho, had to get to soilder iron to 500 degrees celsius to be able to desolder the through hole connections, what a pain, the desoldervacuumpump was a blessing, an absolute bang for the buck

but i managed to rip of a pad before i had the pump, what a bummer, cleaned up the mess and fixed it, ofc i also burned alittle bit of pcb, but nothing tragic, doenst look pretty but hey

just recorded the first song, ahhh it sounds so clean

this project really sparked my interest of doing more stuff like, maybe like a diy equipment project, i also have a notebook that died on, but thats a whole different kind of skill ceiling

i think what can be concluded is if voltages check out, no visible damage and resistors look fine, best shot would be just recapping the i/o card

had this problem since i got this unit couple years ago worked fine the first couple months, after refitting the tubes in different sockets the problem went away for couple months, but the next time it didnt helped.

i am really interested in knowing whats causing this, like how is it behaving like that when a capictator died, but it sporadicaly starts to function again

maybe somone has an thesis

 

[pucho812]

haha yea, replaced all the caps on all 3 cards tho, had to get to soilder iron to 500 degrees celsius to be able to desolder the through hole connections, what a pain, the desoldervacuumpump was a blessing, an absolute bang for the buck

but i managed to rip of a pad before i had the pump, what a bummer, cleaned up the mess and fixed it, ofc i also burned alittle bit of pcb, but nothing tragic, doenst look pretty but hey

just recorded the first song, ahhh it sounds so clean

this project really sparked my interest of doing more stuff like, maybe like a diy equipment project, i also have a notebook that died on, but thats a whole different kind of skill ceiling

i think what can be concluded is if voltages check out, no visible damage and resistors look fine, best shot would be just recapping the i/o card

had this problem since i got this unit couple years ago worked fine the first couple months, after refitting the tubes in different sockets the problem went away for couple months, but the next time it didnt helped.

i am really interested in knowing whats causing this, like how is it behaving like that when a capictator died, but it sporadicaly starts to function again

maybe somone has an thesis

Well the cap might not be totally dead. It may be out of tolorance from age.
Like it’s not holding a full charge like it used to.
Wow ripped a pad off, been there. keep that a secret. Or don’t. But we have all done it and fixed it.
Years ago I looked at a desk where the aux masters had catastrophic failure and all traces were gone. I made new traces out of wire and held them fine with nail polish. It still works to this day. What caused the failure in the first place who knows. But I did get it fixed.

 

[punkt]

Well the cap might not be totally dead. It may be out of tolorance from age.
Like it’s not holding a full charge like it used to.
Wow ripped a pad off, been there. keep that a secret. Or don’t. But we have all done it and fixed it.
Years ago I looked at a desk where the aux masters had catastrophic failure and all traces were gone. I made new traces out of wire and held them fine with nail polish. It still works to this day. What caused the failure in the first place who knows. But I did get it fixed.

trouble in paradise
seems i didnt made that great of a job, was just recording when something popped, opened this badboy up again and saw that the cap exploded???

gonna recap this one now

update: recapped, works again, was the point where i ripped of the pad just added more solder, in the hopes it wont pop again

 

[punkt]

Well the cap might not be totally dead. It may be out of tolorance from age.
Like it’s not holding a full charge like it used to.
Wow ripped a pad off, been there. keep that a secret. Or don’t. But we have all done it and fixed it.
Years ago I looked at a desk where the aux masters had catastrophic failure and all traces were gone. I made new traces out of wire and held them fine with nail polish. It still works to this day. What caused the failure in the first place who knows. But I did get it fixed.

its been a while ... **** went down south i guess, the problem with low output came back

psu measurements are fine, nothing blew up or leaked, resistor are also looking fine

we had a good run i guess

any suggestions?

 

[punkt]

If mic channel is working then there has to be a signal at T8 and T9. You are measuring T8 and T9 near the gain knob, right? Not 8 and 9 near the XLR?

I hope you are not sending +4 dBu to the mic input, or for sure it would distort. Probably should be more like -50 dBu.

Also, I just looked up your multimeter. When measuring AC with the 200V range setting, it is only accurate to 100mV which is not very helpful. It might say no signal when there is actually 25mV present, for example.

Also the multimeter's frequency response is only to 40 to 400 Hz so it's good that you are now using 100 Hz not 1000 Hz.

2,8 on t8 0 on t9
100hz sinwave through instrument input

100hz sinwave -20db through mic input
3,3 t8
0,1 t9
t11 0,9
t12 6,3

 

[pucho812]

something doesn't sound right. I mean that literally. it would be very unusual to have low volume with a working PSU.

Perhaps a tube went south. it can happen.
As always lets go back and do the first check of I/O with line level and see what is what.

 

[punkt]

As always lets go back and do the first check of I/O with line level and see what is what.

sorry, what you mean by that?

already did the tests of line and mic input with the sinewaves

i alread tried to reseat the tubes, these were brand new tube, i now interchanged them with the older ones, no changes

since i got those readings
2,8 on t8 0 on t9
100hz sinwave through instrument input

100hz sinwave -20db through mic input
3,3 t8
0,1 t9
t11 0,9
t12 6,3

i assume v1 and v2 are fine since the signal is leaving but no readings on the output points 6x

so we are back at square one

 

[pucho812]

sorry, what you mean by that?

already did the tests of line and mic input with the sinewaves

i alread tried to reseat the tubes, these were brand new tube, i now interchanged them with the older ones, no changes

since i got those readings
2,8 on t8 0 on t9
100hz sinwave through instrument input

100hz sinwave -20db through mic input
3,3 t8
0,1 t9
t11 0,9
t12 6,3

i assume v1 and v2 are fine since the signal is leaving but no readings on the output points 6x

so we are back at square one

as always I start testing with the line input.
no mic, no instrument. I also turn off the comp and the eq. the idea is that line level input at +4dBu going in will be the same or about the same at the output when the input and output will be the same or about the same within a few tenths difference.

 

[punkt]

as always I start testing with the line input.
no mic, no instrument. I also turn off the comp and the eq. the idea is that line level input at +4dBu going in will be the same or about the same at the output when the input and output will be the same or about the same within a few tenths difference.

as i already stated, nope thsi isnt the case, there is barley an output signal, u cant even notice it without cranking up the gain and outpput

same case for mic,instrument and line input

 

[pucho812]

as i already stated, nope thsi isnt the case, there is barley an output signal, u cant even notice it without cranking up the gain and outpput

same case for mic,instrument and line input

Hmmm.