Avalon VT 737 sp

[TheseGoToEleven]

k9 pin 2 is connected to k7 p3 according to the multimeter, weird,

This is correct if both EQ>COMP and COMP are off because K7 pin 3 eventually goes to K9 pin 2 if you keep following the blue path.

 

[punkt]

This is correct if both EQ>COMP and COMP are off because K7 pin 3 eventually goes to K9 pin 2 if you keep following the blue path.
View attachment 147909

made sure to connect every trace, measured with the multimeter seems ok, but same issue, eq and comp dont work, and when engaging eq>comp sound is very quiet

but atleast sound is back without briding pin 3and4

every thing switched off, unit disconnected and k9 is again stuck at the open position on p3&4 7&8 are cloed tho
i will replace k9 again now since its defect,again,but why?

Yes but if the EQ button is lit then first the signal would need to arrive at K12 pin 3, then K12 pin 4, then go through the EQ, then reach K12 pin 7, then K12 pin 8. From there it would go to K9 pin 8.

So check all those places for AC and see which place is the first to not receive the signal.

just checked signal does make it through all of them, but the eq doesnt affect the sound, like its just passing it thorugh

didnt know where to check on the eq card tho

 

[TheseGoToEleven]

every thing switched off, unit disconnected and k9 is again stuck at the open position on p3&4 7&8 are cloed tho
i will replace k9 again now since its defect,again,but why?

This is expected though! Look at the blue path. K9 pin 3 and K9 pin 4 are shorted together at T12 even if they are not shorted by the internal parts of the relay.

Edit: Heck I even missed this earlier myself, many comments ago. At that time K9 didn’t measure zero resistance between 2 & 3 so it looked faulty anyway.

 

[TheseGoToEleven]

made sure to connect every trace, measured with the multimeter seems ok, but same issue, eq and comp dont work, and when engaging eq>comp sound is very quiet

but atleast sound is back without briding pin 3and4

every thing switched off, unit disconnected and k9 is again stuck at the open position on p3&4 7&8 are cloed tho
i will replace k9 again now since its defect,again,but why?

just checked signal does make it through all of them, but the eq doesnt affect the sound, like its just passing it thorugh

didnt know where to check on the eq card tho

Please don’t worry about the eq card at all until the unit works completely normally with the eq bypassed. The eq card is probably fine.

 

[TheseGoToEleven]

made sure to connect every trace, measured with the multimeter seems ok, but same issue, eq and comp dont work, and when engaging eq>comp sound is very quiet

Are you saying that the blue path (EQ, COMP, and EQ>COMP all OFF) works normally now? No loss of sound? If so, congrats!

Next would be to keep EQ and COMP off, and figure out why sound dies when EQ>COMP is on. Follow along the green path and see where the AC signal disappears.

 

[punkt]

Are you saying that the blue path (EQ, COMP, and EQ>COMP all OFF) works normally now? No loss of sound? If so, congrats!

Next would be to keep EQ and COMP off, and figure out why sound dies when EQ>COMP is on. Follow along the green path and see where the AC signal disappears.

View attachment 147950

Replaced K9, So back again at square 1, because its stillgets lost between pin 4 and pin 3 of k9,

4,7acv on pin 4 and then 0acv on pin 3
please dont tell me relay is bad again...
because i it was brand new and was passing the test outside of the pcb

 

[TheseGoToEleven]

Replaced K9, So back again at square 1, because its stillgets lost between pin 4 and pin 3 of k9,

4,7acv on pin 4 and then 0acv on pin 3
please dont tell me relay is bad again...
because i it was brand new and was passing the test outside of the pcb

Which buttons were on?

 

[punkt]

Which buttons were on?

EQ>COMP...

i just noticed every relay gives a click when pressing,except when pressing eq

edit:

it seems only k9 and k8 are getting about 12vdc k12 and k7 dont get any voltage

 

[TheseGoToEleven]

EQ>COMP...

i just noticed every relay gives a click when pressing,except when pressing eq

Leave EQ off and don’t worry about that until signal passes correctly on the blue and green paths.

Turn on EQ>COMP. Turn off EQ and COMP. What is DC voltage between K9 pins 1 & 10? And at the same time, what is the AC voltage at K9 pin 4? What is the AC voltage at K9 pin 3?

 

[TheseGoToEleven]

it seems only k9 and k8 are getting about 12vdc k12 and k7 dont get any voltage

Ok that would be a separate problem but you can leave EQ off and let’s solve EQ>COMP first, before changing anything else.

 

[punkt]

Leave EQ off and don’t worry about that until signal passes correctly on the blue and green paths.

Turn on EQ>COMP. Turn off EQ and COMP. What is DC voltage between K9 pins 1 & 10? And at the same time, what is the AC voltage at K9 pin 4? What is the AC voltage at K9 pin 3?

man i already told u everything, ..

Which buttons were on?

EQ>COMP...

EQ>COMP was the only thing that was on, EQ was not engaged
4,7acv on pin 4 and then 0acv on pin 3

Replaced K9, So back again at square 1, because its stillgets lost between pin 4 and pin 3 of k9,

4,7acv on pin 4 and then 0acv on pin 3
please dont tell me relay is bad again...
because i it was brand new and was passing the test outside of the pcb

12v dc on k9 and k8

i feel like we're wasting time for information, that i already provide, isnt the first time this is happening, i am really thankful for your help and guidance,, but i am really tired of this, just wanna get through with this asap

 

[TheseGoToEleven]

man i already told u everything, ..


EQ>COMP was the only thing that was on, EQ was not engaged
4,7acv on pin 4 and then 0acv on pin 3

12v dc on k9 and k8

i feel like we're wasting time for information, that i already provide, isnt the first time this is happening, i am really thankful for your help and guidance,

I think we were editing at the same time and you added information while I was replying to the original information, so we accidentally got some miscommunication.

Anyway, if you are saying that while K9 is receiving 12V DC, there is also 4.7V AC on pin 4, also not 4.7V AC on pin 3, then the relay is not shorting those pins together when the 12V DC is there. So the K9 relay has to be bad. I don’t see another conclusion to make.

 

[punkt]

I think we were editing at the same time and you added information while I was replying to the original information, so we accidentally got some miscommunication.

Anyway, if you are saying that while K9 is receiving 12V DC, there is also 4.7V AC on pin 4, also not 4.7V AC on pin 3, then the relay is not shorting those pins together when the 12V DC is there. So the K9 relay has to be bad. I don’t see another conclusion to make.

its probably the fifth time i changed the relay, something has to cause the relay to malefunction

i dont think i can desolder k9 again, already there is no pad left lol

gonna order pcb prototpe boards and solder it on there

and what about the eq&comp?
@pucho812

 

[TheseGoToEleven]

ok just discovered that pin 10 has a loose contact, will connect it to the soilder point

Good find! I was just going to say, the only other explanation I could think of was if the 12V was not getting connected across the 1 or 10 without the probe pushing on it.

 

[TheseGoToEleven]

By the way, to measure for 12V DC on any relay, make sure to put the red probe on pin 1 and at the same time put the black probe on pin 10, not anywhere else. You are probably already doing it that way, but just in case, I'm not sure if I made that clear before. Otherwise it's possible to see +12V on the meter even though pin 10 is disconnected.

 

[punkt]

By the way, to measure for 12V DC on any relay, make sure to put the red probe on pin 1 and at the same time put the black probe on pin 10, not anywhere else. You are probably already doing it that way, but just in case, I'm not sure if I made that clear before. Otherwise it's possible to see +12V on the meter even though pin 10 is disconnected.

i fixed it eq>comp works now, eq still struggles, comp seems to work now

couple traces seemed to be have problems, bridged them with wires
gonna replace the wires with the burned isolation, when everthing is working again

 

[punkt]

By the way, to measure for 12V DC on any relay, make sure to put the red probe on pin 1 and at the same time put the black probe on pin 10, not anywhere else. You are probably already doing it that way, but just in case, I'm not sure if I made that clear before. Otherwise it's possible to see +12V on the meter even though pin 10 is disconnected.

THANKS! i think i have wire pin 1 and 10 of k12 becaue i get 0 dcv while only eq is on

 

[TheseGoToEleven]

i fixed it eq>comp works now, eq still struggles, comp seems to work now

Very nice! (Borat voice) That's good progress

 

[punkt]

Very nice! (Borat voice) That's good progress

nope just soldered them on, even at the soilderpoints of p1 p10 k12 there is no voltage when only eq is egnang

I LIKE

signal doesnt arrive at p7 k12, but its reaching 64

matter of fact all relays get no voltage when eq is on

maybe its a voltage problem with the relay?


when only eq>comp is on k12 also gets no voltage

are these even the right connections, if not please tell me where the voltage comes from for pin 1 and 10,
maybe also for k7, it also doesnt get voltage

 

[TheseGoToEleven]

nope just soldered them on, even at the soilderpoints of p1 p10 k12 there is no voltage when only eq is egnang

I LIKE

Ok so pin 1 or pin 10 is not connected (or both). Check to see if 12V is reaching the diode above K12. Measure DC between the two points circled here.