Avalon VT 737 sp

[TheseGoToEleven]

signal lost is between k12 and k9
its leaving k12 but never arrives at k9

The only way signal leaves K12 is on this trace that I've highlighted. Signal going out of K12 pin 8 travels to K9 pin 8. The signal has to be same at both pins or you'll get no sound.

 

[punkt]

The only way signal leaves K12 is on this trace that I've highlighted. Signal going out of K12 pin 8 travels to K9 pin 8. The signal has to be same at both pins or you'll get no sound.View attachment 147778

yea signal came back, arrived at k9, thought i will go on and try toresolder everything, till i ****** up and destroyed solder points 2-3 on k8

any tips on how to fix this? signal went away again ofc

if i manage to get signal back, i call it a day and just wont use eq>comp

signal stops at pin 4 k8

edit: ofc no measurement on pin 2 and 3 of k8, i ****** it up once again)))))))

already ordered copper foil just in case

01:19AM edit: just discovered while bridging pin 4 and 3, everything works even eq>comp

can i just bridge pin 4-2 with some copper?

 

[punkt]

The only way signal leaves K12 is on this trace that I've highlighted. Signal going out of K12 pin 8 travels to K9 pin 8. The signal has to be same at both pins or you'll get no sound.View attachment 147778

bridged it now, the eq doesnt do anything LOL

pin 7 of k12 has 0ACV if thats the eq output it should have some reading?

 

[TheseGoToEleven]

01:19AM edit: just discovered while bridging pin 4 and 3, everything works even eq>comp

can i just bridge pin 4-2 with some copper?

Looks like you lost the pad rings there. If you still have them, you can suck the solder out of the hole, put the rings back in place, then try soldering the relay back in and see if it makes a connection. But if you've destroyed the possibility of using a particular hole or trace on the motherboard, there is the option to recreate the same connection using plain old wire instead.

 

[punkt]

Looks like you lost the pad rings there. If you still have them, you can suck the solder out of the hole, put the rings back in place, then try soldering the relay back in and see if it makes a connection. But if you've destroyed the possibility of using a particular hole or trace on the motherboard, there is the option to recreate the same connection using plain old wire instead.

i dont have the pad rings, at least i think so, i just bridged pin 4 and 3, but the eq doesnt work now, it bypasses the sound, but doesnt eq it

pin 7 of k12 has 0ACV if thats the eq output it should have some reading?

comp also doesnt work, my desolderingpump doesnt work anymore, new one will arrive later that day

will try to desolder k9 and put some wire trough the holes of the missing pads

 

[TheseGoToEleven]

i dont have the pad rings, at least i think so, i just bridged pin 4 and 3, but the eq doesnt work now, it bypasses the sound, but doesnt eq it

pin 7 of k12 has 0ACV if thats the eq output it should have some reading?

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.

 

[punkt]

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.

it arrives at all pins of k12 except pin 7

but have in mind i bridged 3-4 of k9,

comp also doesnt work, my desolderingpump doesnt work anymore, new one will arrive later that day

will try to desolder k9 and put some wire trough the holes of the missing pads

 

[TheseGoToEleven]

it arrives at all pins of k12 except pin 7

but have in mind i bridged 3-4 of k9,

comp also doesnt work, my desolderingpump doesnt work anymore, new one will arrive later that day

Ok by permanently bridging 3-4 of K9 it creates a loop that will prevent the eq or comp from working unless EQ>COMP is turned on.

 

[punkt]

Ok by permanently bridging 3-4 of K9 it creates a loop that will prevent the eq or comp from working unless EQ>COMP is turned on.

so whats the solution? signal gets lost after k9 pin 4

managed to get a decent amount of solder on 2 and 3, still no luck, i will try to put a wire thorugh, as soon my new desoldergun arrives

dont think the relay itself is faulty, just incase i have one left

 

[punkt]

Ok by permanently bridging 3-4 of K9 it creates a loop that will prevent the eq or comp from working unless EQ>COMP is turned on.

doesnt work regardless if eq>comp is turned on

 

[pucho812]

Sorry I haven't been available for responses. But you guys are doing so well.

I was going to add that, take precaution when desoldering relays or other large bits. They take away heat fast which can leave you pulling traces. Hopefully that hasn't happened. I usually will cut the large component out and then desolder each pin. So for example take a dip16. I clip off the IC leaving me with 16 individual pins that I can easily desolder. I do that with pots if they are directly on the PCB. I hack up relays so I am down to individual pins. It takes longer but it prevents damage.

Also be careful with desolder pumps, they have enough force to pull traces. Always make sure solder is flowing before hitting the suck button. For field use I have a hand held pump that I cut a notch out of the tip so I can go right over my Iron tip. Makes it easy.

 

[TheseGoToEleven]

so whats the solution? signal gets lost after k9 pin 4

dont think the relay itself is faulty, just incase i have one left

But you said signal was passing to K12 before? Anyway, when you get your new gear, get rid of the bridge and let’s get the simplest signal path working before moving on to anything else. Which I mean passing signal from T12 to 64 with all buttons turned off.

 

[punkt]

But you said signal was passing to K12 before? Anyway, when you get your new gear, get rid of the bridge and let’s get the simplest signal path working before moving on to anything else. Which I mean passing signal from T12 to 64 with all buttons turned off.

yea it passes when 3 and 4 are bridged, if theyre not, it stops after 4 of k9, which means no readings/sound on 64 or k12 or anywhere else

so my guess is 3 and 2 of k9 arre faulty and i have to put a wire through to connect both sides, but on the other hand i dont know **** xD

 

[TheseGoToEleven]

I usually will cut the large component out and then desolder each pin.

I like to do that too, especially if I can’t get a desoldering gun underneath, or don’t need to save the part. With these through hole parts my desoldering gun (Hakko FR-301 or similar) keeps the pad rings in place and works well enough that after sucking out all the pins, the part will often fall out just by gravity. Unfortunately that gun doesn’t help much if it isn’t through hole.

 

[punkt]

I like to do that too, especially if I can’t get a desoldering gun underneath, or don’t need to save the part. With these through hole parts my desoldering gun (Hakko FR-301 or similar) keeps the pad rings in place and works well enough that after sucking out all the pins, the part will often fall out just by gravity. Unfortunately that gun doesn’t help much if it isn’t through hole.

So couldnt fall asleep before doing this, measured resistance between t12 and the relays, 70k ohm starting from r9 p3

so i guess, its caused by the ripped off pads

its 4am, i'm going to bed, good night

edit:

managed to desolder k9,cant get the stuck solder of pin 2 out, and the damage is more severe than i thought lol

any tipps, instructions on how to fix the missing pads and how to get out the stuck solder of pin 2 out, would be much appreciated

edit: managd to get solder of pin 2 out, will wait for your reply and suggestions, i think putting a wire thorugh the missing pads, will be the best solution?

edit: made it even worse nvm, put wires through, doesnt help tho, still the same issue, signal only arrives to p4 of k9, when bridged signal passes forward to output


resistance between pin 3-4 is also 70k

 

[TheseGoToEleven]

Look at each bad hole and figure out where each one should connect to (from the diagram). Count how many wires you will need to use.

I think you will have put each relay into all its holes, then solder only the pins that won't use a wire.

Then solder each wire directly to the pins that need them. It might be tricky so try to take your time.

 

[punkt]

Look at each bad hole and figure out where each one should connect to (from the diagram). Count how many wires you will need to use.

I think you will have put each relay into all its holes, then solder only the pins that won't use a wire.

Then solder each wire directly to the pins that need them. It might be tricky so try to take your time.

so i just managed to get the side with p2-3 out, because of the 70k resistance isnt it possible, that the relay is defect?, i ordered new relays just in case

sorry but as far as i understand it pin 4 and 3 of k9 are connected right? whats the difference of how these 2 pins are interacting, when bridged and soldered on, doesnt it communicate inside the relay?, sorry if these questions are stupid, i just wonder how this functions

k9 pin 2 goes to k8 pin 9
k8 pin 1 goes to k9 pin 1

k9 pin 8 is going straight to the pcb trace and connected to k12 pin 8, which doesnt seem to have a problem, since when 3&4 are bridged signal arrives k12 and k9 pin 8

edit:sorry this is the side with p5-10

 

[TheseGoToEleven]

sorry but as far as i understand it pin 4 and 3 of k9 are connected right? whats the difference of how these 2 pins are interacting, when bridged and soldered on, doesnt it communicate inside the relay?

On K9, pin 3 should not connect to pin 4 all the time. Don’t bridge 3 & 4.

When EQ>COMP is off, inside the relay it will connect pin 3 to pin 2 but not to pin 4.

When EQ>COMP is on, inside the relay it will connect pin 3 to pin 4 but not to pin 2.

 

[punkt]

On K9, pin 3 should not connect to pin 4 all the time. Don’t bridge 3 & 4.

When EQ>COMP is off, inside the relay it will connect pin 3 to pin 2 but not to pin 4.

When EQ>COMP is on, inside the relay it will connect pin 3 to pin 4 but not to pin 2.

but why doesnt it work when its not bridged, afaik pin 3 and pin 2 are nowhere connected on the pcb, so whats causing the issue?
whene these 2 pins are communicating inside the relay

so when the relay still was inside, and i bridged pin 3and4 i got a signal, no matter if eq>comp where on or off, comp and eq didnt work tho, sound just got passed thorugh without changing it.

so whats causing this?

i ordered some copper foil, i will try to pluck it inside the holes with a toothpick tommorow, maybe thats a better fix than the copper wire?

 

[TheseGoToEleven]

but why doesnt it work when its not bridged, afaik pin 3 and pin 2 are nowhere connected on the pcb, so whats causing the issue?
whene these 2 pins are communicating inside the relay

There is probably a disconnect somewhere else. When youre ready to test, the first thing to do is test the signal path with all buttons turned off. If it doesn’t work, measure AC at each pin along the signal path until it disappears. The path with all buttons turned off is this:

i ordered some copper foil, i will try to pluck it inside the holes with a toothpick tommorow, maybe thats a better fix than the copper wire?

Does the wire have insulation or is it bare copper wire with no colored jacket? I have never tried copper foil.