jayjayuk
New Head-Fier
- Joined
- May 11, 2014
- Posts
- 47
- Likes
- 10
So i got back on this about a week ago, things are starting to go alot better now. i was being stupid and not using anti static equipment and not cleaning the tip, the problem was the tda amps i was soldering right/carefull enough. i focused on one and threw about 8 in one position (front left) and they keep running hot for 10 secs then would shut down (no sound) after which they just shut off without getting hot at all, i got past this problem with new equipment and clean tip and they have gone in one after another on both boards i have and all work fine... except for the sub on the second blown board i have but that will get worked out.
on my main board i started to rip the track up for the voltage feed to the op-amp, in the end it got so bad that it was either transfer to the other board and work on that, or take a chance on the op-amp bypass for the sub (U15) where i got up the data sheet and joined the + inputs to the outputs, i also remove one shunt resistor R618 and R617+R619 - at first the volume was low for the sub so i lost something... then i removed R617 and R619 and put a bridge across all the terminals for those two resistors (this is the input signal being dropped so is ok for op-amp) the volume improved but it is still low and does not punch as much as it once did, also for people soldering in op-amps. you can use what i said on U15 to bridge it first, then you know if U14 is in correct (this is what i am going to do with second board) then remove the bridge and work on U15 until it works. i am upset about the loss but i have a plan for that, and i am glad everything is working again as it should, all the sats sound fine and good, i have designed a board to be able to put an op-amp back on U15 which i broke as i think it needs to be re-amplified after it has gone through the first part of the signal filter for the sub.
i have also been drawing schematics for this amp board, they will be separate and not professional as they are the first ones i have drawn but i hope that they will help someone if they become stuck like i have and will be able to trace things better. i am still working on a full schematic for the sub (i have done one full op-amp, i am at the point where it runs over to the second op-amp then towards the tda amps) all diagrams will have the components values and codes (except the very small caps, i need to get a new meter to read the low values) but so far i have ready real pics of the board, then a diagram that i have drawn showing the connections for the op-amps and surrounding components for all the sats, thats what i will be posting here today, and also the board i have drawn up for repairing the U15 with components on the board using wires to connect back to the original board, but all the fussy stuff will be on the secondary/break-out board like the 0.1uF caps for the power rails as close as possible to the op-amp rail pins (4&8). so here goes...
Those are for the sat speakers... this next one is for the sub, which i took a camera pic and drew directly on the camera pic to show where the connections go on the top side of the board, the full sub schematic will have all the component values in.
in the end i will have full schematics for this amp board (not control pod lol) they will all be separate for each separate channel except the sub which splits into two but this has to be done as one anyway so in total there will be 6 different schematics for the 6 channels starting from the input at the D-Sub connector right up to the output terminals for the speakers and subs so i am going to do full schematics but also littler ones like the ones posted so can focus on just that area at a time if needed. i will also post fixes that i have had to do. here is one fix that i will be building to replace my broken U15 area which as of now i have bypassed... (i think if i removed some inline and shunt resistors down the signal path from U14 to U15 then i could get the voltage back up and have the power back, but i want to draw up some schematics before big changes happen lol)
(EDIT: Take note of the Negative (N) marker for the electrolytic caps)
took some time to do just this what i have posted and there is lots more to do... hope someone finds it useful.
Cheers
on my main board i started to rip the track up for the voltage feed to the op-amp, in the end it got so bad that it was either transfer to the other board and work on that, or take a chance on the op-amp bypass for the sub (U15) where i got up the data sheet and joined the + inputs to the outputs, i also remove one shunt resistor R618 and R617+R619 - at first the volume was low for the sub so i lost something... then i removed R617 and R619 and put a bridge across all the terminals for those two resistors (this is the input signal being dropped so is ok for op-amp) the volume improved but it is still low and does not punch as much as it once did, also for people soldering in op-amps. you can use what i said on U15 to bridge it first, then you know if U14 is in correct (this is what i am going to do with second board) then remove the bridge and work on U15 until it works. i am upset about the loss but i have a plan for that, and i am glad everything is working again as it should, all the sats sound fine and good, i have designed a board to be able to put an op-amp back on U15 which i broke as i think it needs to be re-amplified after it has gone through the first part of the signal filter for the sub.
i have also been drawing schematics for this amp board, they will be separate and not professional as they are the first ones i have drawn but i hope that they will help someone if they become stuck like i have and will be able to trace things better. i am still working on a full schematic for the sub (i have done one full op-amp, i am at the point where it runs over to the second op-amp then towards the tda amps) all diagrams will have the components values and codes (except the very small caps, i need to get a new meter to read the low values) but so far i have ready real pics of the board, then a diagram that i have drawn showing the connections for the op-amps and surrounding components for all the sats, thats what i will be posting here today, and also the board i have drawn up for repairing the U15 with components on the board using wires to connect back to the original board, but all the fussy stuff will be on the secondary/break-out board like the 0.1uF caps for the power rails as close as possible to the op-amp rail pins (4&8). so here goes...
Those are for the sat speakers... this next one is for the sub, which i took a camera pic and drew directly on the camera pic to show where the connections go on the top side of the board, the full sub schematic will have all the component values in.
in the end i will have full schematics for this amp board (not control pod lol) they will all be separate for each separate channel except the sub which splits into two but this has to be done as one anyway so in total there will be 6 different schematics for the 6 channels starting from the input at the D-Sub connector right up to the output terminals for the speakers and subs so i am going to do full schematics but also littler ones like the ones posted so can focus on just that area at a time if needed. i will also post fixes that i have had to do. here is one fix that i will be building to replace my broken U15 area which as of now i have bypassed... (i think if i removed some inline and shunt resistors down the signal path from U14 to U15 then i could get the voltage back up and have the power back, but i want to draw up some schematics before big changes happen lol)
(EDIT: Take note of the Negative (N) marker for the electrolytic caps)
took some time to do just this what i have posted and there is lots more to do... hope someone finds it useful.
Cheers