Re: Re: Re: C9 & C21 Caps comparison
You could always install C9 on the bottom of the board if it gets too big.
ClaveFremen said:
You could always install C9 on the bottom of the board if it gets too big.
samsagaz said:
Don't throw away the PCB's. They are still good even if the components are blown / burnt/ shot.
I promise to review the build today and look for issues.
At worst case you can ship the brds to me and I will reassemble them and ensure they are working before I ship back.
Dear Samsagaz,samsagaz said:
I don't have my working board in front of me, otherwise we could compare (mine is in parts right now because I am building the case...)
You said you have one working board? I would recommend that you first compare this board with a non-working one. First do a visual compare of all the components. Then do test points like you seem to be doing and see what one board shows versus the other.
Just looking at the diagram you would expect to see less than 36 (obviously you expect about 24) when current is drawn. If no current is drawn there will be no voltage drop across R14.
What does your working board show?
Peter
Re: Re: Re: Re: C9 & C21 Caps comparison
Silmics are 25 mm tall, not so easy to mount on the bottom...
it's easier with C21, like I did for MKP1837. 😉
Upgrading C21 to a MKS2 is cheap and a drop-in one, no space problems and has a big effect. 😎 (at least in my case)
marc brown said:
Silmics are 25 mm tall, not so easy to mount on the bottom...
it's easier with C21, like I did for MKP1837. 😉
Upgrading C21 to a MKS2 is cheap and a drop-in one, no space problems and has a big effect. 😎 (at least in my case)
schro20 said:
Well i already checked the boards and looks all OK. the one that works, start from 0V and start growing. When reach 24V the relay make contact!
the one that dont work start from 0V too but when reach the 24V dont make the Relay to Work!
samsagaz said:
Back up a little.
1. Picture of your pwr supply please. Trafo and wiring to the 3 inputs on the PCB.
2. Can you check the direction of each of the diodes on the boards? Make sure the bands are facing the correct direction.
3. Do you have ~37 volts on the LM3886 pins, ~ 12 volts on the 318 pins and 24 volts at the relay?
troystg said:
1 - Conections are OK, GND close to the BIG CAPS, AC1 and AC2 later
2 - Diodes checked everything OK.
3 - i have 70V between PIn 1 V+ and Pin 4 V- of LM3886 and in the LM318 after i turn on the amp, i get 20V that start droping.. after like 5 seconds i have 17v.
samsagaz said:
1. picture please.
3. 318 should have +/- 12 volts if I am not mistaken. If I recall correctly it is regulated via a 12 volt Zenner.
Correct. See http://www.diyaudio.com/forums/attachment.php?s=&postid=1743773&stamp=1234532041troystg said:
peter
checked everything again using an getter GND reference (the last time contact was not good).
Now i get
LM3886 +34V / -34V
LM318 +12,2V / -12,2V
i was thinking if to check the relays i can direct connect the output of the zeners to the relay to check if work. What do you think?
attached the picture http://www.compurosario.com.ar/_diyaudio/GC_03.jpg
Now i get
LM3886 +34V / -34V
LM318 +12,2V / -12,2V
i was thinking if to check the relays i can direct connect the output of the zeners to the relay to check if work. What do you think?
attached the picture http://www.compurosario.com.ar/_diyaudio/GC_03.jpg
connected the relay in paralel with the working board and the relay workrs, so is not an Relay problem
So looks like the problem are in the speaker protection circuit
will replace all the Transistors to see if it fixed it.
will replace all the Transistors to see if it fixed it.
2 blacks and a grey center tap. What is the AC voltage of the secondaries?
Looks right but small trafo.
Chip NEEDS to be heat sinked if pwred up. No ands if or buts. Pwr on without and spike will kick in.
Now I am going make lunch then I will examine the pics you posted.
Looks right but small trafo.
Chip NEEDS to be heat sinked if pwred up. No ands if or buts. Pwr on without and spike will kick in.
Now I am going make lunch then I will examine the pics you posted.
samsagaz said:
In the first picture you have here, is that "the" working PCB or one of the "broken" ones?
And please email me directly..
troystg @ gmail.com
troystg said:
AC are 24V.
The trafo are small just 100VA, but for testing or low volume will be OK.
the chips works OK, the only problem is in the protection circuit, the Relay dont engage.
LM3886
A question about soldering the 3886: most of the pads where the LM3886 pins sit are oval shaped "normal" pads. But, three of the pads aren't really pads they're just through-holes. Are we supposed to solder the leads to those or do the leads "float?"
I know they shouldn't float. So, are they soldered or cut off?
A question about soldering the 3886: most of the pads where the LM3886 pins sit are oval shaped "normal" pads. But, three of the pads aren't really pads they're just through-holes. Are we supposed to solder the leads to those or do the leads "float?"
I know they shouldn't float. So, are they soldered or cut off?
Re: LM3886
peter
I don't know what the official answer is, but I soldered all of them and it works as expected. See the close-ups in http://picasaweb.google.com/schro20/FinalBuildOfRevCFromKit#marc brown said:
peter