Are you ready to face strong emotions?.. Dx Blame MKII and the Supercharged release!

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#325
To my dear friends that sent me wishes of a Merry Christmas

I would like to thank you all and to say that i had a lovely Christmas night.

regards,

Carlos
 

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#327
Files uploaded by Mitchel are pdfs showing Supercharged blue board

also the part's substitution chart to match each model and a schematic.

A nice work he made..this way, you can build the model you want and these pdfs will help a lot.

Here you have the images..but reduced ones..search for better images using the link Mitchel provided.

regards,

Carlos
 

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#330
Uncle Carlos,

Greetings.

I"ve a problem with my DX blame es build.
There's 2 DC V and 11 DC V at the output
Supply Voltage +/- 32 DC,
I measure 1.5V at the 100R (fuse out the socket)

I've rechecked all component and soldering, they all seems ok

What should I look first?

Many thanks in advance
 
#331
Increase your stand by current to the standard of 4.7V over 100 ohms resistance

and check your off set once again.

Check transistors position, how you have inserted them into the board, or base, colector and emitter position... check if PNP is in PNP's placa and if NPN is in NPN place.

For sure there's a mistake, off set is smaller than 25 milivolts, usually 3 milivolts and sometimes smaller.

Adjusting you will check if your bias adjustment is operating too.

You have checked, but for sure was not a deep check, because you have not found errors..and for sure they exist.

Good luck,

regards,

Carlos
 
#334
Uncle Carlos,

Thank you for the kind help
Yes,, there's mistakes and Im still looking for it
Hopefully , Uncle Carlos Can help me

Increasing the bias on one of the amplifier module (the one with 2V Dc offset) resulted in 0 5 DC V at the o/p but the supply voltage drop to 25V DC

The other module the one with 11v dc offset) the bias won't set correctly


destroyer X said:
and check your off set once again.

Check transistors position, how you have inserted them into the board, or base, colector and emitter position... check if PNP is in PNP's placa and if NPN is in NPN place.

For sure there's a mistake, off set is smaller than 25 milivolts, usually 3 milivolts and sometimes smaller.

Adjusting you will check if your bias adjustment is operating too.

You have checked, but for sure was not a deep check, because you have not found errors..and for sure they exist.

Good luck,

regards,

Carlos
Click to expand...
 
#335
There are several mistakes that can produce this defect

The combination is really big... if you install, for instance, two BD140 at the driver's position..then you gonna have something alike you have.

Also one diode wrong way, the 1N4148 can result in off set from 2.8 to 3.5 volts, depending your supply and other mistakes and adjustments.

Do not try to discover, there are so many possibilities that check each one of them will be waste of time.

Check all your transistors position, if NPN is in the NPN's place...also if PNP are in PNP's places... check if the correct transistor is used...measure if they are good...remove them from the board to test them....check invertions in the small ones...are BC546 in their correct place?.... check it..... if you're using Blue boards, then you have to use 2N5401 and 2N555 or you gonna face troubles..they have coletor and emitter all the way round related the BC546/556.... cannot use BC546/556 in the blue board...also cannot use 2N5401/5551 in the Brazilian green boards or in Todd Johnson's layout (first layout published..the one has beautifull board image, an enhanced image).

After check all transistors..then check resistances...measure them...all them.... understand that they are in the circuit and will measure the correct value or LESS than the correct value because they are in parallel with other parts in the circuit..better to lift one resistance side to check.

Check condensers polarity and value..check diodes polarity and values..check solder below the board...ressolder and use a a magnified glass to observe if you left solder to be made or if you have shorts between leads or copper tracks (happens a lot).

Take it easy and relax...for sure the amplifier is not a bad guy..it works fine and it is tested...soon you gonna find what is wrong..but disengage your intelligence..this increases debugging time.... engage hard work, put energy and patience and check everything.

Make a copy of your schematic..print it..then you go painting with a red pencil or pen, all connections and parts checked..do it till you check everything... search for mistakes till you find them...because for sure they exist.

Do not try to analise... this was statistically proven that takes too much time..waste of time..there are too many possibilities of mistakes..to check each one of them will take 50 times more time than removing parts and measuring them.

regards,

Carlos
 
#336
good advice in post335.
Check and recheck voltages at devices and compare to the correct/expected voltages of a working circuit.

When you find an anomaly concentrate on taking more measurements around that/those component/s. Check currents through resistors, check Vbe of transistors etc.

And power it through a bulb tester.
That bulb tester will not save a device if you accidentally short with your DVM probes, but it will prevent overheating in the quiescent circuit.
 
#339
:smash:Hello Mr.Carlos I would like to wish you and your family a most joyious new year for 2011.😀 Its great to be ouit of the hospital,again. Now maybe I can catch up on the projects I,ve started. Happy New Year Everyone

Peace and Love Evette
 
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