Dx Super A and Dx Regulator Group Buy Interest

[C37]

Boards arrived this morning- well packed, it was a lot faster than what i thought!
Thanks Carlos and Juan

 

[vargasmongo3435]

WOW! thanks C37 this is great make me happy indeed you see how I take care of you guys I pack them with care and love you made my day C37

you see that dear Carlos "muy bien" = well done


Regards
Juan

 

[still4given]

Is there a schematic somewhere with matching part numbers to this board?

Thanks, Terry

 

[vargasmongo3435]

Hello mister Terry this is the latest schematic of the Dx Super A that Carlos post #918 this is the one I use, and the Dx Regulator on post #97


about part numbers actually you don't really have to worried about that just use the silkscreen of the boards



Regards
Juan

 

[vargasmongo3435]

I almost forgot last night I test the first board I made all working good I didn't have no problems at all sound it really good here are some images of the first board now I just got to wait for parts for the second board and the heat sink for the Dx Regulator.

Regards
Juan

 

[still4given]

Hello mister Terry this is the latest schematic of the Dx Super A that Carlos post #918 this is the one I use, and the Dx Regulator on post #97


about part numbers actually you don't really have to worried about that just use the silkscreen of the boards



Regards
Juan

I wanted the part numbers for troubleshooting. I managed to mark up a schematic with part numbers so I could take some measurements. I am going to put this thing on the shelf for a while. I have been pouring over it for two solid days and can't find the problem. Resistors all measure right on. Devices are proper and in the correct orientation as well as the electros. Both boards are doing the same thing so whatever it is I did it to both of them. I'll try to come back to it with fresh eyes after a while.

Blessings, Terry

 

[destroyer X]

I would like to see more details from the pcboard Juan

I would make it myself, but my pcboards have not arrived yet.

Please, use Macro..i would like to see small portions of the pcboard filling the screen.

Send me images if you have problems to edit them.

regards,

Carlos

 

[still4given]

Do you guys think my problem could be fake transistors? I bought a bunch of BC556 transistors from ebay. I used them in this amp as well as one other and both are being a problem. They test fine on my HFE meter but is it possible they are doing something bad once in the circuit? Is there a way to test for that?

Thanks, Terry

 

[vargasmongo3435]

I did buy from E Bay sometimes but not really mister Terry I didn't have problems try On brand from DigiKey I trust them probably you bought a bad fake transistors from E Bay it does happen.

here:



those I bought before from DigiKey and so far they work for me

Regards
Juan

 

[Earthquake]

Do you guys think my problem could be fake transistors? I bought a bunch of BC556 transistors from ebay. I used them in this amp as well as one other and both are being a problem. They test fine on my HFE meter but is it possible they are doing something bad once in the circuit? Is there a way to test for that?

Thanks, Terry

Terry,

Whilst everything is a posiblity if you could post a hi-ish res photo of one or both of your PCB's we may be able to spot something you could have overlooked.

Ian

 

[still4given]

OK, here are some pics.

 

[still4given]

some more

 

[niss_man]

Check for bad solder joints and joints that shouldn't be touching. Also are you connecting the transistors to a heat sink? Best if a heatsink is used and remember to use insulators for the transistors.

 

[still4given]

Yes, I've been over and over the boards looking for solder bridges and bad solder joints. I have to believe that I have a bad device or more. I always use Kapton tape as an insulator and always, always check for a short to the heatsink. I lost some hard to get transistors a few years ago and learned a valuable lesson.

Thanks for your help.

Blessings, Terry

 

[vargasmongo3435]

Mister Terry I was looking at this transistors they probably fake I notice the ones with the pink circles they look fake not like the other ones the green ones is a possibility.

Regards
Juan

 

[still4given]

Hi Juan,

Yes, those are the ones I am worried about. Those are the BC556 that I bought on ebay. They have a silver face. I don't have any other 556's to compare them to so I wasn't sure. They seem to measure ok but I used them on on another amp that is not working either. The ones you circled in green are from On semi. I got those as samples years ago. I 'm sure they are genuine. I will order some BC556B's from Mouser. I will order some 140's too as the ones I have came from the same guy on ebay. The seller's name is Tayda. Beware.

Thanks, Terry

 

[niss_man]

Mister Terry I was looking at this transistors they probably fake I notice the ones with the pink circles they look fake not like the other ones the green ones is a possibility.

Regards
Juan

They certainly do look dodgy don't they.

 

[Earthquake]

Hi Terry, well I have looked at your photos and there is nothing blinding obvious It would be helpful if you could take some voltage mesurements and mark them on one of Carlos's circuit diagrams.

Things we need to know are voltage at all transistors B,C,E junctions what ofset volts are you seeing at the output, is anything getting warm?? how much current is the amp drawing and is this equal on both neg and pos rails hopefully this will help me or others point you in the right direction.

The good news is it it dont look like anything exploded and that is always good news because once the smoke is released there's no return

 

[destroyer X]

I am checking too!

regards,

Carlos

 

[AndrewT]

post95 showing Still4's PCB.
Is that a burnt resistor, or just a shadow?