You're missing something fundementally easy on this if you're still missing 'power' , go back to basics:
- Reflow those solder joints I pointed out (in fact reflow the whole pcb)
- Use a meter in continuity mode to trace the 'power' route onto the board from the back of the board , check not only that the meter beeps but also shows 0 (or close to) as many meters will beep even at 100ohms plus
They will most certainly be genuine
I'd suggest chuck the amazon 'cheap buys' or sell them as a job lot on ebay.
As for cap choice , go with the big brands (Pana, rubycon and nichicon) , and not necessarily 'audio' grade, (I always go for 105degree rating but that's not as important most of the time as the brand) ..... and you won't go far wrong.
Don't run until you can walk
Thank you Mooly. I'm frustrated with that little amp. Wanted to clear my head with something else for now. Come back to it fresh. I'm not giving up on it.
I'm trying not to get to far ahead of myself, but once you start looking into and buying items, working out the voltages. Its like falling down the proverbial rabbit hole.
I'm trying not to get to far ahead of myself, but once you start looking into and buying items, working out the voltages. Its like falling down the proverbial rabbit hole.
Or it wants two isolated 9 Vdc sources (they will be connected in series through this PCB and form +-9VDC, or +18VDC).
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I'm going to be getting back to looking at this. I've got a lot of spare time now.
I've done the checks mooly asked me to look into. Nothing power wise seemed to be happening on the board. I did the checks with the multimeter, none if the voltages that I expected to see at the areas I tested were present.
This could totally be down to me, my lack of knowledge and experience in in both audio electronics, and in electrons in general.
I've done the checks mooly asked me to look into. Nothing power wise seemed to be happening on the board. I did the checks with the multimeter, none if the voltages that I expected to see at the areas I tested were present.
This could totally be down to me, my lack of knowledge and experience in in both audio electronics, and in electrons in general.
and check again the copper is intact - follow the route (i.e. check for continuity) across the board for crucial tracks. (see pic of unpopulated board again)
Bear in mind there are lots of supposed 0V and ground pads, don't assume they are actually your ground ref for your meter measurements. (this is maybe why you're not getting voltage that you expect at some points)
It's the:
Bear in mind there are lots of supposed 0V and ground pads, don't assume they are actually your ground ref for your meter measurements. (this is maybe why you're not getting voltage that you expect at some points)
It's the:
Attachments
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I've got a box full of battery snaps. So all being well I'll have one that works.
I grew up in the 80s, never ending story was one of my favourite films, along with the usual, Terminator, The predator, RoboCop.
They just don't make good films now.
Anyways, I'll be checking back over this thread. Start from the power supply pads, check the traces, make sure the LEDs correctly inserted. Moving through the list again. Until the fault is found.
I grew up in the 80s, never ending story was one of my favourite films, along with the usual, Terminator, The predator, RoboCop.
They just don't make good films now.
Anyways, I'll be checking back over this thread. Start from the power supply pads, check the traces, make sure the LEDs correctly inserted. Moving through the list again. Until the fault is found.
It is a CMoy headphone amplifier (it is easily googled by an image). It wants a bipolar +-9VDC supply (accordingly to the schematics). The text in one of the descriptions says: "Power by 2x PP9 9V batteries (the rectangular ones)."
For example.
For example.
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That 2134 will run on as little as +/-2.5v, although potential output swing will be restricted..
Try soldering wires as shown below and solder in that jumper or reinstall the switch. See below.
I think this is a classic case of operator error. I don't think there is anything wrong with the board. The CMOY generates a pseudo ground using two 4.7K resistors and the supply must float! (grounded PSU could be a no no depending on whether the source feeding the CMOY is actually grounded.)
Confirm your supply is working - delivering 9V at the power connections. (You can also use 18V if you want - performance will be better)
0V is not ground!
This was designed to be powered by one or two 9V batteries in series for portable operation. In order to allow operation on a single 9V battery as simply as possible the whole thing floats and the resistive divider furnishes a connection at the half voltage point of the supply which becomes the ground reference point (pseudo ground). The op-amp inputs and outputs are centered on the supply voltage since the inputs are referenced to the ground reference point.
I think this is a classic case of operator error. I don't think there is anything wrong with the board. The CMOY generates a pseudo ground using two 4.7K resistors and the supply must float! (grounded PSU could be a no no depending on whether the source feeding the CMOY is actually grounded.)
Confirm your supply is working - delivering 9V at the power connections. (You can also use 18V if you want - performance will be better)
0V is not ground!
This was designed to be powered by one or two 9V batteries in series for portable operation. In order to allow operation on a single 9V battery as simply as possible the whole thing floats and the resistive divider furnishes a connection at the half voltage point of the supply which becomes the ground reference point (pseudo ground). The op-amp inputs and outputs are centered on the supply voltage since the inputs are referenced to the ground reference point.
