If the pins were touching it is more likely something in front of the regulators has been damaged. Check the voltage across these caps first. You need at least 18 volts DC across each.
The regulators are prone to failure as reverse biased diodes from output to input and output to ground are not provided. Mine failed too, so I attached these on the underside of the PCB
Unfortunately I already desoldered them but I am relatively sure that we (a friend of mine) checked it before.
So long story short, I could use those others regulators from the link, one positive one negative?
Anyone knows something about headnhifi shop? It just says that Stefan is on longer vacation (good for him 🙂) but I would need a new power adapter and as far I understood it, the one the o2 is using is a "special"one?
"special" means, AC to AC stepdown transformer, which has no rectifier and is not SMPS based (obviously). Hint- Transformer based adapter is heavier than SMPS based.
So, anything above 12V AC min. to 20V AC max. with current capacity of 500mA or above will do. Higher voltages will result in higher heat dissipation across 7812 /7912 regulator
One can also "remove or desolder" rectifier /filter section from any AC to DC transformer-based adapter and then use it .
CAUTION -USE DMM TO CHECK EVERYTHING, DC ADAPTER WILL DESTROY O2!
I use 12V AC adapter salvaged from old an Creative speaker.
Attachments
12V AC after rectification and filter gives 12X1.41 gives approx 16.91-0.8 = 16.11V DC which is well above the 2V drop requirement of regulators. Usually, 12VAC gives output above 13V AC at no load. O2 presents a very light load to any transformer
Okay...got any link to an EU shop? I checked Conrad but the only thing they have are DC adapters?
http://nwavguy.blogspot.com/2011/08/o2-details.html
- Power Jack – For AC line power or charging, connect the AC wall transformer to this jack. The standard plug is 5.5mm outside and 2.1mm inside. The transformer output can be anywhere from 14 VAC to 20 VAC and at least 200 mA. Don’t use more than 20 VAC or less than 14 VAC (except for the 12 VAC transformers listed in the parts list). Do not try to use a DC adapter. A DC adapter may appear to work if batteries are installed, but the amp will be at least partly running off the batteries.
Thanks.
I hate my approach sometimes. What is this thing in the back called for the input of the power supply? I destroyed mine...🙁
Something like this? https://www.conrad.at/de/p/lumberg-...-einbau-vertikal-5-7-mm-2-mm-1-st-738687.html
what kind of measurement it needs?
EDIT: So for the one in the back of the desktop version.
https://lh3.googleusercontent.com/h...8Z6wINGnbZE_CKuU4TyQ=w930-h1240-no?authuser=0
I hate my approach sometimes. What is this thing in the back called for the input of the power supply? I destroyed mine...🙁
Something like this? https://www.conrad.at/de/p/lumberg-...-einbau-vertikal-5-7-mm-2-mm-1-st-738687.html
what kind of measurement it needs?
EDIT: So for the one in the back of the desktop version.
https://lh3.googleusercontent.com/h...8Z6wINGnbZE_CKuU4TyQ=w930-h1240-no?authuser=0
Last edited:
I know but just in that moment I broke the socket 🙂 So I need a new socket as well.
The problem is:
It was actually on my desk, I built it but it was only working with the batteries so I never used it and forgot about it. After picking up again (a year or so) I realized that the power supply was broken. (I measured it but it is 0)
I checked in the meantime a different power supply in an audio shop but it still didn't work without the batteries. So I checked everything again with a friend which has an actual idea about electronics (I don't, obviously) and we came to this conculsion:
Fast forward: I also realized that the end of the cables (right beside R6) that goes to the socket were broken at the socket. While desoldering I got stock in the hole of the socket and melted it...
NOW I hope that: With the new fixed regulators (which I just put in) and a new, working power supply and the socket (that have to order now) it should finally work as a desktop version.
Well...New socket is a couple of cents? New power adapter 15+15 shipping. So yeah, definetely. It will be more than enough for me but I really want to finish it 🙂
I had raised my concerns with NWAVGUY back in 2011, when he was active, regarding running O2 on higher AC voltage, overheating of regulators and lack of protection diodes. But he replied that he had very little space to adjust for heatsinks or diodes. His opinion was that as per datasheets, those regulators can handle that kind of heat dissipations.
Please see attch., 11.5V AC old dusty Creative adaptor, but actual measured voltage is 14.2V AC. I have many such salvaged 12V AC trannies with o/p no-load voltage between 13-15VAC. 230V AC is standard in our country, but actual measured voltage is between 235-240V AC
Attachments
Last edited:
I understand that 12V declared and 14V real is okay. However, we all have different voltages in our houses. I mean real measured 12V is not enough.