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Old 25th December 2012, 07:05 PM   #2961
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The point is, commercial Li-Ion batteries are not "naked" cells but always have electronics associated with them to avoid overcharging or deep discharging. Otherwise they'd never be safe. As a DIYer, you typically have access to the bare cells only.

As for C6/C7, see here. In a nutshell - unless you have actual problems with the negative regulator, .22F should be fine.
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Old 25th December 2012, 08:44 PM   #2962
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Re: lithium cells again, agdr posted an idea here.
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Old 26th December 2012, 06:18 AM   #2963
archro is offline archro  China
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Hi sgrossklass, thank you for your nice replay.
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Old 29th December 2012, 04:25 PM   #2964
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Hi, i'm just in the making of an O2. Is it possible to leave the switches (gain switch, on/off switch) off the amplifier, if I want a simpler look?
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Old 29th December 2012, 04:28 PM   #2965
6L6 is offline 6L6  United States
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Leave them on, just make a faceplate that hides them.
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Old 29th December 2012, 04:46 PM   #2966
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Quote:
Originally Posted by 6L6 View Post
Leave them on, just make a faceplate that hides them.
Oh I see now, if I push the switch I can just fit it behind the faceplate :P Thanks.
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Old 31st December 2012, 02:39 AM   #2967
kuished is offline kuished  Singapore
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Hey guys, I was testing my O2 as per nwavguy's guide. All test were fine until I came to this step:

Check The Raw DC Voltages With amp turned on, no batteries installed, and no headphones, the DC voltages should measure approximately as shown in the diagram to the right (click for larger or right click and open in a new window) with the negative DMM probe connected to the negative terminal of BT1 (ground) as above, Its important to verify the voltage shown on D3 and D4 are within 0.1 volt of each other but opposite polarities. For example if the banded end of D3 is 17.5 volts then the un-banded end of D4 should be 17.4 to 17.6 volts. If there a greater difference, something is likely wrong. See the Troubleshooting Section.

(was on AC power, no batteries. Switch was on. U1 to U4 were all socketed.)

I measured D3 and D4 correctly (around 24 and opposite polarity), and P8 and P4 of U4 correctly as well (around 11.7 and opposite polarity), as well as D1 and D5 correctly (12 and opposite polarity).

However, as I was removing my probe from D1, my hands slipped and contacted against the metal tab of U6. There was a audible crackling sound. I went back to check all the 3 pairs of voltages as mentioned above, and now they are ALL off.

D1 now measures +15.6V, D5 is -12V, D3 +17.5V, D4 is +20V (the number kept flashing on this one), P4 on U4 is -11.7V and P8 on U4 is +16V.

After remeasuring everything. I switched everything off. I realised that C2. C3. C4, C5, U5 and U6 were extremely hot.

I have no ideas where to go from here, and I would appreciate anyone's kind help!
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Old 31st December 2012, 04:03 AM   #2968
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With the AC adapter plugged in, and the O2 switched OFF, measure the DC voltage across C4, C6, C5, and C7. Report back with those voltages.
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Old 31st December 2012, 04:05 AM   #2969
kuished is offline kuished  Singapore
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Sorry, I made a small mistake, D3 was measured at -17.5V, not +17.5V
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Old 31st December 2012, 04:16 AM   #2970
kuished is offline kuished  Singapore
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Quote:
Originally Posted by sofaspud View Post
With the AC adapter plugged in, and the O2 switched OFF, measure the DC voltage across C4, C6, C5, and C7. Report back with those voltages.
Okay, I'm not entirely sure how to ensure consistent voltage polarity in the reading, but here goes:

C4 was +17.5V, C5 was around +19.6V (number kept flashing) (I kept probes in the same orientation, aka when board was flipped upside down, black was on the left contact and red was on the right contact for both C4 and C5)

C6 was +17.2V and C7 was -11.95V (I kept the probes in the same orientation across C6 and C7 as well)

Components heated up real quickly.
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