Rank: Member
Groups: Member
Joined: 9/18/2010(UTC)
Posts: 10
Location: UK
|
OK, have just finished wiring up a placid / buff 2, placid bp/ivy iii combo.
Set up the BP + Ivy first following the manual, and everything seemed fine.
Configuring the placid also seemed to go well, and after powering up the buffalo seems to be ok (regulator leds are on as is the auto-mute led. lock is off but i've not connected a spdif signal yet)
Now to the oddness - I configured the placid for 5.4V output. Once the buffalo is connected however the output of the placid meters at 6.4V. A drop I could understand (if i'd misconfigured the required current) but that increase just scared/confused me so I cut power as quickly as I could. With the buffalo disconnected the placid is back to 5.4V, connect it and it goes to 6.4..
Anyway, it's late and I'm going to give up for the night, but just thought I'd do a bit of a 'it shouldn't do that, should it?' check before risking blowing stuff up tomorrow. Entirely possible that I'm doing something utterly idiotic, in which case feel free to point and laugh.
If not however, any ideas would be very welcome.
|
|
|
|
|
|
Rank: Administration
Groups: Administration, Customer
Joined: 10/24/2006(UTC)
Posts: 2,868
Location: Massachusetts, USA
Thanks: 2 times
Was thanked: 141 time(s) in 134 post(s)
|
1) Get some rest.
2) Check the battery in your meter.
I remember testing a amp once and was seeing DC voltage at the output that was higher than the rail voltages (not possible). Was my meter's battery.
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 9/18/2010(UTC)
Posts: 10
Location: UK
|
Brian Donegan wrote:1) Get some rest.
2) Check the battery in your meter.
I remember testing a amp once and was seeing DC voltage at the output that was higher than the rail voltages (not possible). Was my meter's battery. Cheers, no 2 occured to me as a possible culprit about 10 seconds after posting, I should really think first type second. No 1 is definately a good idea, reckon I'll pursue that one immediately.. Thanks for the ridiculously speedy reply!
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 9/18/2010(UTC)
Posts: 10
Location: UK
|
My meter was fine it was me that was the problem.
I had QP2 in backwards, despite the fact the orientation is clearly drawn on the board. Goodness knows how I managed that one.
I should then have noticed that I was adjusting VR1 not VR2 to change output voltage, but it seems I was on some sort of moronic crusade.
Anyway, I've now reversed the offending part but can no longer adjust voltage via either VR. I'm guessing QP2 didn't like being the wrong way around, or my ham fisted attempts at desoldering.
First step will be to order a replacement - would a BC560C rather then B work? It's available from farnell which is a lot more convenient for me then mouser/digikey.
Looks to be identical but with higher current gain - I'm afraid I'm to ignorant to know if this is a problem in this circuit. (I suppose now would be a good time to read up on how it actually works)
I'm just hoping I didn't fry anything downstream..
ugh.
|
|
|
|
|
|
Rank: Administration
Groups: Administration, Customer
Joined: 10/24/2006(UTC)
Posts: 2,868
Location: Massachusetts, USA
Thanks: 2 times
Was thanked: 141 time(s) in 134 post(s)
|
The C part should be fine.
|
|
|
|
|
|
Forum Jump
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.
