Well I installed a BD139 in Q2. I have no idea how I could have done that, but I did. All the rest of the components look correct. what dammage could I have done with this?
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remove it, replace with BD140
if you need that BD139, check with Hfe test on DMM or with simple diode check or whatever gizmo you have for that
check also small BC556
or just replace it if you have spares
don't despair , your'e not first nor last being stupid
though, I can't remember last mistake I made, but I'm certainly sure it was 12 levels of stupidity above yours
if you need that BD139, check with Hfe test on DMM or with simple diode check or whatever gizmo you have for that
check also small BC556
or just replace it if you have spares
don't despair , your'e not first nor last being stupid
though, I can't remember last mistake I made, but I'm certainly sure it was 12 levels of stupidity above yours
Zen Mod, thank you for all your help.
I cooked the little BC556 and will have to order another one(more). I guess I will have to start ordering duplicate parts from now on...to compensate for the dummy factor.
Again your help is very much appreciated.
I cooked the little BC556 and will have to order another one(more). I guess I will have to start ordering duplicate parts from now on...to compensate for the dummy factor.
Again your help is very much appreciated.
The parts arrived this morning and I replaced the dead BC556.
Checked it over again before turning it on and all values look good.
Now I am getting max 10v/-11v from each trim pot (DM at V+ GND and V- GND) cant get close to the 15v spec. The AC input voltage from transformer is about 39v when checking at AC1/CT/AC2.
Checked it over again before turning it on and all values look good.
Now I am getting max 10v/-11v from each trim pot (DM at V+ GND and V- GND) cant get close to the 15v spec. The AC input voltage from transformer is about 39v when checking at AC1/CT/AC2.
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decrease R8 and R9 to, say, 6K8
even if I'm surprised that you can't get 12V
anyway, decrease them
just in case , check that you have 5V across voltage references
Thanks Zen Mod,
6K8 was not enough on the positive rail. I ended up going down to 5k on both sides, Now both rails are good at +15v and -15v.
The DC offset didn't give any troubles and I was able to zero it on both channels.
Are there any other checks I should be making now?
6K8 was not enough on the positive rail. I ended up going down to 5k on both sides, Now both rails are good at +15v and -15v.
The DC offset didn't give any troubles and I was able to zero it on both channels.
Are there any other checks I should be making now?
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sorry, I wrote 6K8 thinking about 12V for rails ( which I have in Iron Pumpkins)
you did good
as I said, just check do you have 5V at voltage references - LM336 ref. zener diodes
do not forget porn and to inform us how it sounds for ya
you did good
as I said, just check do you have 5V at voltage references - LM336 ref. zener diodes
do not forget porn and to inform us how it sounds for ya
ah, there is the reason for the 11v.
I have yet made another error....2.5v (LM336Z-2.5)not the 5v required.
So by compensating with resistors is this OK to operate under this condition or will there be stability or other issues?
I have yet made another error....2.5v (LM336Z-2.5)not the 5v required.
So by compensating with resistors is this OK to operate under this condition or will there be stability or other issues?
Nice! I should have the 820R's by the end of the week. Really looking forward to listening to this.
I expect I will be coming to you for a turtle in the coming months.
I expect I will be coming to you for a turtle in the coming months.
you can use it as is, before getting 820R
it'll just have little shabbier rails, good enough for start enjoying it
it'll just have little shabbier rails, good enough for start enjoying it
Finished up the Iron pre yesterday with the 820R's and rest of the wiring in the temp chassis.
After passing the initial listen on the "test" system I moved it over to may main one, currently an F5.
It works, nothing exploded, and all the smoke stayed in! But there appears to be significant LF roll off when comparing to the ACP+ or B1K (apart form the LF it sounds very nice). I am guessing there is something similar to what codyt was experiencing in post #1263. I will have to look into where I could have created this issue with the transformer wiring. (please ignore the terrible temporary LED butchery)
After passing the initial listen on the "test" system I moved it over to may main one, currently an F5.
It works, nothing exploded, and all the smoke stayed in! But there appears to be significant LF roll off when comparing to the ACP+ or B1K (apart form the LF it sounds very nice). I am guessing there is something similar to what codyt was experiencing in post #1263. I will have to look into where I could have created this issue with the transformer wiring. (please ignore the terrible temporary LED butchery)
Attachments
found it, post#1274, codyt powered it groundless
as I can see , in post #1394, it would be logical that there is proper GND
so, we need confirmation that there is proper firm AC on both AC pads, ref to CT
as I can see , in post #1394, it would be logical that there is proper GND
so, we need confirmation that there is proper firm AC on both AC pads, ref to CT
