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Old 13th January 2012, 12:58 PM   #981
Zen Mod is offline Zen Mod  Serbia
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Quote:
Originally Posted by oiphy View Post
ok everything hooked up. when starting the bulb gives of bright light then turns off. so what should I messure now?

sorry - I must go now

' be back in few hours
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Old 13th January 2012, 01:02 PM   #982
tinitus is offline tinitus  Europe
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Originally Posted by Zen Mod View Post

remark about jims audio was/is general

that PSU pcb is generic one - their steal is in fact of using FW name on it
indeed, in general, yes

and shows even more how much credit Nelson Pass really deserves, when he choosing to stay and support us
no doubt a dilemma, and a 'challenge'

members have walked away fore much much less than that
just a silly 'reminder'
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Old 13th January 2012, 01:15 PM   #983
oiphy is offline oiphy  Norway
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Default jims audio sucks period.

It was not my intension to "start" something. but I'we read so mutch about other members finnished their amps.... I want to... me to
And CUDOS to Mr Pass himself. for all his exelent work. You other guys.. deserves the best of thanks to.
BTW: bt is glowing nice and dim for now
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Old 13th January 2012, 03:34 PM   #984
AndrewT is offline AndrewT  Scotland
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What power of bulb is fitted in your bulb tester?
What equipment is powered by the PSU.

If the PSU is only the rectifier and smoothing caps then the bulb should not glow.

Can you safely measure the mains voltage arriving at the primary and before the bulb tester?
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Old 13th January 2012, 03:56 PM   #985
oiphy is offline oiphy  Norway
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its a 50w spotligh bulb, gu10socket. as to mainsvoltage in wall socket 228.9vac after bulb 226.8vac
and the deep six is connected aswell as the biasboard

Quote:
Originally Posted by AndrewT View Post
What power of bulb is fitted in your bulb tester?
What equipment is powered by the PSU.

If the PSU is only the rectifier and smoothing caps then the bulb should not glow.

Can you safely measure the mains voltage arriving at the primary and before the bulb tester?
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Last edited by oiphy; 13th January 2012 at 04:17 PM. Reason: incomplete answer
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Old 19th January 2012, 08:59 PM   #986
oiphy is offline oiphy  Norway
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Default biasing problems

so I started to bias today and got in problems right away...
seems I'm not able to get bias over 84,8mVDC or once I turn trimpot to lowest value it jumps to approx 150mV but falls to stable 84,8mV... checked all resistors and they are the right ones. 3x15Kohms and 1x4,75Kohm trimpot are 5k and 1k... on the bias bord.
btw I get the output dc to 0.06v or so.. any ideas?? where do I start to look, what do I meassure?? Could it be that r28 should have lower value?
HELP!

could it be pirated tl431?? ebay
orded new TL431ACL TL431 PRECISION SHUNT REGULATOR - TEXAS now...... just in case
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Last edited by oiphy; 19th January 2012 at 09:13 PM. Reason: tl431
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Old 19th January 2012, 09:34 PM   #987
oiphy is offline oiphy  Norway
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Default nevermind...removed the lb tester then it's ok :)

Quote:
Originally Posted by oiphy View Post
so I started to bias today and got in problems right away...
seems I'm not able to get bias over 84,8mVDC or once I turn trimpot to lowest value it jumps to approx 150mV but falls to stable 84,8mV... checked all resistors and they are the right ones. 3x15Kohms and 1x4,75Kohm trimpot are 5k and 1k... on the bias bord.
btw I get the output dc to 0.06v or so.. any ideas?? where do I start to look, what do I meassure?? Could it be that r28 should have lower value?
HELP!

could it be pirated tl431?? ebay
orded new TL431ACL TL431 PRECISION SHUNT REGULATOR - TEXAS now...... just in case
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Old 19th January 2012, 10:05 PM   #988
oiphy is offline oiphy  Norway
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Default haha bias stable at 258mV

Finaly got it right.... bias stable at 258mv
however the heatsink is bearly getting warm.... could I bias it higher?? like 500mv like nelson speaks about in ba2 initial turn on and adjustment? What is the differens in sound and so on? anyone got any ideas for a newbe

Thanks to zen man for elping out the other day.

stig
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Old 23rd January 2012, 09:58 AM   #989
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Leave the amps on for an hour or so to see how hot the heatsinks get before turning up the bias. Also make sure of your ambient temp. If you are testing the amps in a cool workshop the heatsinks will stay relatively cool compared to a warmer household temp.
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Old 23rd January 2012, 10:18 AM   #990
oiphy is offline oiphy  Norway
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Quote:
Originally Posted by Backbones View Post
Leave the amps on for an hour or so to see how hot the heatsinks get before turning up the bias. Also make sure of your ambient temp. If you are testing the amps in a cool workshop the heatsinks will stay relatively cool compared to a warmer household temp.
amp has been on for 24 hours in the livingroom ambient temp is 22Celsius. The heatsink is around 30C. so I will try to up the bias. However.. is this going to affect the sound in a good way? The higher bias the better sound?
thanks
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