Tea-Bag Napisano Decembar 12, 2010 Share #837 Napisano Decembar 12, 2010 Well, Good Morning guys.I swapped some of the power resistors to Sp300's standards.So ~ .33, .66, .33 - using 1R/.5r 2R/1R, 1R/.5rBias sets around .562v across Upper and Lower, Middle set at 1.1, problem is offset is now -.640v, and wants to go in the direction of down, so I have no room on R12,25 (at min), so it looks like I got to lower R26 (390), R35 (220).Should I start by going half value on each?Other problem is CNY17 in both channels is 1.0v, so this seems to be another problem. Previous measurements were at 1.3v, no problem. So looks like I need to change something here. I assume R28 (200R) needs to be lowered or raised. So just putting this out here looking for encouraging ideas. I assume R28 would be better at 150R.Tea Link to comment Podeli na ovim sajtovima More sharing options...
sp300b Napisano Decembar 12, 2010 Share #838 Napisano Decembar 12, 2010 Well, Good Morning guys.I swapped some of the power resistors to Sp300's standards.So ~ .33, .66, .33 - using 1R/.5r 2R/1R, 1R/.5rBias sets around .562v across Upper and Lower, Middle set at 1.1, problem is offset is now -.640v, and wants to go in the direction of down, so I have no room on R12,25 (at min), so it looks like I got to lower R26 (390), R35 (220).Should I start by going half value on each?Other problem is CNY17 in both channels is 1.0v, so this seems to be another problem. Previous measurements were at 1.3v, no problem. So looks like I need to change something here. I assume R28 (200R) needs to be lowered or raised. So just putting this out here looking for encouraging ideas. I assume R28 would be better at 150R.TeaHi Tea - Check posts 801, 802, 803.I think You have to increase R35 to 300 Ohm approximately and try then what is going on.Once You will be able to set offset with R12, R25 properly, CNY 17 will be OK.Reminder hereR28 could go down, but I think it will be not necessary if You change R35 (increase).Please, try and report. Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Decembar 12, 2010 Autor Share #839 Napisano Decembar 12, 2010 @ Teanegative bias means that lower SS is more open than upper SSif you can't in same time to increase bias and null offset - with trimpot R25 , increase R26 to 470Rleave R28 as is - you need minimal voltage for led operation , and that resistor is set for that - minimal needed voltage Link to comment Podeli na ovim sajtovima More sharing options...
sp300b Napisano Decembar 12, 2010 Share #840 Napisano Decembar 12, 2010 @ Zen - Now I'm confused... what Tea has to do:1) To increase only R352) To increase only R263) To increase bothWhich one is correct ? Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Decembar 12, 2010 Autor Share #841 Napisano Decembar 12, 2010 don't try to confuse me - thats pretty easy these days if offset is negative - that means you need to more open upper SS so - scenario is : if - with R25 on max and R12 on min offset is negative - then increase R26 - to 470 or 510 ohms Link to comment Podeli na ovim sajtovima More sharing options...
sp300b Napisano Decembar 12, 2010 Share #842 Napisano Decembar 12, 2010 Tea disappeared - we confuse him completely Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Decembar 12, 2010 Autor Share #843 Napisano Decembar 12, 2010 naah - he's probably sleeping now Link to comment Podeli na ovim sajtovima More sharing options...
Tea-Bag Napisano Decembar 12, 2010 Share #844 Napisano Decembar 12, 2010 I am not sleeping! Working on this stuff like a good diy soldier.I tried R26 at 470R, brought down to -.500mv, then 680R, no down to four.So, try 500R or 1K pot for R25, or lower R35 to 100R?CNY pin 1 to 2 of DVM is 1.1vIt's like ZM says, R25 on max, R12 on min. Now Bias is higher, .640mv. Link to comment Podeli na ovim sajtovima More sharing options...
sp300b Napisano Decembar 12, 2010 Share #845 Napisano Decembar 12, 2010 I am not sleeping! Working on this stuff like a good diy soldier.I tried R26 at 470R, brought down to -.500mv, then 680R, no down to four.So, try 500R or 1K pot for R25, or lower R35 to 100R?CNY pin 1 to 2 of DVM is 1.1vIt's like ZM says, R25 on max, R12 on min. Now Bias is higher, .640mv.Play twist with (try to adjust offset with him) R25 - Could You make offset 0V ? Link to comment Podeli na ovim sajtovima More sharing options...
Tea-Bag Napisano Decembar 12, 2010 Share #846 Napisano Decembar 12, 2010 Play twist with (try to adjust offset with him) R25 - Could You make offset 0V ?No, it only went more negative on offset. Link to comment Podeli na ovim sajtovima More sharing options...
sp300b Napisano Decembar 12, 2010 Share #847 Napisano Decembar 12, 2010 No, it only went more negative on offset.I would try 300 Ohm instead of 220 Ohm on R35 Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Decembar 12, 2010 Autor Share #848 Napisano Decembar 12, 2010 set R25 to minimum - before increasing R26then go up turning R25what's , on earth , value for R35 at your pcbs ? Link to comment Podeli na ovim sajtovima More sharing options...
generg Napisano Decembar 12, 2010 Share #849 Napisano Decembar 12, 2010 no he is working hard.......... Last Active: 13 minutes agoCurrently:Viewing Topic: SemiSouth power Jfets Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Decembar 12, 2010 Autor Share #850 Napisano Decembar 12, 2010 I would try 300 Ohm instead of 220 Ohm on R35that way - he'll even more open lower SS and offset will go neg. even more Link to comment Podeli na ovim sajtovima More sharing options...
generg Napisano Decembar 12, 2010 Share #851 Napisano Decembar 12, 2010 hear the laughter that no one can hear.............. Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Decembar 12, 2010 Autor Share #852 Napisano Decembar 12, 2010 hear the laughter that no one can hear.............. Link to comment Podeli na ovim sajtovima More sharing options...
Tea-Bag Napisano Decembar 12, 2010 Share #853 Napisano Decembar 12, 2010 set R25 to minimum - before increasing R26then go up turning R25what's , on earth , value for R35 at your pcbs ?I lowered R25 pot, to 0, offset is -.760, turning higher lowers it down a bit to ~.5 to ~.4v.I checked R35, it is 220R.Before swap out of power resistors, both pots were near minimum. Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Decembar 12, 2010 Autor Share #854 Napisano Decembar 12, 2010 so ..... again :set R12 to minimumleave R35 as isif setting R25 to max can't bring you from negative offset -to 0 offset , then :turn back R25 to zero , increase value of R26 for max 220R ( from 390 to ,say, 610-620 (whatever you have in drawer) ) ;turn R25 up , to have 0 offsetset both Iq and offset - fiddling iteratively with R12 and R25Tea - these are simple thingsif you can't do it easily on Sunday afternoon - leave it for tomorrow Link to comment Podeli na ovim sajtovima More sharing options...
generg Napisano Decembar 12, 2010 Share #855 Napisano Decembar 12, 2010 sorry Zen Mod, I was amused by the communication structure between you, sp300b and tea-bag , it was a sort of comedy...... Link to comment Podeli na ovim sajtovima More sharing options...
generg Napisano Decembar 12, 2010 Share #856 Napisano Decembar 12, 2010 we will find the holy grail...... Link to comment Podeli na ovim sajtovima More sharing options...
Zen Mod Napisano Decembar 12, 2010 Autor Share #857 Napisano Decembar 12, 2010 sorry Zen Mod, I was amused by the communication structure between you, sp300b and tea-bag , it was a sort of comedy...... we will find the holy grail......now - it's my turn to ROFLMAO ........(even if today's communication isn't communication at all ........ you can't say who - amongst 3 of us - is more fucked in head today ) Link to comment Podeli na ovim sajtovima More sharing options...
Magura Napisano Decembar 12, 2010 Share #858 Napisano Decembar 12, 2010 structure :rofl:Magura Link to comment Podeli na ovim sajtovima More sharing options...
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