Ok .....🙂 Q3
T= 9.34
M= 9.45
B = 8.78
Q9
M= 0
Dare I believe first stage complete ... ?
Next step please ?
Rich
T= 9.34
M= 9.45
B = 8.78
Q9
M= 0
Dare I believe first stage complete ... ?
Next step please ?
Rich
Rich - Almost. I suggest you add a 50k resistor in parallel with R10, just to increase Vce a bit and ensure that Q3 is forward biased (Vcollector > Vbase > Vemitter or T > M > B). Your Q3 should then land around 8.5 volts which would be excellent.
Pierre
Are those readings with all JFET's installed? If so, everything is good.
Good idea 😉
...... Thanks all !
yep all fets in .... I have 47.5 K +2.5k on hand for testing purposes . I'll replace when I next make an order .
I think I should do the same thing on the other board to give you guys a break and practice some of the things you have helped me with on the first one ...
How say you ?
Rich
yep all fets in .... I have 47.5 K +2.5k on hand for testing purposes . I'll replace when I next make an order .
I think I should do the same thing on the other board to give you guys a break and practice some of the things you have helped me with on the first one ...
How say you ?
Rich
Hi Pierre ,
I put 50k in parallel and got Q3 in the 3's Should I experiment to get 8.5 V
R
Gents,
I got the second board done and got to the last fet and Q3 is acting up again .
My readings are good, but they are fluctuating +/- 0.5 volts from where they should be ...... sounds like the same problem I had before or could it be the Caps charging ?
Rich
Its all settled down now .... The reason the paralleled resistor didn't work is cus I had on bloody R7 .
Sorry ..
Next step is the out stage and seeking guidance .... Please ?
I got the second board done and got to the last fet and Q3 is acting up again .
My readings are good, but they are fluctuating +/- 0.5 volts from where they should be ...... sounds like the same problem I had before or could it be the Caps charging ?
Rich
Its all settled down now .... The reason the paralleled resistor didn't work is cus I had on bloody R7 .
Sorry ..
Next step is the out stage and seeking guidance .... Please ?
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This is without 50 k resistor !
Right board , Q6 collector = 7.52 VDC
Left board , Q6 collector = 8.00 VDC
Is this a problem ?
Right board , Q6 collector = 7.52 VDC
Left board , Q6 collector = 8.00 VDC
Is this a problem ?
Rich - What are the three voltages around Q3 (left and right boards) please. (I know I sound like a broken record). Just want to make sure all is good.
You could solder 47.5k in parallel with R10. The 50k value was not critical. Anything in that ball park will do.
Pierre
Left board
Q3 WITH 47.5K
T=9.36
M=8.66
B=8.00
Right board
Q3
T=9.56
M=7.10
B=6.42
and now the voltages have crashed on the second reading . F%$#%#^%@^% !
Q3 WITH 47.5K
T=9.36
M=8.66
B=8.00
Right board
Q3
T=9.56
M=7.10
B=6.42
and now the voltages have crashed on the second reading . F%$#%#^%@^% !
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Rich - I suggest you resolder R8 and R10 of that board. It is best to make sure the first stage is rock solid before moving on.
Pierre
Pierre
Those readings are good.
What happened? Have you got anything in parallel with R10?
I'm in the process of re-soldering R8,R10 and R7 .... I do have a solder joint that really concerns me . Its very difficult to get it to run ... !
R
R
Dab it with a new bit of solder, that will reflow the joint. Hold the board at a 45 degree angle, solder side down, the excess solder can be removed by running the iron down the component leg.
ITS LIKE A DIFFERENT MATERIAL ... I can't get the whole clear !.... any suggestions ? I know a little about bonding metals ... I made my living fabrication St/St and Ally ... But ,
this aint right ... The exact same hole of the other board was like this too ! I seem to have got lucky with that one though.
R
this aint right ... The exact same hole of the other board was like this too ! I seem to have got lucky with that one though.
R
