Anyone have a picture of a fully stuffed sissy board for me to compare for and obvious and silly mistakes.
Nothing is jumping out at me from the circuit.
.. dB
Nothing is jumping out at me from the circuit.
.. dB
considering that I didn't manage to do that - big frontal pic of populated pcb ... why don't you post pics of both your pbs , so I can see is there anything wrong ?
in next few days I'll include both eagle pcb screenshot and few photos of real deal
thank you - hopefully this is not too large
edit - found a slightly better one
I will try and get more head on pictures with better lighting tonight
..dB
Last edited:
thank you - hopefully this is not too large
edit - found a slightly better one
I will try and get more head on pictures with better lighting tonight
..dB
everything looking good , even if I can't see some important things - did you forgot two wire bridges , made of tiny isolated wire ?
go back to first post , and walk through entire list again .....
is opto oriented as needed , that famous zener of SIT gate oriented against silkscreen ....... do you have adequate number of diodes ( those not shown on schematic and you have place for them are for Babelfish M25 , not for Sissy) etc.......
in any case - if you have doubt in anything , just ask
Well, that was at least part of the problem - hopefully leaving those diodes in didn't damage anything 
this was a very stupid oversight!
Both sides again with the exact same behaviour.
Current in 0R1 starts at 170mA and slowly climbs , offset at around 700mV - I can adjust this down but the current climbs as I do this. If I tweak P1 - I can increase the current flow but at minimum setting the current slowly climbs to 200mA at which time I shut it down.
I looked at all resistor values again and made sure the little opto looked in the correct orientation.
I will take a break and then look with fresh eyes - it has to be something staring me in the face.
..dB
this was a very stupid oversight! Both sides again with the exact same behaviour.
Current in 0R1 starts at 170mA and slowly climbs , offset at around 700mV - I can adjust this down but the current climbs as I do this. If I tweak P1 - I can increase the current flow but at minimum setting the current slowly climbs to 200mA at which time I shut it down.
I looked at all resistor values again and made sure the little opto looked in the correct orientation.
I will take a break and then look with fresh eyes - it has to be something staring me in the face.
..dB
Well, that was at least part of the problem - hopefully leaving those diodes in didn't damage anything
Both sides again with the exact same behaviour.
Current in 0R1 starts at 170mA and slowly climbs , offset at around 700mV - I can adjust this down but the current climbs as I do this. If I tweak P1 - I can increase the current flow but at minimum setting the current slowly climbs to 200mA at which time I shut it down.
I looked at all resistor values again and made sure the little opto looked in the correct orientation.
I will take a break and then look with fresh eyes - it has to be something staring me in the face.
..dB
Congratulations, I feel that you are very happy
Well, that was at least part of the problem - hopefully leaving those diodes in didn't damage anything
Both sides again with the exact same behaviour.
Current in 0R1 starts at 170mA and slowly climbs , offset at around 700mV - I can adjust this down but the current climbs as I do this. If I tweak P1 - I can increase the current flow but at minimum setting the current slowly climbs to 200mA at which time I shut it down.
I looked at all resistor values again and made sure the little opto looked in the correct orientation.
I will take a break and then look with fresh eyes - it has to be something staring me in the face.
..dB
why don't you wait and leave current to go up?
that 3m3 cap is charging pretty slowly
if everything is as intended to be , offset will go down and you could set everything in prescribed current range ...... everything from 1A5 to 2A
when setting , just observe offset , it is of secondary importance (meaning second thing to set) , while Iq is of premium one
is it possible to have damaged the HALL chips? is there a way to check them to see if they are working?
I will try letting it ramp up tonight and see what happens. It is just very odd that it doesn't work as designed, so I know I have something that is not working as ZM designed it to.
My THF51S are not absolutely matched to the 9240 mosfet - fets are 4.12 at 1.8A while tokin SIT is 3.7 at 1.8A , I hadn't anticipated this to be a problem.
..dB
I will try letting it ramp up tonight and see what happens. It is just very odd that it doesn't work as designed, so I know I have something that is not working as ZM designed it to.
My THF51S are not absolutely matched to the 9240 mosfet - fets are 4.12 at 1.8A while tokin SIT is 3.7 at 1.8A , I hadn't anticipated this to be a problem.
..dB
What is the range the SITs should be? Mine are just under 3, at 2.97 & 2.96, or is there no relevance to that. Given what mine are, and dBel84's question above what specs should the 9240 mosfet have to go with it?
Thanks in advance,
Russellc
Thanks in advance,
Russellc
Not yet. When I get home tonight, this is the plan. I was trying to think ahead but will report back on findings..dB
IRFP9140 (or 9240 , whatever) - whatever Ugs ..... it's rarely bellow -4V
SIT ..... I manage to squeeze Opto in 200mV successfully , so go figure ..... up to -3V8, without sorting IRFP
SIT ..... I manage to squeeze Opto in 200mV successfully , so go figure ..... up to -3V8, without sorting IRFP