Anyway I have recieved Two of the PWM3F boards in the mail from a person that Built them and couldn't get them to work.
One of them, he has Totally Fried it. The Other is Repairable.
In order to Fix this one, I did some serious investigation of the schematic and the circuit board. Sorry, I'm Not very Impressed.
1) Looking at the Schematic, I have found some Errors on the pinout of the opto isolators.
2) Even with these resistor and capacitor changes as shown here and elsewhere in this topic, it will not work properly, if at all.
****************************************
QUOTE:
** CAP CHANGES:
channel 1- 0.0047uf
channel 2- 0.01uf
channel 3- 0.047uf
RESISTOR CHANGES:
R4,R5,R6- 10k to 1k
R7,R8,R9- change to zero ohm jumper wire.
****************************************
3) The 100K trimpots for adjusting the Frequencys are Too Large of a values. Making it Totally Impossible to accurately tune this circuit to the required frequencys.
I have now revised this circuit so it will operate and allow for a More Reasonable Adjustment range on the frequencys.
I do Not have any Specifications for the "Specific Function" of U1b, U2b or U3b, so I can't address the issue with these as to weither they function correct or not, with the values shown.
** So I won't comment on this section at this time.
I Still have a few Details to work out but I should have these done in a day or two.
I am NOT Posting the detail of my changes on here, But I will give them out to persons who email me and ask for them.
Take care.......GaryStatistics: Posted by chemelec — Mon Oct 29, 2007 4:38 pm
]]>