....and failing that, further pondering on that green cap strapped across the supply rails! It appears to have a 5V rating, which would indicate a high capacity.
Hoppy
Yes, a 5V rating would indicate high capacity for that size, like 0.1 F or more. Are we wasting our time here? Regarding the schematic discrepancies, I have built it both ways and find the schematic I posted "AkyDoubleTL494.gif" works the best, but is not exhibiting self run. I set up each oscillator separately, then ran them both together. The H4 oscillator I set up for as low a duty cycle as possible and maximum high frequency. Then I set the voltage adjustment so that the H4 oscillator triggers on and off "in a binary manner" by triggering on the ripple voltage on the internal bus. This then gives the HF packets (picket fence) with about a 50% duty cycle of "packets on to packets off". Then I introduce the B4 oscillator with a much lower frequency and low duty cycle. There are many frequency adjustments of this oscillator that cause very discrete bands of dimming then getting very bright, a lot more action to the controls than with the earlier schematic. Since I don't have a clue where the sweet spot is, one could spend an eternity hunting for the best setting position of the 5 controls. GL: Yes, those varistors also come in aqua color from other manufacturers. Regarding John Blade's reverse engineering: I am trying to verify this but need a higher quality scanned version of the print. There are some circled sections of the initial version that need developing, as well as other areas. I will try compare it to the other reverse engineered print of the board. All for now, will experiment more as time permits. For Peter: embellishments (emoticons, quotes, bold, italics etc.) to the post are not working for me, is this my computer problem? I'll try a different computer.
« Last Edit: 2014-05-09, 14:31:43 by ION »
---------------------------
"Secrecy, secret societies and secret groups have always been repugnant to a free and open society"......John F Kennedy
|