Looks like 13.5 at the collectors with square wave with probe connected directly to the collectors. Where I was testing was after the transformers earlier, hence the 33v squarewave
Just now repeated the test by touching the light bulb and pos rail wires together for about 2 seconds. It didnt immediately recover, but only had to power down and wait about ten seconds. But, when it does this, it reads 10mvac at the collectors.
at the rectifier, looks like 2mvac on both sides, not 2vac on both sides.
all four test points this time were on both sides of the rails. Two at the collectors directly, and two at the rectifier inputs. 13vac square wave at collectors, and 33vac at teh rectifier inputs.
Just now repeated the test by touching the light bulb and pos rail wires together for about 2 seconds. It didnt immediately recover, but only had to power down and wait about ten seconds. But, when it does this, it reads 10mvac at the collectors.
at the rectifier, looks like 2mvac on both sides, not 2vac on both sides.
all four test points this time were on both sides of the rails. Two at the collectors directly, and two at the rectifier inputs. 13vac square wave at collectors, and 33vac at teh rectifier inputs.
Correct, I soldered a wire to the audio board. This wire goes to one side of the lamp. The wire that has been removed from the PS board to the audio board is just a flying lead. I have another wire coming from the other side of the lamp. I am touching the wire from the lamp that is not soldered to the audio board to the flying lead that comes from the PS board.
Does not appear there is a q803 on this board. there are only two transistors aside from the big ones and they are labeled c945 which has its emitter going to chassis ground, base to a 11k resistor, and collector to a neg side of a regular diode and a 27k resistor.
the other transistor is labeled P2M and under it is 5Z. pins are labeled KAG on the board? All the normal looking transistors have BCE labeled. This one has no pins labeled and is just called KAG.
the other transistor is labeled P2M and under it is 5Z. pins are labeled KAG on the board? All the normal looking transistors have BCE labeled. This one has no pins labeled and is just called KAG.
Ok! Well, I think we are on to something now! With the SCR removed, it will maintain voltage for 30 seconds (I didnt wait longer, I just stopped the test then) after that, I also touched the wire directly to the audio board for pos rail. No change in voltage. So I guess this means something in the power supply? SCR at fault maybe? Thanks so much for your patience working with a n00b such as myself. Im learning here.
Alright, had a chance to get back to it. I followed this guide for testing the SCR.
Testing SCR - Power Electronics A to Z
My results:
neg on anode and pos on kathode and reading is 4.5Mohm
pos on anode and neg on kathode and reading is OL
shorting gate to anode with neg lead on kathode, still no continuity
from this, I am thinking I can conclude that the SCR is defective?
Testing SCR - Power Electronics A to Z
My results:
neg on anode and pos on kathode and reading is 4.5Mohm
pos on anode and neg on kathode and reading is OL
shorting gate to anode with neg lead on kathode, still no continuity
from this, I am thinking I can conclude that the SCR is defective?
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