With standard 17V rails it can drive an F4 roughly up to 15W RMS 8Ω and you can also reconfigure the voltage gain with R6.
It takes sensitive loudspeakers for such a combination to musically work well though. To can develop satisfying dynamics.
I think I have destroyed the first led in one of the ledbars (the one close to the diodes), probably was not careful enough during the test. It will not light up and in the continuity tester in the DMM I get the reading about 1900 while on all other leds I get about 1470. Could I get away with desoldering the bar, cutting the leds of the first led and soldering a single red led there?
You can also use the DMM's diode mode instead of continuity if it outputs no less than 2V. Can test light up red yellow amber and most green Leds. Clever band aid solution to substitute with regular ones across the two broken bar-Leds by the way. Leds most usually fail open.
DCSTB ready, dual 2x18 transformers 50VA input. With open load, DCSTB output on the side with the band-aid leds:
-17.30, +17.24.
On the other board: 17.18
-17.13, +17.18
Is it ok with those differences between the boards or should I aim for closer values?
I noticed that the second led and the top one light but the light is dim in the problematic led bar.
-17.30, +17.24.
On the other board: 17.18
-17.13, +17.18
Is it ok with those differences between the boards or should I aim for closer values?
I noticed that the second led and the top one light but the light is dim in the problematic led bar.
The voltage values are measuring very usable to a DCG3 as for now. Also order a replacement Led-Bar to properly restore. The band-aid underboard Leds maybe stealing VF voltage space from the ones next to them. Or they got partially hit. The first segment Led is probably compromised too. What was the gone bad experiment that hit the bar?
I guess accidentally shorting with the DMM while probing with the 9V battery on, thus hitting a led with 9V. I was curious to measure the voltage drop to check that the values were reasonable. Probably here applies the saying "curiosity killed the cat". Other than that I can't imagine anything reasonable.
If you are not already a fan of LTSpice you should give it a try for "feeding your curiosity". The digital smoke dissipates much more quickly than real smoke...
What DMM model you use? If it puts out 2V or higher in diode check mode it can also safely light Leds and read VF. Not DCSTB working bias ~5mA mA level VF because DMMs usually employ internal current limiting for saving shorts and battery life. But lighting the Leds satisfactorily enough to validly compare VF with other Leds on same method.
It's an old 20y old mastech. It has a combined continuity/led test mode. But tired enough instead of using it I tested with an external battery to ensure the proper operation of the led bar. Connected the battery across 5 leds with the ledbar soldered on the board and used the multimeter to measure voltage drop across 1,2,3,4 leds etc. And then move up to cover all the leds in the bar. I see that the light of the led closer to the heatsink in the third bar, counting from left to right, does not light up well compared to the rest, although the measurements in the DCSTB output seem fine. I dont' remember testing it, but I am not sure. I guess this one will have to be replaced too.