I will do a measurement first. The transfo's are rated @220VAC prim. So...adding 230-240 to them will rise the 12VAC sec also. Gonna take a look.
should I take 2 in parallel (two transfo's)...for increasing the 30VA....which is maybe to low for a stage one warm-rodding
For sure I have to measure this with a load on it.
30VA & 28Vac (14+14) gives an AC current rating of 1070mAac.
That is equivalent to a continuous maximum current rating of ~535mAdc when feeding a capacitor input filter (the DCB1).
If you draw 60mAdc, then you are using ~11.2% of the rating on the +ve side. The -ve side draws a bit more depending on how you set up your relay drivers.
If you hot rod to 200mAdc then you are using ~37.4% of the rating. This should still run cold if the transformer was any good to start with. It is worth checking your transformer's idle current over the full range of mains voltage, 216Vac to 254Vac.
Is 200mAdc worth trying?
I always recommend that for continuous duty, the transformer be limited to <50% of it's DC capacitor input rating.
That is equivalent to a continuous maximum current rating of ~535mAdc when feeding a capacitor input filter (the DCB1).
If you draw 60mAdc, then you are using ~11.2% of the rating on the +ve side. The -ve side draws a bit more depending on how you set up your relay drivers.
If you hot rod to 200mAdc then you are using ~37.4% of the rating. This should still run cold if the transformer was any good to start with. It is worth checking your transformer's idle current over the full range of mains voltage, 216Vac to 254Vac.
Is 200mAdc worth trying?
I always recommend that for continuous duty, the transformer be limited to <50% of it's DC capacitor input rating.
STAX,
Glad you found the mix-up. Everyone of us has done the same thing at one time.
It takes longer to measure each R before the build, but, doing so allows you to pair L&R channels a little closer by swapping the minor value differences. Can I hear the difference? Probably not, old cloth ears. But I don't mix up values any more either.
Ron
Glad you found the mix-up. Everyone of us has done the same thing at one time.
It takes longer to measure each R before the build, but, doing so allows you to pair L&R channels a little closer by swapping the minor value differences. Can I hear the difference? Probably not, old cloth ears. But I don't mix up values any more either.
Ron
Toshiba and Linear both specify 10Vds for Idss measurement.
9V is pretty close and is generally good enough for rough batching.
Scorpion board troubleshooting. ..
Well, well I found the culprit. ...on LEDS in one of the triplets (non-working side) was "open" ...When my stubbornness pushed me to get an even better measurements matching, I probably overheated one and ended up with a bad connection (no signal continuaty) between the LED and the following component.
Found it while doing a continuity test. Just had to put a tiny copper jumper underneath the board and the thing finally worked.
Final measurements
LEDS: 9,86V and 9,93V
DC Offset: 1,0mV and 1,3mV
Vdrop: 1,28v and 1,36V (down from 1,47V)
Good to go?
Thanks a lot to you all
Regards
Scorpion
Well, well I found the culprit. ...on LEDS in one of the triplets (non-working side) was "open" ...When my stubbornness pushed me to get an even better measurements matching, I probably overheated one and ended up with a bad connection (no signal continuaty) between the LED and the following component.
Found it while doing a continuity test. Just had to put a tiny copper jumper underneath the board and the thing finally worked.
Final measurements
LEDS: 9,86V and 9,93V
DC Offset: 1,0mV and 1,3mV
Vdrop: 1,28v and 1,36V (down from 1,47V)
Good to go?
Thanks a lot to you all
Regards
Scorpion
Salas,
I bought the temperature probe, here are the results with a Mills 1,25R @ 12watts ccs..
Results were measured OUTSIDE the enclosure
Ccs resistors: around 65°C
Rectifier diodes: 56 +/- 2 °C while sinked
Mosfets: 34 +/- 2°C
Heatsinks: 48 +/- 4°C
Temperatures varie slightly on almost every readings (thus the +/-), so stated values are averages.
Regards
Scorpion
I bought the temperature probe, here are the results with a Mills 1,25R @ 12watts ccs..
Results were measured OUTSIDE the enclosure
Ccs resistors: around 65°C
Rectifier diodes: 56 +/- 2 °C while sinked
Mosfets: 34 +/- 2°C
Heatsinks: 48 +/- 4°C
Temperatures varie slightly on almost every readings (thus the +/-), so stated values are averages.
Regards
Scorpion
Like this?
Or like thi$?
An externally hosted image should be here but it was not working when we last tested it.
Or like thi$?
Like this?
An externally hosted image should be here but it was not working when we last tested it.
Or like thi$?
Wow !!!!
More like the one above but blue in color and not by Fluke. Paid around 50$ for it. Probably average stuff, but it gave me an idea...
Regards
Scorpion