Salas hotrodded blue DCB1 build

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#4,503
AndrewT said:
You could add 2Vac of turns to each secondary.
you end up with a 14+14Vac transformer.

That is enough to run a DCB1.
Click to expand...

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.
 
#4,504
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.
 
#4,508
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
 
#4,511
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
 
#4,513
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
 
#4,516
Like this?
An externally hosted image should be here but it was not working when we last tested it.


Or like thi$?😀
FLIR-E8-Promotion.jpg
 
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