Ok, measuring the two square vias roughly under the heatsink I get a nice 23v +/-. So is it safe to assume that the CVS is working?
Finally sorted the BC 327 and 337 ... now I am wondering if I should also match all the résistors... Can I use the 121ohm Dale résistors I got from the GB without matching ?
Values go from 121.3 to 120.5... is this acceptable for the mirrors ?
Values go from 121.3 to 120.5... is this acceptable for the mirrors ?
Powersupply to the bords. You need minimum 2x +/- 25 Volt better 26 V sounds better you can hear that. If not, or only 23 V, the LED 's under
the Headsink are off or not fully on.
I have my Paradise with Peters " proto pre reg " now 3 weeks or 38 hours in Operation and I am absolutly happy Sound is fantastic. When I am back in Ireland I will give more Infos and Fotos, my be with
Alfreds " Calvin buffer" ?????🙂
The opligation is done, next up the freestyl 😀
So Long take it easy
Werner
You are totally sure when you have, taken a ampere meter, and used it to short the shunt output, and got a reading of 110mA's 🙂
You are totally sure that the CVS (above the CCS) is always at +3V above the CCV output voltage (even when shorted) 🙂
Use a lamp of 30Watt in series with the mains to do this all with some safety margin 🙂
Also, 26Vdc is the MINIMUM recommended input voltage for the PSU.
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Thanks for the feedback Werner. These are the 4th pair of boards I've built. I have 28v +/- going into the board from the PSU. The LED's under the heatsink are very definitely lit.
I shall continue measuring until i find something adrift. My meter isn't giving me any current readings at all, even against a 5v motor, so I'm guessing it's broken.
I shall continue measuring until i find something adrift. My meter isn't giving me any current readings at all, even against a 5v motor, so I'm guessing it's broken.
Can you please measure the voltage across R204 (the 10 ohm power resistor)?
Guessing at this point, but I would definitely check the little bipolars in the shunt reg (Q202, Q204) and eventually replace.......
hesener, I get a 1.49v drop on the (bad) negative rail and a 1.52v drop on the (working) positive rail.
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What semis are you using in that shunt (appart from the BC's) ?
Just curious.... after so much évolutions I start to believe some power trannies are preferable to others...
Just curious.... after so much évolutions I start to believe some power trannies are preferable to others...
RC i'm using toshibas on the heatsink for the npn and pnp. They were perfect on my last build.
Then 148mA is being delivered by the CCS, If Vce of the CCS power transistor is about 2 * LED = 3.6 - Vbe = 3 - 1.52V = 1.5V then all is well.
Sure, it works fine when the shunt isn't connected to the rest of the board, when when i close the bridge the voltage across the power resistor drops to 1.9v at one end and 0v at the other and the 9 LED's on the -rail go out.
I replaced the two 327 under the heatsink last night and I replaced the j113 and 327 out front. Neither made any difference to this issue. (yes I use a 1k resistor for the j113)
Would it make sense for me to try powering the rest of the circuit from my working pcb, and then I'd at least know if the fault is with the shunt or the amplification stage?
I replaced the two 327 under the heatsink last night and I replaced the j113 and 327 out front. Neither made any difference to this issue. (yes I use a 1k resistor for the j113)
Would it make sense for me to try powering the rest of the circuit from my working pcb, and then I'd at least know if the fault is with the shunt or the amplification stage?
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The question there is, is the 150mA still flowing (when the lights are out). If so, then the fault has to be in the pre-amp (not the PSU). So, measure the voltage across the 10 Ohm while the lights are out.
Sounds like a short on the neg rail in the amplifier. The likely place for this are the SMD caps on the bottom side, you may want to check those, as well as the underside of the PCB