Hi all,
Two question:
1. Why some guys uses 3.3uF for C4 when manual requires 2.2uF. Any impact of increasing/decreasing capacitance there?
2. What value of elcaps will be recommended to put right prior shunts in pre box ( to feed them from umbilical cord coming from PSU located in separate box)?
Thank you.
Two question:
1. Why some guys uses 3.3uF for C4 when manual requires 2.2uF. Any impact of increasing/decreasing capacitance there?
2. What value of elcaps will be recommended to put right prior shunts in pre box ( to feed them from umbilical cord coming from PSU located in separate box)?
Thank you.
1. Because they recycle used very expensive capacitors from other projects. Anything more than 2.2uF the interstage won't let it play a major role. Subsonic roll off is pre determined earlier. Only when to drive under 10K pre.
2. Same as the main ones in the PSU box if you feel like creating a Pi filter with the umbilical parasitic resistance i.e. some termination heavy filtering before entering the shunts. In my installation I had no RF or SMPS near etc but you may judge for yourself in your own installation by comparing schemes subjectively.
2. Same as the main ones in the PSU box if you feel like creating a Pi filter with the umbilical parasitic resistance i.e. some termination heavy filtering before entering the shunts. In my installation I had no RF or SMPS near etc but you may judge for yourself in your own installation by comparing schemes subjectively.
Sorry Marra, but no known pitfall we experienced to put a thumb on. Human error in stuffing, a bad semi, overheated LED, who knows. Light them all up one by one, do every imaginable visual and correct parts stuffing inspection. It can be an error of omission even. Something you forgot to stuff or solder.
I've been checking my pcb's and it looks like I got confused by the Q3x;y;z designation for the BC560 and soldered it in the outer position by mistake.Will this have taken anything else out on power up?
Just be lucky you did not burn some major semi during the initial power on. Use your bulb tester and cross your fingers. In case you stumble again, post a good picture. You never know what the hawk eyed builders may spot here.
In case it won't be a go we will analyze what else it may took with it. No earlier disaster data for that Q3x Y-Z stuffing fault as we speak. Bulb saves for a quick test I guess.
In case it won't be a go we will analyze what else it may took with it. No earlier disaster data for that Q3x Y-Z stuffing fault as we speak. Bulb saves for a quick test I guess.
Thank you.
I have big RFI entry unit in PSU box and now I hesitate about magnetic junk...
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...And check semis are good, don't use the same wrong positioned semis without looking. Q3x is a K117. Q3Y is a 560.
I'm a bit worried that the sinks rests on the circuit prints... There is only the laquer between. I'm thinking on puting something between just to be sure.
Any thoughts about this?
Any thoughts about this?
Better solder its legs when half mm before rest than using something that will possibly become a mess trapped in heat over the long run. Use paper spacer and then pull it out or something clever to create a tiny gap before soldering it steady. Its only at the edges over some traces, but if it will ease your mind take care of it. The legs are heavy and the load is light, no way it will go anywhere. 2mm thick board eyelets root it well.
But no problems in the tests when resting normally so far.
But no problems in the tests when resting normally so far.
Hi.
Question about the LEDs.
From my Measurements I got for almost all LEDs
1.87-1.89V. I used a 9v battery (which actually supplies around 9.3) and a 1.5k ohm resistor.
Now - with these values I can't hit the targets for the 3 or 4 LEDs array .
Is it really that matters ? I guess I have an accuracy of 2-4% instead of 1-2 %
I am building the kit for MM.
Thanks
Question about the LEDs.
From my Measurements I got for almost all LEDs
1.87-1.89V. I used a 9v battery (which actually supplies around 9.3) and a 1.5k ohm resistor.
Now - with these values I can't hit the targets for the 3 or 4 LEDs array .
Is it really that matters ? I guess I have an accuracy of 2-4% instead of 1-2 %
I am building the kit for MM.
Thanks
The quartets being much alike between channels is the priority. Not the absolute value Vs 7.75V ref. 7.5-7.8V ref is good for bias. 5.6-5.9V ref for the triplets is good too.
I replaced the BC560 and put the new one in the right position;unfortunately no change.With the bulb tester connected the p/s voltage drops to 24v and the 15R resistor gets hot.No led's light up.Here's where I wish my diagnostic skills were better.
Start from the DC input. First to bias the 9610 CCS are the LEDs triplet. See if you can make them shine one by one with DMM in diode mode (confirm it has the ability on a new LED first) or with the battery and resistor. One or more may be dead from a hot iron or reversed?
See if the (-) probe to LEDs that they will shine one way or another is on a square pad as it should.