JSR05 Q and A

[peranders]

a) Yes

b) Yes

c) I have D45H11 which also Farnell has.

d) Yes

e) R7 = R8//R9 (preferable) Gain is set by R8 and R9 and of course you can use a pot

f) Yes

[MacMiniHiFi]

As P-A was kind enought to post the answers I will post also the questions :wink:
a) It seems that all the electrolytic caps, DZ1 and H1 are physically inverted as compared to the JSR03 board. Correct?

b) For IC2 it is ok to use LM329DZ with cathode leg cut and mounted exactly as you/I did on the JSR03 boards (the silkscreen labels looks the same on the 03 and 05 boards)?

c) For T4 I am having trouble in finding a PNP variant of D44H11 in TO-220 case. Any suggestions (preferably from Farnell)?

d) T1 and T6 = BC550C and mounted as the BC556 on JSR03?

e) A god pair of R7, R8 and R9 resistors for 15V (470R / 1k /  845R ok?)? Could I possibly use a pot in place of R8 or R9 (2k or 1k?) for more precise adjustment of the voltage (I always seem to get about 0.5V of target in the end)?

f) All other components and solder-bridges below the board are the same on both JSR03 and 05. Correct?

[peranders]

I'll hope you'll manage to get the negative regulator working.

[MacMiniHiFi]

I got both positive and negative supplies working nicely in the sense that I get good regulate voltage out :-)
One issue though. Even if the regulators appears to be working nicely the red LED does not light up on any of the two supplies ?! In my experience with JSR03 a bad sign.....
Any explanation/solution?
Thanks,
Nic

P.S. 24V supply, LM317/337, 6.9V ref, 15V out.

[peranders]

Something is wrong here. Voltage across H1 and R14?

[MacMiniHiFi]

JSR03
H1=2.67V
R14=1.88

JSR05 (same probe positions):
H1=-2.72V
R14=-1.93V

[peranders]

Which colour have the LED's?

[MacMiniHiFi]

Red, Farnell 1003228

[peranders]

Is the red LED lit? A red LED should have 1.6-1.8 V across it. Is the LED mounted correctly?

[MacMiniHiFi]

The LED is not lit (thats the issue). I have always had darn trouble getting LED's mounted in the right orientation :x The more I think about catode, anode, square and round pads, long and short legs etc. the more confused I get.... For LED's I need dummy instructions like "long leg in square pad" but I know that it is not your job to provide this.
I thought that I would not get any regulation if mounted wrongly.
Nic

EDIT: Changing the LED orientation solved the problem. Funny that it also worked in the wrong direction.......

P.S. Do you think a 15V toroid + rectification will yield high enough tension for a 15V reg?

[peranders]

The long leg of the LED is "plus". Make sure _before_ you solder the LED about the polarity, especially important if you aren't sure.

Most LED's have also a marking in the plastic of the cathode.

15 VAC might work. You must have 4-5 V extra and 15 VAC recified and smoothed will end up with 19-22 V.