electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
Live streaming at radio.electro-music.com

  host / artist show at your time
  Jez Adventures in Sound
Please visit the chat
 Forum index » DIY Hardware and Software » Ken Stone designs - CGS
CGS63 Power Supply Delay not working
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [8 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
sonicwarrior



Joined: Dec 22, 2005
Posts: 229
Location: Cologne, Germany

PostPosted: Thu Jan 17, 2013 12:07 pm    Post subject: CGS63 Power Supply Delay not working
Subject description: Works now (had my PSU's connected the wrong way)
Reply with quote  Mark this post and the followings unread

I have build a CGS63 Power Supply Delay with Omron G5V-2-DC5 relays for +/- 15 V and +5 V and used a 10K directly instead of the 47K but now as I connected it with the PSU it doesn't work. I measure 0 V for all three voltage outputs (+5V, +15V, -15V).
This is how it looks like:

Posted Image, might have been reduced in size. Click Image to view fullscreen.

The voltages on the socket for the 741 opamp are as expected (at least at pin 7: +15V, pin 3: about 8V, 0V or nearly 0V at the other pins).

Is there something obvious I did wrong?

Last edited by sonicwarrior on Sun Feb 03, 2013 3:48 am; edited 1 time in total
Back to top
View user's profile Send private message
sonicwarrior



Joined: Dec 22, 2005
Posts: 229
Location: Cologne, Germany

PostPosted: Thu Jan 17, 2013 3:31 pm    Post subject: Re: CGS63 Power Supply Delay not working Reply with quote  Mark this post and the followings unread

sonicwarrior wrote:
The voltages on the socket for the 741 opamp are as expected (at least at pin 7: +15V, pin 3: about 8V, 0V or nearly 0V at the other pins).


When I measure with the 741 in the socket it's the same except for pin 6 were I get about +14.2V. So I think the 741 is working.

At the link after the BC338 I get nothing. Looking at the BC338 datasheet it looks like the footprint on the PCB is wrong. So I desoldered the BC338 and put it in in reverse but that didn't change anything. Crying or Very sad
Back to top
View user's profile Send private message
sonicwarrior



Joined: Dec 22, 2005
Posts: 229
Location: Cologne, Germany

PostPosted: Fri Jan 18, 2013 12:28 pm    Post subject: Re: CGS63 Power Supply Delay not working Reply with quote  Mark this post and the followings unread

Today I recognized that I looked at the wrong datasheet (Vishay) and was confused by another one. It seems the original BC 338 direction was correct.

So I still have no clue what's wrong and what further stuff I could check. I suspect something is wrong before the relays with the delay/driver circuit as I don't measure any voltage at the point 'RL2' (just before the relays at the topmost link).

Or maybe my BC 338 is faulty as the only thing between pin 6 of the 741 (with the measured +14.2V) and the link is the BC 338 and the two resistors (47K & 10K).

Or is the HFE of the BC 338 important? (I guess not as Ken's page only lists BC338 and no subtype)
Back to top
View user's profile Send private message
marvkaye



Joined: Mar 14, 2011
Posts: 225
Location: Fla

PostPosted: Sat Jan 19, 2013 12:16 am    Post subject: Re: CGS63 Power Supply Delay not working Reply with quote  Mark this post and the followings unread

sonicwarrior wrote:
Today I recognized that I looked at the wrong datasheet (Vishay) and was confused by another one. It seems the original BC 338 direction was correct.

So I still have no clue what's wrong and what further stuff I could check. I suspect something is wrong before the relays with the delay/driver circuit as I don't measure any voltage at the point 'RL2' (just before the relays at the topmost link).

Or maybe my BC 338 is faulty as the only thing between pin 6 of the 741 (with the measured +14.2V) and the link is the BC 338 and the two resistors (47K & 10K).

Or is the HFE of the BC 338 important? (I guess not as Ken's page only lists BC338 and no subtype)


Having been down similar paths with other projects I feel your pain Crying or Very sad

I decided to breadboard the circuit to see if I could come up with some suggestions for you.... first of all I didn't have any BC338s on hand so I subbed a 3904 in its place. I figured since the transistor was only acting as a switch in this circuit the choice of NPN couldn't be too critical. I also didn't have any PCB relays handy so I just put an LED in their place and used an 820R current limiter for RCO. I also didn't install the 1N4002 diode since it looks like it's there as a snubber for the flyback voltage created when the relay coils are de-energized so it didn't make any sense to me to install it in parallel with my LED.

That being said, I put everything else together as outlined on Ken's CGS63 page, using the 10K instead of 47K for the resistor between the 741 output and 3904 base. With the 1uF cap and a setting of about 12.6v (adjusted using the trimmer) on the 741's pin2 the circuit times out and turns on the load in just a little over a second, which is too short a time to take any meaningful voltage readings during the delay. I put a 4.7uF cap in parallel with the 1uF and without changing the trimmer setting the delay now lasted almost 15 seconds... plenty of time to get good readings. You might want to tack a similar cap onto the bottom of the PCB in order to slow things down during testing... it really makes seeing what's going on much easier.

I assume you're using a 15V supply... me too. Power up your board & adjust your trimmer to get about 12V on pin 2 of the 741. Doesn't matter whether it's during the delay time or after, that voltage should remain constant, as should pin 7 @ 15V, and pin 4 @ 0V. During the delay pin 6 measures around 1.3V and after the comparator fires it goes to 14.2V. Pins 1, 5, & 8 should all be 0V. Pin 3 should be at zero before you apply power, then after power is applied it should climb all the way up to that 14.2V range as well... as it passes the voltage referenced on pin 2 the voltage change on pin 6 should take place.

Have you checked your relays to make sure they're working? I see you've got 5V coils and jumpered from the 5V rail to their high side... Do you for sure have 5V on that rail?? If so, power up the board and jumper from RL2 to ground (0V)... the relays should energize and you should now have power on your distribution buses... check your +&- 15 and your 5v, just to be sure. (I assume your supplies are hooked up correctly as well.... hmmm?? Those voltage readings are actually the first that should be taken... just sayin....)

If the voltages on the 741 were right (or close) and the relays are working, about all that's left is the trannie... the emitter goes to ground (0V) and the base goes from about .6v during the delay and up to almost .8v when the comparator fires. When the 338 is off during the delay you should see almost the supply voltage at the collector and that should go to about zero when the delay is up.

Well, there you have it. I hope this helps...

<marv>
Back to top
View user's profile Send private message
sonicwarrior



Joined: Dec 22, 2005
Posts: 229
Location: Cologne, Germany

PostPosted: Sat Jan 19, 2013 8:23 am    Post subject: Re: CGS63 Power Supply Delay not working Reply with quote  Mark this post and the followings unread

Thanks for breadboarding.

I've now replaced the BC338 with a BC549 and discovered something strange:
Between digital ground (for the +5V line) and analog ground (for +/-15V) I measure +5V.
Between the +5V line and analog ground there is 0V.

I don't have a tri output PSU but one linear +/- 15V and a second switching PSU to get the +5V. So maybe that's the cause of the problem. I connected V- of the +5V PSU with digital ground on the CGS63 PCB and V+ to the +5V line there.

Do I have to connect both grounds together? I thought they are already connected via the earth line of the 230 V connector. Confused Embarassed
Back to top
View user's profile Send private message
marvkaye



Joined: Mar 14, 2011
Posts: 225
Location: Fla

PostPosted: Sat Jan 19, 2013 9:46 am    Post subject: Re: CGS63 Power Supply Delay not working Reply with quote  Mark this post and the followings unread

sonicwarrior wrote:
Thanks for breadboarding.

I've now replaced the BC338 with a BC549 and discovered something strange:
Between digital ground (for the +5V line) and analog ground (for +/-15V) I measure +5V.
Between the +5V line and analog ground there is 0V.

I don't have a tri output PSU but one linear +/- 15V and a second switching PSU to get the +5V. So maybe that's the cause of the problem. I connected V- of the +5V PSU with digital ground on the CGS63 PCB and V+ to the +5V line there.

Do I have to connect both grounds together? I thought they are already connected via the earth line of the 230 V connector. Confused Embarassed


Actually, earth ground on your line cord isn't necessarily common with the power supplies' zero volt pins... not unless you make it so by connecting them together. Since you're using two separate power supplies you have the option of making the grounds common between the two supplies or not. Since the 5V is typically used for digital stuff and the +/-15V are your analog supplies, keeping the 0V connections separate and disconnected from the line earth isolates the two supplies, ostensibly keeping any digital noise that sneaks back to those supply lines separate from your analog & audio signals. However, keeping these supply "grounds" isolated obviates the ability of the relay coils being driven by the 5V supply to pull up since the emitter of the transistor in the CGS63 connects to the analog "ground" and not the 5V "ground". The answer is to jumper the 0V pins between the two supplies at the input side of the CGS63, commoning those grounds together. Alternatively you could keep the 0V traces isolated, disconnect the emitter from the trace it goes to presently and jumper it to the 0V side of the 5V supply... that way the circuit can be complete through the switched-on transistor to the relay coils and all would be well. This, of course, assumes that everything else over on the comparator side of the circuit is working correctly as well. Another consideration, though, is that the current being sent to the base to switch on the transistor is coming from the analog side of the circuit, and I don't know if the trannie will see it with its emitter connected to a "ground" not referenced to the base current... it's probably much easier to simply hook the two 0V lines together under the circumstances.

Again, I hope this helps..

<marv>
Back to top
View user's profile Send private message
sonicwarrior



Joined: Dec 22, 2005
Posts: 229
Location: Cologne, Germany

PostPosted: Sun Feb 03, 2013 3:47 am    Post subject: Re: CGS63 Power Supply Delay not working Reply with quote  Mark this post and the followings unread

Sorry for the missing feedback. I have been ill until now.

It works now. Thanks again for the great help marvkaye. Much appreciated.


For those who like to know more:

1. I fixed the PSU's by connecting the grounds with each other.
2. Set up 12V at pin 2 of the 741 as suggested. The readings of the DMM at the 741 were all right.
The relays didn't power up.
3. Then I connected the jumper/link between the transistor (collector) and the +/- 15V relais to 0V and: The relays were working now (and I heared some low volume high frequency noise, maybe from the +5V switching PSU).

Prior to that I got a reading of +2.5V at the jumper/link which is definitely not the needed 0V.

At the transistor base I read +0.78V.
4. Conclusion: It's the transistor which I had changed to a BC549 one.
I desoldered the BC549, put a socket in and tried out the desoldered BC338 and voilà: It works. Smile
Back to top
View user's profile Send private message
marvkaye



Joined: Mar 14, 2011
Posts: 225
Location: Fla

PostPosted: Sun Feb 03, 2013 11:43 am    Post subject: Reply with quote  Mark this post and the followings unread

XLNT!!!! (not because you were ill... sorry to hear that, that sux... XLNT other stuff!) I'm glad that I was able to help. It was a fun exercise, even more so with the happy ending. Keep up the good work.

<marv>
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [8 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » Ken Stone designs - CGS
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use