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Old 30th December 2009, 05:40 PM   #3811
kevinkr is offline kevinkr  United States
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Originally Posted by Jeroen E. View Post
I tried to post a picture, but cannot figure out how. According to the faq there is an 'albums and pictures' link in the user control panel. Except that there really isn't. What am I doing wrong here?

But back to the subject. All that is left of the pad is bare PCB. There is a very small chance that it is repairable though: I noticed a tiny spot of solder on the rear edge of were the pad used to be, right at were the PCB-track starts. So if I retract the resistor lead while heating it, the remaining solder might just flow and form a new pad.
However, I noticed that solder by itself does not really stick to a PCB. Can anyone tell me whether they glue the pads on, or is it really just a question of letting the solder flow at the right temperature?
No, you will need to scrape a little of the solder mask of off the end of the trace where you see the solder blob, and very carefully solder a small piece of kynar 30ga wirewrap wire to that trace. You can form a loop to replace the missing pad or just bring it directly through the existing hole. Once you are sure it is working ok secure it with a little super glue.

Do not solder the resistors directly to these pads, 30yrs of experience and I made the same exact mistake. (I'm fortunate to have several boards - so the one I damaged is now a back up.) Instead use short flexible wire (an inch or so will do) from the two board connections and solder the resistor pair to those. The boards are made of bottom of the barrel phenolic (paper based) and the traces are 1oz copper or less and the adhesive used to secure them is not that strong either.
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Last edited by kevinkr; 30th December 2009 at 05:47 PM.
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Old 31st December 2009, 03:24 PM   #3812
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Thanks for the great advice! I am practicing on the tuner PCB: removing the top layer to get at the traces (more difficult than I thought, usually I scratch straight through the trace as well), soldering on traces and solderpads to find the limits, etcetera.
BTW: Yesterday I was talking with my girlfriend about the queen's christmas speech, wherein she said that all these contacts in the virtual world lead to an impoverished social life. Well, I have a problem in the Netherlands, and people from the USA, Italy, Poland, and Canada have chimed in with advice. How much more social can you get?
So thank you all, and have a good 2010.
Jeroen

PS: here's a pic of the problem.
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Old 1st January 2010, 10:59 AM   #3813
marosik is offline marosik  Poland
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it's a standart problem. use a male plug. solder it sraight in position. Your's pad's will be safe. photo below shows the type of the nest. use 3 pin nest.
big drop of solder should keep this nest in proper position.

Check something different. Solder a 20R rezistor on the R957. You gonna love this mod.
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Old 1st January 2010, 12:18 PM   #3814
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Quote:
Originally Posted by Jeroen E. View Post
Thanks for the great advice! I am practicing on the tuner PCB: removing the top layer to get at the traces (more difficult than I thought, usually I scratch straight through the trace as well), soldering on traces and solderpads to find the limits, etcetera.
BTW: Yesterday I was talking with my girlfriend about the queen's christmas speech, wherein she said that all these contacts in the virtual world lead to an impoverished social life. Well, I have a problem in the Netherlands, and people from the USA, Italy, Poland, and Canada have chimed in with advice. How much more social can you get?
So thank you all, and have a good 2010.
Jeroen

PS: here's a pic of the problem.
Have a nice 2010, Jeroen

And off course to all you guys on this forum.

Anton.
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Old 1st January 2010, 05:48 PM   #3815
kevinkr is offline kevinkr  United States
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Quote:
Originally Posted by marosik View Post
it's a standart problem. use a male plug. solder it sraight in position. Your's pad's will be safe. photo below shows the type of the nest. use 3 pin nest.
big drop of solder should keep this nest in proper position.

<snip>.
This is actually what I have done on both the damaged and undamaged pcb I have on hand. Works like a charm.. You may have a suitable connector that can be removed from one of the other boards.

Happy New Year to all!
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Old 2nd January 2010, 12:30 PM   #3816
Tony X is offline Tony X  France
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Quote:
Originally Posted by marosik View Post

Check something different. Solder a 20R rezistor on the R957. You gonna love this mod.
Sorry, Marosik, but could you be more precise. What do you mean by solder a resistor on the R957?
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Old 2nd January 2010, 12:53 PM   #3817
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Yes, Marosik, tell us more. What exactly did you do and what changes/improvements did you hear?

Fran
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Old 2nd January 2010, 03:48 PM   #3818
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hmmm - R957 supplies +5v to the internal DAC - since I use my Shiga only as a transport and don't need the DAC, I've actually removed R957 to reduce the +5v load.

whatever a 20R resister does it is only going to affect the analogue outputs - shouldn't have any effect on the dig out.
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Old 2nd January 2010, 06:02 PM   #3819
kevinkr is offline kevinkr  United States
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Originally Posted by herewegoagain View Post
hmmm - R957 supplies +5v to the internal DAC - since I use my Shiga only as a transport and don't need the DAC, I've actually removed R957 to reduce the +5v load.

whatever a 20R resister does it is only going to affect the analogue outputs - shouldn't have any effect on the dig out.
Removing the power to the dac probably isn't such a great idea - all of the digital signals driving the dac portion of the IC are now driving unpowered ports which may have the effect of overloading them depending on whether the device is cmos or bipolar - you may in effect be increasing the current consumed by other parts of the IC whilst also degrading its performance. I would carefully consult the chip data sheet to see if this is OK. If they do not specifically mention this as an acceptable choice you should leave it powered.
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Old 2nd January 2010, 10:01 PM   #3820
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Originally Posted by kevinkr View Post
Removing the power to the dac probably isn't such a great idea - all of the digital signals driving the dac portion of the IC are now driving unpowered ports which may have the effect of overloading them depending on whether the device is cmos or bipolar - you may in effect be increasing the current consumed by other parts of the IC whilst also degrading its performance. I would carefully consult the chip data sheet to see if this is OK. If they do not specifically mention this as an acceptable choice you should leave it powered.
I hear exactly what you're saying Kevin - I do have a full set of datasheets and refer to them regularly when experimenting on this board - unfortunately there is no specific mention of this on the DSP datasheet.

It has always seemed to me to be good practice to remove any 'unused' power users from any supply - although I must admit that the 'dead ends' that would remain inside the chip when I removed the DAC power was not something I had thought about
I actually removed R957 when I was clearing the board of the unecessary bits and perhaps got a bit carried away - In practice I don't think it has made any difference at all - positive or negative, but I like the idea of my supply going to the bits that use it and not the bits that don't ........ I may give it it's supply back next time the board is out for a mod and have a more critical listen!!
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