Just completed a Pork Barrel and I'm not getting any chorus effect.
Voltages on both the 4558 and 072 look good but the 3007 and 3101 seem off.
Can anyone tell me where/what to look for?
3007
1. 8.9V
2. 4.38V
3. 5.4V
4. 8.13V ---Not good docs say 0V
5. 0V ---Not good
6. 4.27V
7. 8.67V
8. 8.67V
3101
1. 8.94
2. 4.27
3. 0
4. 4.28
5. Vari
6. 4.37 Docs say should be 0
7. Vari
8. 8.13
Make sure you have turned the trim pot to full and check for a solder bridge on your bbd chips
Quote from: FastEdTex on February 20, 2017, 05:51:29 AM
Just completed a Pork Barrel and I'm not getting any chorus effect.
Voltages on both the 4558 and 072 look good but the 3007 and 3101 seem off.
Can anyone tell me where/what to look for?
3007
1. 8.9V <--docs say should be 4.38
2. 4.38V
3. 5.4V
4. 8.13V ---Not good docs say 0V
5. 0V ---Not good - re-checked schematic and this is correct - ground
6. 4.27V
7. 8.67V
8. 8.67V
3101
1. 8.94
2. 4.27
3. 0
4. 4.28
5. Vari
6. 4.37 Docs say should be 0
7. Vari
8. 8.13
The values below are from the PDF doc for the Pork Barrel
IC1 4558 IC3 MN3007
1 6.2 1 4.94 - 4.99
2 6.2 2 4.95 - 4.99
3 6.19 3 4.31
4 0 4 0
5 6.2 5 0.62
6 6.2 6 5.45
7 6.2 7 4.65
8 9.19 8 9
IC2 MN3101 IC4 TL062
1 0.62 1 varies
2 2.4 - 2.7 2 4.54 - 4.59
3 7.3 - 7.8 3 varies
4 varies 4 0
5 4.65 5 4.54 - 4.58
6 0 6 4.58 - 4.6
7 4.61 7 varies
8 9 8 9.19
I have subbed a TL072 for the TL062 but I'm sure that is OK as the voltages look right.
I have adjusted the trim pot so my voltages look the same as the published voltages. (so I know the trim pot is working)
I have pulled the board from the enclosure and checked all the solder joints with a magnifying glass and no bridges.
I re-flowed any joint that remotely looked suspect.
Check the polarized caps and they are all correctly orientated and correct values.
I'm still lost.
I need to re-check those voltages in the PB. I think I have a couple written down incorrectly. I would hold off before doing anything else (should be able to check in the morning).
Quote from: madbean on February 21, 2017, 12:02:57 AM
I need to re-check those voltages in the PB. I think I have a couple written down incorrectly. I would hold off before doing anything else (should be able to check in the morning).
Me and my sanity will be standing by! :o
Quote from: madbean on February 21, 2017, 12:02:57 AM
I need to re-check those voltages in the PB. I think I have a couple written down incorrectly. I would hold off before doing anything else (should be able to check in the morning).
Re-read the docs and saw that there was a note about the jumper pads.
I used sockets so I could change the jumper config without soldering. Just in case I could not find a 3007 that worked or was not counterfeit.
I have jumper horizontal across the sockets and I get voltage reading on the one closest to the 3007 so I'm guessing the sockets are not the problem.
Solder must have flowed or there would be no voltage at the top of R20 and pin 1 of the 3007.
Did you check the resistor values? That is an easy mistake... I've made many times
Quote from: blearyeyes on February 23, 2017, 04:57:20 PM
Did you check the resistor values? That is an easy mistake... I've made many times
Thanks for the reply, all replies are welcome! ;)
I did that last night, pain staking as it was, with a resistor color code chart, schematic, parts list in hand.
checked all the Caps as well.
Found no errors - checked and re-flowed all solder points night before last.
Got the thing making a chorus effect now. Only took 3 MN3007 IC's before I got one that worked. >:(
Touched up all the soldering the night before and it still was not working. Didn't start working until I inserted the 3rd MN3007.
I got 10 sets of the 3007's and the 3101's from a seller in china on eBay. So if I can get 2 more sets out of the group that work, I'm ahead of the curve on price per set. HOWEVER, I still say $10.95 from Small Bear for a 3007 that is guarantied to work, is a lot less of a headache! and the way I would go in the future.
Quote from: FastEdTex on February 23, 2017, 08:44:03 PM
Quote from: blearyeyes on February 23, 2017, 04:57:20 PM
Did you check the resistor values? That is an easy mistake... I've made many times
Thanks for the reply, all replies are welcome! ;)
I did that last night, pain staking as it was, with a resistor color code chart, schematic, parts list in hand.
checked all the Caps as well.
Found no errors - checked and re-flowed all solder points night before last.
Got the thing making a chorus effect now. Only took 3 MN3007 IC's before I got one that worked. >:(
Touched up all the soldering the night before and it still was not working. Didn't start working until I inserted the 3rd MN3007.
I got 10 sets of the 3007's and the 3101's from a seller in china on eBay. So if I can get 2 more sets out of the group that work, I'm ahead of the curve on price per set. HOWEVER, I still say $10.95 from Small Bear for a 3007 that is guarantied to work, is a lot less of a headache! and the way I would go in the future.
Yea I have some eBay chips that I haven't tried yet. Really hit and miss. Most of the U.S. computer/ electronic waste is sold to china and there is a large industry that strips the chips and re-surfaces them. I'm glad you got it working!
Quote from: blearyeyes on February 23, 2017, 04:57:20 PM
Yea I have some eBay chips that I haven't tried yet. Really hit and miss. Most of the U.S. computer/ electronic waste is sold to china and there is a large industry that strips the chips and re-surfaces them. I'm glad you got it working!
Thanks!
Thought I would post my first etch job on the enclosure the Pork Barrel is going in.
(https://s17.postimg.org/jm6dwkhy7/IMG_0602.jpg)
That's a really nice etch!