Hello again,
Finally I ended with the build of such ambitious project (including the expansion board). My first mistake was not reading the complete instructions and soldered the IC7 BEFORE the complex calibration process... In the desoldering process I broke one of the pins of the not cheap MN3005. OK, I resolved now to socket it just in case and installed a new one (no Chinese fake).
After my first attempt to biasing the pedal, I could achieve echo but distorted (I can easily deduce that the wiring is correct. Refering to the forums, some users experienced such issue and some claims that changing some resistances the problem is gone. But now in my second attempt the things went even worse. I become absolutely no echo signal. The Level control works and the Blend too. Although I still did not measured voltages and did not audioprobed yet, the case is confusing. Was the socketing not a good idea? Was something fried in the way? Well, I attach some pictures now. Apparently there are no cold joins but I can check with a magnifying glass again. Same thing with the wiring. In the meantime, if there is some seasoned builder around who can give me some advice or helping hand, would be great!!
Nice regards,
Ariosto
Some more pictures:
Can't say anything without voltages.
Quote from: Scruffie on March 16, 2019, 12:06:51 AM
Can't say anything without voltages.
THANKS FOR THE QUICK ANSWER!!!
I am sort of incompetent with electronics (and even so I succeeded with most of my buildings! Including the Naughty Fish, the Aquaboy and the Stage Fright). I must take a look at some Youtube tutorials about how to make it correctly and -as Arnold Schwarzenegger once said- "I´ll be back".
Quote from: Scruffie on March 16, 2019, 12:06:51 AM
Can't say anything without voltages.
Hey, I am here again. I learnt quickly how to measure voltages and did my job. Well, the values I´ve got are not far away from the ones in the Total Recall PDF document. Now I hope there is some good soul out there to give me a helping hand with the build.
Here the measurements:
IC1: IC3: IC6:
1: -7.3 1: -6.51 1: 0
2: -7.3 2: -3.25 2: -7.46
3: -7 3: -3.15 3: -6.59
4: -14.66 4: -14.66 4: -6.59
5: -6.74 5: -7.18 5: -14.84
6: -7.4 6: -7.41 6: -7.47
7: -7.4 7: -7.41 7: -1.93
8: 0 8: 0 8: -13.82
IC2: IC4: IC7:
1: -13.43 1: -7.41 1: 0
2: -12.78 2: -7.41 2: -7.46
3: -12.78 3: -7.06 3: -11.49
4: -14.66 4: -14.66 4: -11.64
5: -12.86 5: -8.53 5: -14.84
6: -12.67 6: -8.76 6: -8.76
7: -4.78 7: -8.76 7: -8.76
8: -12.86 8: 0 8: -13.85
9: -12.86
10: -6.74
11: --8.41 IC5: IC9:
12: -12.87 1: -7.41 1:Varies
13: 0 2: -7.41 2: -7.09
14: -12.78 3: -7.18 3: Varies
15: -12.78 4: -14.66 4: -14.84
16: -13.45 5: -6.13 5: -7.12
6: -6.74 6: -7.12
7: -6.74 7: Varies
8: 0 8: 0
IC8: IC10(TRXPN): IC11(TRXPN):
1: -7.48 1: 0 1: 0
2: -7.35 2: -7.46 2: -7.46
3: -7.22 3: -5.34 3: -12.13
4: 0 4: -5.33 4: -12.13
5: 0 5: -14.82 5: -14.84
6: 0 6: -7.46 6: -7.46
7: -14.84 7: -2.98 7: -12.82
8: -14.84 8: -13.86 8: 0
9: -14.84
10: -7.47
11: -7.47
12: -14.84
13: -7.47
14: 0
REG LM7915
I: -23.1
G: 0
O: -15
IC6 pins 3 and 4 must be -10.12 in my pcb measues only -6.59. IC7 pin 3 and 4 are in my build around 11.49 and must be 9.71. I think the rest are barely slightly different but I am a noobie.
I didn't see in your pictures that you're trying to use 2 x 3005 and 2 x 3008, the 4047 clock is only good for driving 2 x 3005 unaided, that will probably cause issues.
The voltages on this look mainly fine apart from your BBD bias voltage on IC6 is definitely too low and IC7 is probably a little high, plus pin 6 & 7 measure the same but I'm thinking that's probably a typo but worth checking again in case there's a short there.
Quote from: Scruffie on March 18, 2019, 10:34:27 PM
I didn't see in your pictures that you're trying to use 2 x 3005 and 2 x 3008, the 4047 clock is only good for driving 2 x 3005 unaided, that will probably cause issues.
The voltages on this look mainly fine apart from your BBD bias voltage on IC6 is definitely too low and IC7 is probably a little high, plus pin 6 & 7 measure the same but I'm thinking that's probably a typo but worth checking again in case there's a short there.
Thank you very much for the reply!
Als I already said, I am a noob who is slowly learning yet. You mean, I must replace the two MN3008 in the TRPXN, or the CD4047 instead?
Get rid of the TRPXN board and re-bias your two MN3005.
Quote from: Scruffie on March 19, 2019, 11:59:59 AM
Get rid of the TRPXN board and re-bias your two MN3005.
OK, I´ll do it. The question is, can I after the re-biasing connect again the TRPXN, or is it completely useless?
From the Madbean´s TRXPN PDF Document:
"The TRXPN is an expansion board for the Total Recall project. It allows one to use four MN3008 BBDs in place of two
MN3005 (both totaling about 550ms of delay). The TRXPN has its own bias trimmers for the two added BBD stages and
when wired to the TR main board, they are inserted as stages 2 and 3 of the delay."
Does it mean that if I installed two MN3005 in the Total Recall and two MN3008 in my TRXPN could I have incompatibility issues?
The document is saying you can use either 2 x MN3005 OR 4 x MN3008.
So the short answer is settle for the 2 x 3005 and use the TRXPN board elsewhere.
Quote from: Scruffie on March 19, 2019, 07:34:50 PM
The document is saying you can use either 2 x MN3005 OR 4 x MN3008.
So the short answer is settle for the 2 x 3005 and use the TRXPN board elsewhere.
I have no idea where else could I use the TRXPN. I thought it was designed only to use with the Total Recall. Yet another stupid question: What if I change to the 4 x MN3008 configuration?
Then you'll have 2 extra MN3005 you can use on another project!
BIASING REPORT AFTER TRXPN-OUT:
..... Disconnected the TRXPN (as the user Scruffle recommended), I began with the biasing procedure again. The bad new is, that the Total Recall refuses to work. Although the "Level" and "Blend" controls are working normally, but not the Delay and consequently the Feedback knobs. Anyway I proceed according to the instructions in the PDF document:
IC7 removed
DELAY - full up
FDBK - a little less than halfway up
MOD - all the way down
LEVEL - about 1/3rd up
BLEND - doesn't matter (you should leave the circuit output disconnected since we will be audio probing)
CH/VB switch - doesn't matter
All the trimmers in their halfway position to start
Well, I become audio signal WITHOUT DELAY through the audio probe in IC6 (pin3 sounds louder as pin4). Adjust the trim until becoming undistorted signal.
In IC4 pin7 I became distorted audio signal, and GAIN 1 makes no variation as I rotated the trimpot.
Reinstalled IC7 and still no delay signal........
Is maybe the 4558 in IC4 dead? As curiosity, I checked the other ICs with the audio probe and I become signal in everyone of them. I could check the wiring again, but it worked more or less good before. Very strange.
Hope that someone could give a tip, thanks in advance!
Ariosto
Bias 2 affects the biasing of IC4, does adjusting it change the distorted signal you get at pin 7?
Quote from: Scruffie on March 20, 2019, 08:21:45 PM
Bias 2 affects the biasing of IC4, does adjusting it change the distorted signal you get at pin 7?
I can say you next Monday, because I forgot the power supply in the Music School where I work. By the way, do you have experience with the Aquaboy Delay? I experienced a very strange issue with mine.
Ariosto
Quote from: Scruffie on March 20, 2019, 08:21:45 PM
Bias 2 affects the biasing of IC4, does adjusting it change the distorted signal you get at pin 7?
Scruffle! H E L P !!!!!! With the audio probe I get audio signal (distorted and with a throbbing pulse included) only in IC6. No signal in IC4, neither in IC7. I think the pedal is bewitched. Must I desolder the whole components and begin everything from the beginning again?
Throbbing pulse sounds like the modulation is on.
So on pin 7 of IC6 you get cleanish audio signal, yes? Have you adjusted the bias trimmer while audio probing its output?
Quote from: Scruffie on March 27, 2019, 09:09:03 PM
Throbbing pulse sounds like the modulation is on.
So on pin 7 of IC6 you get cleanish audio signal, yes? Have you adjusted the bias trimmer while audio probing its output?
Yes, it means clean audio signal WITHOUT delay. It sounds a bit distorted but I guess that it is normal... I tried adjusting both BIAS trimmers in search of audio signal in the following ICs but nothing happened.
Don't worry that you do not yet have a working project. You picked a very difficult build even for an experienced builder, and it would not be unusual for that person to have to find and fix problems to get it working.
Your board is (probably) not bewitched, but it is a complex build that might have more than one issue in it that you will need patience to find and fix. You already have corrected the big problem of trying to build the board with two different sets of memory chips where only one of the two sets is supposed to be used. Any time you find and fix a problem you can see if the board works, and if it does not start over looking for the next problem.
Go back and measure all or your voltages again and see what you get because removing the extra set of memory chips may have changed some of those voltages. Then check to make sure you have good ground connects on the board for the different parts of the circuit diagram that shows a connection to ground. It may take a while to work through these issues, so don't worry if you set it down for a while and go build another project where you might learn a bit more that will help you get this one working. It helps to realize that you probably have 99% of the board put together correctly and you just need to find a fix a few things to get it working.
Quote from: zgrav on March 28, 2019, 06:24:34 PM
Don't worry that you do not yet have a working project. You picked a very difficult build even for an experienced builder, and it would not be unusual for that person to have to find and fix problems to get it working.
Your board is (probably) not bewitched, but it is a complex build that might have more than one issue in it that you will need patience to find and fix. You already have corrected the big problem of trying to build the board with two different sets of memory chips where only one of the two sets is supposed to be used. Any time you find and fix a problem you can see if the board works, and if it does not start over looking for the next problem.
Go back and measure all or your voltages again and see what you get because removing the extra set of memory chips may have changed some of those voltages. Then check to make sure you have good ground connects on the board for the different parts of the circuit diagram that shows a connection to ground. It may take a while to work through these issues, so don't worry if you set it down for a while and go build another project where you might learn a bit more that will help you get this one working. It helps to realize that you probably have 99% of the board put together correctly and you just need to find a fix a few things to get it working.
Thanks a lot for the advice! I must take a deep breath, make a pause and come back to the "operation table". Well, step 1 should be measuring the voltages again. What I don´t know is how to detect if an IC is dead or not. Another way to find the problem could be using an audio probe from the output back to the input, but as already said, I become audio signal when the effect is engaged, the "Level" and "Blend" potentiometers are working correctly obviously without delay signal......