Hi everyone
I acquired a part built kit last year and finally finished the job last week. I have encountered a few issues though...
1. I noticed some 'magic smoke' earlier this evening and noticed that R151 had burnt out. I researched the forum and note that I likely have a fake CD4011BE, so will order a new one. Could this fake CD4011BE have damaged any other components?
2. Only the Toms, Cymbal and Cowbell are generating sound - the rest are 'clicking' - could this be due to problems with the fake CD4011BE, or do I have issues to debug on each of those voices?
Cheers
Tim
Fake CD4011BE / burnt R151 issue
As far as I know, the CD4011 issue only damaged R151 in people's Yocto's.
I think you have to debug each voice. I built 5 units and did almost no mistake of parts positioning, but I still encountered issues... some were unsoldered pads and some were related to the volume knobs of the corresponding voice. For example some part's pins were not touching the pot body and this leaded to not hear any sound from the voice.
I think you have to debug each voice. I built 5 units and did almost no mistake of parts positioning, but I still encountered issues... some were unsoldered pads and some were related to the volume knobs of the corresponding voice. For example some part's pins were not touching the pot body and this leaded to not hear any sound from the voice.
Hi Gihaume
Soon I hope I can solve the problems and finally use the wood sides you sold me last year.
So, I replaced the fake CD4011BE with a new CD4011BE (I also have a HCF4011BE to try).
And yes, almost all the channels are generating sounds when triggered, so - in effect - the unit is working straight after soldering, which is a good thing.
However, I do have some issues:
Bassdrum does not seem low enough in tone
Snare drum channel is producing a Tom sound
Rimshot sounds wrong
HandClap is not generating sound (I think I have BA chip positioned incorrectly, will check)
Cymbal sounds too noisy
HiHats are just very short clicks
I think I have a few more hours "fun" to get this sounding correctly.
Cheers
Tim
Soon I hope I can solve the problems and finally use the wood sides you sold me last year.
So, I replaced the fake CD4011BE with a new CD4011BE (I also have a HCF4011BE to try).
And yes, almost all the channels are generating sounds when triggered, so - in effect - the unit is working straight after soldering, which is a good thing.
However, I do have some issues:
Bassdrum does not seem low enough in tone
Snare drum channel is producing a Tom sound
Rimshot sounds wrong
HandClap is not generating sound (I think I have BA chip positioned incorrectly, will check)
Cymbal sounds too noisy
HiHats are just very short clicks
I think I have a few more hours "fun" to get this sounding correctly.
Cheers
Tim
About the snare, hi-hats and clap, you have an issue with the noise generator. Probably you don't have the correct voltage (130mV AC if I remember correctly) on the pin to check for the calibration of the trimmer. There is firstly the Yocto's instructions to change the value of a resistor but some people said they weren't able to get the correct value this way. So maybe you aren't able to get it because your 2SC828 has a low hFE. Someone told me that you need one with a hFE of at least 300 and it from my experiments it seems to be exact. Also another workaround I think it to be about this issue is the modification told on the TR-808 service manual. I suspect that now there isn't anymore people complaining about this issue because e-licktronic maybe gives 2SC828's with a high hFE.
Thank you for the comprehensive reply Gihaume, most kind of you to take the time to reply with such detail.
I will make quantitative checks later this evening.
I did notice a strange behaviour... If I flexed the mainboard slightly, the clap, hihat and snare triggered correctly. I suspect there might be two component legs touching, or maybe a short, or a broken trace, or maybe a bad solder joint in the Noise section.
I am looking forward to further testing this evening. I am excited at how the unit sounds so far, and this is before serious calibration or making any tweaks to component values.
Cheers
Tim
I will make quantitative checks later this evening.
I did notice a strange behaviour... If I flexed the mainboard slightly, the clap, hihat and snare triggered correctly. I suspect there might be two component legs touching, or maybe a short, or a broken trace, or maybe a bad solder joint in the Noise section.
I am looking forward to further testing this evening. I am excited at how the unit sounds so far, and this is before serious calibration or making any tweaks to component values.
Cheers
Tim